Note: Descriptions are shown in the official language in which they were submitted.
7~9
_ELD OF THE INVENTION
This invention relates to a dry method and apparatus for
recovering hydrocarbons from a mater;al such as oil sand.
BACKGROUND OF T~E INVENTION
As is further discussed below, the invention is not limited
in application to oi.l sand; however it has been developed in connection
with the treatment of such material and therefore the following disclosure
describes it in connection with that particular feedstock.
Whole oil sand is a material whose composition and characteristics
have direct influence on the design of apparatus and method for treating
it. It's composition includes granular mineral solids, water and bitumen.
The granular solids comprise coarse solids,~mainly sand having particle
sizes in the range 80 - 200 mesh) and fine solids (mainly clay having
particle sizes less than about -44~). The whole oil sand further comprises
rocks, ranging from pebbles to boul~ers, and cohesive lumps of granular
solids. In winter, the whole oil sand, which is mined by huge draglines
or rotating bucket wheels, commonly reports in the form of frozen chunks -
S~weighing in the order of two tons. In summer, the as-mined material
reports as a sticky mass which is diff-icult to screen to remove the over-
size rocks and lumps. When used herein, the term "whole oil sand" means
this as-mined material, although it may have been subjected to pre-
liminary rough screening or the like to remove easily separable large
boulders.
Oi~l sands are today commercially treated with what is commonly
known as the hot water extract;on process. This process involves first
conditioning the whole oil sand by mixing it with steam and some hot water
for a period of time in a horizontal rotating drum. With heat and dilution,
the solid and hydrocarbon components of the oil sand separate to an ex-
tent which permits oversize material to be removed by screening. The
product is then diluted with hot water and introduced into a settling
tank. Here the coarse sand settles out and is discarded as an underflow.
The b;tumen, attached to air bubbles incorporated in the mixture in the
conditioning drum, floats as a froth and is recovered. A dragstream -
containing mainly water, some non-floatable bitumen, and fine solids -
is drawn from the centre of the tank. This dragstream is treated in a
sub-aerated flotation cell to produce a contaminated bitumen froth and a
watery underflow. The underflows are combined and discarded; the froths
- 3 --
~,'æ~ ~L~
There are presently two commercial plants of this type in
operation in Canada. The second-built plant is des;gned to produce about
125,000 barrels of net synthetic crude per day and its construction cost,
including the mining and upgradin9 facilities, was in the order of several
billions of dollars.
There are a number of disadvantageous features, of interest with
respect to this invention, which characterize the hot water extraction
prc~cess. For example, it uses enormous quantities of water. Since it
is intended to produce a million or more barrels of product per day~from
the Canadian oil sands, the pressure on the finite water supplies in the
oil sand area is a serious problem. Secondly, the wet tailings produced
have to be retained for years in gigantic diked ponds before the water in
them ;s sufficiently clean to be re-used in the process. This is because
the clay particles suspended in the water are very slow to settle out.
Thirdlyg the need to heat process water and produce steam consumes some
of the hydrocarbons produced. Fourthly, there is a need to upgrade the
bitumen with an on-site refinery before it can be pumped, due to its high
viscosity.
With these disadvantages in mind, it has heretofore been
proposed to pyrolyze the oil sand using a solid carrier to provide the
heat. More particularly, this "dry" scheme contemplates mixing oi~l sand
with hot recycled sand, thereby effecting heat transfer and vaporizing
and cracking bitumen and producing coked sand. The coke on the coked
sand is subsequently burned to heat the sand so that it may be recycled
to the heat transfer operation.
This dry scheme reduces water consumption and disposal. It
has the possibility of yielding higher liquid hydrocarbon recoveries
than the hot water process including refining. Furthermore, it will
yield a less viscous l;quid product which will be more easily
pumpable than the hot water ~ product.
This invention is concerned w;th a novel dry processor and
with the process performed in it.
- 4 -
li~l7~9
The present processor has been developed w;th the following
criteria in mind. It should be capable of doing the following:
l. processing whole oil sand without or with minlmal prior
screening;
2. converting whole oil sand into a form from which oversize
rocks may be separated and rejected and then mak;ng such
a separat;on;
3. reducing the size of lumps of oil sand so that at least some
of them become part of the normally processable feed~stream,
4. heating the mater;al ;n stages so as to vaporize the water
and hydrocarbons in different zones, with the result that
they may be separate1y recovered and thus do not contaminate
each other to an undesirable extent;
5. vaporizing and crack;ng hydrocarbons so that they may be
w;thdrawn and collected in a desirable product form,
6. conserving energy by burning coked sand to provide some,
if not all, of the heat needed for the process in the form
of hot sand, from which-heat may be extracted by heat
transfer;
7. eFficiently recovering heat from recycled hot sand to
further conserve energy, and
8. carry;ng out these operat;ons in a s;ngle processor unit
which is capable of maintaining substantial segregation
of the gaseous atmospheres in the various zones where
clifferent operations are simultaneously progressing.
Bennett, in United States Patent No. 3,481,720, describes a
dry thermal processor which meets some, but not all, of these objectives.
This processor was developed in connect-ion with treating oil shale, but
the patent states it has utility for oi:l sand as well. The Bennett unit
comprises rotatable, horizontal, concentrically arranged, spaced inner
and outer tubes having first and second ends. The inner tube provides a
preheat zone at its first end and a vaporization zone at Its second end.
The annular space between the tubes is divided into a combustion zone at
the second end and a heat-transfer zone at the first end. The feed is
pre-crushed and then advanced through the pre-heat, vaporization, combustion
and heat-transfer zones sequentially and undergoes different processes
- 5~ L'7~ 1
(a) Feeding crushed raw Feed stock into the pre-heat zone. Here
the feed ;s heated to about 200 ~ 300F by heat exchange,
through the inner tube wall, with hot gases assoc;ated wlth
hot solids advancing through the heat-transfer zone of the
annular space. By preheatlng the raw feed, conta;ned moisture
is converted into steam, which is recovered through a pipe
extending into the preheat zone;
(b) Mixing the preheated feed with hot recycled solids in the
vaporization zone and efFecting heat exchange through sollds
contact to produce a mixture having a temperature in the
order of 900F. As a result of this operation, contained
hydrocarbons are volatilized, so~e are cracked, and the
gaseous products are recovered:from the zone through a pipe
extendlng thereinto - also, coked solids are left as a
residue 9
(c) Transferring the coked solids into the combustion zone and
mixing them with injected air to efFect combustion of the
coke and raise the temperature of the solids tn 1400 -
: 1600F;
(d) Recycling a portion of the hot solids produced in thecombustion zone into the vaporization zone to heat the
preheated solids and advancing the balance of the hot
solids past the recycle point and through the heat-exchange
zone, to heat the wall of the inner tube and thus the
solids contained therein ;n the preheat zone, and
(e) Discharging the sol1ds from the first end of the heat-
exchange zone to waste.
Bennett teaches the use oF augers to advance the solids through
the inner tube and back through the annular space. The augers are welded
around their inner and outer circumFerences to the relevant containing
tube. By a combination of these augers and a chokin~ aotion uslng feed
solids ~achieved by varying the pitch of the augers), Bennett segregates
the preheat zone gases, the vaporization zone gases and the combustion
zone gases from each other.
~z~
With respect to the objectives previously set forth, ;t will
be noted that Bennett relies on:
(1) Augers ko move the material. This requires that the feed
stock be of generally uniForm part;cle size. Bennett
achieves this by requiring crushing of the feedstock be-
fore it is introduced into the processor;
(2) The augers and solids choking to achieve segregation of
the gaseous atmospheres; and
(3) The use of gases in the heat-transfer zone to conduct
heat from the recycled hot solids in the zone to the
wall of the inner tube for conductance throu~h the wall
to the solids in the pre-h,eat zone.
SUMMARY OF THE INVENTION
The present inventlon prov;des a dry processor in which features
have been combined to enable the unit to successfully process whole oil
sand.
Like Bennett's unit, the present processor comprises spaced,
substantially horlzontal, generally concentric inner and outer tubular
members having first and second encls. The members are connected for
rotation together and means are provided for rotatably supporting them and
sealing the ends of the outer member and the first end of the inner member.
Further means are provided for rotating the members. The inner tubular
member provides a preheat zone at its first end and a vaporization zone
at its second end. The annular space between the rnembers comprises a
combustion zone at its second end and a heat-tra~lsfer zone at its first
end. Means are provided for feeding whole qil sand into the preheat zone.
Means are also provided for removing water vapor from the preheat zone.
Further means are provided for advancing oi~l sand solids through the
preheat and vaporization zones and back through the combustion and heat-
transfer zones. Means are provided for removing h~drocarbon gases from
the vaporization zone. Means are also provided for transFerring coked
sol;ds from the vaporization zone to the combustion zone, sa;d means
cooperating with the coked solids to prevent significant gas movement
therethrough between these zones. Further means are provided for intro-
ducing oxygen~containing gas into the combustion zone to react with the
'coke and effect combustion. Means are further provided for removing
combustion gases from the annular space. Means are also provided for
recycling a portion of the hot solids produced in the combustion zone
back into the vaporization zone, said means cooperating with the hot oil
sand solids to prevent significant gas movement therethrough between
the annular space and the vaporization zone. Further means are provided
for remoYing oil sand solids from the heat-transfer zone for disposal.
However, the invention is characteri2ed by incorporating into
this prior combination at least some of the following novel features:
(1~ the preheat and vaporization zones are substantially
open spaces, as are the combustion and heat-transfer zones;
(2) separate suction means, which may comprise a fan and
conduit means, are provide'd to withdraw gases from each
of the preheat, combustion and vaporization zones, with
the greatest suction preferably being drawn on the vapor-
izationizonej
(3) means are provided in the preheat zone for advancing, lifting
and mixing the whole oil sand solids by a cascading action
to effect size reduction of the oil sand lumps,
(4~ means are also provided, at the second end of the preheat
zone, for separating oversize solids from the oil sand
being treated and removing them from the zone, preferably
for discharge into the heat-transfer zone whereby they
may subsequently be carried to waste;
(5) means are also provided, downstream of the rock removal
means and between the preheat and vaporization zones for
restricting the movement of gases between the zones while
permitting de-rocked oil sand to be rnoved therebetween;
(6~ means are carried by the outer tubular mennber in the
heat-transfer zone for lifting hot solids advancing from
the combustion zone and dropp;ng them onto the outer surface
of the wall of the preheat portion of the inner tubular
rnember to effect heat transfer at a desirable rate
through the wall, with the result that heat.i$ effi~iently
transferred from the hot solids to oii sand proceeding
through the preheat zone; and
(7) means are provided at the first end of the outer tubular
mQmhQ~ f~r ~l;nn ~n~ ~mnQn;n~ th~Q hot sand solids as thev
4~
located in the annular space, exterior of the processor
or in both of these locations.
The processor as described operates in the following manner.
.
- 9 ~
Whole oil sand (from which easily separable large boulders
and -the like may have been removed by a preliminary screening operation)
is introduced into the preheat ~one of the rotating inner tubular member.
Here the oil sand is heated, preferably to a temperature in the order of
450F, while it is cascaded due to the rotation of the conta;n;ng wall.
Substantially all of the contained water is vaporized and withdrawn off
by means such as a suction fan and conduit. At the same time, lumps
of cohesive oil sand are worked and reduced in size by the combination of
bitumen viscosity reduction and thawing of frozen lumps due to heating, and
cascading, arising from rotat;on of the inner member. Upon reduction of the
bitumen viscosity~ oversize rocks and remaining lumps of oil sand may
now be separated from the preheated feed by a sc~eening operation, which
is conducted at the second end of the preheat zone. These rocks are
remo~/ed to reduce damage to the processor seals and to avoid piugging of
downstream components. Thus, in summary, preheating of sand and bitumen,
water vaporization and removal, ablation of lumps, and oversize separation
and rejection are effected in the preheat zone.
The remaining oil sand ;s then advanced through the aforementioned
means which permit solids movement from the preheat zone into the vapor-
ization zone, but which restrict gas movement therebetween. Such means
may comprise a wall extending transversely across the bore of the inner
member at the interface of the preheat and vaporization zones, said wall
being apertured around its periphery. The solids and gases both can
move through these apertures, but the gas movement is somewhat restricted,
relative to what it would be if there were no wall in place. The reason
for restricting the gas flow i5 clarified below.
On entering the vaporizat;on zone, the preheated oil sand
(typically having a temperature in the order of 450F) is mixed with
recycled hot solids from the combustion zone (typically having a temperature
in the order of llOO - 1300F) to produce a product typically having a
temperature in the order of 900 - 1050F. Mixing is obtained in the
vaporization zone by a gentle nlixing or cascading action prQduced Qn the soli`ds
by rotation of the inner member in cooperation with the advance elements.
As a result of heating of the oil sand, the ~itumen volatiles are vaporized,
some cracking takes place~ and-coked sand is left as the solids product.
The gaseous hydrocarbons are withdrawn from the vaporization zone by
suitable means, such as a fan and conduit. The major portion of these
hydrocarbons may subsequently be condensed in suitable apparatus to
- 1o- ~ Lr~L~
Coked solids are transferred from the vaporization zonP into
the combustion zone. Here an oxygen conta;n;ng gas, such as air, is
introduced and thoroughly mixed with the coked sol;ds to support col,m,-
bustion. Additional heat may be introduced with a burner. As a result,
the solids are raised in temperature, for example to 1100F - 1300F.
The hot solids from the combustion zone are then advanced
through the annular space. A part of these solids is recycled into the
vaporization zone. The balance of the solids enters the heat-transfer
zone, where it is lifted and dropped onto the surface of the pre-heat zone
section of the inner member wall. This solid-to-solid contact results
in efficient heat transfer to the wall. The transferred heat is
conducted through the wall to provide the heat rèquirements for raising
the temperature of the oil sand passing through the preheat zone.
Means, such as a fan and conduit, are used to withdraw
combustion gases from the annular space.
The extent Of suction drawn separately on each of the annular
space, the pre-heat zone, and the vaporization zone is preferably con-
trolled to maintain slight pressure differentials between them, thereby
ensuring that a small amount of outside air i5 drawn through the sealing
means into the annular space, a small amount of the gases in the annular
zone is drawn into the preheat zone, and a restricted amount o~ the gases
in the preheat zone is drawn into the vaporizaton zone through the apertures
of the restrictive wall. In this manner, migration of hydrocarbon gases
into the pre heat zone and the annular space is substantially prevented.
As a result, the preheat zone may be open to accommodate whole oil sand
feed; the heat-transfer zone may be open so that lifters may be in-
corporated therein to effect solid-to-solid contact of hot sand with the
inner member wall; and the vaporizaton zone may be open so that adequate
mixing by cascading is obtained therein to ensùre eFficient heat transfer.
Broadly stated, the invention comprises an apparatus for
recovering hydrocarbons from whole ail sand containing sand and clay
solids in discrete and lump Forms, water, bitumen and oversize rocks. Said
apparatus comprises spaced, substantially horizontal generally concentric
inner and outer tubular members having first and second ends, said ~embers
being connected to rotate together, said inner member -forming substantially
open pre-heat and vapori~ation zones at its first and second ends
respectively, said members combining to form a substantially open annular
_____ L~ m~ t +~n 7~ t thQ c~rrln~l Pnrl th~Y~Pr~f ~nrl
7'~9
supporting the members; means for seal;ng the ends of the outer member
and the first end of the inner member; means for rotating the members;
means for feeding whole oil sand into the preheat zone; means for advancing
Ojl sand solids along a path extending through the preheat and vaporization
zones and back through the combustion and heat-transfer zones; said outer
member carrying means in the heat-transfer zone for lifting hot
sand solids being advanced therethrough and dropping them onto at least
part of that section of the wall of the inner member which forms the
preheat zone to cause heat to be transferred through such wall section,
whereby water in the whole oil sand may be vaporized in the preheat zone
and whereby lumps of oil sand may be reduced in size by a comb;nation
of heating and cascading effected by rotation of the inner member; first
means for removing water vapor from the preheat zone; means
for separating oversize solids from the whole oil sand belng advanced
through the preheat zone and transferring them into the annular space
for disposal; means carried by the inner member for restricting gas
movement between the preheat and vaporization zones while permitting
remainlng preheated oil sand to be advanced from the preheat zone into
the vaporization zone; means for recycling hot sand soli.ds, be;ng
advanced through the annular space, into the first end of the vaporization
zone for mixing with oil sand issuing from the preheat zone to raise its
temperature and thereby vaporize and crack hydrocarbons and produce coked solids ,
said means cooperating with the hot sand solids to prevent significant
gas movement therethrough between the annular space and the vaporization
zone; second means for removing gases from the vaporization zone for
recovery; means for transferring coked solids from the vaporization zone
-to the combustion zone, said means cooperating with the coked solids to
prevent significant gas movement therethrough between said zones; means
for introducing oxygen-containing gas ;nto -the combus-tion zone for burning
coke to produce hot sand solids; third means for drawing combustion
yas from the annular space for disposal; and means for removing sand
solids from the heat trans~fer zone for disposal.
p (` ~
In ~ he~ aspect, the invention broadly comprises means for
.~ .
controlling said first, second and third means whereby the pressure in
the vaporization zone is less than that in the preheat zone and annular
space.
In another broad aspe.ct,.the.lnvention compri:ses a method
for reccvering hydrocarhons; from whole oi1 sand containing sand and
cla~ in d;.scre.te and lump forms., water, bitumen and oversi:ze so'lids,
usi'ng a processor whi`ch comprises rotata61e i`nner and outer spaced
S tubular members, having flrst and second ends:, said outer member being
sealed at i:ts ends and said ;nner member bei:ng sealed at its f;rst end,
said i.nner member providing an open preheat zone at its first end and
an open vapori:zati:on zone at its second end, said members combining to
forrn an open substantiall~ annular space havi'ng a combustion zone at its
second end and a heat transfer zone at i`ts fi`rst end. The method comprises
advancing the whole oi:l sand th.rough the pre-heat zone and cascading
it therein whi:le heati:ng ;t 6y heat transfer through the wall of the inner
member to vaporize subs.tanti.ally all ~he water, ~ithout significant vapori-
zati.on of hydrocarbons, and to effect s;ze reducti:on of oil sand lumps,
separating and removi:ng oversi:ze solids at the second end of the pre-heat
zonei advanci:ng the remaining pre-heated oil sand through the vaporization
zone while further heati:ng i.t by mix;.ng i:t with hot recycled solids. to
vapori.ze and crack hydrocarbons and produce coked solids; removing the
greatest part of the water and the greatest part of the hydrocarbon vapors
separately.from the processor; trans.ferring coked soli.ds from the vaporizationzone i.nto the combusti'on zone, burn;:ng at least part of the coke on the
coked so'lids in the combusti.on zone to heat the solids and removing
combust;on gas.es produced from the processor; advanc;ng combusti:on-heated .
solids from the comb.us.tion zone to the heat-transfer zone; recycl;ng part
of the combus.tion-heated soli:ds into the vaporization zone to heat the pre-
heated tar sand; advancing combusti.on-heated solids through the heat-transfer
zone and li.fting sai.d s;oli`ds and dropping them onto the wall of that portionof the inner member forming the pre-heat zone to transfer heat through
s.ai.d w.all; removing combustion-h.eated s.olids ~rom the processor as they
complete. th.ei:r travel through th:e hea.t transfer zone.; and mai.ntai:n;ng the
gaseous atmospheres i'n th.e pre-heat and vapori.zati:on zones and the annular
space s:ubstanti.`ally segregated one from another.
,~,,.~
- lla -
DESCRIPTION OF THE DRAWINGS
Figure 1 is a flow sheet of the process and apparatus of the
present invention;
Figure 2 is a schematic drawing of the processor illustrating
the flow of solids therethrough;
Figure 3 is a schematic drawing of the processor illustrating '.
the preferred flow and removal of the gases produceci;
Figure 4 is a sectional v;ew~ taken along line 2-2 of Figure 9, .
showing the main features of the processor;
Figure 5 is a fragmentary perspective view of the closely
packed advance plates and keying elements in the preheat zone;
Figure 6 is a fragmentary perspective view of the advance
plates and mixing spikes in the vaporization zone;
Figure 7 is a fragmentary perspective view of the flat-face
lifters in association with the advance elements used in the combustion
zone,
Figure 8 is a fragmentary perspective view of the cup-faced
lifters and advance elements used in the heat-exchange zone,
Figure 9 is an end on view , partially in section, of the
feed end structure of the processor;
Figure 10 is a cross sectional view taken along line 10-10
of Figure 4, of the preheat and heat-transfer zones;
Figure 11 is a cross sectional view, taken along line 11-11
of Figure 4, showing the oversize removal rneans;
Figure 12 is a fragmentary perspective view oF the oversize
removal rneans and the partition wall;
Figure 13 is a fragmel1tary perspective view of the partition
wall and the recycle means;
Figure 14 is a cross sectional view, taken along line 14-14
of Figure 4, showi.ng the recycle means;
Figure 15 ;.s a fragmentary perspective vi.ew o~ the recycle
rneans;
Figure 16 is a cross secti.onal view taken along line 16-16 of
Fi.gure 4, showing the means for transferri.ng coked solids frorn the
vaporization zone to the combustion zone, a portion of the end plate is
cut away ~ further clarificati.on;
Fiallr~ 17 is a cross sectional view~ taken alonq line 17-17
- 13 -
L7~9
DESCRIPTION OF THE PREFERRED EMBODIMENT
IN GEN~RAL
The apparatus of the present invention is a dry thermal
processor 1 for producing and separating, from hydrocarbon-containing
solids, a hydrocarbon product stream and a solids waste stream. A
schematic drawing of the processor in flow sheet form is shown in Figure
1.
The oil sand feed material is introduced into the processor 1
as whole oil sand. The term whole oil sand refers to the run-of-the-mine
oil sand material, such as that obtained from the Athabasca oil sand
deposits of Alberta. The material comprises coarse sand, fine clay,
bitumen and water. It usually includes a mixture of cohesive lumps,
often in a frozen condition~ and discrete ~articles of oi:l sand.
Also included in the whole oil sand are rocks and other mine slte debris,
some of which are embedded in the cohesive lumps of oil sand.
With reference to Figure 2, -the processor 1 is seen to com-
prise radially spaced, concentric, substantially horizontal inner and outer
tubular members 2,3. The tubular members 2, 3 are generally co-
extensive and rigidly interconnected for rotation together as a single
unit about the;r common long axis. An annular space A is formed between
the walls of the members. Each of the tubular members 2,3 have first
ends at B and second ends at C respectively. The inner tubular member 2
provides a preheat zone D at its first end and a vaporization zone E at
its second end. The annular space A is divided into a combustion zone
F at its second end and a heat-transfer zone G at its first end. It
should be understood that the terrns first and second ends are used
loosely to refer to adjoining expanses within wall portions of the tubular
members as defined by the side and end walls of the tubular members 2, 3.
The outer tubular member 3 extends between a stationary feed
end structure 4 and a stationary product end structure 5. The feed end
structure 4 provides means for sealing the first ends of the inner and
outer tubular members 2, 3 while the product end structure 5 provides means
for seal;ng the second end of the outer tubular member 3.
.
14 ~ 9
Advancing means 6 are affixed along the inner surfaces of the
tubular members 2,3 to advance the solids therein as the tubular members
are rotated. In the inner tubular member 2, the sol;ds are advanced
toward the product end structure 5; in the annular space AJ the solids
are advanced back toward the feed end structure 4.
Whole oil sand solids are i.ntroduced through the feed end
structure 4 into the preheat zone D. As the feed material i.s advanced
through the preheat zone D, it is progressively heated by heat transferred
through the wall of the inner tubular member 2. This heat is obtained from
hot solids in the surrounding heat-transfer zone ~, which solids are
lifted and dropped onto the inner tubular member 2. The temperature
in the preheat zcine is controlled to a level which i.s suffici:ent to
remove substantially all of the water assojciated with the feecl material
without substantial VdpOriZation of the bitumen component of the oil sand
material. In the preheat zone D, the solids are cascaded as the containing
tubular member is rotated. This cascading action arises from the closely
packed advance means 6 and keying element 6a provided in the preheat zone.
This preheating, together with the cascading action, reduces the particle
size of the lumps of oil sand material and releases rocks and other debris
from these lumps for their subsequent removal. The water vapor and steam
from the preheat zone are withdrawn by fi.rst gas removal means 7.
Also provided in the preheat zone D i.s means 8 for separating
and trans.~erri.ng oversize soli.ds from the preheated and ablated feed
material. This oversize material, whi.ch i:ncludes rocks, lumps of oil sand
materi.al resistive to particle size reduction and other large debris, is
clropped into the annular space A for disposal..
Means 9 are yrovided between the preheat and vaporization zones
D, E for restricting gas movement between these zones while permi:tting
-the remai.ning preheated oil sands to be advanced therethrough.
In the vapori.zati.on zone E, the remaining preheated solids
are mi.xed with hot recycle solids recycled from the combustion zone F
through recycle means 10. The temperature of the preheated solids is
thereby rapidly rai.sed to a level suffici:ent to thermally crack and
vaporize a portion of the bitumen component. The hydrocarbon vapors
produced are removed as a product by second gas removal means 11 pro-
vided at the second end of the inner tubular member 2.
- 15 -
As a result of thermally cracking and vaporizing hydrocarbons
in the oil sand material, coked solids particles are produced. These
coked solids comprise a coke residue in association with the remaining
sand. At the second end of the inner tubular member 2, means 12 are
provided For transferring the coked solids from the vaporization zone E
into the combustion zone F. These means 12 cooperate with the coked
solids to prevent any significant gas movement between these zones E, F.
Means 13 are provided for introducing an oxygen-containing
gas, such as air, into the combustion zone F ~or burning at least part
of the coke on the coked solids to produce hot sand solids. This
combustion, together with any supplemental heat which may be required,
raises the temperature of the sand solids to a level sufficient to
cause vaporization in the vaporization zone when such hot solids are
recycled. Supplemental heat can be provided by introducing heated air from
a burner 14 into the annular space A.
As the combustion-heated solids are advanced toward the feed
end structure 4, a portion of such hot solids is recycled to the vaporization
zone E as described previously. The remaining combustion-heated solids are
advanced back through the heat-transfer zone G.
In the heat-transfer zone G, the hot combustion-heated solids
are lifted and dropped onto that section 15 of the wall 16 of the inner
tubular member 2, which section forms the preheat zone D. For this
purpose, lifting means 17 are provided along at least part of the inner
surface of that section 18 of the wall 19 of the outer tubular member 3,
which section forrns the heat-transfer zone G. Waste heat which would
otherw-ise be lost is thus recovered and transFerred to the solids in the
preheat zone D.
Cornbustion produced ~ases are withdrawn from the annular
space A by gas removal means 20 at the first end of the outer tubular
member 3.
The sand solids completing travel through the heat
transfer zone G are removed from the annular space A by the removal
means in~icated at 21. The ho.t sands are thereafter cooled.and conveyed
to a deposit area.
- 16 -
S~ gatin~ and Removing the Gases Produced~3L~3L7 ~ 9
The gases and vapors produced as abovedescribed are of
three types, namely, the water vapor produced in the preheat zone D, the
hydrocarbon gases and vapors produced in the vaporization zone E, and
the combustion gases produced in the combustion zone F. ~or purposes of
saFety and economics of recovery, these gaseous atmospheres are pre- ;
ferably substantially segregated from each other and withdrawn from the
tubular members 2, 3 by separate gas removal means.
As shown in Figures 1, 2 and 3, the water va~or and steam
stream H, produced in the vaporization zone E, is withdrawn by a suction
fan 22 into the feed end structure 4. The water vapor and steam stream
H is drawn into the conduit 23 past a damper 24 and into a steam condensor
25 before be;ny vented to the atmosphere. ~
The hydrocarbon gases and vapors stream I, produced in the
vaporization zone E, is drawn by a suction fan 26 toward the product end
structure 5. These gases and vapors are withdrawn through the conduit 27
into one or more dust extractors 28, to remove the fine particulates there-
from. A cooler 29 and condensor 30 are provided to condense a portion
of the vapors into a liquid product stream, which can be pumped to a
remote or adjacent processing facility. The non-condensible hydrocarbon
vapors are compressed and further cooled before being conveyed to a
processing facility.
A combustion gas stream J is withdrawn from the annular space
A into the feed end structure 4 by a suction fan 31. The gases are
drawn through a conduit 32 through a cyclone 33 and wet scrubber-type dust
extractor 34 before being vented to the atmosphere throuyh an exhaust
stack (not shown). The scrubber-type extractor 34 is operative to remove
the fine particulates carried with the gases. PreFerably the water in
the extractor 34 has a high content of calicum ;ons. The dissolved
calcium sulphate oxidizes to form water-insolu~le calcium sulphate. The
sludge removed from the dust extractor 34 is passed through sludge
thickener 78 and disposed of with the tail;ngs solids.
To control the movement of the gases in the tublllar members
2,3, sealing means are provided, which means are not absolute seals but
permit a net movement of gases in a manner to be hereinaFter described.
It ;s difficult to attain absolute seals when dealing with the rotating
tubular members 2,3 operating at high temperatures.
The feed end and product end structures 4,5,as previously
mentioned, provide end seals 35, 36 for the f;rst and second ends B,C
of the outer tubular member 3. These seals 35, 36 are constructed so as
to permit a slight inward leakage of air into the annular space A. The
pressure within the tubular members 2,3 is maintained at slightly less
than atmospheric pressure, or in other words, negative relative to atmos-
pheric pressure. This negative pressure is drawn by the suction fan 31 re-
moving the combustion gases. This pressure differential between the
atmosphere and the annular space A prevents combustion gases from escaping
into the atmosphere. The pressure different;al is small, maintaining a
pressure of about -0.1" W.G. in the annular space A.
Most preferably, slight pressure differentials are maintained
between the annular space A and zones D and E, to prevent hydrocarbon
vapors from leaking into either the preheat zone D or combustion zone
F. To that end, the pressure in the vaporization zone E, as drawn by
the suction fan 26,is maintained less than the pressures in the preheat
zone D and the annular space A. The pressure in the vaporization zone E
ls typically kept at about -0.2" W.G. The pressure in the preheat zone
D is typically kept at about -0.12" W.G. And, as previously stated, the
pressure in the annular space A is typically kept at about -0.1" W.G.
Additionally, rneans 9 are provided in the inner tubular member 2 inter-
mediate the preheat and vaporization zones D, E for restricting gas
movement therebetween. 8riefly, these means 9 comprise a solid circular
partitiol1 wall 37 having perforations 38 around its periphery to permit
the tar sand solids to be passed therethrough while restricting gas
movenlent. By ~Irestric-tiny~ is meant that the yas movement ;s less than
would be the case if the gases were permitted to freely diffuse between
the zones.
By maintaining these pressure differentials, the net movement
of gases is such that a small amount oF outside air is drawn into the
annular space A, a small amount of the gases in the annular space A is
drawn into the preheat zone D, and a small amount of gas from the preheat
zone D is drawn into the vaporization zone E. In this manner, significant
loss of the product hydrocarbon gases to the preheat zone D and annular
space A is prevented, to thereby maximize recovery and minimize the
possibility of creating explosive gaseous mixtures.
~3L 749
Other net results of this method of segregating the gases are
that, with the elimination o~ absolute seals, the preheat zone D ;s open
to accommodate whole o;l sand feed~ the heat-transfer zone G is open to
accommodate lifting means ~or efficient heat transfer9 and the vapor;zation
zone E is open to achieve adequate mixing by gentle cascading of the
hot recycle sands and the preheated solids.
It should be pointed out that the recycle means 10, to be dis-
cussed more fully hereinafter, cooperate with the hot oil sand solids being
transferred therein (from the combustion zone F to the vaporization zone E)
to prevent significant gas movement between these zones. Also, the means 12
for transferring coked solids from the vapor;zation zone E to the combustion
zone F cooperate with said coked solids to prevent s;gnif;cant gas movement
between these zones. These means however do not form absolute seals, thereby
perm;tting the desired net movement of gases as d;scussed above.
If desired, a cons;derable portion of the steam and water
vapor produced in the preheat zone D may be drawn through the vaporization
zone E by controlling the suction drawn on these two zones. The water
vapor may thereby be used as a stripping agent in the thermal cracking
of the hydrocarbons in the vaporization zone.
As shown in Figure 4, an emergency gas removal conduit 79 is
provided at the second end of the outer tubular member 3 to remove gases
from the processor 1 in the event of an emergency shut-down.
The Inner and Outer Tubular Members
The rotating apparatus of the present invention includes
a horizontally disposed inner tubular member 2 having first and second
ends and a horizontally disposed outer tubular member 3 having first and
second ends. The tubular members 2, 3 may be constructed from fabricated or
cast metal cylinders. The outer tubular member 3 is generally co-
extensive with the inner tubular member 2 and is radially spaced therefrom
The tubular members are r;g;dly connected together by suitable means 39
for concurrent rotation about their common long axes.
The outer tubular member 2 is prov;ded with one or more
riding rings 40 fixed around its outer circumference. The riding rings
40 rest on rollers 41. An electrical motor 42 or other suitable power
source is used to impart rotary motion to the apparatus through-a ring
gear 43 affixed to the outer tubular nnember 3. The rate of rotation
is variable to control the mo~ement of the feed material being advanced
through the apparatus.
- l9 -
To support the inner tubular rnember 3 w;th;n the outer tubular
member 2, a series of radially extending braces 39 are bolted between them.
The braces 39 are enclosed in insulative material, whi~h in turn is surrounded
with suitable abrasive resistive material (not shown) The insulat;on is
included to isolate the braces from the high temperatures ;n the apparatus
and to reduce the dimension changes caused by temperature fluctuations.
The outer tubular member 3 is provided with an outer l;ning 94
constructed of a refractory material with a coarse grog to minimize heat loss
from the apparatus. Along the length of the combustion zone F, the outer
surface of the inner tubular member 2 may be lined with a refractory material
~not shown) to prevent the inner vaporization zone E from being over-
heated. This lining also serves to protect the outer surface of the
inner tubular member 2 from abrasive or oxidative damage.
' Advancing means 6 are provided along the inner surfaces of
the inner and outer tubular members 2,3 to move the solids therealong as the
members are rotated. Such advancing means 6, may be metal plates inclined
relative to the long axes of the tubular members 2, 3. Counterclockwise
rotation of the tubular members 2, 3 as viewed from the feed end causes
advancement of the solids in the inner tubular member 2 from the f1.rst end
toward the second end thereof and solids in the annular space A from the
second end toward the first end thereof. The degree to which the advance
plates 6 are inclined together w;th 'the number and spaci.ng of the plates
are varied to control the speed at which the solids are moved through
the apparatus. Also provided in the preheat zone are keying e'lements 6a
which comprise metal plates closely packed with the advance plates 6. The
keying elements 6a promote l-ifting and mixing of the oil sand solids. The
advance plates 6 and keying elements 6a are bolted to the wall 16 of the
inner menlber 2 and, being oF metal, aid in the heat transfer through the
wal'l 16. At the entrances to the preheat, vaporization and combustion zones
D,E,F, the advance plates 6 are arranged to move the solids qu;ckly into
the zone in question to prevent build-up of the solids. Further into
these zones, the advance plates 6 are angled to cause slower movement of
the solids. In the preheat zone D, the advance plates 6 are closely packed
and inclined at a steep angle. Together with the keying elements 6a, the
advance plates 6 provide a cascading action to the feed material as-the
tubular members 2,3 are rotated, which action aids in reducing the particle
size of the feed material.
In the vaporization zone, the combination of the advance plates 6
- 20 - ~
Lifting means 17 are provided in the heat-transfer zone G
to lift and drop hot sand solids onto the outer surface of the inner
tubular member 2. These liFting means 17 comprise cup-faced li~ters 44,
as detailed in Figure 7, bolted to the side wall 1~ of the outer tubular
member 3. These cup-faced lifters 44 are operative to lift and drop the
hot solids over the top of the rotating inner tubular member 2 as the
tubular members rotate.
Similar lifting means of sma11er lifting capacity may be
used in the preheat and combustion zones D, F if desired.
The Feed End Structure
With reference to Figures 2 and 9, the feed end structure 4
is shown to include means ~5 for feeding whole ~il sand solids into the
preheat ~one D. The feeding means 45 includes a conveyor assembly 46
which drops the whole oil sand solids into an enclosed feed chute 47
opening into the first end of the inner tubular member 2.
A ring seal 48 is provided between the feed chute 47 and
the inner tubular member 2 to form a gas seal therebetween. An air lock
member ;49 is provided to permit the oil sand solids to enter the inner
tubular member 2 without significant gas movement. The ring seal 48
cooperates with the enclosed chute 47 and the air lock member 49 to
prevent any significant quantities of external air from being drawn into
the inner tubular member, thereby forming means for sealing the first end
of the inner tube.
Oversize Solids Removal
Overs;ze feed material solids, which include rocks, large
lurnps oF oil sand or other debr;s, are transferred from the inner tubular
member 2 to the outer tubular member 3 at the second end 50 of the preheat
zone D. To that end, curved metal bars 51 having one end affixed to the
walls 16 of the inner tube 2 and the other end affixed to a bypass chute
52 are provided. The curved bars 51 are spaced from each other to forrn
a screen throughwhich the de-rocked feed material may pass as the inner
tube 2 rotates. The oversize particles, larger than the spacing of
the bars 51, roll along the bars into the bypass chute 52. The bypass
chute 52 opens into the annular space A. A door 53 is provided on the
bypass chute 52 which is spring-biased or cam operated to a non~ally
7~
directly into the annular space A for disposal. The door 53 minimizes the
transfer of gases be-tween the two tubular members 2, 3.
The Partition Wall
__
The means 9 for restricting gas movement between the preheat
and vaporization zones D, E, as shown in Figures 4, 13 and 14, comprises
a perforated wall member 37 extending across the inner tubular member
between the two zones and positioned downstream of the oversize removal
means. The wall member 37 comprises a solid circular plate 54 blocking
the central portion of the inner tube 2. A plurality of curved tubular
members 55 are affixed to the wall 16 of the inner member Z through
the plate 54. The tubular members provide openings 38 through the plate 54.
The tubular members have open ended first and second ends, 56, 57,
the first end 56 opening into the preheat zone D and the second end
57 opening into the vaporiation zone E. A plurality of circular spaced
bars 58 are provided over the openings 38. The bars 58 screen the il
sand material entering the tubular members 55 to prevent oversize material
from blocking the openings or from being transferred into the vaporization
zone D. The bars 58 are spaced in an L-shaped configuration over the
first ends 56 of the tubular members 55. This configuration is shown clearly
in Figures 12 and 13. The tubular members 55 are oriented so as to
scoop the preheated oil sands thereinto on rotation of the inner tubular
member 2. On further rotation, the oil sand falls therethrough into
the vaporization zone. The number and size of openings provided is
determined by quant;ty of sand to be passecl and the deyree of gas
control needed.
The ends of the tubular members 56, 57 are the only openings
between the preheat and vaporization zones D, E. Since the tubular
members 55 are at least partially fu'll of tar sand solids while the
processor 1 is rotated, the sands cooperate with the perforated wall 37
to restrict gas movement between the two zones D, E .
Preferab'ly, a removable access door 54a is provided in the
plate 54 to allow one access to the vaporization zone E for repairs
or the like during a shut-down period.'
- 22 - ~ 3L~ 9
_cycling Hot Oil Sand Solids From the Annular Space to the
.
Vaporization Zone
The recycle means, as shown in Figures 4, 14 and 15 and
generally indicated at 10, functions to divert a portion of the hot
sand solids being advanced through the annular space A back into the
vaporization zone E, where it is combined with the il sand solids
issuing from the prehea-t zone D. The recycle means 10 includes an annular
housing 59 affixed to outer member 3 adjacent the
entrance to the vaporization zone E. The annular housing 59 is divided
into compartments 60 by dividing walls 61 extending between the walls of
the housing 59 and the outer member 3. Recycle tubes 62 extend from
each compartment 60 through the walls 19, 16 of the outer and inner
members into the vaporization zone E. The recycle tubes 62 are
tapered toward the inner membPr 2. Screened openings 63 are provided
through the walls 19 of the outer member 3 into compartments 60.
As the tubular members 2, 3 are rotated, hot sand soli:ds
being advanced from the combustion zone F to the heat-exchange zone G
pass over the screened openings 63 and fall into the compartments 60 for
recycle. The screens 64 prevent large particles from being recycled.
As the filled chambers 60 are rotated to an elevated posi-tion, the hot
sand solids fall through the tapered tubes 62 into the vaporizat;on
zone E. The remaining hot sand solids are advanced to the heat-
transfer zone G.
It will be understood that, since the hot sand solids
passing between the combustion and heat-transfer zones F, G must pass
over the screened openings 63, the compartments 60 must be preferentially
filled before the excess solicls can be advanced to the heat-transfer zone G.
As previously disclosed, the hot tar sand solids at least
partially filling the compartments 60 and recycle tubes 62 cooperate
with the recycle means 10 to prevent significant gas movement between
the annular space A and the vaporization zone E.
- 23- ~2~7~
To adjust the rate of the recycle flow, a removable plate 65
is bolted to each of the tubes 62 to form an outlet open;ng 66 between the
recycle tube 6Z and the inner tube 2. By adjusting ei.ther the size or
location of the plates 65, the dimenions of the outlet openings 66
may be altered thereby adjusting the amount of material being recycled
as required to achieve the desired process;ng result.
Preferably weir plates 59a are provided partially closing
the entrance into the h.eat-transfer zone G. The plate 59a causes hot sand
solids being advanced past the recycle means 10 to accumuiate over the
screened openings 63 before fall;ng into the heat-transfer zone G.
As shown in the drawi.ngs, an optional second recycle means (,not
shown) is provided to recycle hot sand solids from the heat-exchange zone
G to the preheat zone D. The second recycle means are provided for use
in the event that oil sand solids in the preheat zone D adhere to the ;nner
surface 16 or advance elements 6 of the inner tube 2., The operation and
construction of the second recycle means are simi.lar to recycle means 10
described above. A number of the tubes 62 or compartments 60. are closed
to recycle only a Fraction of the amount of material being recycled by means
10. In most applications tne second recycle:means is not needed and all
compartment openings 63 and recycle tube outlets 66 are closed.
Transferrin"g Coked Solids From the Vaporizati.on Zone to the Combusti'on Zone
Means 12 are provided at the second end C of the inner tubular
means 2 for transferring hot coked solids from the vaporization zone E to
the combustion zone F. These means are shown i.n detail in Figures 16 and
17. The second end C of the inner tubular member 2 is provided with spaced
inner and outer radial end plates 68, 69 fi:xed to the walls 16 of sa~d member
2 and sealed around the vapor removal conduit 27. A serles oF spaced
baff'les 70 are provided between the plates 68, 69 thereby forming compart-
ments 71. As the inner member 2 rotates, coked solids from the vaporization
zone E are fed into these compartlnents 71 through openings 72 provided
near the periphery of the inner radial plate 68. Further rotation causes
the solids to fall inwardly toward the central axis of the inner tubular
member 2. The baffles 70 are inclined so as to direct the solids t'oward
a central slot 73 located in the outer plate 69 around the vapor discharge
conduit 27. The coked solids issuing from the slot 73 fall as a curtain
through the space 74 between the second ends C of the tubular members 2,3
into the combustion zone F.
- 24 -
a'f ~9
As the coked solids are being discharged through the slot 73,
a moving solids seal is formed between the vaporization and combustion
zones E, F to prevent s;gnificant gas movement between these zones. The
circular slot 73 is further sealed during the remaining 360 of rotation
by an adjustable seal plate 75. The seal plate 75 is sprlng mounted to
the second end C of the outer tubular rnember 3 on adjustable rods 76
and sealed around the vapor removal conduit 27. The seal plate 75 is
spaced from the circular slot opening 73 by an adjustable distance
as set by the length of the rods 76. Spring mounting the plate 75
allows intermittent discharge of oversize material without permitting
significant gas movement into the vaporization zone E.
End Seals of the Outer Tubular Member
The first end B of the outer tubular member 3 is sealed by a
ring seal 35 between the wall 19 of the member 3 and the stationary
feed end structure 4. As previously disclosed, this seal 35 permits a
small amount of outside air to be leaked into the annular space A.
The second end C of the outer member 3 is sealed by the ring
seal 36 between the stationary product end structure 5 and the wall 19
of the outer member 3. The stationary product end structure 5 is
sealed to the vapor discharge conduit 27 by a rotary pipe seal 80.
The vapor discharge conduit 27 preferably comprises an
outer stationary section 81 rigidly secured to the rotary pipe seal 80
and a rotating inner section 82 affixed to and rotati.ng with the end
plates 68, 69 on the inner tubular member 2.
- 25 -
7'~9
I troducing Oxygen-Containing Gas
With reference to Figures 4 and 18 , means B are prov;ded
for introducing an oxygen-contain;ng gas, such as air, into the combust;on
zone F. More particularly7 a slotted air discharge plenum 83,is provided
in the space 74 between the second ends C of the tubular members
2,3. The plenum 83 is connected through a conduit 84 to a fan 85 which
forces heated air through ~he plenum 83. The air is heated in heat exchangers
77 which recover heat from the hydrocarbon vapours withdrawn from the
vapori7ation zone E. A direct fire burner 14 supplies additional heated
air to the combustion zone F to supplement the heating provided by
combustion. The plenum 83 is curved in the manner shown in the drawings
to allow maximum contact of the heated air with-the curtain of hot coked
solids issuing from the inner tubular member 2. At the base of the plenum
83 a horizontal plenum nozzle 86 extends a small distance into the annular
space A. This nozzle 86 supplies a high velocity stream of air along the
annular space A to ensure that combustion continues along the extent of
the combustion zone F.
Sand _ lids Removal
The sand solids are removed from the annular space A at the
first end B of the outer tubular member 3 by means generally indicated at
21 in Figures 2 and 4. The sand solids are dropped onto an enclosed
conveyor belt ~1 external of the outer member 3, where they are cooled
and dampened with water. The cooled sands are conveyed through an air
lock 87 to a disposal site. The stearn resulting from cooling the hot
sands, shown as stream K in Figure 3, is cornbined with the steam and
water vapor stream H From the preheat 7.0ne D and cooled ~n the previously
disclosed manner.
Operation
To process oil sand feed rnaterial, the temperature in the
apparatus is initially raised to about 1000F by introducing hot air
at a temperature of about 1100F through the burner 14. The apparatus 1
is then purged with steam to remove oxygen therefrom. With the tubular
- 26 - '~L'~ 7''~9
members 2, 3 rotating, whole oil sands solids, which may have been pre-
screened to remove large boulders, are conveyed into the preheat zone D
through the feed chute 47. The h;gh angle of attack of the advance
plates 6, move the feed material quickly into the preheat zone D.
In the preheat zone D, the feed mater;al is heated, dehydrated and
ablated as it is advanced therethrough by the inclined advance plates 6.
The heat is provided by heat transferred through the wall 16
of the inner tubular member 2 from the hot sand solids being dropped
thereon in the surrounding annular space A. The oil sands are preferably
preheated to a temperature of about 450F. This heating causes a
substantial reduction of the bitumen viscosity. As the tubular members
2,3 rotate, the feed material is repeatedly raised and dropped to create
a cascad;ng effect. The advance plates 6 and keying elements 6a are closely
spaced to aid in this lifting act;on. This preheating and cascading of
the whole oil sand in the preheat zone D causes lumps of oi.l sand to be
ground and reduced i.n particle size. This combined action also conditions
the feed material to release oversize debris such as rocks from the lumps
of oil sand. Oversize solids can thus be subsequently removed without
losing a large quantity of oil sands.
The preheating step also vapori.zes essentially all of the
water assoc-iated with the oil sand feed material. The'temperature in the
preheat zone is maintained below about 700F , to prevent any substantial
amount of vaporization of the bitumen. The temperature i.n the preheat
zone D is controlled by the residence time of the feed materi'a'l therein.
Res;dence time varies with the speed of rotation of the tubular members
2,3 and the size and spacing of the advance plates 6 in the preheat zone
D. ~lternately the degree of lifting and dropping of the hot sand sol;ds
onto the outer surface 16 of the i.nner member can be varied. The water
vapor and steam are withdrawn from the preheat zone D by the suction fan
22 and conduit 23 to the steam condensor 25.
By lowering the vi.scosi.ty of the bi.tumen in the oil sand
solids, the feed material i.s much.less cohesive and more amenable to
flow and to screeni.ng of oversize solids.
The steam and water vapor produced i.n the preheat zone D
creates a sli.ghtly greater pressure in the preheat zone D than ln
the vaporization zone E. Th.i.s provides an inert sealing atmosphere whichg
together with the parti.ti.on wall 9, is operati.ve to prevent significant
~ r ~ L _ ,. ~ ~ A ~ . A A A + ~ + ~ 7 A~ n c n F
- 27 - ~L1~ 7~9
It will be appreciated that if the amount of wate~ present in
the whole oil sand feed material i5 not suffi~ci~ent to generate t~i`s s-team
barrier, water may be injected directly into the preheat zone D. Alter-
nately the damper 24 on the steam removal means 7 can be closed so that
the steam and water vapor are drawn into the vaporization zone E and
removed with the hydrocarbon vapors.
At the second end 50 of the preheat zone D, overs;ze solids,
including rocks and other debris or large lumps of oil sand solids, are
separated and removed into the annular space A by the oversize removal
means 8. Solids larger than the spacing of the curved bars 51 roll or
slide along the bars 51 into the discharge chute 52 and are ejected into
the annular space A. In this way9 damage to the downstream equiDment
in the vaporization and combustion zones E, F is prevented.
Downstream of the oversize removal means 8, the de-rocked
and preheated oil sand solids are passed through the openings 38 around
the periphery of the partition wall 37 into the curved tubular members
55. Rotation of the inner tubular member 2 drops the solids into the
vaporization zone E. Since the tubular members 55 are at least partially
filled with the solids as the apparatus rotates, the solids cooperate
with the wall 37 to restrict gas movement between the zones D, E.
In the vaporization zone E the preheated solids are further
heated by introducing hot recycled solids through the recycle means 10 at
the first end 88 of this zone. These hot sol;ds recycled from the
combustion zone F are typically at a temperature of about 1100 - 1300F.
Rotation of the tubular members 2, 3 creates a gentle m;xing or cascading
action in the vapor-ization ZQne E to bring the overall temperature of the
solids to about 900 - 1000F. Advance plates 6 and mixing spikes 6b,
positioned along the inner surface 16 of the inner tubular member 2
defining the vaporization zone E, advance and rnix the solids toward the
second end C of the inner member 2. The quantity of hot solids recycled
is varied by adjusting the size of the outlet openings 66 provided by the
recycle means 10. By varying the amount of solids recycled, the temperature
in the zone can be controlled to optimize the degree of vaporizaton. It
is desirable to try to reduce turbulence of the solids in the vaporization
zone E to a minimum and thereby reduce the amount of fine particulates in
the atmosphere.
- 28 -
~lZ1~9
The heat added in the vaporization zone E to the oil sand is
sufficient to cause thermal cracking and ~ of a portion of the
bitumen and to produce a gaseous hydrocarbon product stream. The pro
duct stream is withdrawn from the vaporization zone E through the vapor
discharge conduit 27 by the suction fan 26. The vapors are cleaned in one
or more dust extractors 28 to remove the fine particulates entrapped
therein. The vapors are then cooled and condensed to produce a liquid
product. The non-condensible hydrocarbon vapors are further cooled and
condensed to produce a gaseous hydrocarbon product.
After vaporizing at least a portion of the bitumen, a coke
residue is left in association with the solid mineral particles. The
coke residue and mineral solids are collectively referred to as coked
solids.
At the second end 89 of the vaporization zone E, the coked
solids are transferred into the combustion zone F. As described pre-
viously, the means 12 for trans~erring the coked solids between these zones
drops the solids in a curtain-like pattern. The curtain of falling
particles is struck by a stream of high velocity hot air emitted from the
plenum 83. The hot ai.r sup~orts combustion of at least
a portion of the coke residue on the coked solids. By this combustion
and supplemental heating with the burner 14, the overall temperature of
the coked solids may be raised to about 1100 - 1300F.
The combustion-heated solids are advanced through the annular
space A toward the first end B of the outer tubular member 3 by tile
advance plates 6. A high velocity hot air stream is projected along the
annular space A to support combus-tion therealong. In addit;on, the
combustion-heated solicls are preferably lifted and dropped in the combustion
zone F by lift elernents 90. As shown in Figure 7, the lift elements 90
are flat-type lifters. This lifting and dropping action provides maxirnum
contact between the air and solids to rnaximize combustion.
The combustion gases and combustion-heated solids give up
a portion of their heat, by convection and conduction, to the inner
tubular member 2.
While it is believed that the majority of the combustion takes
place in the annular space A, some combustion will also take place in the
space 74 between the sécond ends C of the tubular members 2,3~ Thus the
- 28 a _ ~L1~17~9
term "annular space" as used in the claims should be taken to re~er
both to the annular space between the walls l6, 19 o~ the tubular members
2,3 and the space 74 between the;r second ends C. It is conceivable
that the outer tubular member 3 could be extended to enlarge the space
74 if a larger combust;on zone ;s des;red.
- 29 - ~L~LZ~L7~9
A portion of the combustion-heated solids are recycled back
from the annular space A into the vapor;zation zone E, to provide the
hot recycle solids. As the tubular members 2,3 rotate, the combustion-
heated solids are advartced over and fall into the screened openings 63
to the compartments 60. Further rotation of the tubular members 2,3
drops the hot recycle solids through the recyc'le tubes 62 into the
vaporization zone E. The solids at least partially fi'lling the recycle
tubes 62 form a moving solids seal between the combustion and vaporization
zones E, F to prevent significant gas movement therebetween. Also, since
the combustion-heated solids must pass over the screened openings 63 and
over the weir plate 59a as they are advanced through the annular space A,
the recycle rneans lO are preferentially filled before the hot sulids are
advanced for disposal. This preferential filling of the recycle means lO
ensures a moving solids seal and a supply of hot recycle solids to the
vaporization zone E even when the rate of feed material ;nput is temporarily
reduced.
That portion of the combustion-heated solids which is not
recycled is advanced through the heat-transfer zone G. In the heat-transfer
zone G these hot solids are repeatedly lifted and dropped onto the
section 15 of the wall 16 of the inner tubular member 2 which defines
the preheat zone E. In this way, waste heat frorn the hot solids is
efficiently transferred to the feed material in the preheat zone E. By
achieving a sliding solid-solid contact between the wall 16 of the inner
member 2 and the hot solids, a desirable amount of heat is transferred.
The lifting and dropping of the hot sol1ds is achieved by the cup-faced
lifters fi~ affixed to the inner surface of the outer tubular member 3.
lhis type of liFter has a large lift;ny capacity and actually lifts and
drops the solids over the top of -the rotating inner member 2 to contact
the surface area of the inner tubular mernber 2.
The rate of' so'lids movement through the heat-transfer zone
G is relatively slow, as provided by the large spacing and'small size
of the advance plates 6 in this area. The slow rate of advance allows
a maximum amount of heat to be recovered from the hot solias.
~17~9
A suction fan 26 at the first end C of the outer tubular
member 3 withdraws the combustion gases from the annular space A. The
combustion gases are passed through a gas cleaning cyclone and wet
extractor before being vented to an exhaust stack (not shown).
Solids from the heat transfer zone ~, wh;ch include oversize
sol;ds and combustion-heated solids, are removed by dropping the solids
from the first end R of the outer tubular member 3 onto the enclosed
conveyor belt 91. The solids are cooled and dampened on the belt 91 by
spraying them with a cooling fluid such as water. Steam produced in
cooling the solids is directed through the condu;t 92, past damper 93 and
combined and removed with the steam from the preheat zone D. T~he
dampened solids are conveyed through the air lock 87 to a disposal site.
Alternately the solids may be cooled and dampened in the annular space
A just prior to being removed from the processor 1. In some cases it
may be desirable to cool and dampen the solids in both the annular space
and exterior of the processor as is shown in Figure 4. The
cooling fluid may include thickened sludge withdrawn from the wet dust
extractor as shown in Figure 2.
As described above the gases produced in each of the
preheat zone D, vaporization zone E and annular space A are substantially
segregated from one another and removed from the apparatus 1 by separate
gas removal means 7, 11 and 20 respectively. Preferably the pressures
in each of these zones is controlled to maintain a pressure in the
vaporization zone E which is less than the pressure in the preheat zone
D and annular space A. Most preferably the pressures in the vaporization
zone E, preheat zone D and annular space A are ma;ntained at levels wh;ch
ascend respectively. These pressures are preferably neyat;ve with
respect to the atmospher;c pressure outs;de the apparatus. Th;s pressure
control, as disclosed prev;ously, is operative to maximize the removal
of hydrocarbon vapors for recovery while minimiz;ng movement oF hydro-
carbon vapors into another zone and movement of combustion gases out of
the apparatus.
A pilot plant unit processor was operated using Athabasca oil
sand from Alberta. The processor was sized to handle 5 tons of feed
material per hour. The processor had an inner tubular member having
d;mensions of 5.51 in diameter by 20' ;n length. The outer tubular
mPmhPr w~c q' ;n tl;~mPtPr hv ?~' ;n lPntlth Rnth thP nrPhf~at and hPa~.
-- 31 --
~217~
zones were each 8' in length. The processor was rotated at about 3 to
6 R.P.M. most preferably at 4 R.P.M.
Retention times and temperatures for the various zones
are shown in Table 1. A typical product analysis from a particular feed
material is shown in Table 2.
TABLE 1
one Retent;on Tirne _emperature
Preheat Zone 4 min. ambient to 450F
Vaporization Zone 2 min. 450F - 950F
Combustion Zone 1.5 min. . 950F - 1080F
Heat-Transfer Zone 5 m;n. , 1080F - 500F
Final Cooling < 1 min. 500F- 180F
Vapor Exit Temperature 970F
Combustion Gas Exit Temperature 520F
TABLE 2
(For Vapor Zone Temperature 900 - 1050F)
Feed Analysis Product Analysis
Oil 9%, 7API Liquid Yield 60 - 72% of feed
Water 7.5% API gravity 13 API
Host Sand and Clay 83.5% Sediment and Water < 2%
Sulphur 4.3% Sulphur 3.7%
Uiscosity @ 20~ 300 c.s.
Coke Yield 18 - 30% of feed
Crack Gas Yield ~C4~) 7 - 13%
of feed
Due to processing considerations in the test unit auxil;ary
heating was needed to provide a substantial amount of the heat requirements.
Approximately 3 gallons of fuel oil per ton of feed were burned in
auxiliary burners.
.
- 32 -
As previously mentioned, the invention has only been practiced
on oil sands. However, it is anticipated that other materials comprising
host solids associated with hydrocarbons (such as oil shale) may also be
processed by the invention.
It will be realized that oil shales and certain oil sands
do not contain connate water. For this reason it rnay be necessary to
inject water or an inert gas into the preheat zone D to maintain an
inert atmosphere therein. Such materials may not contain oversize
solids, in which case the oversize removal means 8 may be omitted.
While the present invention has been disclosed in connection
with the preferred embodiment thereof, it should be understood that
there may be other embodiments which fall within the sp;rit and scope
of the present invention as defined in the following claims.
