Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
` ~ 1 162~4~ D.76,187-FB
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This lnv~n~ion relates to the ~2nufacture of
gaseous mixtures comprising H2 and CO, e.g., synthesis g2s,
fuel gas, and reducing Oas by the partial oxidation of
pumpable slurries of solid carbonaceous fuels in 2 liquid
: : ~
;~ - 5- c2rrier 2nd/or liau~d or Oaseous hydroczrbon fuel. In one
of its more specific aspects, the present inveniion relates
to an imoroved burner for ~uch ~ s manuf2cture.
~; Annulus-type burners have been employed for
introducing liquid hydrocarbonaceous fuels into a pbrtial
lO. oxidation gas generator. For example~, our U.S.
~ ~:
Patent 3,~528,930 show3 a single 2nnulus burner, and~
oul U.S. ~Patents 3,758,037 and 3,847,564 sho~;doukle
nn~1us~ burners. To obtain proper mixing, atomizat~lon; and
stabillty or operation a burner is sized for a s~eclflo
throughput.~ Should the requlred output or~product;gas
chan2e subst~antial7y, wi~h prior-~rt burners, shut-down of
;the~ system~is~req;uired in order to replace the prior-art
burner~with~one~of proper size;. This~problem~is avolded and~
c~ostl~ shut-downs are avolded~by the sub~ect Durner whlch
operate at varying l~vels of output while retainlng
fflclencD~;and;staDility.~ he more~comple~. process for
pre:qe~tln6~a gas cenerator by me2ns cf a Dreheat burner,
removinO the~Dreheat burner from ~the ~asifier, and ~nsertinO
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.
a separate production burner is descri.bed in our United States Patent No.
4,113,445.
The nozzle tip of the central conduit of such prior art burners is
substantially flush with or close to the face of the burner, and substantially
no premixing of the reactants takes place upstream from the face of the burner.
Accordingly in such burners, substantially all of the atomizing and mixing of
the fuel stream with the oxygen stream takes place downstream from the face of
the burner.
In the partial oxidation of liquid phase slurries of solid carbonaceous
fuels. to produce synthes.is gas, fuel gas, or reducing gas, problems of combust-
ion instability and poor efficiency which may be encountered with flush face
burners have been eliminated by employing the subject invention.
This invention provides a burner for intimately mixing together at least
two separate feedstreams comprising a pumpable slurry of solid carbonaceous fuel
in a liquid carrier, and a feedstream of free-oxygen containing gas, with or
without admixture with a temperature moderator to produce a multiphase mixture
for reaction by partial oxidation in a gas generator to produce raw synthesis gas,
fuel gas or reducing gas comprising mixtures of l-12, C0, C02 and at least one
material from the group H20, N2, A, CH4, H2S, and COS, and entrained particulate
matter characterized by: central flow means coaxial with the central longitudinal
axis of the burner and having upstream inlet means through which a first feed-
stream or feedstreams may be separately introduced, and downstream outlet means
that discharges into a central coaxial pre-mix zone; an outer first coaxial
conduit concentric with and surrounding said central flow means and havillg an ~p-
stream inlet through which a second feedstream may be separately introduced and
a coaxial circular exit outlet terminating said outer conduit at the do~nstream
tip of the burner and comprising a partially converging frusto-conical rear
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portion and a right cylindrical front portion whicll terminates at the downstream
face of the burner, and the height of tlle front cylindrical portion of said exit
nozzle is in the range of about 0.1 to 1.0 times it~ O-YIl diameter, an annular
shaped face-cooling cllamber surrounding said exit outlet at the burner tip;
wherein the do~Ynstream termination of said central flow means is retracted up-
stream from the downstream face of the burner a distance of two or more times
the minimum diameter of said outer conduit downstream outlet to provide said
central pre-mix zone comprising one or more communicating pre-mix chambers in
tandcm and coaxial with the central longitudinal axis of the burner; and means
for supporting said central flow means and outer conduit with respect to each
other to provide a passage or passages theTebetween through which said second
feestream may separately pass concurrently with said first feedstream(s) into
said central pre-mix zone where said feedstreams are intimately mixed together
and a controlled amount in the range of about 0 to 100 vol. % of the licluid car-
rier is vaporized without burning to produce said multiphase mi~ture prior to
being discharged through said outer conduit exit outlet at a discharge velocity
hich is greater than the flame propagation velocity.
In a second aspect this invention provides a burner for the partial
oxidation of reactant fuel feedstream selected from the group consisting of a
pumpable slurry of solid carbonaceous fuel in a liquid carrier, liquid or gaseous
hydrocarbon fuel, and mixtures thereof with a reactant feedstream of free-oxygen
containing gas, comprising: a central conduit, said central con~uit being closed
at the upstream end and having an unobstructed downstream circular exit orifice
at the tip of the burner; an outer conduit coaxial and concentric with said
central conduit along its length and in spaced relationshiptherewith and forming
an annular passage therebetween, said outer conduit and annular passage being
closcd at the upstream end and having an unobstructod downstream anllular exit
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orifice at the tip of the burner and wherein the central longitudinal axis of
the annular passage is parallel to the central longi~udinal axis of the burner
throughout its length; a central bunch of tubes passing through the closed end
of said central conduit and making a gastight seal therewith, the tubes of said
central bunch of tubes extending down said central conduit and having upstream
inlet means for introducing a f.irst feedstream and downstream ends through which
said first feedstream is discharged, and wherein the downstream ends of said
central bunch of tubes are retracted upstream from the burner face a distance
of about 0 to 12 times the minimum diameter of the central conduit exit orifice
at the tip of the burner, means for spacing and supporting said central bunch of
tubes with respect to the inside wall of said central conduit and to each other,
and upstream inlet means for introducing a second feedstream into said central
conduit and the passages and interstices when present between the central bunch
o tubes; an annular bunch of ~.ubes passing through the closed end of said annu-
lar passage and making a gastight seal therewith, the tubes in said annular bunch
of tubes having upstream inlet means for introducing a third eedstream into.said
tubes and downstream ends through which said third feedstream is discharged, and
wherein said downs~ream ends of said annular bunch of tubes are retracted upstream
from the burner face a distance of about 0 to 12 times the minimum width of the
annular exit orifice at the tip of the burner, means for supporting said annular
bunch of tubes with respect to the inside wall of said annular passage and to each
other, and upstream inlet means for introducing a fourth feedstream into said
annular passage and the passages and interstices when present between the annular
bunch of tubes in said annular passage; and wherein ignition of mixtures of the
reactant feedstreams takes place downstream from the face of the burner.
The subject novel burner includes an internal pre-mix ~one in which two
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or three feedstreams tb the react~on zone of a partial oxidation gas generator
are mixed together without ignition and optionally pre-heated to vaporize from
0 to 100 vol. % of the liquid carrier. The burner comprises a retracted central
coaxial conduit and an outer coaxial conduit with an annular passage therebetween.
A converging exit noæzle may terminate the outer conduit at the do~nstream end
of the burner. In another embodiment, an intermediate coaxial conduit may be
interposed b~tween the central and outer conduits thereby providing intermediate
and outer annular passage~. Optionally~ the intermediate conduit may contain
a plurality of small diameter holes or passages to permit at least a portion of
the gaseous material
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flowing in the outer annular passage to pass through and mix
with the materials flowing through the intermediate annular
pass~ge and/or the pre-mix zone.
The tip of the inner central conduit and the
interli~ediate conduits if any, may be retrac~ed upstream from
the face of the burner a distance of respectively two or
more tlmes, say 3 to 10 times, and 0 to 12 times, say 2 to 5
times the minimum diameter of the converging exit nozzle at
the tip of the burner, thereby providing a pre-mix zone
10. comprising one or more, say 2 to 5 coaxial pre-mix chambers
in series. ~he pre-mix zone is locaied bet~7een the down-
stream tip of said central conduit and the face of the
burner at the downstream end. The reactant streams are
separately introduced into the pre-mix zone by way of said
15. central conauit and annular passage or passages. In the pre-
mix zoner the reactants are thoroughly mixed together and
simultaneously about 0 to lO0 vol. ~, say about 2 to 80 vol.
% of the liquid carrier may be vaporized. In one embodiment,
the mixture leaving one pre-mix chamber may expand into the
next pre-mix chamber in the line. The change in velocity of
the mixture flowing through the successive pre-mix chambers
assures a thorough mixing of the feeQ streams prior to
discharge from the burner. The multiphase mixture may be passed
through ~ converaing exit nozzle on the downstream end of
2~ the outer conduit at a discharge velocity which is greater
than the flame propagating velocity.
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A further emDodiment comprises a burner having a
high turndown feature and comprising: a central conduit
that terminates in an unobstructed circular exit orifice
at the burner face; a central bunch of parallel tubes that
5. extend longitudinally through said central conduit and having
downslream ends which are retracted upstream from the burner
face, preIerably by a distance of about 3 to 10 times the
minimum diameter of the central conduit exit orifice; an
outer conduit coaxial with said central conduit and forming
lG an annular passage therewith that terminates in an unobstruct-
ed annular orifice at the burner face; and an annular bunch
of parallel tubes that extend longitudinally throuqh said
annular passage and having downstream ends which are retract-
ed upstream from the burner face a distance of about 0 to 12
75. times, e.g. 3 to 10 times, the minimum width of the annular
exit orifice.
Separate portions of the fuel feed may be passed
through the central bunch of tubes and/or the annular bunch
of tubes while simultaneously, the stream of free-oxygen
20 containing gas is passed through the corresponding central
conduit and/or the annular passage which respectively surrounds
the bunch or bunches of tubes in use. Temperature moderators
may be optionally in admixtur~ with the gaseous oxidant
- and/or the fuel feedstreams. By this means the free-oxygen
25. containing gas may be introduced into the interstices between
the tubes and more elficient mixing of the reactant streams
is achieved. Alternately, separate portions of the free-
oxygen containing gas may be passed through the central
and/or annular bunches of tubes while simultaneously the
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f~el ~eed is p2ssed through the corresponding central conduit
and/or annular passage which respectively surroun2s the
bunch or bunches of tubes in use.
In another emboaiment of the burner, aoditional
5. mixing of the re~ctant streams may be obtained by providins one
or more cC2~:ial cylindrical shcped pre-mi~ ch2mbers in
series in the central conduit and/or one or more cnnular
sh2ped pre-mix chambers in series in the annular passage.
In the pre~mix chambers, the feedstrecms to the reaction
zone of a partial oxidation cas generator cre mi~ed together
without ignition and optionally pre-heated to ~aporize from
0 to 100 volume percent of the liqui~ carrier. Jets of a
saseous r,aterial i.e. steam, free-oxygen containing gas,
C02, N2, recycle product gas, and mixtures thereof may be
15. optionally introduced into at least one of the pre-mix
chambers. ~he change in velocity of the mixture flowing
through the successive pre-mix chambers assures a thorough ,
mixing of the feedstreams prior to discharge from the
burner. The multiphase mixture is passed, for example,
20. through a converging exit orifice at the downstream end of
the central conduit and/or annular passage at a discharge
velocity which is greater than the flame propagating velocity.
,
ManUal or automatic control means may be provided
for adjusting the throughput levels of the fuel and oxidant
25. streams through the subject burner - up or down - to produce
many levels of gasifier output while retaining efficiency
and stability.
Starting up the partial o~idation gas generator is
simplified by a new procedure which emplo~s the subject
30. burner only. Separate preheat burners are thereby eliminated.
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A yet further embodiment may comprise a swirl burner
having pre-mix and/or high turndown features. By means of
the subject burner separate swirling feed streams may be
intimately mixed together to produce a multi-phase mixture
5- for reaction in a partial oxidation gas generator compris-
ing: a central bundle of open-ended helical tubes whose
central longitudinal axis is coaxial with the c~ntral
longitudinal axis of the burner and comprising a plurality
of helical tubes having inlet portions in communication
10- with upstream inlet means by which a first reactant feed
stream may be introduced and then split into a plurality
of separate streams which pass down through said central
bundle of helical tubes and are then discharged through the
downstream ends of said tubes; a first coaxial cylindrical
15- conduit concentric with and surrounding said central bundle
of helical tubes, said first conduit being closed near the
upstream end so that the inlet portions of said plurality
of helical tubes may pass through and make a gastight seal
therewith and having an unobstructed circular downstream
20- outlet at the tip of the burner; upstream inlet means in
communication with said first con~uit through which a
second reactant feed stream may be separately introduced
: and split into a plurality of swirling streams which may
pass down through a plurality of related helical-shaped
25- passages formed in the cylindrical space that surrounds
said central bundle of helical tu~es and/or through the
interstices, if any, between said helical tubes; and means
for supporting said central bundle of helical tubes with
respec~ to said first conduit and each other; and wherein
the downstream tips of said central bundle of helical tubes
are retracted upstream from the downstream face of the
burner a distance of about 2 or more, e.g. about 3-10 times,
the minimum diameter of said first conduit downstream
outlet; and said first and second swirling reactant feed
strea~ms impinge together and are intimately mixed~
When the two swirling reactant streams impinge,
either upstream in a pre-mix zone or downstream from the
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face o~ the burner, intimate mixing and atomization may
take place. The combustion efficiency of the burner is
thereby improved.
In another embodiment, the burner includes a
5. coaxial annular bundle of helical tubes surrounding said
first conduit and a plurality of related annular passages
formed in the annular space occupied by said annular bundle
of helical tubes. By this means, flow through the burner
may be easily turned up or down. For example, the burner
10. may be operated with the first and second feed streams
passing through the central bundle of helical tubes and the
related surrounding passages and/or with the second and third
feed streams passing through the annular bundle of helical
tubes and the related surrounding passages,
15. When a pre-mix zone is employed, the reactants
are thoroughly mixed together and simultaneously about 0 to
100 vol. %, say about 2 to 80 vol. % of the liquid carrier
may be vaporized~ In one embodiment, the mixture leaving
one pre-mix chamber expands into the next pre-mix chamber
20. in the line as described above.
Specific embodiments of the invention will now be
described by way of example and with reference to the
accompanying drawings, in which:
Figure 1 is a general illustration of the burner
25. assembly;
Figure 2 is a diagrammatic longitudinal cross-sect-
ion through the downstream end of the burner, taken at line
A-A of Figure 1 and showing an embodiment of a burner accord-
ing to the invention;
30. Figure 3 is a view of another example of the tip
exit orifice at the downstream tip of coaxial outer conduit
16 shown in Figure 2;
Figure 4 is a view of another example of the down-
stream tip of outer conduit I6 shown in Figure 2 which the
35~ exit orifice is made from an erosion-resistant material such
as silicon carbide or tungsten carbide 35;
Figure 5 is a diagrammatic longitudinal cross-sect-
ion through the downstream end of the burner, taken at line
~ ~20~
-8-
~-A of Figure 1 which shows another embodiment of the burner
in which there is one annular passage 17 and the pre-
mix zone comprises two free-flow coaxial chambers 25 and 40
in series;
5. Figure 6 is a diagrammatic longitudinal cross-
section through the downstream end of the burner, taken at
line A-A of Figure 1 and showing another embodiment of the
burner in which there are two annular passages 17 and 51 and
the pre-mix zone comprises three free-flow coaxial pre-mix
10. chambers 25, 40, and 41 in series;
Figure 7 is a diagrammatic vertical longitudinal
schematic representation showing another embodiment of the
invention;
Figure 8 is a transverse section through line8-8
15. of the embodiment of the burner shown in Figure 7;
Figure 9 is a schematic representation of one em-
bodiment of the invention showing control means for rapidly
changing throughput levels - up or down;
Figure 10 is a vertical longitudinal schematic
20. representation of a further embodiment of the burner showing
two central and annular pre-mix chambers in series and
central and annular bunches of tubes with their ends re-
~ :trated upstream from the face of the burner;
.: Figure 11 is a diagrammatic longitudinal cross-
section through a further embodiment of the invention in -the
form of a swirl burner employing a central bundle of helical
~: tubes with retracted ends to provide a pre-mix chamber;
Figure 12 is a view of another example of the
downstream outlet of conduit 16 shown in Figure 11 and,
: Figure 13 is a vertical longitudinal schematic
representation of a yet further embodiment of the subject
burner having a high turn-down capability, in which central
and annular bundles of helical tubes with downstream retract-
: ed ends provide two central and annular pre-mix chambers in
~ 3' sexies.
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The present invention involves a novel burner for the
manufacture of gas mixtures comprising H2, C0, C02 and at
least one material selected from the group consisting o~
H20, N2, A, CH4, H2S and COS, such as synthesis gas, fuel gas,
and reducing gas, by the partial oxidation of a reactant
stream selected from the group consisting of a pumpable slurry
of solid carbonaceous fuel in a liquid carrier, liquid or
gaseous hydrocarbon fuel, and mixtures thereof with or with-
out admixture with a temperature moderator, with a reactant
stream of free oxygen containing gas with or without admixture
with a temperature moderator. The product gas mixture is
produced in the reaction zone of a noncatalytic, refractory-
lined, free-flow partial oxidation gas generator, such as
describe~ in our U.S. Patent No. 2,809,1-4 at a temperature in
the range of about 1700 to 3500F. and a pressure in the range
of about 1 to 300 atmospheres, such as about 5 to 250 atmos-
pheres, say about 10 to 100 atmospheres.
Problems of combustion instability and poor efficiency
may be encountered when prior art flush face burners are used
for the gasification of li~uid phase slurries of solid carbon-
aceous fuels. For example, at times varying from start-up to
10 hours after start-up, with coal-water slurry feeds the
following changes in the operation of the generator could
occur: (1) the te~perature measured at the top of the reac*icn
zone may rise rapidly while there may be little or no rise of
temperature at the bottom; (2) the product gas rate may
decrease; at the same time, the C02 content of the gas may
incxease; (3) the particle size and amount of unconverted
solids may increase. It may not be possible to correct the
aforesaid rise in temperature in the reaction zone or the
other changes mentioned by decreasing the oxidation rate or
increasing the slurry rate. Further, said changes may occur
re rapidly at higher pressures. The aforesaid problems may
indicate poor mixing of the feeds. Purther, part o~ the coal
may be passing through the gas generator ~ithout contacting
significant amounts of ox~ygen and the coal may be only
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devolatilized and fused. In such case, unreacted oxygen in
the reaction zone may then react with the product gas.
These problems and others are avoided by employing the
subject novel burner in which two or three feedstreams to
the reaction zone of a free-flow partial oxidation gas gener-
ator are mixed together without igniting in an internal pre-
mix zone and optionally pre-heated to vaporize from O to 100
vol. % of the liquid carrier of the slurry feedstream. For
example, a slurry of solid carbonaceous fuel in water is
passed irlto the burner in liquid phase. There it is
thoroughly mixed with a separate stream of free-oxygen con-
taining gas, and optionally with a temperature moderator.
The feedstreams are mixed together in a pre-mix zone located
within the burner upstream from the exit nozzle. Optionally,
the feed slurry may be simultaneously heated in the pre-mix .
~one of the burner by direct heat exchange with the other
; feedstreams and/or indirect heat exchange with a portion of
the combustion gases that are recirculating on the outside
of the burner. By this means, from O to 100 vol. % such as
about 2 to 80 vol. ~, say about 5 to ~5 vol. % of the liquid
carrier in the slurry feed may be vaporized before the multi-
phase mixture of reactants leaves the pre-mix zone by way of
a converging exit nozzle at the downstream end of the burner
and directly enters the reaction zone of the partial oxida-
tion gas generator.
Embodiments of the subject burner include single and
double annulus types with one or more, sa~ 2 to 5 coaxial
cylindrically shaped pre-mix chambers in series. In one
embodiment, the mixture leaving one pre-mix chamber expands
into the next pre-mix chamber in the line. The change in
velocity of the mixture flo~ing through the successive pre-
mix chambers assures a thorough mixing of the feedstreams
prior to discharge from the burner. The mixture is acceler-
ated through the converging exit nozzle at the downstream
end of the burner directly into the reaction zone of the
partial oxidation gas generator.
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Pumpable slurries ir. liquid phase having a dry solids
content in the range of about 30 to 75 wt. %, say about 40
to 60 wt. ~ are passed through an inlet passage of the sub-
ject burner. The inlet temperature of the slurry is in the
range of about ambient to 500F., but below the vaporization
temperature of the liquid carrier at the given inlet pressure
in the range of about 76 to 4500 psia, say about 150 to 1500
psia~
In one embodiment, the liquid slurry comprises 40 to 60
wt. ~ of solid carbonaceous fuel in liquid C02.
In another embodiment, a single annulus pre-mix burner
is employed and the feedstream comprises a slurry of liquid
hydrocarbonaceous material and solid carbonaceous fuel. H20
in liquid phase in the amount of about 5 to 95 wt. % may be
mixed with the liquid hydrocarbonaceous carrier, for example
as an emulsion. Alternately, a portion of the H20 i.e.,
about 0 to 25 vol. % may be introduced as steam in admixture
with the free-oxygen containing gas.
For all embodiments of the subject retracted central
conduit single and multi-annulus~type burners, the downstream
tip of the central and intermediate conduits are retracted
upstream from the face of the burner a distance of respect-
ively o~ two or more times say 3 to 10 for the tip of the
central conduit, and 0 to 12, say 1 to 5 for the tip of the
intermediate conduit times the minimum diameter of the con-
~ ~ verging ori~ice of the outer conduit at the burner tip. In
; ~ one embodiment the set-back for the tip of the intermediate
conduit is greater than the set-back for the tip of the
center conduit.
The set-back provides space for a pre-mix zone. The
pre-mix zone comprises one or more, say 2 to 5 coaxial pre-
mix chambers in series. When supplemental steam is employed
as a temperature moderator, all of the steam may be passed
through one passageway. Alternatively, about 0 to ~5 volume
percent of the steam may be mixed with the stream of free-
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oxygen containing gas and passed through one passag~way, and
the remainder of the steam may be passed through the remain-
ing passageway.
The subject single and multi-annulus pre-mix burners
may be operated with the feedstreams passing through alter-
nate passages in the burner. Typical modes of operation are
summarized in Tables I to III below.
Table I lists the materials being introduced into the
gasifier by way of the burner and their corresponding symbol.
The solid carbonaceous fuel (B), water (C), and liquid hydro-
carbonaceous material (E) may be mixed together in various
combinations upstream from the burner inlet to produce a
pumpable slurry which may be introduced into the burner and
then passed through one of the several free-flow passages of
the burner as shown in Table II for the single annulus pre-
mix burner (see Figures 2 and 5); and as shown in Table III
for the double annulus pre-mix burner (see Figure 6). For
example, the irst entry in Table II shows that a pumpable
slurry stream comprising solid carbonaceous fuel (B) in
admixture with water (C) may be passed through the retracted
central conduit 15 of a single annulus pre-mix burner i.e.
Fig. 2 and 5 while simultaneously a stream of free-oxygen
containing gas may be passed through annular passage 17.
Other modes of operation of the subject invention are
possible in addition to those shown in Tables II and III.
With respect to the operation of a double annulus
embodiment of the subject burner, the second entry of Table
III shows that free-oxygen containing gas (A) may be passed
through both annular passages. In such case, any member of
the following group may be simultaneously passed through one
or both annular passages 17 and 51: air, oxygen-enriched
air, and substantially pure oxygen. Also, as shown in the
seventh entry in Table III, free-oxygen containing gas (A)
in admixture with steam (D) (say up to 25 vol. % of the
total amount of H20) may be passed through the central
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conduit 15 and the remainder of the H20 as ~ater (C) may be
passed through the intermediate annulus 17 as part of the
liquid carrier for the slurry.
When the liquid carrier for the slurry of solid carbon-
aceous fuel is a liquid hydrocarbonaceous material premature
combustion within the burner may be avoided by one or more
of the following:
(1) keeping the fuel below its autoignition temperature,
(2) including water in the solid fuel slurry,
(3) using air or air enriched with oxygen i.e. up to about
40 vol~ % 2'
(4) mixing steam with the air,
(S) employing a double annulus pre,mix burner (Fig. 6) in
which the tip of the intermediate exit nozzle has about
0 retraction from the face of the burner. In such case,
the free-oxygen containing gas such as substantially
pure oxygen may be separately passed through the outer
annular passage of the burner and into the reaction zone
of the gas generator where it reacts by partial oxidation
with the multiphase mixture discharged from the pre-mix
zone of the burner, and
(6~ discharging the multiphase mixture at the exit orifice
at the tip of the burner with a discharge velocity which
ls greater than the flame propagation velocity.
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TABLE I
Material Symbol
Free-Oxygen Containing Gas A
Solid Carbonaceous Fuel B
Water C
Steam D
Liquid Hydrocarbonaceous Material E
Temperature Moderating Gas F
TABLE II
SINGLE ANNULUS PRE-MIX BURNER (See Figures 2 and 5)
Çentral Conduit 15 Annulus 17
B + C A
B + C + E A
B + E A + D
A . B + C
A B + C + E
A +.D ~ B + E
TABLE III
DOUBLE ANNULUS PRE-MIX BURNER (See Figure 6)
Intermediate Outer
Central Conduit 15 Annulus 17 Annulus 51
A B + C A
B + C A A
B + C A F
A B + C + E A
A - B + C + E A + D
D . B + C + E A
A + D B + C + E A
B + C ~ E A
B + C + E - D A
B + C + E A D
A . B + E A + D
A + D B + E A
A + D B + E A + D
D B + E A
A B + E D
B + E A + D A + D
B + E A A + D
B + E D - A
B + E A D
A B ~ E F
B + C A E
A B ~ C E
E : B + C A
B + C E . A
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Other embodiments of the invention can in addition
avoid the following problems which can occur during use.
During operation of a partial oxidation gas generator, it
may be necessary to rapidly turndown the production of the
effluent gas to about l/8 to 3/4 of the plant-design output,
without replacing the burner. Changing the burner requires
- a costly shut-down period with resultant delay. Thus, in
combined cycle operation for power generation a durable
burner is required which offers minimum pressure drop and
with which throughput levels may be rapidly changed - up and
down - without sacrificing stable operation and efficiency.
Further, the burner should operate with a variety of liquid,
solid, and gaseous fuels, and mixtures thereof. These
requirements have been fulfilled with the subject burner.
These problems and others may be avoided by an embodi-
ment of the invention comprising: a cer.tral conduit, ~aid
central conduit being cIosed at the upstream end and having
an unobstructed downstream circular exit orifice at the tip
of the burner; an outer conduit coaxial and concentric with
said central conduit along its length and in spaced relation-
ship therewith and forming an annular passage therebetween,
said annular passage being closed at the upstream end and
having an unobstructed downstream annular exit orifice at
; the tip of the burner; a central bunch of tubes in symmet-
rical spaced relationship passing through the closed end of
said central conduit and making a gastight seal therewith,
the tubes of said central bunch of tubes being parallel to
each other and to the burner axis and extending along said
,~ .
central conduit without touching each other and having
upstream inlet means for introducing a first feedstream and
downstream ends through which said first feedstream is dis-
charged, means for spacing and supporting said central bunch
of tubes with respect to the inside wall of said central
conduit and to each other, and upstream inlet means~for
introducing a second feedstream into said central conduit and
the interstices between the central bunch of parallel tubes;
.
~ 16204~
- 16 -
an annular bunch of tubes in symmetrical spaced relation-
ship passing through the closed end of said annular passage
and making a gastight seal therewith, the tubes in said
annular bunch of tubes being parallel to each other and to
the burr.er axis and extending along said annular passage
without touching each other and having upstream inlet means
for introducing a third feedstream into said tubes and down-
stream ends through which said third feedstream is discharged,
and wherein the do~nstream ends of said annular bunch of
tubes are retracted upstream from the burner face a distance
of about 0 to 12 times the minimum width of the annular exit
orifice at the tip of the burner, means for spacing and
supporting said annuIar bunch of tubes with respect to the
inside wall of said annular passage and to each other, and
upstream inlet means for introducing a fourth feedstream intD
said annular passage and the interstices between the annular
bunch of parallel tubes in said annular passage.
By means of these embodiments a large volume of the
first reactant stream is split into a plurality of separate
streams of reactant fluid flowing through the central bunch
of parallel tubes. This permits the introduction of the
second s*ream of reactants passing concurrently through the
central conduit into the interstices surrounding the central
bunch of tubes. Similarly, a large volume of the third
reactant stream is split into a plurality of separate streams
of reactant f-luid flowing through the annular bunch of
parallel tubes. The fourth stream of reactants passing con-
currently through the annular passage is introduced into the
interstices surrounding the annular bunch of tubes. The
greater the number of tubes in a bunch, the better the distri-
bution of one reactant within the other reactant. The mixing
of the reactant streams whish takes place downstream of the
ends of the tubes is facilitated by this improved distribution.
Such efficient mixing of the feedstream facilitates a more
uniform partial oxidation of the fuel to prod~ce H2 and C0.
The combustion efficiency of the process is thus increased.
,~
'
1 ~62~
- 17 -
Furthermore the above stated problems may be avoided by
a further embodiment of the invention constituted hy a swirl
burner which is contructed in the following manner. A first
cylindrical conduit is closed at the upstream end and has an
unobstructed circular exit orifice at the downstream tip of
the burner. A central bundle of open-ended helical tubes,
extends longitudinally down said first conduit. The upstream
inlet portion of each individual helical coil in said central
bundle of helical tubes preferably passes perpendicularly
through a tube-sheet located below the closed end of said
first conduit and makes a gastight seal therewith. The
upstream open ends of the central bundle of helical tubes are
in communication with a chamber, such as a cylindrical
- 18 - 116~0~
manifold, through which a first feed stre~m is introduced.
By th~s means said first reactant feed stream may be spllt
into a plurality of separate streams which pass down through
the separate helical tubes in said central bundle and then
discharge as a plurality of swirling streams.
The separate helical coils in the central bundle
of helical tubes are supported and op~ionally spaced within
the first conduit and with respect to each other by means of
conventional supports and spacers. By this means a plurality
of related free-flow helical-shaped passages may be formed
in the cylindrical space occuDied by ~he central bundle of
helical tubes. A second feed stream is introduced near the
upstream end Or said first conduit, splits into separate
streams upon p2ssing down through said helical passages or
into the interstices between the helical tubes, and then
discharges as a plurality of swirling or ~urbulent streams.
The plurality of first and second feed streams impinge
elther downstream from the face of the burner or in a
~ ~ pre-mix zone upstream from the face of the burner where
; 20 intimate;mixing and atomization takes place.
The central bundle of helical tubes is coaxial
with the ce~ntral longitudinal axis of the burner and
preferably comprises at least one and~with larger burners
a plurality of equaIly spaced concentric rings o~ multiple
helices with a common axis occupying a cylindrical space.
Preferably, the inlets and outlets of the plurality of
helical coils in the central bundle are located at the
intersections of at least one and preferab~y a plurality of
evenly spaced radial rows and said concentric ring or rings.
~ ~ 30 The sides of the individual helical coils in adJacent
; concentric rings may or may not touch. ~Yhen they touch,
19 - ~ 1620~
at least a port~on of the second reactant feed stream may
flow through said plurality of helical passages formed
within said first conduit by tne screw-shaped outside surfaces
of said central bundle of helical tubes. By separating the
helical coils in ad~acent rings, more of the second feed
stream may be made to flow into the interstices between the
helical coils in said central bundle. Thorough mixing
together of the first and second feed streams is provided
by either one or both of these schemes. Further, atomization
may take place.
In another embodiment, the previously described
swirl burner has a high-turn-down capability. In this
embodiment .a second coaxial cylindrical conduit ls radially
spaced from and surrounds said first coaxial cylindrical
conduit along its length. An annular space is thereby
provided between said first and second coaxial conduits.
The annular space is closed at the upstream end and has
an unobstructed downstream annular exit orifice at the tip
of the burner.
2~ An annular bundle of open-ended helical tubes
comprising a plurality of concentric helical coils with a
common axis occupies said annular space. The upstream
inlet portion of each individual helical coil in said bundle
of annular helical tubes preferably passes perpendicularly
through an annular tube-sheet located below the closed end
of said annul æ~space and makes a gastight seal therewith.
The upstream open ends of the annular bundle of helical
; tubes are in communication with a chamber, such as an
annular manifold t~ough which a third feed stream is
3o introduced. By this means said third L eed stream may be
- 20 - 91620~6
split into a plurality of separate st~e~ms whlch pass down
through the separate heIical tubes in said annular bundle
and discharge as a plurality of swirling streams.
The separate ~elical coils in the annular bundle
of helical tubes are supported and optionally spaced within
said annular space and ~ith respect to each other by means
of conventional supports and spacers. ~y this means a
plurality of related helical-shaped passages may be formed
in the annular space which is occupied by the annular bundle
of helical tubes. A fourth feed stream is introduced near
the closed upstream end of said second condult, splits into
separate streams upon passing down through sai~d helical
passages or lnio the interstices between the helical tubes,
and discharges as a plurality of swirling or turbulent
streams~. The plurality of third and fourth swirling feed
streams impinge together and intimately mix. Further,
atomization may take place.
The annular bundle of helical tubes is coaxlal
- with the central longltudlnal axis o~ the burner and
preferably comprises at least one and preferably a plurality
of equally spaced concentric rings of multiple helices
with a~common axis occupying~said annular space. Preferably,
the inlets and outlets of helical co1ls in the annular bunale
are located at the inte~sections of said evenly spaced
radial row or rows and said evenly spaced concentric ring
or rings. In the manner discussed previously in connection
with the central bundle of helical tuhes the sides of
individual helical coils in adjacent concentric rings may
or may not touch. ~Jhen they touch, said plurality of
helical passages are formed within said annular space by the
.
:
1 ~20~
- 21 -
screw-shaped outside surfaces of said annular bundle of
helical tubes. By separating the helical coils in adjacent
rings, more of the fourth feedstream may be rnade to flow
into the interstices between the helical coils in said
annular bundle.
In either of the above described embodiments where a
central bundle of parallel or helical tubes and an annular
bundle of parallel or helical tubes are provided, said first
and third feedstreams and said second and fourth feedstreams,
preferably, are respectively split streams from a fuel stream
and a gaseous oxidant stream. In one embodiment, however,
the first and fourth feedstreams, and the second and third
feedstreams are respectively split streams from a fuel stream
and a stream of gaseous oxidant. Flow control means may be
provided in these embodiments for controlling the introduction
of said four feedstreams into the burner. sriefly, a manual
or automatically controlled fluid-controller is placed in each
feed line. For slurry fuel and some viscous liquids e.g.
resid feed lines, a signal from the controller is trans-
mitted to a speed control for a positive displacement pump.
For most liquid or gaseous hydrocarbon fuel feed lines and
for oxidant feed lines, the signal from the controller is
transmitted to a flow control valve. Responsive to said
signal, the speed of said pump is varied, or alternately
the opening in said flow control valve is changed. By
this means, the ratio for the streams of fuel and/or oxidant
passing through the burner may be adjusted up or down, say
up to about 50% of the Design Conditions. Alternatively, a
flow control valve may be inserted in each of the four feed
streams to start or stop the flow of the feed streams to the
central conduit and/or the annular passage and to their re-
spective bundles of tubes. By this means, three ranges of
flow through the burner may be obtained. Further, both of
these flow control schemes may be combined to vary the flow
rate of each feed stream from 1/8 to 3/4 of maximum.
In the embodiments utilizing helical tubes, the central
bundle of hel~cal tubes may number in the range of about 1-200
~: :
I lB2~
- 22 -
or more, such as about 2-180, say about ~-48 helical coils.
The annular bundle of helical tubes may number in the range
of about 1-600 or more, such as about 2-580, say about
8-96 helical coils. There may be 1 to 7 or more concentric
circular rings of helical tubes in the central and/or annular
bundles. All of the helical coils in either the central,
annular, or both bundles of helical tubes are t~listed in the
same direction i.e. clockwise or counterclockwise. ~lowever
in one embodiment, all of the helical coils in the central
bundle of helical tubes are twisted in one direction i.e.
either clockwise or counterclockwise, and all of the helical
coils in the annular bundle of helical tubes are twisted in
the opposite direction.
In general for large-sized burners, the greater the
number of tubes in a bunch, the better the distribution of
one reactant within the other reactant. The mixing of the
reactant strear,lswhich takes place downstream of the ends of
the tubes is facilitated by this improved distribution. Such
efficient mixing of the feedstreams facilitates a more uniform
partial oxidation of the fuel to produce H2 and C0. The
combustion efficiency of the process is thus increased. In
one embodiment for a small sized burner, the central and/or
annular bundles of helical tubes are replaced by a single
central helical coil and/or a single annular helical coil.
By means of the subject invention, the reactant streams
impinge and are intimately mixed together to produce a
swirling mixture which is reacted by partial oxidation in the
reaction zone of the gas generator. The reactions are made
to proceed in local regionq where there is less opportunity
for overheating the fuel with an insufficient supply of
oxygen to result in the formation of soot. Thus, the amount
of unconverted particulate carbon produced for a given oxygen
~to carbon atomic ratio in the feed may be substantially
reduced. Further, "overburning" of the fuel to produce carbon
dioxi e is substantially reduced. It is recommended that the
subject burner be made from heat and corrosion-resistant metal
,
::
alloys.
The velocity of the reactant stream through the central
and annular bunches of tubes, whether ~arallel or helical,
or alternatively through the central conduit or annular
passage surrounding said tubes is in the range of about 5-100,
say 10-50 feet per second at the face of the burner when said
reactant stream is a liquid hydrocarbon fuel or liquid slurry
of solid carbonaceous fuel, and in the range of about 150 feet
per second to sonic velocity, say 200-5(~0 feet per second when
said reactant stream is a gaseous hydrocarbon fuel or a free-
oxygen containing gas with or without admixture with a temp-
erature moderator.
The central bunch of tubes, in the embodiments utilizing
parallel tubes, may number in the range of about 2-200 or
more, say about 6-36. The annular bunch of such tubes may
number in the range of about 4-600, or more, say about 12-108.
There may be 1 to 7 or more concentric rings of tubes in eah
bunch.
The ratio of the total tube cross-sectional area (basis
inside diameter) for the annular bunch of tubes (TA)(whether
parallel tubes or helical tubes) to the total tube cross-
sectional area (basis inside diameter) for the central bunch
of such tubes (Tc~ may be in the range of about 2-8. Simi-
Iarly,the ratio of the annular interstitial cross-sectional
area (IA) surrounding the annular bunch of tubes to the
central interstitial cross-sectional area (Ic) surrounding the
central bunch of tubes may be in the range of about 2-8~
The inside diameter of the parallel tubes in either
bunch may range from about 1/16 to 2 inches in diameter. The
length of the tubes in the central and annular bunches and
their spacing are such as to permit the external reactant
stream to flow evenly into the interstices between the tubes.
For example, the length of the tubes in either tube bundle may
range from about 1/2 to 24 inches or longer and preferably
from about 4 to 10 inches, with greater lengths required as
the number of tubes and the total size of-the burner increases.
Preferably, the ratio of the length to inside diameter of the
l 16~6
- 24 -
tubes should be at least 8. Preferably, the inside diameter
and the length of each tube should be the same for all tubes
in the central bunch or the annular bunch. By this means
equal flow may be obtained through all of the tubes.
The inside diameter of the helical tubes in the central
and/or annular bundles may range from about 1~16 to 2 inches,
or more. The height, spacing, and pitch of the individual
coils in the central and annular helical bundles of tubes
are such as to lmpart the desired swirl to the related feed-
streams and/or to permit the external reactant stream to flow
evenly into the interstices between the tubes. For example,
the overall height of~the coils in either tube bundle may
range from about 1 to 36, such as 4 to 12 inches or more.
Greater heights may be required as the number of tubes and
the to-tal size of the burner increases. Preferably, the
inside diameter of each tube should be the same for all tubes
in the central and/or annular bundles. By this means equal
flow may be obtained through all of the tubes.
Alighnment pins, fins, centering vanes, spacers and other
conventional means are used to symmetrically space the tubes
and conduits with respect to each other and to hold same in
stable alignment without obstructing the free-flow of the
feedstreams in the central and annular interstitial zones.
The downstream exit ends of the plurality of annular
and central bunches of tubes (parallel or helical) preferably
are circular in cross-section and terminate in the same plane
perpendicular to the longitudinal central axis of thè burner.
The ends of the central, and, in some embodiments, of the
~annular, bunch of tubes are retracted upstream from the
burner ~ace to provide substantial mixinq of t~e reactants
and volatilization of the slurry medium prior to discharge.
The central conduit exit orifice and/or the annular exi~
orifice may have converging sections. For example, the
central conduit exit orifice may comprise a frusto-conical
rear portion having a converging angle in the range of about
; ~ ~,,,
: :
~ 16~04~
- 25 -
15 to 90 from the central longitudinal axis of the burner.
The rear portion may develop into a normal cylindrical, or a
diverging frusto-conical (e.g. at a half angle of about 15
to 90 ), front portion which terminates at the dowmstream
face of the burner. The cylindrical front portion may have
a height in the range of about 0 to 1.5 times its own diameter.
Similarly, said annular exit orifice may comprise a generated
converging frusto-conical shaped annular rear portion having
a converging angle in the range of about 15 to 90 from the
central axis of the frusto-conical section, said central axis
being parallel to the central longitudinal axis of the burner.
The rear portion may develop into a generated normal cylind-
rical, or a divering frusto-conical (e.g. at a half angle of
about 15 to 90), annular front portion which terminates at
the downstream face of the burner. The cylindrical front
portion may have a height in the range of about 0 to 1.5
times its own width.
In one embodiment, the central conduit exit orifice
and/or the annular exit orifice are in the shape of or is
generated by an American Society of Mechanical Engineer's
standard long-radius nozzle. A further description of said
nozzle may be found in "Thermodynamics Fluid Flow and Heat
Transmission" by Huber 0. Croft, page 155, First Editlon,
1938 McGraw-Hill Book Company.
The burner may be cooled on the outside by means of
cooling coils that encircle the outside barrel of the burner
along its length. The downstream end of the burner may be
provided with a cored face plate through which a coolant is
circulated. For example, an annular cooling chamber may
encircle the annular exit orifice and/or the central conduit
exit orifice. The cooling chamber, central conduit exit
orifice and/or the annular exit orifice may constitute a
single piece of thermal and wear resistant material such as
tungsten carbide or silicon carbide. Any suitable coolant
m~y be employed e.g. waterO
'
~ 1620~
- 26 -
In one embodiment of the subject burner, a plurality of
high pressure high velocity jet streams of a gaseous material
is passed into the central conduit and/or annular passage at
various locations along their length. By this means atom-
i~ing of the fuel feedstream and, optionally, mixing it withthe oxidant stream may be facilitated. For example, the
gaseous material may be passed through a plurality of small
diameter passages or holes i.e. about .032 to .50 diameter
that lead into said central conduit and/or annular passage.
The gaseous material may be selected from the group con-
sisting of steam, free-oxygen containing-ga~ C02, N2, fuel
gas, a recycle portion of the product gas, and mixtures
thereof. The gaseous material may be introduced into the
burner at a temperature in the range of about ambient to
1500F and a velocity in the range of about 100 feet per
second to sonic velocity. The pressure of the gaseous mater-
ial may be in the range of about 76 to 4500 psia and is
greater than the pressure of the other feedstreams passing
through the burner.
The discharge velocity for the material leaving through
the central exit orifice is in the range of about 0.5 to 1.5
times, and preferably the same as, the discharge velocity of
the material leaving through the annular exit orifice. The
streams leaving the two exit orifices mix together and atom-
ization may take place immediately downstream from the face
of the burner.
In another embodiment of the invention, additional mix~
ing of the reactant streams is effected in at least one, say
2 to 5 coaxial cylindrical shaped pre-mix chambers in series
in the central conduit and/or at least one, sa~ 2 to 5 annular
shaped pre-mix chambers in series in the annular passage ~hen
provided. In such case, the downstream ends of the central
bunch of tubes are retracted upstream from the face of the
burner a distance of 2 or more, e.~. about 3 to 10, times the
minimum diameter of the circular exit orifice and/or the down-
stream ends of the anrular bunch of tubes are retracted
) 16~
_ 27 -
upstr~am from the face of the burner a distance of 0 to 12,
such as 2 or more, say about 3 to 10, times the minimum
width of the annular exit orifice. Preferably, the down-
stream ends of the central and annular bunches of tubes are
retracted upstream from the entrance to the first pre-mix
chamber in the line. For example, the set back of the ends
of the tubes from the entrance to the first pre-mix chamber
may be in the range of about 0.1 - 2.0 times the diameter of
the first pre-mix chamber.
In one embodiment, each of the pre-mix chambers in the
central conduit except the first are cylindrical shaped and
comprises a coaxial cylindrical body portion ~ollowed by a
coaxial at least partially converging outlet portion. The
first cylindrical shaped pre-mix chamber in the central con-
duit comprises a normal coaxial cylindrical body portion that
discharges directly into the next in line coaxial cylindrical
shaped pre-mix chamber. Each pre-mix chamber in the annular
conduit except the first is annular shaped and comprises a
coaxial generate~-normal cylindrical annular body portion
followed by a coaxial generated converging frusto-conical
shaped annular outlet portion. The first annular shaped pre-
mix chamber comprises a coaxial generated normal cylindrical
annular body portion that discharges directly into the next
in line coaxial annular shaped pre-mix chamber. The con-
verging outlet portions of said pre-mix chambers may be made
from tungsten carbide or silicon carbide for increased wear
resistance.
The size relationship between successive pre-mix chambers
in the subject burners may be expressed in the following
3~ manner: For burners in which the pre-mix chambers in the
central conduit are successively numbers 1 to 5 and/or the pre-
mix chambers in the annular passage are numbered 6-10, then
the ratio of the diameter of any one of said central chambers
to the diameter of the next central chamber in the line i.e.
Dl:D~; D2:D3; D3:D4; or D4:D5 may be in the range of about
0.2-1.2. The ratio of the length of any one central pre-mix
~ ~6204~
- 28 -
chamber in said central conduit to the length of the next
central pre-mix chamber in the line i.e. L1:L2; L2:L3;
L3:L4; or L4:L5 may be in the range of about 0.1-1Ø The
ratio of the annular width of any one of said annular pre-mix
ch~mbers to the width of the next annular chamber in the line
6 7; 7 B; W8:W9; or Wg:W10 may be in the range of
about 0.1-1.2. The ratio of the length of any one annular
pre-mix chamber in said annular passage to the length of the
next annular pre-mix chamber in the line, i.e. L6:L7; L7:L8;
L8:Lg; or L9:Llo may be in the range of about 0.1-1Ø
In most other respec~ the design of this pre-mix embodi-
ment of the buxner, including the tubes, passages, orificesr
water-cooled face-plate and cooling coils, high pressure high
velocity jets of a gaseous material entering said central
and/or annular pre-mix chambers, and flow control means are
substantially the same as previously described. Further, the
temperature, pressure and velocity ranges for the streams of
materials passing through the various passages of the burner
are substantially the same as those discussed previously.
In the operation of the embodiment of the burner employ-
ing pre-mix chambers flow control means may be used to control
the flow of the four feedstreams to the tubes and passages in
the burner in the same manner as described pxeviously. The
feedstreams entering the burner and simultaneously and con-
currently passing through at different velocities impinge and
mix with each other in the first pre-mix chambers. The
impingement of one reactant stream, such as the liquid slurry
of solid carbonaceous fuel in a liquid medium optionally in
admixture with a temperature moderator, with another reactant
stream, such as a gaseous stream of free-oxygen containing gas
optionally in admixture with a tempera*ure moderator at a
higher velocity, causes the liquid slurry to break up into a
fine spray. The multiphase mixture produced then successiv~ly
passes through any remaining pre-mix chambers where additional
mixing takes place. As the mixture passes frPely through the
subject unobstructed burner its velocity changes many times.
~ ~62~
- 29 -
For example, at various points in the burner the velocity of
the mixture may range from about 20 to 600 ft. per sec. As
the mixture flows from one pre-mix chamber to the next, the
velocity changes are mainly the result of changes in the
diameter of the flow path and the quantity and temperature
of the mixture. This promotes a thorough mixing of the com-
ponents as well as swirling which takes place when helical
tubes are used. By operating in the region of turbulent flow,
mixing may be
~ ~620~
maximized. Further, direct heat exchange between the materials
takes place within the burner. From 0-100 vol. %, say about
5-25 vol. % of the liquids in the feedstreams may be vapor-
ized before the feedstreams leave the burner. By means of
converging exit orifices, the feedstreams may be accelerated
directly into the reaction zone of the partial oxidation
gasifier.
Burning of the combustible materials while passing
through the pre-mix 7one of the burner may be prevented by
discharging the multiphase mixtures at the central and
annular exit orifices at the tip of the burner with a dis-
charge velocity which is greater than the flame propagation
velocity. Flame speeds are a function of such factors as
composition of the mixture, temperature and pressure. They
may be calcaluted by conventional methods or determined
experimentally. The ratio of the discharge velocity for the
.
muItiphase mixture being discharged through the central exit
orifice to the multiphase mixture being discharged through
the annular exit orifice may be in the range of about 0.5 to
1.5, such as 1.0
Depending on such faators as the temperature,
~ .
velocity, dwell time and composition of the feedstreams; the
deslred amount o~ vaporization of liquid carrier; the tempera-
~ ture and amount of recycle gases in the generator; and the
; ~ desired life of the burner; cooling coils may or may not
encircle the outside barrel of the burner along its length.
For similar reasons, the burner may or may not be provided
with an annular shaped cooling chamber at the downstream
end.
The multiphase mixtures simultaneously departing
- from the central orifice and~or the annular orifice at the
:
: . '
- 31 ~ 0~
downstream tip of the burner mix together downstream from
the face of the burner.
Advantageously, by means of the subject burner,
the exothermic partial oxidation reactions take place a
sufficient distance downs~ream from the burner face so as to
protect the burner from thermal damage.
Liquid hydrocarbon fuels and/or pumpable slurries
of solid carbonaceous fuels having a dry solids content in
the range of about 30 to 75 wt. %, say about 40 to iO wt. %
may be passed through the inlet passages of the subject
burner. For example, the fuel streams may be passed througn
the central and/or annular bunch of tubes. The inlet temp-
; eratu~e of the liquid hydrocarbon fuel or the slurry is in
the range of about ambient to 500 F., but preferably below
the vaporization temperature of the liquid hydrocarbon at
; the given inlet pressure in the range of about I to 300
atmospheres, such as 5 to 250 atmospheres, say about 10 to
lO0 atmoshperes.
The term solid carbonaceous fuels, as used herein
2C to describe suitable solid carbonaceous feedstocks, is
intended to include various materials and mixtures thereof
from the group consisting of coal, coke from coal, char from
coal, coal liquefaction residues, petroleum coke, parti-
culate carbon soot, and solids derived from oil shale, tar
sands, and pitch. All types of coal may be used including
anthracite, bituminous, sub-bituminous, and lignite. The
particulate carbon may be that which is obtained as a by-
product of the subject partial oxidation process, or that
which is obtained by burning fossil fuels. The term solid
carbonaceous fuel also includes by definition bits of
garbage, dewatered sanitary sewage, and semi-solid organic
.
- 32 _ ilB204~
materials such as asphalt, rubber and rubber-like materials
including rubber automobile tires which may be ground or pul-
verized to the aforesaid particle size. ~y suitable grind-
ing system may be used to convert the solid carbonaceous
fuels or mixtures thereof to the proper size.
The solid carbonaceous fuels are preferably ground to a
particle size so that 100~ of the material passe~ through an
ASTM E 11-70 Sieve Designation Standard 1.4 mm ~Alternative
No. 14) and at least 80% passes through an ASTM E 11--70 Sieve
Designation Standard 425 ~m (P.lternative No. 40).
The moisture content of the solid carbonaceous fuel
particles is in the range of about 0 to 40 wt. ~, such as 2
to 20 wt. %. Predrying may be required if necessary in some
instances to reach these levels.
The term free-oxygen containing gas, as used herein is
intended to include air, oxygen-enriched air, i.e., greater
than 21 mole % oxygen, and substantially pure oxygen, i.e.,
greater than 95 mole % oxygen, (the remainder comprising N2
and rare gases).
Simultaneously, a stream of free-oxygen containing gas
is supplied to the reaction zone of the gas generator by way
of a free passage in the burner, such as through the central
` conduit and/or annular pas.sage, when provided, at a tempera-
ture in the range of about ambient to 1500F., and preferabIy
in the range of about ambient to 300F., for oxygen-enriched
air, and about 500 to 1200F., for air, and a pressure in the
range of above about 1 to 300 atmospheres, such as 5 to 250
atmospheres, say 10 to 100 atmospheres. The atoms of free-
oxygen plus atoms or organically combined oxygen in the
solid carbonaceous fuel per atom of carbon in the solid
- 33 -
1 1620~
carbonaceous fuel (O/C atomic ratlo) may be in the range of
0 5 to 1.95. With free-oxygen containing gas in the reaction
zone the broad range of said O/C atomic ratio may be about
0.5 to 1.7, such as about 0.7 to 1.4. More specifically,
with air feed to the reaction zone, said O/C atomic ratio
may be about 0.7 to 1.6, such as a~out 0.9 to 1.4O
The term temperature moderator as employed herein
includes water, steam, CO2, N2, and a recycle portion of the
product gas stream. The temperature moderator may be in
admixture with the fuel stream and/or the oxidant stream.
For example in one embodiment, the ~eedstream
comprises a slurry of liquid hydrocarbonaceous material and
solid carbonaceous fuel. H2O in liguid phase may be mixed
with the liquid hydrocarbonaceous carrier, for example as an
~emulsion. A portion of the H2O i.e., about 0 to 25 weight
of the total amount of ~2 present may be introduced as
steam in admixture with the free-oxygen containing gas. The
weight ratio of ~20/fuel may be in the range of about 0 to
5, say about 0.1 to 3.
The term liquid carrier, as used herein as the
suspending medium to produce pumpable slurries of solid
carbonaceous fuels is intended to include various materials
from the group consisting of water, liguid hydrocarbonaceous
material, and mixtures thereof. However, water is the
~ preferred carrier for the particles of solid carbonaceous
i fuel. ~n one embodiment, the liquid carrier is liquid
carbon dioxide. In such case, the liquid slurry may
- comprise 40-70 wt. ~ of solid carbonaceous fuel and
the remainder is liguid CO2. The CO2-solid fuel slurry
may be introduced into the burner at a temperature
. ~ .
~ 34 ~ ~620~
in the range of about -67 F to 100 F depending on the
pressure.
The term liquid hydrocarbonaceous material as used
herein to describe suitable liquid carriers, is intended to
include various materials, such as liquified petroleum gas,
petroleum distillates and residues, gasoline, naphtha,
kerosine, crude petroleum, asphalt, gas oil, residual oil,
tar sand oil and shale oil, coal derived oil, aromatic
hydrocarbon (such as benzene, toluene, xylene fractions),
coal tar, cycle gas oil from fluid-catalytic-cracking
operation, furfural extract of coker gas oil, methanol,
ethanol and other alcohols and by-product oxygen containing
liquid hydrocarbons from oxo or oxyl synthesis, and mixtures
thereof.
The subject burners as shown in Figures 7 to 13 may ke
operated with the feedstreams passing through alternate
passages in the burner. Typical modes of operation are
summarized in Tables I and II below.
Table I lists the materials being introduced into
the gasifier by way of the burner and their corresponding
symbol. The solid carbonaceous fuel ~B), water (C), and
llquid hydrocarbonaceous material (E) may be mixed together
in various combinations upstream ~rom the ~urner inlet to
produce a pumpable slurry which may be introduced into the
burner and then passed through one of the several free-flow
passages of the burner as shown in Table II. For example,
the first entry in Table II shows that a pumpable slurry
stream comp~ising solid carbonaceous fuel (B) in admixture
with water (C) may be passed through the central and/or
annular bunch of tubes in the burner, i.e. Fig. 7 or lO or 11 or 13.
Whenever a fuel stream is lntroduced into the burner, a
`
-
- 35 ~ ~ 162046
corresponding stream of free~oxygen containing gas is
simultaneously passed throuah th~ related central conduit
and/or annular passage. Some additional examples follow:
(1) separate streams of free-oxygen containing gas are
passed through said central and/or annular bunches of tubes;
and simultaneously separate corresponding streams of a
pumpable slurry of solid carbonaceous fuel in a liquid
carrier are passed through the related central conduit,
and/or annular passage.
(2) separate streams of free-oxygen containing gas are
passed through said central conduit and said annular pas-
sage; while simultaneously a corresponding stream of liquid
hydrocarbonaceous material is passed through the related
central and/or annular bunches of tubes; and simultaneously
a pumpable slurry of solid carbonaceous fuel in a liquid
carriex is passed through the free bunch of said tubes, if
any.
(3) separate streams of free-oxygen containing gas are
passed through said central and/or annular bunches of tubes;
while simultaneously a corresponding stream of liquid
hydrocarbonaceous material is passed through the related
central conduit and/or annular passage; and simultaneously
;~ a pumpable slurry of solid carbonaceous fuel in a liquid
carrier is passed through the free passage, if any.
.
- 36 - 11~2~
TAsLE I
Material Symbol
Free-oxy.gen Containing Gas A
Solid Carbonaceous Fuel B
h'ater C
Steam D
Liquid Hydrocarbonaceous Material E
Temperature Moderating Gas F
Gaseous Hydrocarbon Fuel G
TABLE II
Central Central Annular Annular
Conduit Bunch of Tubes Passage Bunch of Tubes
A B+C A B+C
A+D B+C A+D B+C
B+~ A . B+C A
A B+C B+C A
B+C A A B+C
A B~C+E A B+C+E
B~C+E A~D ~ B~C+E A+D
A E A E
A+D B+E A+D B~E
B+E A+D B+E A~D
A+D E A B+C
E A E A
B+C A E A
. E . A B+C A
A . G A B+C
A . G A+D E
A E+F A E+F
E~F A+D E+F A~D
Other modes of operation of the subject invention
are possible in addition to those shown in Table II.
For example, jet streams of a gaseous material may
be simultaneously introduced into the central conduit and/or
annular passage, as previousIy described.
When one of the fuel streams is a liguid hydro-
carbon or the liquid carrier for the slurry of solid car-
bonaceous fuel is a liquid hydrocarbonaceous material pre-
mature combustion within the burner may be avoided by one ormore of the following:
,
_ 3~ _ ~162~
(1~ keeping the fuel belo~ its autoignition temperature,
(2) including water in the solid f~-el slurry,
t3) using air or air enriched with oxygen i.e. up to about
40 vol. ~ 2'
(4) mixlng steam with the air,
(5~ employing about 0 retraction of the ends of the central
and annular bunches of tubes from the face of the
burner. In such case, the free-oxygen containing gas
such as substantially pure oxygen may be separately
discharged from the burner without first contacting the
fuel stream.
(6) discharging the multiphase mixture at the central and
~nnular exit orifices at the tip of the burner with
discharge velocities that exceed the flame propagation
velocity.
The suhject burner assembly is inserted downward
through a top inlet port of a compact unpacked free-flow
noncatalytic refractory lined synthesis gas generator, for
example as shown in our U.S. Patent No. 3,544,291.
The burner extends along the central longitudinal axis of
the gas generator with the downstream end discharging
directly into the reaction zone.
The relative proportions of the reactant feed-
streams and optionally temperatuxe moderator that are intro-
duced into the gas generator are carefully regulated to
convert a substantial pvrtion of the carbon in the fuel
e.g., up to about 90% or more by weight, to carbon oxides;
and to maintain an autogenous reaction zone temperature in
the range of about 1700 to 3500F., preferably in the range
of 2000to 2800F.
The dwell time in the reaction zone is in the
range of about 1 to 10 seconds, and preferably in the range
of about 2 to 8. With substantially pure oxygen feed to the
gas generator, the composition of the effluent gas from the
gas generator in mole % dry basis may be as follows:
- 38 ~ 2~
H2 10 to 60~ C0 20 to 60~ C02 5 to 40, CH4 D.01 to 5, H2S~COS
nil to 5, N2 nil to 5, and A nil to 1.5. ~Tith air feed to
the gas generator, the composition of the generator effluent
~ gas in mole ~ dry basis may be about as rOllOws:
H2 2 to 30, C0 5 to 35, C02 5 to 25, CH4 nil to 2, H2S+COS
nil to 3, N2 45 to 80, and A 0.5 to 1.5. Unconverted carbon
and ash are contained in the ef~luent gas stream.
The hot gaseous effluent stream ~rom the reaction
zone o~ the synthesis gas generator is quickly cooled belo~
the reaction temperature to a temperature in the range of
about 250 to 700F. by direct quenching in water, or by
indirect heat exchange for example with water to produce
steam in a gas cooler.
Advantageously, in another embodiment of the
subject invention the subject burner may be used as the
preheat burner during start-up of the gasifier, as well as
the production burner. Start-up procedures are thereby
simplified. Previously, time was lost when the gas preheat
burner was replaced by the production burner, and the
gasifler cooled down. Now the gasif1er may be brought up to
operating temperature and held there by slmultaneously
passing fuel gas through the central or annular bundle of
tubes and air through the related central conduit or annular
.
passage. Alternately, the fuel gas may be passed through
the central conduit or annular passage in the burner and the
air is passed through the related central or annular bundle
of tubes. The fuel gas and air are mixed together to produce
a well-distributed blend. Burning of the mixture by sub-
; stantially complete combustion then takes place in the
3~ reaction zone Or the gas generator at an absolute
'
_ 39 _ 1162~4~
pressure in the range o~ about o.56 to 300 atmospheres, and
preferably at 1 atmosphere. The products o~ the complete
combustion are removed from the reaction zone. For example,
they ~.ay be vented to the atmosphere. By this means~ the
reaction zone is heated to the temperature required ~or
ignition Or the autothermal partial oxi~ation reaction of
the principal fuel selected from the group consisting of a
pumpable slurry of solid carbonaceous fuel, liquid or
gaseous hydrocarbon fuel, and mixtures thereor with a free-
oxygen containing gas and with or without a temperaturemoderator. For example, the autoignition temperature may be
in the range of about 2000 to 270CF. At this point, the
principal fuel, with or without admixture with a temperature
moderator, is passed through either the central or annular
bunch of tubes, or alternately the central conduit or
annular passage, whichever is occupied by the fuel gas and
air. Simultaneously a stream of free-oxygen containi~g gas,
with or without admixture with a temperature moderator,!is
passed through either the central conduit or annular passage
of the burner, or alternately through either the central or
annular bunch of tubes which ever is assoclated with the
bunch of tubes or alternately with the conduit or passage
through which the principal fuel is flowing.
'
The stream of principal fuel and free-oxygen
containing eas are mixed together to produce a well-distributed
blend. The mixture ignites by autoignition and burns by
partial oxidation downstream in the reaction zone of the
free-flow noncatalytic gas generator at an autogenous temper-
ature in the range of about 1~00 to 350C~ F., a pressure in
',1
.
0~
- 40 -
the range of about 1 to 300 atmospheres, an atomic ratio of
oxygen carbon in the range of about 0.5 to 1 D 7 and H2O/fuel
weight ratio in the range of about 0 to 5.0, such as 0.1
to 3.
At the moment t~lat the partial oxidation of the
principal fuel commences, the fuel gas and related air
supply may or may not be cut off. For e~ample, the fuel gas
and related supply of oxidant may be continued at the same
flow rate or at a reduced flow rate i.e. about 1/8 to 3/4 of
the maximum flow rate. Further, if the supply of the fuel
~as to the burner is continued, then the flow rate of the
fuel gas stream and the associated stream of oxidant is
adjusted to provide an atomic O/C ratio in the range of D.5
to 1.7 and the partial oxidation of the fuel ga~ rather than
complete combustion. Optionally, dep~nding on the desired
composition of the product gas, the air may be replaced by
another free-oxygen containing gas. For example, oxygen
enriched air or substantially pure oxygen is preferred to
make synthesis gas.
In another embodiment, the stream of fuel gas in
the burner is replaced by an alternate fuel stream selected
from the group consisting of a pumpable slurry of solid
carbonaceous fuel in a liquid carrier i.e. water, hydrocarbon,
oxygenated hydrocarbon, liguid or gaseous hydroc~rbon fuel,
and mixtures thereof. Similarly, the air stream may be re-
placed with a stream of free-oxygen containing gas other
than air. The reactant streams are mixed together to produce
a well-distributed blend in the proper proportions for reacting
said alternate fuel by partial oxidation. After autoignition,
1 16~04B
- 41
said mixture is burned by partial oxidation downstream in
the reaction zone of the gas generator simultaneously with
the partial oxidation of the principal fuel and at the same
operating conditions. The alternate fuel and the associated
free-oxygen containing gas streams may be passed through the
same or alternate passages in the burner as previously
occupied respectively by the fuel gas stream and the associated
air stream.
A raw stream of synthesis gas, fuel gas, or reducing
gas (depending on the composition of the product gas) is
produced and removed from the reaction zone. The hot ra
gas stream may be then cooled, cleaned and purified by
conventional methods.
In one embodiment, the aforesaid fuel gas in the
preheat stage may be replaced by a liquid hydrocarbon fuel.
A free-oxyg-n containing ~as may be employed as the oxldant.
,
~ ~ '
~ 162~4~
- 42 -
DESCRIPTION OF THE DRAWING
A more complete understanding of the invention may
be had by reference to the accompanying schematic drawing
which shows the subject invention in detail~ Although the
drawing illustrates a preferred embodiment of the invention,
it is not intended to limit the subject invention to the
particular apparatus or materials described. Corresponding
parts in the several figures have the same reference numbers.
Referring to FIG. 1, the burner assembly for a retrac-
ted central conduit pre-mix burner having a single annulus
and one pre-mix chamber is indicated generally as 1. Face-
cooling chamber 2 is located at the downstream tip of the
burner. Circulating cooling water enters by way of inlet
pipe 3. The cooling water departs by way of coils 4 that
encircle the outside diameter of the burner along its length
and through outlet pipe 5. By means of cooling chamber
2 and cooling coils 4, burner 1 may be protected from thermal
damage. Face 6 is at the outermost downstream tip of burner
1. Burner 1 is installed do~nwardly through a port in the
top of a free-flow partial oxidation synthesis gas generator
(not shown). The longitudinal central axis of burner 1
is preferably aligned along the central axis of the synthesis
gas generator by
: , .
2 04 ~
- 43 -
means of mounting flange 7. Reactant streams pass into the
burner by way of inlets 8 and 9.
In FIG. 2, the downstream end of burner 1 is shown
in cross-section. This view is taken between A-A of FIG. 1
and comprises unobstructed inner coaxial retracted central
conduit 15 and outer concentric coaxial conduit 16 which is
disposed longitudinally about inner central conduit 15.
Spacing means 18 provide a free-flow annular passage 17
between the outside diameter of central cylindrical conduit
15 and the inside diameter of outer cylindrical conduit 16
Exit orifice 20 at the downstream tip of central conduit lS~
is preferably straight, circular in cross-section, and
perpendicular to the longitudinal axis of the burner.
Alternately, exit orifice 20 may be converging or diverging.
Outer conduit 16 terminates at the downstream end of the
burner with converging nozzle 21. A vertical cross section
of exit orifice 21 may be frusto-conically shaped, which may
or may not merge into a~right cylinder. Preferably for wear
resistance, as shown in Fig. 2, nozzle 21 comprises a frusto-
conical rear portion 22 that develops into a right cylin-
- drical front portion 23 which terminates at the downstream
face 6 of the burner. The cylindrical exit section will
permit: (1) additional burner life because of increased
surface available for abrasion, and (2) fabrication of a
ceramic or refractory insert or an entire cooling chamber
from a .hermal and abrasion resistant material i.e., tungsten
or silicon carbide in order to reduce damage and to extend
burner life.
~'
~ ~6~04~
- 44 -
The height of the front cylindrical portion 23 of
exit no7-zle 21 is in the range of about 0 to 1.5, say about
0.1 to 1.0 times, its own diameter i.e. the minimum diameter
of converging nozzle 21. The diameter of exit orifice 20 of
central conduit 15 is in the range of about 0.2 to 1.5,
say about 0.5 to 0.8 times the minimum diameter of con-
- verging nozzle 21.
The downstream end of the burner may or may not be
cooled. Preferably, as shown in Figs. 2,4,5 and 6, coaxial
annular shaped cooling chamber 2 surrounds exit orifice 21
at the burner tip. By passing water through cored section
; 24 of cooling chamber 2, the tip of burner 1 may be pre-
vented from overheating. Optionally for simiIar reasons,
outer conduit 16 may be kept cool by passing water through
coils 4. Suitable converglng angles for orifice 21 are in
the range from about 15 to 90 from the central longi-
tudinal axis of the burner. The downstream tip of exit
orifice 20 of central conduit 15 is severely retracted
upstream from face 6 of burner 1 a distance of two or more
times the minimum diameter of converging exit nozzle 21.
For example, the setback of tip 20 of central conduit 15
from burner face 6 may be in the range of about 3 to 10 times
;~ the minimum diameter of converging exit nozzle 21. The
space between tip 20 of central conduit 15 and burner face 6
constitutes the unobstructed pre-mix zone 25.
In the operation of burner 1, either reactant
stream i.e. see Table II supra, may enter burner 1 by way of
inlet 9 of Fig. 1 and pass directly from the upstream
portion down through free-flow central condui, 15, through
0 ~ ~ '
- 4~ _
exit orifice 20, and into pre-mix zone 25, as shown in Fig.
2. Simultaneously and concurrently, the other reactant
stream may enter burner 1 by way of inlet 8 of Fig. 1 and
pass directly from the upstream portion 30 of outer conduit
16 down through free-flow annular passaye 17 and into pre-
mix zone 25 where intimate mixing of the two reactant
streams takes place. Further, direct heat exchange between
the two reactant streams takes place in pre-mix zone ~5. The
temperature in the pre-mix zone is controlled so that a
controlled amount of the liquid carrier may be vaporized
without burning i.e. from 0 to 100 vol. % say about 2 to 80
vol. %. Temperature control in the pre-mix zone may be
effected by controlling such factors as dwell time and heat
content of the entering streams, and amount of external
cooling such as by coils 4, if any. Pre-mix zone 25 is
substantially free from any obstruction to the free-flow of
the materials pas~ing therethrough.
The velocity of the slurry of solid carbonaceous
fuel in liqu.id carrier passing through exit orifice 20 of
central conduit 15 or alternately exiting from annular
passage 17 is in the range of about 0.5 to 75 f~. per sec, say
about 2 to 20 ft. per sec., while the corresponding velocity
for the free oxygen containing gas simultaneously passing
through the other passage in the burner optionally i~ ad-
mixture wIth steam, is in the range of about 85 feet per
second to sonic velocity, say about 100 to 600 ft. per sec.
The slurry of solid carbonaceous fuel in liquid carrier
enters the pre-mix zone in liqu;d phase at a temperature in
the range of about ambient to 500F., and below the vapor-
`~ 30 ization temperature of the liquid carrier, and at a pressure
~ .
2~4~
- 46 -
in the range cf about 76 to 4500 psia. While simultaneously,
the free-oxygen containing gas stream, optionally in ad-
mixture with steam, enters into the pre-mix zone at a
temperature in the range of about ambient to 1200F., say
about 100 to 600F., and at a pressure in the range of about
76 to 4500 psia. Intimate mixing and direct heat exchange
takes place between the two reactant streams in the pre-mix
zone. Volatilization of the liquid carrier in the pre-mix
zone may amount to about 0 to 100 vol. %, say about 20 to 35
vol. % when the free-oxygen containing gas is introduced at
a temperature in the range of about 300 o 600F~; or from
about 70 to 100 vol. % when the free-oxygen containing gas
is introduced as air preheated to a temperature in the range
of about 1000 to 1200F. The multiphase mixture in the pre-
mix zone is at a temperature below its autoignition temp-
erature. The multiphase mixture lea~es burner 1 by way of
exit orifice 21 at a discharge ~elocity in the range of
about 75 to 600 ft. per sec., say about 150 to 350 ft. per
sec., and above the flame propagation velocity and passes
downwardly directly into the unobstructed reaction zone of
the partial oxidation gas generator.
FIG. 3 is a vertical sectional view of another
embodiment of the downstream end of outer conduit 16 as
shown in Fig. 2. In Fig. 3, converging exit nozzle 21 is in
the shape of an American Society of Mechanical Engineer's
(A.S.M.E.) standard long-radius nozzle. It may or may not
be cooled, such as by means of annular cooling chamber 2, in
the manner shown in Fig. 2. A further description of said
nozzle may be found in "Thermodynamics Fluid Flow and Heat
` 30 ~ransmission" by Huber O. Croft, page 155, First Edition,
1938 McGraw-Hill Book Company.
2 0~ 6
- 47 -
FIG. 4 is a vertical sectional view of ano'her
embodiment of the downstream end of outer conduit 16 as
shown in Fig. 2. In Fig. 4, exit nozzle 35 at the tip of
the burner is made from a wear resistant material such as
tungsten carbide or silicon carbide. Exit nozzle 35 com-
prises a frusto-conical rear portion 22 which develops into
a coaxial right cylindrical front portion 23. The frusto-
conical outside diameter of exit orifice 35 is supported by
coaxial .rusto-conical mating cavity 36 in annular cooling
chamber 2. For example, exit orifice 35 made from tungsten
carbide may be connected to the downstream tip of outer
conduit 16 by joining the back surface 37 of cooling
chamber 2 to the front surface of end flange 38 at the
downstream end of outer conduit 16. ~Cooling water may be
introduced into cored section 24 of cooling chamber 2 in the
manner shown for inlet pipe 3 in Fig. 1. OptionaIly/ a
cooling coil may encircle outer conduit 16 in the manner
shown for coil 4 in Fig. 1. Hot high velocity slurries of
solid fuel are abrasive. The life of the subject burner may
be considerably extended by making exit nozzle 35 rom a
wear reslstant material.
FIG. 5 is a vertical sectional view of the downstream
end of another embodiment of the pre-mix burner shown in Figures
1 and 2~ Concurrent streams of different materials flowing
through coaxial retracted central conduit 15 and simul-
taneously through annular passage 17 are successively mixed
together in pre-mix chambers 25 and 40. While the pre-mix
zone in the embodiment in Fig. 5 is shown as comprising two
' 30
'
1 1620il~
- 48 -
separate coaxial pre-mix chambers 25 and 40 in series, the
pre-mix zone for other embodiments of the subject invention
may actually comprise one or more, such as 2 to 5 coaxial
pre-mix chambers. For example, as previously noted, the
embodiment of the burner shown in Figures 1 and 2 have one
pre-rnix chamber 25, while three pre-mix chambers 25, 40, and
41 are included in the embodiment of the burner shown in
Fig. 6. Each pre-mix chamber in Figures 5 and 6, except for
the first chamber in~the line, comprises a coaxial cylin-
drical body portion 45 followed by a coaxial at least
partially converging outlet portion 22 or 46 in Fig. 6 that
may optionally develop into a straight cylindrical portion
49. Optionally, such outlets may be made from a thermal and
wear resistant material i.e. silicon or tungsten carbide,
such as described previously in connection with Fig. ~. In
embodiments having a plurality of pre-mix chambers, the
first pre-mix chamber in the line may have a straight
coaxial çylindrical body portion 47, that discharges through
circular orifice 39 directly into the next in line coaxial
pre-mix chamber 40. Preferably, the mixture leaving one
pre-mix chamber expands into the next successive pre-mix
chamber. When the mixture is accelerated and expanded
~ ; through a final exit nozzle at the tip of the kurner into
; ~ the combustion chamber, a more stable and efficient com-
bustion pattern results. The temperature, pressure and
velocity ranges for the streams of materials passing through
the various passages of the burner are substantially the
same as those discussed previously. The inlet to the first
pre-mix chamber 25 may have a converging inlet 48 as shown
,:
1 1~204~
- ~9 -
in Fig. 5, or that shown in Fig. 2. One or more of the pre-
mix chamber-~ may be a converging frusto-conical shaped
section.
FIG. 6 is a vertical sectional view of the down-
stream end of an embodiment of a retracted central conduit
15 pre-mix burner similar to burner 1, as shown in Fig. 1,
but modified to provide two coaxial annular passages i.e.
intermediate annular passage 17 and outer annular passage
51. Further, the pre-mix zone comprises three successive
free-flow coaxial pre-mix chambers 25, 40, and 41. By
spacing means 18, concentric coaxial outer conduit 52,
retracted coaxial intermediate conduit 53, and retracted
coaxial centr~l conduit 15 may be radially spaced from each
other to provide said separate annular passages and ~re-mix
chambe~s with substantially no obstruction to the free-f~ow
of materials therethrough. The downstream tip 20 of central
conduit 15 is retracted upstream from fa¢e 6 of the burner a~
distance in the range of 2 or moxe, say 3 to 10 times the
minimum diameter of converging exit orifice 21. The down-
stream tlp 54 of intermediate conduit 53 lS retracted
upstream from face 6 of the burner a distance in the range
of 0 to 12, say 1 to 5 times the minimum diameter of con-
verging exit orifice 21. Central conduit 15, and annular
: :
passages 17 and 51 are respectively connected upstream to
separate inlets, in a manner s~imilar to that shown in Fig.
1. The burner tip may be cooled by means of annular cooling
chamber 2 which is coaxial with the central longitudinal
axis of the burner at the downstream end in the manner
shown. Alternately, cooling chamber 2 may be eIiminated.
l 16204~
- 50 -
In the operation of the embodiment of the burner
shown in Fig. 6, the feedstreams simultaneously and con-
currently passing through central conduit 15 and inter-
mediate annular passage 17 at different velocities impinge
and mix with each other in the first pre-mix chamber 25.
The impingement of one reactant stream, such as the liquid
slurry of solid carbonaceous fuel in a liquid medium with
another reactant stream, such as a gaseous stream of free-
oxygen containing gas, steam, or temperature moderator at a
higher velocity causes the liquid slurry to break up into a
fine spray. The multiphase mixture then passes into the
second pre-mix chamber 40 for additional mixing. Leaving
chamber 40 by way of converging e~it nozzle ~6 and circular
orifice 54 at the downstream tip of chamber 40, the multi-
phase mixture passes into the third pre~mix chamber 41. The
third feedstream enters the burner upstream through a
separate inlet (not shown), and passes down outer annular
passage 51~ When the set bac~ of orifice 54 at the tip of
intermediate conduit 53 from face 6 of the burner is greater
than 0, say in the range of about 1.0 to 5 times the minimum
diameter~of exit orifice 21, then the third feed stream may
mix with the first and second feed streams in pre-mix
chamber 41 to produce a multiphase mixture. Further, in
such embodiment, there may be 2 or more say 2 to 5 cylin-
~drical coaxial pre-mix chambers in series. The multiphase
mixture passes through converging nozzle 21 at the down-
stream tip of the burner into the reaction zone of the gas
generator.
'
' . , .
l 1 6 ~
- 51 -
In the embodiment of the burner with a setback
of orifice 54 of about 0, then the third feedstream passing
through outer annular passage will contact and mix with the
multiphase mixture of the other two feedstreams from the
pre-mix zone downstream from face 6 of the burner, say about
l to 24 inches. Further, in such embodiment, there may be
one or more say 2 to 5 cylindrical coaxial pre-mix chambers
in series. For example, the stream of free-oxygen containing
gas is passed through either the central or outer annular
passage and the stream of liquid hydrocarbonaceous material
is passed through the other passage i.e. the central conduit
or outer annular passage whichever is free. SimultaneousIy,
a slurry stream of solid carbonaceous fuel and water is
passed through the intermediate passage. Alternately,
the stream of free-oxygen containing gas is passed through
either the intermediate or outer annular passage and thè
stream of liquid hydrocarbonaceous material is passed
through the other passage i.e. the intermediate or outer
annular passage whichever is free. Simultaneously, a slurry
stream of solid carbonaceous fuel and water is passed through
the central conduit. The temperature, pressure and velocity
ranges for the streams of materials passing through the
various passages of the burner are substantially the same as
~; those discussed previously. For example, see the discussion
; with respect to Fig. 2. The conditions for the liquid
hydrocarbonaceous material are substantially the same as
those given for the slurry of solid carbonaceous fuel. The
feedstream flowing through the outer conduit of the burner
mixes with the multiphase mixture of th~ other two feedstreams
.
204~
- 52 -
from the pre-mix zone. ~owever, this mixing takes place
dcwnstream from the face of the burner in the reaction zone
of the free-flow partial oxidation gas generator~
Burning of the slurry while passing thxough the
pre-mix zone of the burner may be prevented by discharging
the multiphase mixture at the exit orifice at the tip of the
burner with a discharge velocity which is greater than the
flame propagation velocity. Flame speeds are a function of
such factors as composition of the mixture, temperature and -
pressure. They may be calculated by conventional methods or
determined experimentally.
Advantageously, by means of the subject retracted
central conduit pre-mix burner, the exothermic partial
oxidation reactions take place a sufficient distance down-
stream i~e. 6 inches to 2 feet from the burner face so as to
; ~ protect the burner from thermal damageO
~ As the mixture passes freely through the subject
; unobstructed burner its velocity changes many times. At
various points in the burner the velocity of the mixture may
range from about 20 to 600 ft. per sec. As the mixture
fIows from one pre-mix chamber to the next, the velocity
changes are mainIy the result of changes in the diameter of
the flow path and the quantity and temperature of the
mixture. This promotes a thorough mixing of the components.
Further, by operating in the region of turbulent flow,
mixing may be maximized. Other burner design considerations
such as size, length and number of chambers, and external
-cooling may be calculated from such factors as quantity,
~ 162~
- 53 -
temperature and composition of the feedstreams, and desired
amount of volatilization of the liquid carrier i.e. 0 to 100
vol. %.
The si~e relationship between successive pre-mix
chambers in the subject burners may be expressed in the
following manner: For burners having 1 to 5 pre-mix
chambers successfully numbered 1 to 5 with chamber 5 being
located closest to the downstream tip of the burner, the
ratio of the diameter of any one of said chambers to the
next chamber downstream in the line i.e. Dl~ D2; D2: D3;
D3: D4; or D4: D5 may be in the range of about 0.2-1.2.
Similarly, the ratio of the lengths of any one pre-mix
chamber to the next downstream pre-mix chamber in the line,
LI L2; L2 ~3; L3 L4; or L4: L5 may be in the range
of about 0.1-1Ø
Advantageously, in one embodiment of the subject
burner, as shown in Fig. 6 the material passing through
outer annular passage 51 i.e. see Table III sup~a is heated
by indirect heat exchange with the hot gaseous reaction
products that recirculate in the reaction zone on the
.
outside of the burner. By indirect and direct heat ex-
.
change, the heated material in annular passage 51 may then
heat the other reactant materials simultaneously and con-
currently passing through the burner. In such case, all or
a portion of the cooling coils 4 may be eliminated from the
burner. Further, the reactants may be preheated and the
liquid carrier may be vaporized from 0 to 100 vol. %.
.
:~ ,
., .
- ~ 1620~
- 54 _
In still another embodiment of the subject burner
shown in Fig. 6, a gaseous material is passed through outer
annular conduit 51. At least a portion i.e. about S to 100
vol; % of the gaseous feedstream passing through annular
conduit 51 is bled through a plurality of small diameter
passages i.e. about .03~ to 0.50 inches diameter or holes
of the same diameter, in a plurality of circumferential
rings in the walls of intermediate conduit 53 at one or more
locations 60-62 along its length. In such case, th~ down-
stream outlet 56 of outer annular passage 51 may be com-
pletely or partially blocked. For example, annular plate
57 i5 optionally shown in Fig. 6. Optionally, plate 57 may
contain a plurality of small diameter holes 58 i.e. .060 to
.75 inches diameter leading into pre-mix chamber 41. An-
nular plate 57 may be placed perpendicular to the central
longitudinal axis of the burner. By this means at least a
portion of the third feedstream flowing in outer annular
passage 51 may be pre-mixed with the materials simultaneously
flowing through at least one or all of the following passages
-20 in the burner at a Iower pressure; intermediate passage 17,
and pre-mlx chambers 25, 40, and 41. For example, atomizing
of the slurry of solid carbonaceous fuel and mixing it with
the other feed streams may be facilitated by means of high-
velocity, high pressure jet stream of a gaseous stream
passlng through said passages at one or more locations 58
and 60-62. The gaseous material may be selected from the
group consisting of ~team, free-oxygen containing gas,
CO2, N2, a recycle portion of the product gas, and mixtures
; thereos. The gaseous material may be introduced into the
- ~ .
I le204~
- 55 -
burner at a temperature in the range of about ambient to
1500F and a velocity in the range of about 100 feet per
second to sonic velocity. The pressure of the gaseous
material may be in the range of about 76 to 4500 psia and is
greater than the pressure of the feedstreams passing through
the central and intermediate passages.
In other embodiments, converging inlet 48 and the
converging portion 22 of exit orifice 21 of the burners
shown in Figures 5 and 6 and converging portion 46 in the
burner shown in Figure 6 may be made from a wear resistant
material such as tungsten carbide or silicon carbide. The
wear resistant material may be shaped in the manner des-
cribed in connection with the embodiments shown in Figures 3
and 4.
SPECIFIC EXAMPLE
The following is an example of the subject process
and appar~tus employed in the partial oxidation of a slurry
of coal and water with air; but the invention is not to be
construed as limited thereto.
EXAMPLE 1
Fuel gas is produced in a vertical cylindrical
refractory lined steel pressure vessel free from catalyst or
any obstruction to the free-flow of materials therethrough.
The volume of the reaction zone is about 160 cubic feet.
The feedstreams are introduced into the reaction
zone by way of a single annulus pre-mix burner having a
retracted central conduit and two coaxial cylindrically
shaped pre-mix chambers in tandem as shown in Fig. 5. The
pre-mix burner is vertically mounted in a flanged port at
30
I 1620d~
- 56 -
the top of the gas generator along the central longitudinal
axis of the gas generator. Exit orifice 20 of the burner is
retracted about 26 inches from the downstream face of the
burner, and about 6 inches from circular exit orifice 39 at
the end of the first pre-mix chamber 25. The length of the
second pre-mix chamber 40 is 20 inches and the length of
cylindrical portion 23 of exit nozzle 21 is 1.5 inches. The
diameters of exit orifices 39 and 23 are 3.1 inches each.
The outside and inside diameters of central conduit 15 are
respectively 1.315 and 1.049 inches. The inside diameter of
passage 17 and the diameter of pre-mix chamber 40 are 4.563
inches each.
A slurry of bituminous coal and water having a
solids content of 65 wt. % is prepared and passed through
the center conduit 15 of the burner in liquid phase at a
temperature of 100F, pressure of 600 psig~ and velocity
of 10.4 feet per sec. The slurry comprises about 10,300
lbs. per hr of coal and 5~470 lbs. per hr of water. The
coal is ground to a particle size so that 100% passes
through an ASTM E 11-70 Sieve Designation Standard 1.4 mm
and a* least 80% passes through an ASTM E 11-70 Sieve
Designation Standard 425Jlm. The ultimate analysis of the
coal in wt. % (moisture free basis) comprises: carbon
69.52; hydrogen 5.33; nitrogen 1.25; sulfur 3.86; oxygen
10.02; and ash 10.02.
Simultaneously, about 11.8 cubic feet per second
of air comprising 21 mol ~ oxygen at a temperature of
1000F., pressure of 600 psig, and velocity of 113 feet per
f ~ second are passed through the annular passage 17 of the
~ ' 30
1 1~20~5
- 57 -
burner. Mixing of the two feedstreams together takes place
in pre-mix chamber 25. The mixture leaves through orifice
39 at a velocity of 271 feet per sec. and expands into pre-
mix cha~ber 40 where intimate mixing of the components takes
place. About 100 vol. % of the water in the slurry vaporizes
in the burner and the mixture passes through pre-mix chamber
40 at a velocity of 125 ft. per sec. The multiphase mixture
passes through exit nozzle 21 at the downstream tip of the
burner at a temperature of 423~F and a velocity of 194 ft.
per sec. and directly enters the reaction zone of the partial
oxidation gas generator.
Noncatalytic partial oxidation of the solid fuel
takes place in the reaction zone at an autogenous temperature
of 2800F and a pressure of 500 psig. About 23 million
standard cubic feet per operating day of low BTU fuel gas
are produced having the following'composition in mole %:
C0 17-1, H2 10-1, C02 6.7, H20 12.4, N2 52.6, A 0.6, H2S 0~5O
The heating value of the purified gas streams is a~out 110
BTU per SCF.
Advantageouslyl by employing the subject burner in
place of a conventional burner, the specific oxygen consump-
tion may be reduced 10% and problems of combustion instabil-
ity are avoided.
Referring to FIG. 7, a high turndown burner assembly
i5 depicted. Burner 111 is installed downwardly through
a port in the top of a free-flow partial oxidation synthesis
gas generator as shown in FIG. 9. The longitudinal central
axis of burner 111 is preferably aligned along the central
axis of the synthesis gas generator by means of a mounting
flange. Burner 111 comprises central conduit 112, central
bunch of parallel tubes 113 that pass longitudinally through
central passage 114 of central conduit 112, co~xial concen-
tric outer conduit 115, annular passage 116 between the
outside diameter of central conduit 112 and the inside diam-
eter of outer conduit 115 along its length and annular bunchof parallel tubes 117 that pass l.ongitudinally through annu-
lar passage 116. Conduit 112 is a cylindrical wall that
~;
;
~ 1620~
- 58 -
separates central passage 114 and annular passage 116.
The downstream ends 118 of the central bunch of tubes 113,
and, in some embodiments, also the downstream ends 119 of
annular bunch of tubes 117 is/are retracted upstream from
burner face 1110. Central circular orifice 1111 and annular
orifice 1112 are determined by said imaginary plane perpen-
dicular to the central axis of the burner at face 1110.
Central orifice 1111 has a diameter equal to the minimum
inside diameter of central conduit 112 or nozzle if any
at face 1110. The width of annular orifice 1112 is equal
to the minimum inside diameter of outer conduit 115 or nozzle
if any less the maximum outside diameter of central conduit
112 or nozzle if any at face 1110.
Wall brackets or tube spacers 1113 hold tubes 113
in a fixed parallel non-touching position with respect to
each other and the inside wall of central conduit 112.
Central bunch of tubes 113 are passed through and
sealed into disc shaped fixed tube sheet 1115. Tube sheet
1115 closes off the upstream end of central conduit 112.
Similarly, annular bunch of tubes 117 are pas.sed through
and sealed into annular shaped fixed tube sheet 1116. Tube
sheet 1116 closes off the upstream end of outer conduit
115 and annular passage 116. Conventional means i.e. welding,
: turning, crimping, threading, rolling may be employed to
provide a gas-tight seal or joint where the central and
annular tubes penetrate the respective tube sheets. Mech-
anical pressure fittings and coupling devices may be also
employed.
The upstream ends 1117 of the central bunch of tubes
113 are connected to outlet means 1118 of central cylindrical
shaped manifold 1119. Inlet feed pipe 1120 is connected
to and in communication with manifold 1119. By this means,
for example, a portion of a first reactant feedstream in
feed pipe 1120 may be introduced into central manifold 1119,
split into a plurality of streams which pass through outlet
means 1118 and the individual tubes in th~ central bundle
113, and are then discharged at ~he face 1110 of the burner.
~ ~62~
- 59 -
Simultaneously, for example, a portion of a second reactant
feedstream may be passed through inlet pipe 1125. Pipe
1125 is connected to and in communication with central con-
duit 112 near its upper end and below tube sheet 1115.
By this means, the portion of said second feedstream may
fill the interstices between and surrounding all of the
tubes in the central bunch 113 as it freely flows down
through said central conduit 112 and is discharged through
central orifice 1111 at the face 1110 of the burner.
The upstream ends 1126 of the annular bunch of tubes
117 are connected to outlet means 1127 of annular-shaped
manifold 1128. At least one inlet pipe 1129 is connected
to annular manifold 1128. By this means, for example) the
remaining portion of said first reactant feedstream may
be introduced into annular manifold 1128, split into a plur-
ality of streams which pass through outlet means 1127 and
the individual tubes in the annular bundle 117, and then
discharged at the face 1110 of the burner. Simultaneously,
for example, the remaining portion of said second reactant
2Q feedstream may be passed through inlet pipe 1135. Pipe
1135 is connected to and in communication with annular con-
duit 116 near its upper end and below tube sheet 1116.
By this means, the remaining portion of said second reactant
stream may fill the interstices between and surrounding
aIl of the tubes in the annular bunch 117 as it freely flows
down through said annular passage 116 and is discharged
through annular orifice 1112 at face 1110 of the burner.
Ignition of the multiphase mixtures of first and second
reactant feedstreams takes place downstream from the face
of the burner.
.
.~ , . ' .
0 4 ~
- 60 -
Wall brackets or tube spacersl~6 hold tubesll7 in
a fixed paxallel nontouching position with respect to each
other and the inside wall of outer conduit115 and the outside
wall of central conduit112. Central conduit~12 and outer
conduitl\5 may be radially spaced by similar means and by tube
sheet nl6.
Cooling coilsll37 through which a coolant flows
encircle the outside downstream end of outer conduit\15.
In another embodiment, a cored water cooled face-
plate including converging nozzles terminating central conduit1t4 and annular passage116 comprises the front portion at,the
extreme tip of the burner, in the manner to be shown and
further described for cored faceplate ~07 in FigurelO of the
drawing.
FIG. 8 is a transverse section through line 8-8 of
the embodiment of the burner shown in FIG. 7. In FIG. 8,
central bunch of tubes113, are enclosed by central conduit112.
The central interstitial cross-sectional area (Ic) surround-
ing a suitable layout of116 parallel tubes in the bundle of
tubes113 is depicted. The reactant feedstream passing longi-
tudinally down through the central passage passes freely
through the interstitial area surrounding the central bunch
of evenly spaced tubesit3. Thus, there is provided thorough
intermixing at the face of the burner of the feedstreams
passing through ~he central bunch of tubes and the central
interstitial area for the central conduit. The annular
bunch of tubes117 in Fig. 8 is represented bylll2 parallel
tubes in a single rina. There may be one to seven concentric
coaxial radially spaced rings of tubes in annular passage~16
'
- ~ 16~0~
- 61 -
and also in the central passagen4. The inside diameter of
all tubes are preferably equal. The reactant feedstream
passing longitudinally down through annular passage~6 freely
flows into the annular interstitial cross-sectional area
(IA) surrounding the evenly spaced annular bunch of tubes~\7.
Thus, there is provided thorough intermixin~ at the face of
the burner1ll~ of the reactant streams freely flowing through
the annular bunch of tubes~17 and the annular interstitial
cross-sectional area surrounding the annular bunch of tubes.
FIG. 9 is a schematic representation of one em-
bodiment of the invention showing control means for rapidly
changing throughput levels of the four feedstreams to the
burner shown in FIG. 7 - up or down over the flow range for
which the burner is designed in order to adjust for a change
in demand for the product gas. Further, another use for the
control system is to maintain the desired composition of the
product gas by adjustments to the flow rates Or one or both
reactants.
By the subject flow control system, the flow rates
for all four of the reactant streams are separately controlled
so that tne atomic ratio of oxygen to carbon in the reaction
zone is maintained within a desired range, and a specified
amount of raw effluent gas is produced.
While the control system shown in Figure 9 is
specifically designed for a solld carbonaceous- fuel slurry,
~ ~ by simple modifications to the means for changing the flow
; rate of the fuel stream it may also control liquid and
gaseous hydrocarbon fuels. These modifications are described
below.
Burner11l, as previously described in Figures 7 and
8, is mounted in centraI flanged inlet1140a located in the
~ 1~2û~
- 62 -
upper head of conventional refractory lined free-flow syn-
thesis gas generator\l41 along the central longitudinal axis.
Burneri~l is designed so that the required system output for
steady-state operation may be achieved or even exceeded by a
specified amount when the flow rate through all passages in
both sections of the two-section burner is a maximum. The
control system can change the flow rate of from one to four
of the reactant streams as required. At the same time the
ratio of oxidant to fuel in both sections of the burner is
kept constant.
The metered feedstream of solid carbonaceous fuel
slurry i.e. coal-water slurry in line\~42 is split into two
feedstreamsll43 andll44 by separate flow control means in each
line. The weight or volumetric rate of flow for the slurry
flowing through each of the feedlines to the burner is a
function of the burner design. For example the burner
passages may-be sized so that one-third of the total quantity
of solid carbonaceous fuel slurry flowing through linell42
may be discharged through central bunch of tubes113 in the
specified velocity range. Simultaneously the remaining
:
two-thirds of the total quantity of solid carbonaceous fuel
slurry is d;ischarged through annular bunch of tubesll7 in the
specîfied velocity range. Valvesll76 andl~77 are normally
open but they may be manually or automatically operated to
completely close off the stream flowing through one or both
of the ~alves. This may be done for example in another
~embodiment to be further described when it is desired to
turn down the burner by operating the burner either in the
central section i.e. central tubesll3 and annular passagell4
or in the outer annular section i.e. annular tubesU7 and
~"' annular passage116.
.. :
.
0 162~
63 -
The portion of the slurry feedstream in linel143is pumped into the reaction zone of synthesis gas generator
1141 by way o~ positive displacement pulTlp11~5 equipped with
speed controlll46, linell47, flow measurer and transmitter~i48,
line~l49, normally open valve1t77 linell50, inletll20 of burner
~lt, central manifold~l9, and central bunch of tubes~3.
The slurry flow rate through linell43 is controlled
by the speed of positive displacement pumpl145. The rate of
slurry flow is measured and a signal a is provided by flow
10 transmitter~l48 corresponding to the flow rate of the slurry
in line1143. Flow recorder-controllerl15l receives signal a
and provides a signal to sp-eed control~146 to adjust up or
down the speed of pumpll45, if necessary so that the charge
slurry flow rate assumes a given vaIue or set point~ By
this means, the adjustment to the rate of flow may be made,
for example, up to 50% of the maximum flow rate for which
the burner was originally designed. The set point flow rate
in each case may be determined by conventional calculations
based on heat and weight balances :Eor the entire system.
20. Alternately, the parameters for said calculations may be
~: ~ measured by conventional detectors and the signals respon-
sive thereto including signal a, for example, may be fed to
an overall control means or computerll40. The computer
c:alculated value or the manually inserted set point for the
desired slurry rate of flow is compared with signal a and
responsive thereto signal c is provided for adjusting the
speed of pumpl145. Signal c may be fed directly to speed
controlll46, or indirectly by way of flow recorder-controller
tl51. Alternately, flow record-controllerllSl may receive signal
~ .
.
1 16~0~
-- 64 --
a from flow transmitterll48 and signal c from control means
1140 and compute the speed adjustment signal for the operation
of speed controll146.
Simultaneously, the remainder of the slurry feed-
stream in line1144 is pumped into the reaction zone of syn-
thesis gas generatorl14l by way of p{:sitive displacement pump
1155 equipped in the speed controll156, linell57, flow measurer
and transmitter\l58, lineU59, normally open valve1l76, line
1160, inletll29 of burnerlll, annular manifoldll28, and annular
bunch of tubesl~7.
The slurry flow rate through line 1144 is controlled
by the speed of positive deplacement pulTpl155. The rate of
slurry flow is measured and a signal d is provided by flow
transmitterll58 corresponding to the flow rate o the slurry
in line\144. Flow recorder-controller~16l receives signaI d
and provides a signal to speed controll\56 to adjust up or
down the speed of pump1155, if necessary, so that the charge
slurry flow rate assumes a given value or set point. By
:
this means,~ the adjustment to the rate of flow may be made,
for example, up to 50% of the maximum flow rate for which
the burner was originaIly designed. Alternately, control of
the slurry flow rate in linell44 may be effected by sending
sigrlal d to control means1140. Signal f from control means
1140 is sent to flow recorder-controller1~6l or directly to
speed control1156 for controlling the speed of pump1155 in the
: manner described previously for controlling the flow rate
, ~
:~ ~ for the slurry in line1143.
~; : Simultaneously, the proper amount of free-oxygen
containing gas in linel162 for the partial oxida`tion o~ the
: ``'''
.
1 162~
- 65 -
related amount of solid carbonaceous fuel slurry flowing in
line1142, is split into two streamsU63 and1164 by flow control
means in each line~ The flow rate for the free-oxygen con-
taining gas flowing through each of the feed lines to the
burner is a function of the burner design. For example, the
burner p~ssages may be sized so that one-third of the total
quantity of free-oxygen gas flowing through line~62 may be
discharged through annular passage1l4 at the specified veloc-
ity range. Valves~165 and\~66 may be manually or automatic-
ally operated to respectively adjust the flow rate in lines
1163 and1l64. For example, an adjustment of up to 50~ of the
maximum flow rate for which the burner was originally de-
igned for may be made.
Simultaneously, the remaining two-thirds of the
total quantity of free~oxygen containing gas is discharged
through annular passagel16 of the second section o~ the
burner in the specified velocity range. ~alvesl~65 andU66
are normally open but they may be manually or automatically
operated to partia~ly close off the stream flowing through
one or both of the valves. In the embodiment to be further
descr~ibed, the burner may be operated in either the central
section or in the outer section hy completely closing re-
spectively valvell66 orl165, while keeping the other valve
open or partially closed. Valves\165 and~66 are normally
operated simultaneously so that the change in the quantity
of flow through linesn63 andll64 is the same. Simultaneously,
adjustments to speed controlsll46 and1\56 a~e made to effect a
corresponding change in the slurry flow rate through lines
1143 andl144. By this means, the O/C atomic ratio in the
reaction zone is maintained at the given value.
,
'
846
-- 66 -
The portion of the free-oxygen containing gas
stream in linell63 is introduced into the reaction zone of
the synthesis gas generatorl~4l by way of flow transmitter
1167, line~l68, normally open valvell65, line1170, and inletl~25
to cen'tral passagell4 of burnerlll. The rate of flow for the
free oxygen containing gas through linell63 is controlled by
valvell65. The rate of flow for the free-oxygen containing
gas is measured and a signal b is provided by flow trans-
mitterl~67 corresponding to the flow rate for the free-oxygen
containing gas in linell63. Flow recorder-controller q74
receives signal b and provides a signal to valvell65 to
adjust up or down, the rate of flow, if necessary, so that
the free-oxygen containing gas flow rate assumes a given
value or set point. By this means, the adjustment to the
rate of flow may be made, for example, up to 50g6 of the
maximum flow rate for which the burner was originally
designed. Conventional or computerized calculations based
on heat and weight balances for the system may be made to
determine the set point, as' previously described.
Simultaneously, the remainder of the free-oxygen
cc>ntaining gas feedstream in linell64 is introduced into the
reaction zone of synthesis gas generator\141 by way of flow
transmitterll71, linell72, normally open valvell66, linetl73, and
inletll35 to annular passage116 of burnerlll. The rate of Elow
for the free-oxygen containing gas through linell64 is
controller by valvel~66. The rate of flow for the free-
oxygen eontaining gas is measured and a signal e is
provided by flow transmitterll71'corresponding to the
~low rate for the free-oxygen containing yas in linell64.
~ 1~2~46
- 67 -
Flow recorder-controllerll75 receives signal e and provides a
signal to valvell66 to adjust up or down, the rate of flow,
if necessary, so that the free-oxygen containing gas flow
rate assumes a given value or set point. By this means, the
adjustment to the rate of flow may be made, for example, up
to 50~ of the maximum flow rate for which the burner was
originally designed.
Alternately, control means~0 may be employed to
control the rate of flow of one or both streams of free-
oxygen containing gas. Thus, signal b from flow transmitter
1~67 and/or signal e from flow transmitter~71 are compared in
control meansll40 with the computer calculated value or the
set point. Responslve thereto signal j and/or h are respec-
tively provided for partially opening or closing valve1165
and/or valveU66. Alternately, flow recorder-controlIerID4
and/or1l75 may receive respectively signals j and h and/or
signals b and e and compute the flow rate adjustment signal
for the operation of valve1165 and/or1~6.
.
In normal operation, all of the valves in the sys-
tem are open so that the fIow through the burner is about
that of Design Conditions. A turndown of 50% of Design Con-
ditions for burner1l~is achieved, for example, by ~imuItan-
eously decreasing the speed~of pumpsi~45 andl155 and partially
closing valves\~65 andU66 so as to reduce by~about 50% the
respective flow rates of both slurry streams in lines~)50 and
: . .
1160 and both streams of free-oxygen containing gas in lines
1170 andll73. Flow control valves1l77 andll76 remain open. The
design value for the ratio of the oxygen atoms in the free-
oxygen containing gas to the carbon atoms in the solid car-
.
bonaceous fuel slurry (O/C atomic ratio) in each section of
the burner and in the reaction æone remains unchanged.
'~ ' '
¢
- 68 -
Speed controls1146 andll56 a~d valves1165 and\K6 may
be operated manually or automatically by control means\~0,
as previously described. The input to flow control means~40
may be manual or a signal from a computer, analyzer, or
sensor. Control means~t40 comprises conventional circuits
and components for providing signals i.e. pneumatic or elec-
tronic to operate said speed controls and valves. The
aforesaid procedure for reducing the total flow through the
burner is applicable only when the discharge velocities for
the various feedstreams do not fall ~elow the flame propaga~ion
tion velocity.
Other ways of turning down burner1l~is by main-
taining flow through either central conduit114, or outer
annular passagel16, and their respective tubes. This turn-
down procedure may be combined with the previously mentioned
procedure in which the flow rate in either or both sections~
of the burner may be reduced, say up to 50%. Either manual
or automatic control may be used to shut off one set of
tubes and its related surrounding passage. By such means,
two other ranges of flow may be obtained. For example, as
shown in FIG. g, one-third of the Design Conditions of flow
through burner1ll may be achieved by only employing central
conduitll4 and the associated central bunch of tubes113. In
such case valvesU77 and~65 are open and valves1176 andll66 are
closed. Valves176 and1166 which are normally open may be
closed manually or respectively by signals g and h from
control meansl140. This rate of flow may be further reduced,
say up to 50% as previously described by now operating speed
control1~6 and partially closing val~ell65. In another
. , .
1 ~620~
-- 69 --
exæTn?le, two-thirds Or the Design Conditions of flow through
burnerlll may be achieved by only employing rlow through
outer annular passagell6 and the ~ssociated annular bunch of
tubesll7. In such case, valves~76 andll66 are open and valves
ll77 and ~65 are closed. valves\l77 and l~65 which are normally
open may be closed manually or respectively by signals i and
j from control means1140. This rate of flo~ may be further
reduced say up to 50~ by now operating speed controlll56 and
partially closing valvel~66.
The size o~ the burner tubes and conduits may be
changed for other splits. For example, in another embodi-
ment, 1/4 of the Design Conditions of flow f`or the fuel and
oYidant streams may be passed through the central tubes and
central conduit and the remaining 3/4 of the Design Condi-
tions of flow for the fuel and oxidant streams may be passed
through the annular tubes and annular passage.
FIG. ~o is a vertical longitudinal schematic rep-
resentation of another embodiment of the sub;ect burner.
Two pre-mix chambers in series are located in the central
conduit and also in the annular passage. The ends of the
central and annular bunches of tubes are retracted upstream
rrom the face of the burner. In FIG. IO, burner280 comprises
central conduit281 which in part constitutes the wall282
between central passageZ133 and coaxial radially spaced
annular passage 284, two rows of a central bunch of parallel
tubes~85 that pass longitudinally through the upper portion
of central passage~83 and having upstream ends~86 that pass
through tube sheet287 making a gastight hermetic seal there-
with, and dowr~stream ends 188 which are retracted upstream
3 ~rom face289 at the downstream end of burner~80, coaxial
concentric radially spaced outer conduit~90 surrounding said
annular passage 284 along lts length, two rows Or annular
-- 70 --
b~lnch Or p2rallel tubes 295 that p~ss longituainally throu~h
an!~ular passage '84 ~ ith u?stream ends 296 passing through
tube sheet 97 and making an ~as,ight seal therewith and
having downstream ends 298 retracted upstream from face ~89,
annular manifold 2100 in communication with the upstream ends
.96 o~ said annular bunch of tubes 295, manifold ~101 which may
be cylindrical-shaped in communication with the upper ends
286 o~ said central bunch of tubes 285, inlet means aO2 for
introducing a first feedstream into said central manifold
10 2101, inlet means2103 for introducing a second feedstream
into said central passage 283 and in the interstices surrounaing
said central bunch of tubes 285, inlet means 2104 for introducing
a third feedstream into said annular mani~old ~100, inlet
means ~105 for introducing a Iourth feedstream into said
annular passage ~84 and into the interstices surrounding the
annular bunch of tubes295, cooling coils ~106 which encircle
the outside diameter of outer conduit 280 along its length,
and cored cooling chamber 2107 at the downstream tip of the
burner.
I isc shaped central tube sheet 2B7 closes off
central passage283 below its upstream end. Similarly,
annular shaped tube sheet 297 closes o~f annular passage 284
below its upper end. Conventional means i.e. welding,
turning, crlmping, threading, rolling may be employed to
provide a pressure and gastight hermetic seal or joint where
the central and annular bunches of tubes penetrate the
respective tube sheets. Mechanical pressure fittings and
coupling devices may be also employed.
Plate 2108 which may be disc-shaped seals off the
3 upper end of central conduit~f31. The space between plate
2108 and tube sheet ~87 constitutes said central manifold ~101.
13y this means, ~or example, a portio~l o~ a ~irst reactant
feedstream in ~eed pipe 2102 may be introduced into central
9 ~82~
1 ~L62~6
- 71 -
manifold2101 and then split into a plurality of streams
which pass through tube sheet287 and the individual tubes
in central bundle285. Annular shaped disc2109 seals off
the upper end of annular passage284. The space between
annular disc ~09 and annular t~be sheet~97 constitutes annular
manifold2100. Simultaneously and concurrently with the
introduction of the first reactant feedstream, the third
reactant feedstream in feed pipe2104 may be introduced into
annular manifold~100, split into a plurality of streams which
pass through tube sheetl97 and the individual tubes in annular
bundle~95.
Wall brackets or tube spacers2115 hold the in-
dividual tubes in annular tube bundle~95 in a fixed parallel
nontouching relationship with respect to each other and the
inside of outer conduit290. Similarly, wall brackets or
tube spacers2116.hold the individual tubes in central tube
bundle285 in a fixed parallel nontouching relationship with
respect to each other, the inside diameter of central conduit
~81, and the outside diameter of central conduit281.
While the pre-mix zones i~ the embodiment in FIG.
l~ are shown as comprising two separate coaxial central pre~
.
mix chambers U17 and ~18 in series in central conduit~83,
and two separate coaxial annular pre-mix chambers ~19 and
~: 2120 in series in annular passage~84, the pre-mix zone of
other embodiments of the subject invention may actually
comprise one or more, such as 2 to 5 coaxial central and/or
annular pre-mix chambers~ Each central pre-mix chamber,
except for the first chamber in the line, comprises a coaxial
cylindrical body portion ~21 followed by a coaxial at least
. , .
- 72 ~ 2~4~
partially converging frusto-conical outlet portion ~22 that
may optiorally develop into a normal cylindrical portion
2123. This outlet portion is shown in FIG.~o as a converging
. central nozzle ~24 which terminates at the downstream face
of the burner. Optionally, nozzles 124 and'133 to be further
described may be made from a thermal and wear resistant
material i.e. silicon carbide or tungsten carbide.
The first central pre-mix chamber in the line may
have a straight coaxial cylindrical body portion ~25, that
discharges through circular orifice~l26 directly into the
next in l;ne central coaxial pre-mix chamber ~18. Pre-
ferably, the inlet to the first central pre-mix chamber21I7
is a portion of a converging frusto-conical shaped section
U27.
Each of the coaxial annular shaped pre-mix chambers
2120 except the first annular shaped chamber7119 comprises a
coaxial generated normal cylindrical annular body portion
~30 followed by a coaxial generated at least partially
converging frusto-conical shaped annular outlet portion~l31
that may optionally develop into a coaxial generated normal
cylindrical annular portion2132. This outlet portion is
shown in FIG.lO as a converging annular exit nozzle ~33
which terminates at the downstream face of the burner. The
first coaxial annular shaped pre-mix chamber ~19 comprises a
coaxial generated normal cylindrical annular body portion
- ~34 that discharges through annular orifice ~35 into the
next in line coaxial annular shaped pre-mix chamber2120.
Preferably, the inlet to the first annular shaped pre-mix
chamber2119 comprises a portion of a coaxial generated con-
verginy frusto-conical shaped section2136.
~ ~20~
- 73 -
Cored faceplate2107 comprises a front portionll37
at the extreme tip of the burner, which may be flat or
curved, and which contains a coaxial central annular shaped
cooling cham~er2138 surrounding the central condui, e~it
nozzle2124 and/or a coaxial radially spaced annular shaped
cooling chamber2139 surrounding said annular exit nozzle ~33
at the tip of the ~urner. The cooling chamber may be joined
to the otherwise flat ~urner tip such as shown in FIG. 7, or
it may be an extension of the central and outer conduits.
Cold cooling water in line2140 enters annular shaped cooling
cham~er2139, splits by means o~ baffles and flows about
180, and leaves by way of an opposite outlet which is con-
nected to outer coils2106. Cooling water is introduced into
central annular cooling chamber2138 by way of line ~45 which
is connected to passage2146 that passes longitudinally down
through wall~82 in central conduit281. The cool water
splits by means of baffles, flows about 180 around central
cooling channel~l38, and leaves by way of an opposite coaxial
longitudinal passage ~not shown) similar to passage 146 but
2D in another location in wall~82.
Optionally, a gaseous feedstream selected ~rom the
group consisting of steam, free-oxygen containing gas, CO2,
N2, fuel gas, recycle portion of the product gas, and
mixtures thereof may be introduced into at least one of the
~central and/or annular pre-mix chambers by way of at least
one inlet pipe ~49 which is connected to at least one longi-
tudinal passage ~47 in wall~82 of central conduit281, and ~t
least one branch passageZ148 connecting longitudinal passage
,:: , ':
147 with said pre-mix chambers.
:
l 1~2~8
- 74 -
Figure 11 shows a further embodiment which is equiv-
alent to the construction described above with reference
to Figures 1 and 2, with the exception that the inner central
conduit 15 is replaced by a central bundle of helical tubes
15'. The same reference numerals have been used for equiv-
alent features in the construction of Figures 1 and 2 and
the corresponding construction of Figures 11 and the follow~
ing description of the latter construction will be confined
; to the features of that construction which differs ~rom the
construction of Figures 1 and 2.
In Fig. 11, one embodiment of the swirl burner is
shown in diagrammatic longitudinal cross-section. This
view comprises unobstructed central coaxial retracted central
bundle o~ helical tubes 15' which is surrounded by outer
concentric coaxial conduit 16. One coaxial concentric ring
of two helical coils is shown. Spacing and supporting means
18 may provide a plurality of related free-flow helical-
shaped passages 17 in the cylindrical space surrounding
the central bundle of helical tubes 15'.
In another embodiment, not shown, the inlets~ and
outlets of the separate helical coils in central bundle
of helical tubes 15' are located at the intersections of
a plurality of coaxial concentric rings and a plurality
o~ evenly spaced radial rows. The sides of the helical
: G~ ~ coils in adjacent concentric rings may or may not touch.
By this means the feed stream entering outer conduit 16
~;~ by~way of inlet 8 may pass down through a plurality of heli-
cal passages or into the interstices between the helical
coils.
~ E~it orifices 20' at the downstream~tips of the plur-
ality of helical coils 19 in the central bundle of helical
tubes 15' preferably are circular in cross-section and ter-
`minate in a plane perpendicular to the longitudinal axis
of the burner. Outer conduit 16 terminates at the down-
stream end of the burner with converging nozzle 21.
In the operation of the burner as shown in Fig. 11,
; either reactant stream i.e. see Table II supra, may enter
: `,i~ ~; :
:
1 ~20~
- 75 -
the burner by way of inlet 9 and pass directly into central
manifold 25a. Central manifold 25a is a closed cylindrical
chamber comprising upper closed head 26 and lower tube sheet
27. The upstream open ends 28 of the plurality of helical
coils 19 pass perpendicularly through tube sheet 27 and
make gas-tight hermetic seals therewith. By this means,
the upstream ends of helical passages 17 in outer conduit
16 are closed.
The feed stream in central manifold 25ais split into
a plurality of streams which swirl down through the plurality
of free-flow helical coils 19, out through exit orifices
20, and into pre-mix zone 25, as shown in Fig. ll~ Simul-
taneously and concurrently, the second reactant stream enters
the subject burner by way of inlet 8 and is split into a
plurality of streams which swirl down from the upstream
portion 30 of oute~ conduit 16 through the plurality of
free-flow helical passages 17 or down through the interstices
between individual spaced helical coils, or both. The two
reactant streams impinge in pre-mix zone 25 where intimate
mixing of the streams takes place. Further, direct heat
exchange between the two reactant streams takes place in
pre-mix zone 25. The temperature in the pre-mix zone is
controlled so that a controlled amount of the liquid carrier
may be vaporized without burning i.e. from 0 to 100 vol.
% say about 2 to 80 vol. %. Temperature control in the
pre-mix zone may be
:
,
:
0~ 6
- 76 -
e~fected by controlling such factors as dwell time and heat
content Or the entering streams, and amount of external
cooling such as by coils 4, if any. Pre-mix zone 25 is
substantially free from any obstruction to the free-flow of
the materials passing therethrough.
The veloclty of the slurry of solid carbonaceous
fuel in liquid carrier passing through exit orifices 20
of the central bundle of helical tubes 15'or alternately
exiting from passages 17 is in the range of about 5.0 to
100 ft. per sec., such as 10 to 50 ft. per sec., say about
2 to 20 ft. per sec. The corresponding velocity for the
free oxygen containing gas simultaneously passing through
the other passage in the burner optionally in aamix;ture with--
steam, is in the range of about 150 feet per second to sonic
v~elocity, such as about 100 to 600 ft. per sec., say about
2~0 to 500 ~t. per sec. The slurry of solid carbonaceous
fuel in liquid carrier enters the pre-mix zone in liquid
phase at a temperature in the range of about ambient to
500F., and below the vaporization temperature of the liquid
; ~ 20 carrier. The pressure may be for example in the range o~ about
76 to 4500 psia. While simultaneously, the free-oxygen
containing gas stream, optionally in admixture with steam,
enters into the pre-mix zone at a temperature in the range
of about ambient to 1200F., say about 100 to 600F., and
at a pressure in the range of about 76 to 4500 psia.
Intimate mlxing and direct heat exchange takes place between
the two reactant streams in the pre-mix zone. Volatilization
of the liauid carrier in the ?re-mix zone ~ay amount to abcut
0 to 100 vol. %, say about 20 to 35 vol. ~0 when the free-
oxygen containing gas is introduced at a temperaiure in
the range of about 300 to 600F., or from about 70 to 100
I 16204B
- ~7 -
vol. % when the free-oxygen containing gas is introduced
as air preheated to a temperature in the range of about
1000 to 1200F. The multiphase mixture in the pre-mix ~one
is at a temperature below its autoignition temperature.
The multiphase mixture leaves burner 1 by way of exit orifice
21 at a discharge velocity in the range of about 75 to 600
ft. per sec., say about 150 to 350 ft. per sec., and above
the flame propagation velocity and passes downwardly directly
into the unobstructed reaction zone of the partial oxidation
gas generator.
The downstream end of outer conduit 16 as shown in
Fig. 11 may, in another embodiment, have the form as shown
in Fig. 3 as described above with reference to those Figures.
As shown in Fig. 12, in a further embodiment, at the down-
stream end of outer conduit 16 as shown in Fig. 11, theexit nozzle 35, which is made from a wear resistant material
such as tungsten carbide or silicon carbide, comprises a
frusto-conical converging rear portion 22 which develops
into a frusto-conical diverging front portion 23. The frusto-
conical converging outside diameter of exit orifice 35 issupported by coaxial ~rusto-conical mating converging cavity
36 in annular cooling chamber 2. For example, exit orifice
35 made from tungsten carbide may be connected to the down-
stream tip of outer conduit 16 by joining the back surface
37 of cooling chamber 2 to the front surface of end flange
38 at the downstream end of outer conduit 16. Cooling water
may be introduced into cored section 24 of cooling chamber
2 in the manner shown for inlet pipe 3 in Fig. 1. Optionally~
a cooling coil may encircle outer conduit 16 in the manner
shown for coil 4 in Fig. 1. Hot high velocity slurries
of solid fuel are abrasive. The life of the subject burner
may be considerably extended by making exit nozzle 35 from
; a wear resistant material.
Fig. 13 is a vertical longitudinal schematic represen-
tation of another embodiment of the subject swirl burnerbut with the additon of pre-mix and high turndown features.
This construction corresponds in many respects to the
1 1~20~B
- 78 -
construction shown in Fig. 10 and like reference numerals
have been used for similar parts which will therefore not
be described again in detail. Two pre-mix chambers in series
are located in the central conduit and also in the annular
passage. The ends of the central and annular bundles of
helical tubes are shown retracted upstream from the face
of the burner. The burner may be operated with feed streams
passing through either the central, annular, or both bundles
of helical tubes and through the plurality of helical pas-
sages in the related conduits surrounding said bundles oftubes. By this means, flow through the burner may be turned
up or down. In Fig. 13, burner 280 comprises a central
section and an annular section. The central section is
similar to the embodiment shown in Fig. 11. A central bundle
of helical tubes 285' passes down through the upper portion
of cent~al passage 283. The central section of Fig. 13
includes a single coaxial concentric ring, with two helical
coils 289. However, the central sections of other embodi-
ments may include a plurality of coaxial concentric rings
containing a plurality of helical tubes. Upstream inlets
286' of helical coils 289 pass through tube sheet 287 and
make a gas-tight hermetic seal therewith. These inlets
are shown lying in two radial rows spaced 180 apart. Down-
stream ends 288' are retracted upstream from face 2137 at
the downstream end of burner 280. Supporting and optionally
spacing means 218 may provide a plurality of related free-
flow helical-shaped passages 217 in the cylindrical space
surrounding the central bundle of helical tubes 2~5'.
In the annular section of burner 280, coaxial con-
centric radially spaced outer conduit 290 surrounds annular
passage 284' along its length. An annular bundle of helical
tubes 295' passes down through annular passage 284' and
comprises four coaxial concentric rings of helical coils
~95'. Only two of the plurality of radial rows are shown.
Further, two of the plurality of helical coils are shown
in each concentric ring for illustrative purposes only.
For clarity~our of the helical coils have been cut-off near
~ "
- \
~ ~8~04~
- 79 -
the upstream inlets. The actual number of helical coils
in a concentric ring is a function of pipe size, ring diam-
eter, and spacing between radial rows. Spacing and support-
ing means 291 may provide a plurality of related free-flow
helical passages 292 in the annular space surrounding the
annular bundle of helical tubes 295i. Upstream inlet ends
296' of concentric helical coils 295' pass through tube
sheet 297 and make gas-tight seals therewith. Downstream
tube outlet ends 298' are shown retracted upstream from
face 2137. In another embodiment (not shown) in which there
are no pre-mix chambers in annular passage 284', the down-
stream ends 298' of helical coils 295' may be flush with
burner face 2137. Annular manifold 2100 is in communication
with the upstream ends 296' of said annular bunch of tubes
295'. Manifold 2101, which may be cylindrical-shaped, is
in communication with the upper ends 286' of said central
bunch of tubes 285'.
Inlet means 2102 is employed for introducing a first
feed stream into said central manifold 2101. Inlet means
2103 near the upstream end of central conduit 282 is used
to introduce a second feed stream into the upstream end
of central passage 283 and from there into the helical pas-
sages and/or interstices surrounding central bunch of tubes
285'. Similarly, inlet means 2104 is employed for introduc-
ing a third feed stream into annular manifold 2100. Inletmeans 2105, near the upstream end of outer conduit 290 is
used to introduce a fourth feed stream into the upstream
end of annular passage 284' and from there into the helical
passages and/or interstices surrounding the annular bunch
of tubes 295'. Optionally to provide additional swirl,
; inle-ts 2103 and/or 2105 may be oriented so that the second
and fourth feed streams may be respectively introduced tan-
gentially into central conduit 281 and outer conduit 290.
Optionally, inlets 2102 and/or 2104 may be oriented so that
the first and third feed streams may be respectively intro-
duced through the top of manifolds 2101 and 2100. Wall
brackets or tube spacers 291 hold the individual tubes in
I ~B2~46
- 80 -
annular bundle of helical tubes 295' in a fixed touching
or non~touching relationship with respect to each other
and the inside of outer conduit 290. Similarly, wall brackets
or tube spacers 218 hold the individual tubes in central
bundle of helical tubes 285' in a fixed touching cr non-
touching relationship with respect to each other and the
inside diameter of central conduit 281.
While the pre-mix zones in the embodiment in Fig.
13 are shown as comprising two separate coaxial central
pre-mix chambers 2117 and 2118 in series in central conduit
283, and two separate coaxial annular pre-mix chambers 2119
and 2120 in series in annular passage 284, the pre-mix zone
of other embodiments of the subject invention may actually
comprise one or more, such as 2 to 5 coaxial central and/or
annular pre-mix chambers as described above with reference
to Fig. 10.
~ odifications and variations of the above described
embodiments may be madewithin the spirit and scope of the
invention as defined in the appended claims.
:
:: :
.
