U.S. patent application number 11/349883 was filed with the patent office on 2007-03-08 for method and device for producing synthesis by partial oxidation of slurries made from fuels containing ash with partial quenching and waste heat recovery.
This patent application is currently assigned to Future energy GmbH and Manfred Schingnitz. Invention is credited to Torsten Bergt, Friedemann Mehlhose, Manfred Schingnitz.
Application Number | 20070051043 11/349883 |
Document ID | / |
Family ID | 37828768 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051043 |
Kind Code |
A1 |
Schingnitz; Manfred ; et
al. |
March 8, 2007 |
Method and device for producing synthesis by partial oxidation of
slurries made from fuels containing ash with partial quenching and
waste heat recovery
Abstract
A method and a device for the gasification of solid fuels such
as bituminous coal and coke such as bituminous coal, lignite, and
biomass, as well as petroleum coke, that are finely ground and
mixed with water or oil to make fuel-liquid suspensions, so-called
slurries, and their gasification together with an oxidizing medium
containing free oxygen by partial oxidation at pressures between
atmospheric pressure and 100 bar, and at temperatures between 1200
and 1900.degree. C., in an entrained flow reactor. The method
includes the steps of slurry preparation and infeed to the reactor,
gasification in an entrained flow reactor with cooled reaction
chamber contour, partial quenching, waste heat recovery, and wet or
dry dust separation, with the crude gas being pretreated so that it
can be fed to other technological steps such as crude gas
conversion or desulfurization.
Inventors: |
Schingnitz; Manfred;
(Freiberg, DE) ; Mehlhose; Friedemann; (Freiberg,
DE) ; Bergt; Torsten; (Freiberg, DE) |
Correspondence
Address: |
WILLIAM COLLARD;COLLARD & ROE, P.C.
1077 NORTHERN BOULEVARD
ROSLYN
NY
11576
US
|
Assignee: |
Future energy GmbH and Manfred
Schingnitz
|
Family ID: |
37828768 |
Appl. No.: |
11/349883 |
Filed: |
February 8, 2006 |
Current U.S.
Class: |
48/210 ;
48/101 |
Current CPC
Class: |
C10J 3/86 20130101; C10J
3/526 20130101; C10J 2300/0973 20130101; C10J 3/84 20130101; Y02P
20/129 20151101; C10K 1/101 20130101; C10K 1/04 20130101; C10J
3/845 20130101; C10J 2200/09 20130101; C10J 2300/0983 20130101;
C10J 2300/0903 20130101 |
Class at
Publication: |
048/210 ;
048/101 |
International
Class: |
C10J 3/00 20060101
C10J003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 7, 2005 |
DE |
10 2005 042 640.9 |
Claims
1. A method for the gasification of fuels such as bituminous coals
and cokes such as bituminous, lignite, biomass, and petroleum coke
in the entrained flow with an oxidizing medium containing free
oxygen, the method comprising the following steps: slurrying a
pulverized fuel with a grain size <200 .mu.m with water with
added surfactant, to obtain a fuel-in-water slurry with a solids
concentration of 40-70 wt. %; bringing the slurried fuel to a
gasification pressure of 100 bar by pumping, for which the slurry
is preheated to temperatures up to 400.degree. C.; feeding the fuel
to the reactor through a supply pipe together with an oxidizing
medium containing free oxygen; subjecting the fuel to partial
oxidation in the reaction chamber at pressures between atmospheric
pressure and 100 bar, the reaction chamber having a contour
confined by a cooling shield; melting ash of the fuel; transferring
the melted ash through a discharge device to a quenching chamber of
a quenching cooler along with hot crude gas; partially quenching
the crude gas in the quenching cooler with cooling of the crude gas
to temperatures between 700 and 1,100.degree. C.; cooling the
partially quenched crude gas in a waste heat boiler to temperatures
between 150 and 400.degree. C. with generation of steam; subjecting
the cooled crude gas to a crude gas scrubber and partial
condensation, or to dry mechanical dust separation by centrifugal
force or filtration, to separate entrained dust; and sending the
cooled gas freed of dust to additional treatment steps.
2. A method pursuant to claim 1, wherein a crude gas scrubber is
used, and the crude gas scrubber is a single- or multiple-stage
Venturi scrubber.
3. A method pursuant to claim 2, wherein the Venturi scrubber is
supplied with fresh water or recycled condensates that result from
the cooling of the gas.
4. A method pursuant to claim 1, wherein the waste heat boiler is
operated at temperatures of 700 to 1,100.degree. C.
5. A method pursuant to claim 2, wherein the crude gas scrubbing
takes place at temperatures of 150 to 300.degree. C.
6. A method pursuant to claim 2, wherein the Venturi scrubber is
supplied with circulated water or recycled condensate.
7. A method pursuant to claim 1, wherein the fuel is supplied to
the reactor as a fuel-in-water slurry.
8. A method pursuant to claim 1, wherein the fuel is supplied to
the gasification reactor through one or more burners.
9. A method pursuant to claim 1, wherein granulated slag from the
quenching cooler is discharged through one or more outlets from the
quenching cooler.
10. A method pursuant to claim 1, wherein the partially quenched
gas leaves the quenching cooler through one or more gas
outlets.
11. A method pursuant to claim 1, wherein one or more varieties of
coal are gasified at the same time.
12. A method pursuant to claim 1, wherein the amount of slurry in
the supply pipe is measured, monitored, and regulated.
13. Device for gasification of fuels such as bituminous coals and
cokes such as bituminous, lignite, biomass, and petroleum coke in
the entrained flow with an oxidizing medium containing free oxygen,
comprising: a system for producing and feeding slurry; a reactor
for the gasification of supplied powdered fuel with an oxidizing
medium containing free oxygen, comprising a supply pipe for the
slurried fuel and a line for the oxidizing medium, burners for
feeding the slurried fuel and oxidizing medium into a reaction
chamber of the reactor, said reaction chamber having a cooling
shield consisting of water-cooled pipes welded gas-tight, and an
outlet device; a quenching cooler with no internals connected to
the reactor via the outlet device, the quenching cooler having
nozzles arranged in one or more nozzle rings through which is
sprayed water for partial quenching, said nozzles being integrally
incorporated in an inner jacket; a waste heat boiler following the
quenching cooler; and equipment for purifying the gasified
fuel.
14. A device pursuant to claim 13, wherein a reaction chamber of
the quenching cooler is connected directly to the waste heat
boiler, in which heat of the crude gas is utilized through tubes to
produce steam, and wherein there are discharge openings in a bottom
of the waste heat boiler for crude gas and for slag withdrawal with
a water bath.
15. A device pursuant to claim 13, further comprising a crude gas
scrubber and a partial condensation system following the crude gas
scrubber for purification.
16. A device pursuant to claim 15, wherein the crude gas scrubber
is a single- or multiple-stage Venturi scrubber.
17. A device pursuant to claim 13, further comprising a mechanical
dry dust separator for gas purification.
18. A device pursuant to claim 15, wherein there are further gas
treatment stages connected in line after the water scrubber and
partial condenser or the mechanical dry dust separator.
19. A device for gasification of fuels such as bituminous coals and
cokes such as bituminous, lignite, biomass, and petroleum coke in
the entrained flow with an oxidizing medium containing free oxygen,
comprising: a system for producing and feeding slurry; a reactor
for gasification of supplied fuel dust with an oxidizing medium
containing free oxygen, the reactor comprising a supply pipe for
receiving slurried fuel and a line for the oxidizing medium, said
slurried fuel and oxidizing medium being fed by burners into a
reaction chamber of the reactor, said reaction chamber comprising a
cooling shield made of water-cooled pipes welded gas-tight and a
discharge device; a quenching cooler connected to the discharge
device; a waste heat boiler connected to the quenching cooler via a
transfer line for receiving partially cooled crude gas, said boiler
being equipped with boiler tubes and utilizing heat of the crude
gas to produce steam; a crude gas scrubber and a partial
condensation system following the crude gas scrubber, or a
mechanical filtration dust separator.
20. A device pursuant to claim 19, further comprising water baths
in both the quenching cooler and the waste heat boiler, in which
water baths cooled slag is collected.
21. A device pursuant to claim 19, further comprising devices for
discharging slag on both the quenching cooler and the waste heat
boiler.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a gasification method and a device
for implementing the method. The method consists of the process
steps of slurry preparation, fuel infeed, gasification reaction,
partial quenching, gas scrubbing, and partial condensation. Gas
scrubbing and partial condensation can be replaced by mechanical
dust separation, to produce gases containing CO and H.sub.2 by
partial oxidation of powdered fuels containing ash with a
gasification medium containing free oxygen, at high temperatures
and elevated pressure.
[0003] To achieve long operating times, the pressurized jacket of
the gasification reactor has to be protected reliably against the
action of crude gas and against the high gasification temperatures
of 1200-1900.degree. C. This is done by confining the reaction or
gasification chamber with a cooled tubular shield that is hung in
the pressurized jacket. The annular gap between tubular shield and
pressurized jacket is flushed.
[0004] The fuel as a slurry is brought to the gasification pressure
by pump transport and is fed to the head of the reactor through
burners. One or more fuels or varieties of coal can be gasified at
the same time. The crude gas leaves the gasification chamber
together with the liquefied slag at the bottom of the reactor and
is then partially cooled to 700.degree. C. to 1100.degree. C. by
injecting water, and is freed of entrained fines after recovering
the waste heat. The scrubbed crude gas is then fed to further
treatment steps.
[0005] 2. The Prior Art
[0006] The autothermic entrained flow gasification of solid,
liquid, and gaseous fuels has been known in the technology of gas
production for years. The ratio of fuel to gasification medium
containing oxygen is chosen so that higher carbon compounds are
completely cracked for reasons of synthesis gas quality into
synthesis gas components such as CO and H.sub.2, and the inorganic
components are discharged as molten slag; see J. Carl, P. Fritz,
NOELL-KONVERSIONSVERFAHREN, EF-Verlag fur Energie und Umwelttechnik
GmbH, 1996, p. 33 and p. 73.
[0007] According to various systems used in industry, gasification
gas and molten slags can be discharged together from the reaction
chamber of the gasification device, as shown in DE 197 131 A1.
Either systems with refractory linings or cooled systems are used
for the inner confinement of the reaction chamber structure of the
gasification system; see German Patent No. DE 4446 803 A1.
[0008] European Patent No. EP 0677 567 B1 and PCT Publication No.
WO 96/17904 show a method in which the gasification chamber is
confined by a refractory lining. This has the drawback that the
refractory masonry is loosened by the liquid slag formed during
gasification, which leads to rapid wear and high repair costs. This
wear process increases with increasing ash content. Thus, such
gasification systems have a limited service life before replacing
the lining. Also, the gasification temperature and the ash content
of the fuel are limited. Feeding in the fuel as a coal-water slurry
causes considerable losses of efficiency--see C. Higman and M. van
der Burgt, "Gasification", Verlag ELSEVIER, USA, 2003--which can be
prevented or reduced by using oil as a carrier medium or by
preheating the coal-water slurry. A quenching or cooling system is
also described, with which the hot gasification gas and the liquid
slag are carried off together through a conduit that begins at the
bottom of the reaction chamber, and are fed into a water bath. This
joint discharge of gasification gas and slag can lead to plugging
of the conduit and thus to limitation of availability.
[0009] German Patent No. DE 3534015 A1 shows a method in which the
gasification media, powdered coal and oxidizing medium containing
oxygen, are introduced into the reaction chamber through multiple
burners in such a way that the flames are mutually deflected. The
gasification gas loaded with powdered dust flows upward and the
slag flows downward into a slag-cooling system. As a rule, there is
a device above the gasification chamber for indirect cooling
utilizing the waste heat. However, because of entrained liquid slag
particles, there is the danger of deposition and coating of heat
exchanger surfaces, which hinders heat transfer and may lead to
plugging of the pipe system and/or erosion. The danger of plugging
is counteracted by cooling the hot crude gas with a circulated
cooling gas.
[0010] Ch. Higman and M. van der Burgt in "Gasification", page 124,
Verlag Elsevier 2003, describe a method in which the hot
gasification gas leaves the gasifier together with the liquid slag
and directly enters a waste heat boiler positioned perpendicularly
below it, in which the crude gas and the slag are cooled with
utilization of the waste heat to produce steam. The slag is
collected in a water bath, while the cooled crude gas leaves the
waste heat boiler from the side. A series of drawbacks detract from
the advantage of waste heat recovery by this system, such as the
formation of deposits on the heat exchanger tubes, which lead to
hindrance of heat transfer and to corrosion and erosion, and thus
to lack of availability.
[0011] Chinese Patent No. CN 200 4200 200 7.1 describes a "Solid
Pulverized Fuel Gasifier", in which the powdered coal is fed in
pneumatically and gasification gas and liquefied slag are
introduced into a water bath through a central pipe for further
cooling. This central discharge in the central pipe mentioned is
susceptible to plugging that interferes with the overall operation,
and reduces the availability of the entire system.
SUMMARY OF THE INVENTION
[0012] It is therefore an object of the invention to provide a
gasification method that takes into account the different ash
contents of fuels and has high availability, with reliable
operation.
[0013] This task is accomplished by a gasification method for the
gasification of solid fuels containing ash with an oxidizing medium
containing oxygen, in a gasification chamber designed as an
entrained flow reactor, at pressures between atmospheric pressure
and 100 bar, in which the reaction chamber contour is confined by a
cooling system, with the pressure in the cooling system always
being chosen to be higher than the pressure in the reaction
chamber. The method is distinguished by the following features:
[0014] The fuel, e.g. bituminous coal, bituminous coke and lignite
coke, as well as biomass coke and/or petroleum coke and/or their
mixtures, are pulverized to a grain size of <500 .mu.m,
preferably <200 .mu.m, and are mixed to make a fuel-in-water or
fuel-in-oil suspension, a so-called slurry, by adding liquids such
as water or oil. Stable solids concentrations of up to 70 wt. % are
achieved when using water as the carrier medium with added
surfactants. These are brought to the desired gasification pressure
of up to a maximum of 100 bar by means of suitable pumps, and are
fed for the gasification reaction through suitable burners that are
attached at the head of the gasification reactor. The fuel
concentration in the slurry and the amount of flowing slurry are
monitored, measured, and regulated by measurement devices, control
devices, and monitors. An oxidizing medium containing free oxygen
is fed to the burner at the same time, and the fuel is converted
into crude synthesis gas by partial oxidation. The gasification
takes place at temperatures between 1,200.degree. C. and
1,900.degree. C. at pressures up to 100 bar. The reactor is
equipped with a cooling shield that consists of water-cooled pipes
welded gas-tight.
[0015] The hot crude synthesis gas leaves the gasification chamber
together with the liquid slag formed from the fuel ash, and arrives
at a chamber perpendicularly under it, in which partial quenching
occurs by injecting water or by feeding in a cold gas, whereby it
is cooled to temperatures between 700.degree. C. and 1,100.degree.
C. At this temperature, the entrained liquid slag has been cooled
to the extent that it can no longer adhere to the metallic
surfaces. The crude gas cooled to temperatures of 700.degree. C.
and 1,100.degree. C. then arrives at a waste heat boiler together
with the likewise cooled solid slag, to utilize the sensible heat
for steam production. This partial quenching or partial cooling
prevents or sharply reduces the risk of slag caking on the waste
heat cooling pipes. The water or recycled gas condensate needed for
the partial quenching is fed in through nozzles that are located
directly on the jacket. The cooled slag is collected in a water
bath located at the bottom of the waste heat boiler. The crude gas,
cooled to 200.degree. C.-300.degree. C., leaves the waste heat
boiler at the side and reaches a crude gas scrubber, suitably a
Venturi scrubber. The entrained dust is thereby removed down to a
grain size of about 20 .mu.m. This degree of purity is still
inadequate for carrying out subsequent catalytic processes, for
example crude gas conversion. It also has to be considered that
salt mists are also entrained in the crude gas, which have detached
from the powdered fuel during gasification and are carried off with
the crude gas. To remove both the fine dust <20 .mu.m and the
salt mists, the scrubbed crude gas is fed to a condensation step in
which the crude gas is chilled indirectly to about 5.degree. C. to
10.degree. C. Water is thereby condensed from the crude gas
saturated with water vapor, which absorbs the described fine dust
and salt particles. The condensed water containing the dust and
salt particles is separated in a following separator. The crude gas
purified in this way can then be fed directly, for example, to a
crude gas converter or desulfurization system.
[0016] Instead of the scrubbing and condensation steps, a
mechanical dust separator can be provided that operates at
200.degree. C. to 300.degree. C., for which centrifugal separators
or filter systems can be used.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Other objects and features of the present invention will
become apparent from the following detailed description considered
in connection with the accompanying drawings. It is to be
understood, however, that the drawings are designed as an
illustration only and not as a definition of the limits of the
invention.
[0018] In the drawings, wherein similar reference characters denote
similar elements throughout the several views:
[0019] FIG. 1 shows a lock diagram of the technology;
[0020] FIG. 2 shows a gasification reactor with partial quenching
and perpendicularly arranged waste heat boiler; and
[0021] FIG. 3 shows a gasification reactor with partial quenching
and adjacent waste heat boiler.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0022] 320 tons/hour of bituminous coal with a composition of
TABLE-US-00001 C 71.5 wt. % H 4.2 wt. % O 9.1 wt. % N 0.7 wt. % S
1.5 wt. % Cl 0.03 wt. %,
an ash content of 11.5 wt. %, and a moisture content of 7.8 wt. %,
is to be gasified at a pressure of 40 bar. The calorific value of
the coal is 25,600 kJ/kg. The gasification takes place at
1,450.degree. C. 245,000 m.sup.3 (standard)/h of oxygen is needed
for the gasification. The coal is first fed to a state-of-the-art
grinder in which it is pulverized to a grain size range between 0
and 200 .mu.m, and is then mixed in a special system 1 according to
FIG. 1 with water with added surfactants to make a stable coal dust
in water suspension, the so-called slurry. The solids concentration
in this slurry is 63 wt. %, and the amount of slurry is 485
tons/hour. The slurry is brought to the desired gasification
pressure of 100 bar by means of a pump suitable for pumping
solid-liquid suspensions, and is fed to the burner of the
gasification reactor 2 of FIG. 1 through the supply line 1.1, with
the amount being monitored, measured, and regulated. To conserve
oxygen, the slurry can be preheated up to 400.degree. C., depending
on the gasification pressure, prior to being fed into the
gasification reactor 2.
[0023] FIGS. 2 and 3 show the gasification reactor. The slurry
flowing to the gasification reactor through the feed line 1.1 at
465 tons/hour is subjected to partial oxidation at 1450.degree. C.
along with the 245,000 m.sup.3 (standard)/hour of oxygen flowing to
the gasification chamber 2.3 through the line 2.1, with 565,000
m.sup.3 (standard)/hour of crude gas being formed with the
following composition: TABLE-US-00002 H.sub.2 18.5 vol. % CO 70.5
vol. % CO.sub.2 6.1 vol. % N.sub.2 2.3 vol. % NH.sub.3 0.003 vol. %
HCN 0.002 vol. % H.sub.2S 0.5 vol. % COS 0.07 vol. %.
[0024] The gasification chamber 2.3 is confined by a cooling shield
2.4 that consists of a water-cooled tube system welded gas-tight.
The crude gas together with the liquid slag flows through the
outlet opening 2.5 into the chamber 3.1 for partial
quenching/partial cooling of the crude gas to temperatures of
700.degree. C.-1,100.degree. C. At this temperature, along with the
crude gas, the slag is also cooled to such an extent that it cannot
be deposited in the pipes 4.1 of the waste heat boiler that follows
according to FIG. 1. The steam generated in the waste heat boiler 4
is utilized in the process to preheat the oxidizing medium
containing oxygen or as a gasification moderator to preheat the
slurry. The slag is collected in a water bath 4.2 located at the
bottom of the waste heat boiler and is discharged through 4.3. The
crude gas leaves the waste heat boiler through 4.4 and arrives at
crude gas scrubber 5 according to FIG. 1. Waste heat boiler 4,
however, can be located according to FIG. 3 directly beneath
gasification reactor 2 and partial quencher 3, but also, as shown
in FIG. 4, beside it. In this case, there is a slag discharge 4.3
beneath partial quencher 3 and also one below waste heat boiler
4.6. The crude gas leaving waste heat boiler 4 through outlet 4.4
then arrives at the crude gas scrubber 5 according to FIG. 1, which
is an adjustable Venturi scrubber to which is fed about 100
m.sup.3/h of wash water. The wash water is freed of absorbed solids
in the usual way and is fed again to the Venturi scrubber. The wash
water can be preheated in order to wet the crude gas further at the
same time as the washing. To remove fine dust <20 .mu.m in size
and salt mists not separated in the Venturi scrubber, the
water-washed crude gas is subjected to partial condensation 6
according to FIG. 1, with the crude gas being chilled indirectly to
about 5-10.degree. C. The finest dust and salt particles are taken
up by the water vapor condensing during the chilling and thus
removed from the crude gas. The crude gas cleansed of solids then
has the following composition: TABLE-US-00003 H.sub.2 13.4 vol. %
CO 51.4 vol. % CO.sub.2 4.5 vol. % N.sub.2 1.5 vol. % NH.sub.3
0.0022 vol. % HCN 0.0012 vol. % H.sub.2S 0.36 vol. % COS 0.05 vol.
% H.sub.2O 37.30 vol. %
[0025] The purified, wet crude gas amounts to 775,000 m.sup.3
(standard)/hour. It can be directly sent to a crude gas converter
or to other treatment steps.
[0026] Accordingly, while only a few embodiments of the present
invention have been shown and described, it is obvious that many
changes and modifications may be made thereunto without departing
from the spirit and scope of the invention.
LIST OF REFERENCE NUMERALS
[0027] 1 Slurry preparation and infeed [0028] 1.1 Slurry line
[0029] 2 Reactor [0030] 2.1 Line for oxygen [0031] 2.2 Burner
[0032] 2.3 Gasification chamber [0033] 2.4 Cooling shield [0034]
2.5 Outlet opening [0035] 3 Quenching cooler [0036] 3.1 Quenching
chamber [0037] 3.2 Nozzles in 3 [0038] 3.4 Transfer line from 3 to
4 [0039] 4 Waste heat boiler [0040] 4.1 Cooling pipes in the waste
heat boiler 4 [0041] 4.2 Water bath with slag in 4 [0042] 4.3 Slag
discharge from 4 [0043] 4.4 Opening from 4 to the crude gas
scrubber 5 [0044] 4.5 Water bath with slag 4 [0045] 4.6 Slag
discharge from 4 [0046] 5 Crude gas scrubber [0047] 6 Partial
condenser
* * * * *