PROCEDE DE FABRICATION D'UN GAZ DE SYNTHESE PAR OXYDATION PARTIELLE D'UN COMBUSTIBLE CONTENANT UN HYDROCARBURE GAZEUX A L'AIDE D'UN BRULEUR CO-ANNULAIRE A ORIFICES MULTIPLES

A PROCESS FOR THE MANUFACTURE OF SYNTHESIS GAS BY PARTIAL OXIDATION OF A GASEOUS HYDROCARBON-CONTAINING FUEL USING A MULTI-ORIFICE (CO-ANNULAR) BURNER

Abrégé français

L'invention concerne un procédé de fabrication d'un gaz de synthèse par réaction d'un gaz contenant de l'oxygène, utilisé comme oxydant, et d'un combustible hydrocarboné gazeux qui sont introduits dans la zone de réaction d'un générateur de gaz non catalytique. Le procédé consiste à injecter ledit combustible et ledit oxydant dans la zone de réaction à travers un brûleur co-annulaire à orifices multiples comprenant un réseau de n passages ou canaux séparés qui sont coaxiaux par rapport à l'axe longitudinal dudit brûleur, n étant un nombre entier >/= 2 (2, 3, 4, 5...) et le (n-1)<ième> passage étant le passage intérieur par rapport au n<ième> depuis l'axe longitudinal dudit brûleur. On fait passer le combustible hydrocarboné gazeux et éventuellement un modérateur dans un ou plusieurs de ces passages, mais au moins dans le n<ième> passage (extérieur), tout en laissant au moins un passage libre, on fait passer l'oxydant et éventuellement un modérateur dans un ou plusieurs des passages laissés libres, mais au moins dans le (n-1)<ième> passage. L'oxydant présente une vitesse supérieure au combustible hydrocarboné gazeux lors du passage dudit oxydant dans n'importe lequel des deux passages adjacents et dudit combustible hydrocarboné gazeux dans l'autre passage.

Abrégé anglais

A process for the manufacture of synthesis gas by reacting oxygen-containing
gas, applied as oxidiser and gaseous hydrocarbon-containing
fuel in a reaction zone of a non-catalytic gas generator comprising the steps
of injecting the said fuel and the said oxidiser into
the reaction zone through a multi-orifice (co-annular) burner comprising
arrangement of n separate passages or channels coaxial with the
Longitudinal axis of said burner, wherein n is an integer >= 2 (2, 3, 4,
5...) wherein the (n-1)th passage is the inner passage with respect to
the n th passage, measured from the longitudinal axis of the said burner, and
wherein geseous hydrocarbon-containing fuel and, optionally, a
moderator is passed through one or more of the passages, but at least through
the n th (outer) passage whereby at least one passage remains;
oxidiser and, optionally, a moderator, is passed through one or more of the
remaining passages, but at least through the (n-1)th, passage. In
any two adjacent passages in which oxidiser is passed through the one passage,
and gaseous hydrocarbon-containing fuel is passed through
the other passage, the said oxidiser has a higher velocity than said
hydrocarbon-containing fuel.

Revendications

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CLAIMS:


1. A process for the manufacture of synthesis gas by
reacting an oxygen-containing gas, applied as oxidiser, and
a gaseous hydrocarbon fuel in a reaction zone of a
substantially non-catalytic gas generator comprising the
steps of
injecting the fuel and the oxidiser into the
reaction zone through a multi-orifice (co-annular) burner
comprising an arrangement of n separate passages or channels
coaxial with the longitudinal axis of the burner, wherein n
is an integer >= 2, wherein the (n-1)th passage is an inner
passage with respect to the n th passage, measured from the
longitudinal axis of the burner;
passing the gaseous hydrocarbon fuel, optionally
with a first moderator gas, through one or more of the
passages, but at least through the n th passage, whereby at
least one passage remains; and
passing the oxidiser, optionally with a second
moderator gas, through one or more remaining passages, but
at least through the (n-1)th passage, and in such a manner
that in any two adjacent passages in which oxidiser is
passed through the one passage, and gaseous hydrocarbon fuel
is passed through the other passage, the oxidiser has a
higher velocity than the hydrocarbon fuel,
and provided that when n is 4, then all four
passages are used.

2. The process as claimed in claim 1, wherein the
velocity of the gaseous hydrocarbon fuel is 0.2-0.8 times
the velocity of the oxidiser in any two adjacent passages in
which oxidiser is passed through the one passage, and


-11-


gaseous hydrocarbon fuel is passed through the other
passage.

3. The process as claimed in claim 1 or 2, wherein,
for n >= 3, at least part of the gaseous hydrocarbon fuel is
passed through the n th passage and the remainder of the
gaseous hydrocarbon fuel is passed through one or more
remaining passages.

4. The process as claimed in claim 3, wherein at
least 20% of the gaseous hydrocarbon fuel is passed through
the n th passage.

5. The process as claimed in any one of claims 1
to 4, wherein the velocity of the oxidiser is 20-150 m/s.

6. The process as claimed in any one of claims 1 to 5
carried out at a pressure of 0.1-12 MPa abs.

7. The process as claimed in any one of claims 1
to 6, wherein the gaseous hydrocarbon fuel is natural gas.

8. The process as claimed in any one of claims 1
to 7, wherein the oxidiser contains at least 90% pure
oxygen.

9. The process as claimed in any one of claims 1
to 8, wherein the velocity of the oxidiser and the velocity
of the gaseous hydrocarbon fuel are measured or calculated
at outlets of the concentric passages or channels through
which the oxidiser and hydrocarbon fuel are passed into the
reaction zone.

10. The process as claimed in any one of claims 1
to 9, wherein the first moderator gas is steam, carbon
dioxide or water or a combination thereof.



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11. The process as claimed in any one of claims 1
to 10, wherein the second moderator gas is steam, carbon
dioxide, water or a combination thereof.

12. The process as claimed in any one of claims 1
to 11, wherein a third moderator gas is passed through an
(n+1)th passage.

13. The process as claimed in claim 12, wherein the
third moderator gas is steam, carbon dioxide, water or a
combination thereof.

14. The process as claimed in any one of claims 1
to 13, wherein no passage is reserved for a fuel other than
gaseous hydrocarbon fuel.

Description

W O 96!03345 PCT/EP95/02877
a:~~~~il r ~ 2195554
y A PROCESS FOR THE MANUFACTURE OF SYNTHESIS GAS
BY PARTIAL OXIDATION OF A GASEOUS HYDROCARBON-CONTAINING
FUEL USING A MULTI-ORIFICE (CO-ANNULAR) BURNER
The invention relates to a process for the manufacture of
synthesis gas by partial oxidation of a gaseous hydrocarbon-
containing fuel using a multi-orifice (co-annular) burner.
In particular, the invention relates to a process for partial
oxidation of a gaseous hydrocarbon-containing fuel wherein an
oxygen-containing gas, which is applied as an oxidiser, and a
gaseous hydrocarbon-containing fuel are supplied to a gasification
zone through a multi-orifice (co-annular) burner comprising a
concentric arrangement of n passages or channels coaxial with the
longitudinal axis of said burner, wherein n is an integer _> 2, and
wherein autothermically a gaseous stream containing synthesis gas is
produced under appropriate conditions.
The oxygen-containing gas, which is applied as an oxidiser, is
usually air or (pure) oxygen or steam or.a mixture thereof. In order
to control the temperature in the gasification zone a moderator gas
(for example steam, water or carbon dioxide or a-combination
thereof) can be supplied to said zone.
Those skilled in the art will know the conditions of applying
oxidiser and moderator.
Synthesis gas is a gas comprising carbon monoxide and hydrogen,
and it is used, for example, as a clean medium-calorific value fuel
gas or as a feedstock for the synthesis of methanol, ammonia or
hydrocarbons, which latter synthesis yields gaseous hydrocarbons and
liquid hydrocarbons such as gasoline, middle distillates, lub oils
and waxes.
In the specification and in the claims the term gaseous
hydrocarbon-containing fuel will be used to refer to hydrocarbon-
containing fuel that is gaseous at gasifier feed pressure and
temperature.



WO 96103345 PC1'IEP95I02877
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According to an established process, synthesis gas is produced
by partially oxidising in a reactor vessel a gaseous fuel such as
gaseous hydrocarbon, in particular petroleum gas or natural gas, at
a temperature in the range of from 1000 °C to 1800 °C and at a
pressure in the range of from 0.1 MPa to 6 MPa abs. With the use of
an oxygen containing gas.
Synthesis gas will often be produced near or at a crude oil
refinery because the produced synthesis gas can directly be applied
as a feedstock for the production of middle distillates, ammonia,
hydrogen, methanol or as a fuel gas, for example, for heating the
furnaces of the refinery or more efficiently for the firing of gas
turbines to produce electricity and heat.
In co-annular (multi-orifice)- gas burners it has appeared that
the burner lifetime is restricted by phenomena of pre-ignition or
flame-flashback. Because of such phenomena the temperature of the
burnez-internals becomes too high and serious burner damage will
occur. Further, there are problems with corrosion of the gas burner
tips.
It is an object of-the..invention.to-provide a process for
partial oxidation of a gaseous hydrocarbon-containing fuel wherein a
good and rapid mixing or contacting of oxygen-containing gas
(oxidiser), fuel and, optionally, moderator gas in the gasification
zone is achieved beyond the exit of the burner and wherein burner-
damage by corrosion, pre-ignition or flame-flash-back is suppressed.
The invention solves the above burner damage problem in that in
the process of the invention the oxygen-containing gas applied as
oxidiser and the gaseous hydrocarbon-containing fuel are supplied to
the gasification zone through specific passages at specific
velocities.
The invention therefore provides a process for the manufacture
of synthesis gas by reacting oxygen-containing gas, applied as
oxidiser, and gaseous hydrocarbon-containing fuel in a reaction zone
of a substantially non-catalytic gas genera~ot comprising the steps
of injecting the said fuel and the said oxidiser into the reaction
zone through a multi-orifice ico-annular) burner comprising an

CA 02195554 2004-11-26
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arrangement of n separate passages or channels coaxial with the
longitudinal axis of said burner, wherein n is an integer _> 2 (2, 3,
4, 5 ...), wherein the (n-1)th passage is the inner passage with
respect to the nth passage, measured from the longitudinal axis of
the said burner, and wherein the said gaseous hydrocarbon-containing
fuel (optionally with a moderator gas) is passed through one or more
of the passages, but at least through the nth passage, whereby at
least one passage remains; the said oxidiser (optionally with a
moderator gas) is passed through one or more of the remaining
passages, but at least through the (n-1)th passage, and in such a
manner that in any two adjacent passages in Which oxidiser is passed
through the one passage, and gaseous hydrocarbon-containing fuel is
passed through the other passage, the said oxidiser has a higher
velocity than said hydrocarbon-containing fuel, and provided
that when n is 4, then all four passages are used.
In this manner the oxygen-containing gas (oxidiser) entrains
the gaseous hydrocarbon-containing fuel after which the partial
oxidation takes place in the gasification zone, and the burner-
internal blades that form the internal separation wall between the
oxygen-containing gas (oxidiser) and the hydrocarbon-containing gas
and which have a finite thickness, are cooled by the oxygen-
containing gas (oxidiser) and the hydrocarbon-containing gas (in
particular by connective cooling) to lower the flame temperature
just behind the tips.
Behind the tip of the blade there is unavoidably at least a
recirculation area in which both gaseous fuel and oxygen-containing
gas, applied as oxidiser, are present.
If the hydrocarbon-containing gas would have the highest
velocity, there will be oxygen-rich conditions at the burner-
internal-tip by means of "entrainment" which will lead to high flame
temperatures, high tip temperatures and serious loss of burner
material.
If the oxygen-containing gas, applied as oxidiser, has the
highest velocity, in the recirculation area there will be mainly
oxygen-depleted conditions, which will lead to lower flame
temperature. Thus, serious burner damage will not occur, which leads



VJO 96103345 PCTIEP95/02877
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to a long burner-lifetime.
Advantageously, for n 2 3, at least part (e.g. 20$) of the
gaseous hydrocarbon-containing fuel is passed through the said nth
passage and the remainder of the gaseous hydrocarbon-containing fuel
is passed through one or more of the remaining passages. The (
velocity of the oxygen-containing gas, applied as oxidiser, is
advantageously 20-150 m/s.
The velocity of the gaseous hydrocarbon-containing fuel is
advantageously 0.2-0.8 times the velocity of the oxygen-containing
gas, applied as oxidiser, in any two adjacent passages in which
oxidiser is passed through the one passage, and gaseous hydrocarbon-
containing fuel is-passed through the other passage.
In an advantageous embodiment pf the invention the respective
velocities are measured or calculated at the outlet of-the said
respective channels into the gasification zone. The velocity
measurement or calculation can be carried out by those skilled in
the art in any way suitable for the purpose and will therefore not
be described in detail. -
In another-advantageous embodiment of the invention-the
moderator gas is steam and/or water and/or carbon dioxide and the
oxidiser contains at least 90$ pure 02. In-still anothei
advantageous embodiment of the invention the gasification process is
carried out at a pressure of-.0_1-12 MPa abs.
Multi-orifice burners comprising arrangements of annular ,
concentric channels for supplying oxygen-containing gas (oxidiser),
fuel and moderator gas to a gasification zone are known as such
(vide e.9. EP-A-0,545,281 and DE-OS-2,935,754) and the mechanical
structures thereof--will therefore not be described in detail.-
Usually such burners comprise a number of slits at the burner
outlet and hollow-wall members with internal cooling fluid (e. g.
water) passages. The passages may or may not be converging at the
burner outlet. Instead of comprising internal cooling fluid
passages, the burner may be provided with a suitable ceramic or
refractory lining applied onto or suspended by a means closely
adjacent to the outer surface of the burner (front) wall for



W096103345 _.. __ _ _ PGTYEP95I02877
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resisting the heat load during operation or heat-up/shut down
situations of the burner.
y No fuel passage is reserved for a fuel other than gaseous
hydrocarbon-containing fuel.
The invention will now be described in moze detail by reference
to the following examples.
A number of examples are given in the Table. In this Table the
following abbreviations are made:
Feed l:Natural Gas with the following typical composition
CHq : 94.4$ by volume
C2H6 . 3.0$
C3H8 . 0.5$
C4H10 : 0.2$
CSH12+: 0.2$
. C02 . 0.29
N2 . 1.5$
The supply temperature to the burner.of this feedstock is 150-
2so ac.
Feed 2: Natural Gas with the following typical composition
CH4 : 81.8$ by volume
C2H6 . 2.7$
C3H8 . 0.4$
C4H10 : O.I$
CSH12+: 0.1$
_Cp2 . 0.9$
N2 : 14.0$
C02._is supplied as a moderator gas to the said natural gas in such a
manner that the mass ratio of moderator gas C02 to Natural Gas is
0.6-0.8. The supply temperature to the burner of this feedstock is
280-320 °C~-_
oxidiser l: 99.5$ pure 02 with a temperature of 230-250 °C.
oxidiser 2: a mixture of a gas with 99.5$ pure 02 with 20-30$ (by
mass) of moderator gas. This mixture has a temperature of 250-270 °C
and the moderator gas is steam at a temperature of 280-300 °C.


WO 96103345 PCTIEP95102877
r.: 2 i 95554
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A number of 9 examples has been presented. The following Table
indicates the distributions of the respective fuels and oxidisers
for these examples. The typical synthesis gas compositions are also
given. The values of n as used in the description and claims are
indicated and passage 1 is the first-or central passage. !
r


W 0 96103345 PCT/EP95/01877
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_,_
Table With Examples
Exam 1e number 1 2 g


Value of n 7 6 6


'S Typical synthesis
gas
composition -3 -7 -3
CO [8 Vol, dr ]


CO [B Vol, dr ] 34-35 39-40 34-35


i
H [8 Vol, dr ] 62-63 47-48 62-63


Reactor ressura [MPa]9-5 2-3 5-,


3
Reactor temperature
Ide CI 300-1400 250-1350 300-1400


Passa a 1 T a of feed 1 oxidiser oxidiser 1
as 1


Mass flow [k /s] 1-1.5 1.2-1.8 1-1.5
i


Velocit [m/s] 30-45 80-120 50-75


Passa a 2 T a of oxidiser feed 2 feed 1
as 1


Mass flow jk Js) 2.6-4 0.9-0.6 1.1-1.6


i Velocit [m/s] BO-120 30-45 25-35


- Passa a 3 T a of feed 1 feed 2 oxidiser 1
as


Mass flow [k /s] 2.1-3.1 2.1-3.1 2-3


Velocit [m/s] 30-45 80-120 50-75


Passa a 4 T a of oxidiser feed 2 feed 1
1 as 1


Mass flow [k /s] 2.7-4 0.6-0.9 1.8-2.7


Velocit [m/s] 80-120 30-45 25-35


Passa a S T a of feed 1 oxidiser oxidiser 1
as 1 .


Mass flow [k /s] 2.1-3.1 1.2-1.8 2-3


Velocit [m/s] 30-45 80-120 50-75


Passa a 6 T a of oxidiser feed 2 feed 1
as 1


f
Mass flow [k /s] 3-4.5 0.76-1.1 1-1.5


Velocit [m/s] 80-120 30-45 20-30


) Passa a 7 T a of feed 1
as


Mass flow (k /s1 1-1.5


Velocit [m/s] 30-45





W 0 96103345 PCTIEP95/02877
2195554
~ic~=~t ~:~. ; ,_
-8_
Table With Examples (Continued)
Exam 1e aumber 4 S 6


Value of n 5 4 3


Typical synthesis
gas
composition -10 -5 -5
CO [~ Vol, dr ]


CO [8 Vol, dr ] 36-37 32-33 32-33


H [fl Vol, dr ] 47-48 62-63 62-63


Reactor ressure [MPa]2-3 I-1.5 2-3


Reactor temperature
[de C] 1200-1300 1300-1400 1300-1400


Passa a 1 T a of as feed 2 feed 1 feed 1


Mass flow [k /s] 1-1.5 - 2-3 0.7-1.1


Velocit [m/sj 40-60 80-120- 45-80


Passa a 2 T a of as oxidiser.2 feed 1 oxidiser 1


Mass flow (k /s] 1.6-2.4 0.6-0.9 1.7-2.6


Velocit [m/s] 95-140 30-45 100-150


Passa a 3 T a of as feed 2 oxidiser feed 1
2


Mass flow [k /s] 2-3 6.2-9.3 0.9-1.3


Velocit [m/s] 40-60 80-120 35-40


Passa a 4. T a of oxidiser feed 1 moderator as
as 2


Mass flow (k /s] 1.6-2.4 1.3-2 0.6-0.9


Velocit [m/s] 70-100 25-35 55-80


Passa a 5 T a of as feed 2


Mass flow [k /s] 1-1.5


Velocit (m/s] 30-45






W 0 96103345 PCT/EP95/02877
'~'~~Vr~~ i 4~ _ g _ ~~~~554
Table With Examples (Continued)
Exam 1e number 7 8 g


Value of n 3 3 2


3 Typical synthesis
gas
composition -5 -3 -5
CO [8 Vol, dr ]


CO [8 Vol, dr ] 32-33 34-35 32-33


H [6 Vol, dr ] 62-63 62-63 62-63


Reactor ressure [MPa]2-3 4-5 7-10


Reactor temperature
[de C] 1300-1400 1300-1400 1300-1400


Passa a 1 T a of as oxidiser feed 1 oxidiser 2
2


Mass flow [k /s] 2.5-3.5 2-3 6-8


Velocit [m/s] 40-60 40-70 95-60 .


Passa a 2 T a of as oxidiser oxidiser feed 1
2 1


Mass flow [k /s] 1.7-2.6 4-6 4-5.6


Velocit [m/s] 100-150 80-120 25-35


Passa a 3 T a of as feed 1 feed 1


Mass flow [k /s] 2.5-3.7 1.3-2


Velocit [m/s] 30-45 30-45


It will.be appreciated by those skilled in the art that any
slit width suitable for the purpose can be applied, dependent on the
burner capacity.
Advantageously, the first or central passage has a diameter up
to 70 mm, whereas the remaining concentric passages have slit widths
in the range of 1-20 mm.
Various modifications of the present invention will become
apparent to those skilled in the art from the foregoing description.
Such modifications are intended to fall within the scope of the
appended claims.