SYSTEM AND METHOD FOR COOLING SYNGAS
PRODUCED FROM A GAS1F1ER
BACKGROUND OF THE INVENTION
[000 1] The present disclosure relates generally to integrated
gasification combined-axle (IGCC) power generation and, more specifically, to a
method and apparatus for cooling syngas from a gasifier.
002 At least some known IGCC power generation systems use
gasifiers that convert hydro-carbonaceous feedstock into a partially oxidized gas. The
partially oxidized gas, known as syngas," is used to fuel at least some combustion
turbines. However, before the syngas can be used, generally impurities such as
entrained solids carbon dioxide, and or hydrogen sulfide must be removed from the
syngas.
|0003 | Known IGCC power generation systems produce syngas at a
high temperature. To remove entrained solids, at least some known power operation
systems cool the syngas using radiant and convection syngas coolers. Known coolers
recover heat from syngas, thus reducing the syngas temperature to enable entrained
solids to drop out of the syngas stream in the form of slag and particulate matter. After
cooling and removing slag and particulate matter, the syngas is at a temperature that is
suitable for carbon dioxide and hydrogen sulfide removal. However, known coolers
are relatively large and expensive, and require an array of pumps, piping and steel
drums to effectively cool the syngas. Moreover, known coolers may require frequent
maintenance to avoid fouling problems.
1 00 1 Thus, a need exists for a less expensive, more compact syngas
cooler that is resistant to fouling and that does not require large amounts of anci llary
equipment. Furthermore, it is expected that energy will become more costly. Thus,
there is also a need for cooling equipment with enhanced efficiency and lifespan.
BRIEF DESCRIPTION OF THE INVENTION
|()005| n one aspect, a syngas cooler is provided. The syngas cooler
includes an outer wall that defines a cavity. A first membrane water wall is positioned
within the cavity. L thermal siphon is positioned between the first membrane water
wall and the outer wall and is configured to channel a flow of syngas therethrough to
facilitate cooling the channeled syngas.
[0006] In another aspect, a gas turbine engine system is provided.
The gas turbine engine system includes a compressor and a combustor in flow
communication with the compressor to receive at least some of the air discharged by
the compressor. A syngas cooler is coupled in flow communication with the
combustor for channeling a flow of syngas to the combustor. The syngas cooler
includes an outer wall that defines a cavity. A first membrane water wall is positioned
within the cavity. A thennal siphon is positioned between the first membrane water
wall and the outer wall and is configured to channel a flow of syngas therethrough to
facilitate cooling the channeled syngas.
1 0071 In a further aspect a method for cooling syngas produced in a
gasifier and separating slag and particulate matter from the syngas is provided. The
method includes surrounding a flow of syngas with three concentric, vertically oriented
membrane water walls inside a syngas cooling unit. Cooling fluid is channeled
through the three concentric membrane water walls. The syngas is passed down
through a first of the three membrane water walls to partially cool the syngas and
separate slag and particulate matter from the syngas. A thermal siphon is utilized to
pass the partially cooled syngas up between the first of the three membrane water walls
and a second of the three membrane water walls and then down between the third of
the three membrane water walls and the second of the three membrane water walls to
produce cooled output syngas.
BRIEF DESCRI PTION OF THE DRAWINGS
1 00 1 Figure is a schematic diagram of an exemplar) IGCC power
generation system.
[ 009] Figure 2 is a schematic diagram of an exemplary syngas cooler
system for use in the IGCC power generation system shown in Figure 1.
0010 Figure 3 is an isometric view of an exemplars' syngas cooler
for use in the syngas cooler system shown in Figure 2.
[00 11 Figure 4 is a cut-away isometric view of the syngas cooler
show in Figure 3 and taken along Line 3-3.
|00 12| Figure 5 is a cut-aw ay oblique top vie of a portion of the
syngas cooler shown in Figure 3 and taken along Line 4-4.
1 J Figure 6 is an isometric hidden-line view of a hal f pipe cooling
system that is coupled to an outer wall and that may be used with the syngas cooler
shown in Figure 3.
1 14] Figure 7 is cut-away isometric view of an alternative syngas
cooler shown in Figure 3 and taken along Line 3-3.
[0015] The figures of the drawings are not necessarily drawn to scale.
However, corresponding reference characters indicate corresponding parts throughout
the drawings.
DETAILED DESCRIPTION
[00 16] As used herein, the word "exemplary " is defined as
' characteristic of its kind or illustrating a general rule," and not necessarily as
"desirable " or "best. " Neither indi vidually cited exemplary embodi ments nor their
drawings shown herein necessarily il lustrate all of the inventi ve features that may be
combined in an embodiment. Also, some exemplary embodiments and/or their
drawings may show features not inventive by themselves but useful for understanding
the context of inventive features.
[0017] Moreover, the terms "first," "second," Hhird," etc., are
intended only to distinguish similar types of objects recited in the disclosure and/or
shown in the drawings. They are not meant to imply a numerical ordering for the
corresponding objects or any indication of time or quality unless explicitly stated.
Moreover, the presence of a "first," a "second." or a "third" object in an embodiment
does not necessarily imply the existence of any other similar objects in that particular
embodiment. For example an embodiment having a "first" wall does not necessarily
have a "second" such wall. Similarly, an embodiment having a "second" wall does not
necessarily have a first" such wall.
[0 | As used herein, the term "syngas" refers to synthesis gas made
from partially oxidized hydro-carbonaceous feedstock. Syngas varies in its exact
composition based on the feedstock used, but comprises mainly carbon monoxide,
hydrogen, water, carbon dioxide and possibly impurities such as hydrogen sulfide.
Syngas is used as fuel in combustors of at least some GCC plants.
[0019] Figure 1 illustrates an exemplary IGCC power generation
system 10 that includes an integrated syngas cooler system 11, a gas turbine engine
system 15, and a steam turbine engine system 23. Gas turbine engine system 15
includes a compressor 18, a combustor 16, a turbine 20 drivingly coupled to
compressor 18 and to a first electrical generator 22. Combustor 16 is coupled to
compressor 18 such that combustor 16 is in flow communication with compressor 1 .
Steam turbine engine system 23 includes a heat recovery steam generator (HRSG) 24,
a steam turbine 26 and a second electrical generator 28. In the exemplary embodiment
integrated syngas cooler system includes a gasifier 12 and a syngas cooler 14.
Gasifier 2 partially oxidizes fuel such as coal refinery residues, petroleum coke,
residual oil. oil emulsions, tar sands or other hydro-carbonaceous feedstock to make
syngas. Integrated syngas cooler system 11 is coupled to combustor 16 such that
integrated syngas cooler system 11 is in flow communication with combustor 16 for
channeling a flow of syngas to combustor 16. Combustor burns the syngas as fuel
to produce hot, high pressure gas. Compressor 8 draws in and compresses air. Hot.
high pressure gas from combustor 16 and compressed air from compressor 8 are
mixed together and channeled towards turbine 20. As the combustion gases expand,
turbine 20 is rotated to power first electrical generator 22. HRSG 24 produces steam
using waste heat from turbine 20. HRSG 24 supplies the steam to turbine 26, which
powers second electrical generator 28.
I0020 l In many cases, the hydro-carbonaceous feedstock contains
impurities such as ash, metal and minerals. Syngas generated from feedstock
containing such impurities often contains solid impurities in the form of entrained slag
and particulate matter. Thus, in some embodiments, the present invention separates
slag and particulate matter from the syngas, before carbon dioxide and hydrogen
sulfide removal, to avoid plugging and fouling. The syngas is at a high temperature
when discharged from gasifier 12. To facilitate the removal of slag and particulate
matter, the syngas is cooled by syngas cooler 14, after leaving gasifier 2 and before
the syngas enters combustor 16.
[002 1 Figure 2 is a schematic diagram of a syngas cooler system 30
for use in IGCC power generation system 10. Figure 3 is an isometric view of a
syngas cooler 3 for use in syngas cooler system 30. Figure 4 is a cut-away isometric
view of syngas cooler 31. Identical components shown in Figure 3 and Figure 4 are
labeled with the same reference numbers used in Figure 2 . In the exemplary
embodiment, syngas cooler system 30 includes a gasifier 29 positioned within syngas
cooler 31, a heat exchanger 32 coupled to syngas cooler 31. and a syngas scrubber 33
coupled to syngas cooler 3 1 and heal exchanger 32. A transfer line 1 2 is coupled
between syngas cooler 3 and heal exchanger 32. A first, or scrubbed syngas conduit
114 is coupled to syngas scrubber 33. transfer line 112, and heat exchanger 32 for
channeling a flow of scrubbed syngas from syngas scrubber 33 to transfer line 1 2 and
heat exchanger 32. A second, or heated scrubbed syngas conduit 6 is coupled
between heat exchanger 32 and combustor 1 for channeling a flow of heated scrubbed
syngas from heat exchanger 32 to combustor 16. In one embodiment, a gas cleaning
system 8 is coupled between heat exchanger 32 and combustor 16 for cleaning a
flow of heated scrubbed syngas from heat exchanger 32.
[0022] During operation of syngas cooler system 30, coal and oxygen
are channeled into gasifier 29 to facilitate production of syngas. Gasifier 29 channels
syngas through syngas cooler 3 1 for reducing a temperature of the syngas. A first
syngas flow 34 is channeled from syngas cooler 3 1 to transfer line 112 and to heat
exchanger 32 for heating a second, or scrubbed syngas flow 35 from syngas scrubber
33. Heat exchanger 32 further cools first syngas flow 34 by facilitating a transfer of
heat from first syngas flow 34 to second syngas flow 35. In an alternative
embodiment, heat exchanger 32 facilitates heating a flow of boiler feed water by
facilitating a transfer of heat from first syngas flow 34 to the boiler feed water to
generate high pressure steam. Heat exchanger 32 channels the syngas to syngas
scrubber 33 to scrub the syngas with water to facilitate removing particulates and
chlorides. More specifically, heat exchanger 32 channels first syngas flow 34 to
syngas scrubber 33 for facilitating removal of particulates and chlorides from first
syngas flow 34. Syngas scrubber 33 channels a first portion 36 of scrubbed second
syngas flow 35 to transfer line 1 2 to facilitate reducing a metal temperature in transfer
line 112 and to facilitate preventing fouling of and solids deposition within transfer
line 112 and heat exchanger 32. Syngas scrubber 33 further channels a second portion
38 of scrubbed syngas flow 35 to heat exchanger 32. A small amount of dry, heated
recycled syngas gas is then mixed with the scrubbed syngas to desaturale (superheat)
the syngas and to dry any carryover solids to facilitate eliminating solid deposition in
heat exchanger 32. Second syngas flow 35 includes syngas with a substantially
reduced flow of particulates and chlorides. As second syngas flow 35 enters heat
exchanger 32, heal from first syngas flo 34 is transferred to second syngas flow 35.
First portion 36 is further channeled from transfer line 112 to heal exchanger 32 to be
mixed with second portion 38 and healed. Heat exchanger 32 channels a third, or
heated scrubbed syngas flo 40 towards combustor 16 for use in combustion. In one
embodiment, heat exchanger 32 channels third syngas flow 40 to gas cleaning system
118.
0023 In the exemplary embodiment, syngas cooler 3 1 includes a
syngas cooler outer wall 37 that defines a cavity 42, a feed injector 39, a cooled syngas
outlet 41, and a plurality of membrane water walls 43 positioned within cavity 42.
Gasifier 29 is contained within syngas cooler 3 and is positioned in a top section 46 of
a first membrane water wall 44. Feed injector 39 is configured to channel a flow of
fuel, such as coal or other carbonaceous material, and oxygen to gasifier 29. Gasifier
29 facilitates the production of syngas and channels the syngas through syngas cooler
31. Hot syngas from gasifier 29 is circumscribed by, and enters through, first
membrane water wall 44. First membrane water wall 44 is substantially cylindrical
and is substantially centered about a vertical centerline 1 0 through gasifier 29 and
syngas cooler 31, such that at least most slag contained in the hot syngas falls
downward and is collected at a lockhopper 45 coupled to syngas cooler outer wall 37.
In the exemplan embodiment, first membrane water wall 44 contains a plurality of
tubes or passages (not shown) through which cooling fluid circulates. The syngas and
cooling fluid are not in direct contact, although heat from the syngas is transferred to
the cooling fluid through radiation and convection as the syngas is channeled through
first membrane water wall 44. In some embodiments, first membrane water wall 44 is
fabricated at least partially from a high alloyed material (for example, Incology 800
LC) to facilitate preventing high temperature sulfidalion and corrosion. First
membrane water wall 44 includes top section 46, a second or mid section 47, and a
third or lower section 48. In one embodiment, top section 46 and/or gasifier 29 is
coated with a ramming mix refractory layer such as, but not limited to, a chromium or
silicone carbide (SiC) based material.
02 In the exemplary embodiment, mid section 47 includes a first
obliquely oriented wall 49 that defines a passage 5 1 inside first membrane water wall
44. First wall 49 defines a passageway that terminates in passage 5 1 that is narrower at
its lower end than at its upper end, such that an area/diameter ratio and a more uniform
resident time distribution for the syngas and slag passing therethrough are each
facilitated to be increased. As a result, the amount of coarse slag is facilitated to be
increased. In the exemplary embodiment, first wall 49 is fabricated from refractory
brick to facilitate withstanding the high temperature syngas. In other embodiments, a
decreased water wall radius may be achieved by removing tubes (not shown in the
Figures) from first membrane water wall 44. A second obliquely oriented wall 55
belo passage 5 1 defines a passageway that is narrower at its upper end than at its
lower end. In the exemplars embodiment, first wall 49 and second wall 55 are each
fabricated from refractory brick to facilitate withstanding the high temperature syngas.
1 02 -In the exemplar) embodiment, a second membrane water wall
59 circumscribes first membrane water wall 44 inside syngas cooler 31. As such,
second membrane water wall 59 has a larger diameter than first membrane water wall
44. Second membrane water wall 59 includes a plurality of first radial wing walls 57
that extend radially inwardly to support second membrane water wall 59 and that
couple to first membrane water wall 44. First radial wing wall 57 can be of any size,
shape, dimension and number, without departing from the scope of this disclosure. For
example, in the exemplary embodiment, more than fifteen first radial wing walls 57 are
used. n another embodiment, more or ess than fifteen first radial wing walls 57 are
used. In still other embodiments, more or less than fifteen first radial wing walls 57
are used.
[0026] Also, in the exemplary embodiment a third membrane water
wall 1 circumscribes second membrane water wall 59 inside syngas cooler 3 1. Third
membrane water wall 6 1 is substantially similar to second membrane water wall 59 but
has a larger diameter than water wall 59. Third membrane water wall 6 in some
embodiments is supported against syngas cooler outer wall 37. Also, third membrane
water wall 6 1 includes second radial wing walls 69 that extend radially inwardly to
support third membrane water wall 6 and that couple to second membrane water wall
59. The number, size, and dimensions of second radial ing walls 69 can vary
between embodiments, but in some embodiments, the same number of first radial wing
walls 57 and second radial wing walls 69 are used such that each walls 57 and 69 are
aligned in the same radial pattern. In some embodiments, first membrane water wall
44, second membrane water wall 59, and third membrane water wall 6 1 are
substantially concentrically aligned.
10027 1 In the exemplar* embodiment, a plurality of first uncooled
baffles 63 extends from a bottom 62 of second membrane water wall 5 . Baffles 63
are oriented inwardly to define a first lower passage 65. Also, in the exemplary
embodiment, a plurality of second uncooled baffles 7 1 extends from a bottom 70 of
third membrane water wall 61. Baffles 7 1 are oriented inwardly to define a second
lower passage 73. Lockhopper 45 is positioned below second lower passage 73 to
collect coarse slag falling from the syngas stream, while the cooled syngas is
channeled from syngas cooler 3 1 through syngas outlet 41. Lockhopper 45 is
maintained with a level of water that quenches the flowable slag into a brittle solid
material that may be broken into smaller pieces when removed from syngas cooler 31.
The cooled syngas discharged from syngas outlet 4 1 may contain fine slag particles,
which can be removed with additional processing. Substantially all of the coarse slag
is removed via lockhopper 45.
[0028] Syngas entering syngas cooler 3 1 through gasifier 29 is
substantially cooled by flowing downward along first membrane water wall 4
Passage , located at or substantially near a center of first membrane water wall 44,
facilitates concentrating the slag stream into the center of first membrane water wall 44
to promote recirculation of the syngas. In contrast to the coarse slag, which falls under
the force of gravity into lockhopper 45, partially cooled syngas flows in an upwardly
direction 75 into an annular space 74 divided by first radial wing walls 57 and defined
between first membrane water wall 44 and second membrane water wall 59. This
syngas is further cooled and flows in a downwardly direction 76 into an annular space
77 divided by second radial wing walls 69 and defined between second membrane
water wall 59 and third membrane water wall 61. A thermal siphon 79 created by a
density difference between the upwelling syngas, indicated by arrow 75 and the
downwelling syngas indicated by arrow 78, creates the desired ow pattern (i.e., hot
gas rises, cold gas falls). The existence of thermal siphon 79 allows hot, coarse slag to
be removed from the syngas while allowing the syngas to be cooled to a temperature
that is suitable for carbon dioxide and hydrogen sulfide removal. In the exemplaryembodiment,
syngas channeled through lower section 48 of first membrane water wa l
44 includes a temperature between about 00 F to about 1 00 F. As syngas flows
upwardly through annular space 74 and into thermal siphon 79, the sv ngas is further
cooled, such that syngas entering annular space 77 includes a temperature between
about I30()°F to about 200 . Syngas channeled through annular space 77 and
through thermal siphon 79 is further cooled, such that syngas entering lower passage
73 includes a temperature between about lOOO to about 800°F.
[0029] Figure 5 is a cut-away oblique top view of a portion of syngas
cooler 3 1 shown in Figure 3 and taken along Line 4-4. Identical components shown in
Figure 5 are labeled with the same reference numbers used in Figure 4. In the
exemplary embodiment, at least one coolant entry 80 is coupled to at least one
membrane water wall 43 for channeling a flow of cooling fluid through membrane
water wall 43. In an alternative embodiment, coolant, e.g., water, is supplied to first
membrane water wall 44 via one or more first coolant entries Similarly, coolant is
supplied to second membrane water wall 59 via one or more second coolant entries 83,
and coolant is supplied to third membrane water wall 1 via one or more third coolant
entries 85. Although entry points and egress points for steam and coolant are not
illustrated on Figures I, 2, and 3, after becoming familiar with the embodiments
described herein, one of ordinary skill in the art would be able to choose such entrypoints
and egress points as a design choice. In one embodiment, one or more steam
headers 86 extend through passageways (not shown) between either first membrane
water wall 44 and second membrane water wall 59, and or between second membrane
water wall 59 and third membrane water wall 6 1 .
[0030] In the exemplary embodiment, and referring to Figure 6, a
plurality of "half pipes" 89 with semicircular cross-sections are positioned on syngas
cooler outer wall 37 or may be welded to an interior surface 90 of third membrane
water wall 61. In the embodiments using a replacement wall, an outer surface (not
shown) of the replacement wall is welded to an interior surface of syngas cooler outer
wall 37. n at least one embodiment, half pipes 89 are coolant pipes fabricated from
low alloy that is coated with a protective SiC coating. Although not shown in the
drawings, in some embodiments, second radial wing walls 69 extend inwardly to
couple to second membrane water wall 5 . Second uncooled baffles 7 1 are angled
inwardly to form second lower passage 73. In embodiments with a plurality of half
pipes 89, coolant circulating in ha f pipes 8 facilitates cooling the flow of syngas
indicated by arrow 78 (shown in Figure 4).
003 Figure 7 is a cut-away isometric view of an alternative syngas
cooler 202 for use the IGCC power generation system 10. A quench wall 208 extends
downstream from third membrane water wall 6 1 to define a portion of main syngas
flowpath 78. In the exemplary embodiment, quench wall 208 is substantially conical
and tapers inward, or converges, from an upstream end 2 1 towards a downstream end
12. Downstream end 12 is coupled to a quench ring 214 within a quench chamber
2 16 positioned below second lower passage 73. In the alternative embodiment, quench
chamber 2 16 facilitates the rapid cooling of syngas flowing therethrough. Moreover,
in the alternative embodiment, quench chamber 2 16 includes quench ring 2 4. a dip
lube 2 18, a draft tube 220, splash plate 222, a water bath 224, and a syngas outlet 226.
Although water is described herein as the fluid used to quench the syngas, any suitable
non-reactive fluid, such as a liquid and/or a gas, may be used for quenching. In an
alternative embodiment, quench ring 2 14 may be coupled to a sump (not shown), a
quench water supply (not shown), and/or any other suitable component that enables
syngas cooler 202 to function as described herein.
[0032] In an alternative embodiment, dip tube 2 18 and draft tube 220
are substantially concentrically aligned with centerline 110. An upstream end 230 of
dip tube 2 1 and an upstream end 232 of draft tube 220 are positioned adjacent to
quench wall 208. A downstream end 234 of dip tube 2 18 and a downstream end 236
of draft tube 220 extend into water bath 224. Furthermore, in the exemplary
embodiment, splash plate 222 is generally annular and extends about draft tube 220.
|0033 | Water bath 224 includes, in the exemplary embodiment, water
(not shown), a sump (not shown), and or a blowdown line (not shown). Although
water bath 224 is described as having water therein water bath 224 may include
fluids other than water and still be considered a " water bath. "' Rather, water bath 224
is a portion of quench chamber 216 that is configured to retain water therein. In the
exemplary embodiment, dip tube 218 and draft tube 220 are each at least partially
submerged in water within water bath 224. In addition, in the exemplary
embodiment, quench chamber 216 includes at least one syngas outlet 226 that extends
through syngas cooler outer wall 37.
[0034] During system operation, syngas produced from gasifier 29 is
channeled downward along first membrane water wall 44 through passage 5 1 and into
lower section 48. Second membrane water wall 59 channels partially cooled syngas
upwardly into annular space 74 and into thermal siphon 79. As syngas is further
cooled, third membrane water wall 6 1 channels cooled syngas downwardly through
annular space 77 and into quench chamber 216. More specifically, third membrane
water wall 6 and quench wall 208 channel the syngas into quench chamber 216.
Water is channeled into quench ring 2 14 for discharge into quench chamber 2 16 along
dip tube 2 1 and into water bath 224. Slag (not shown) formed as the syngas cools
falls into water bath 224 for discharge from syngas cooler 202. As the syngas flows
through and/or along dip tube 218, draft lube 220, and/or splash plate 222, the
particulates within syngas form slag. The remaining syngas is substantially
particulate-free and is discharged from syngas cooler 202 through syngas outlet 226.
In one embodiment, syngas channeled from syngas cooler 202 through syngas outlet
226 includes a temperature between about 350°F to about 300°F.
[0035] At least some of the advantages of the above-described
embodiments include greater heat transfer surface for the syngas, as both sides of first
membrane water wall 44 and an additional, second membrane water wall 59 are used
for cooling, as well as one side of an additional, third membrane water wall 6 1 or its
replacement with half pipes 89. Thus, much more heat transfer surface density is
achieved than is possible in embodiments that include only one membrane water wall.
Additionally, the high alloy heat transfer materials are used with greater efficiency
because both sides of the high alloy heat transfer surface are used. n addition, slag is
disengaged after a first pass through syngas cooler 31, i.e., through first membrane
water wall 44 to facilitate minimizing fouling on the second two passes extending
through the thermal siphon 79. In addition, a long effective syngas path length defined
through syngas cooler 3 1 with shorter sight lengths promotes heat transfer. The long
path length promotes pure plug flow, maximizes syngas temperature, and improves
radiant heat transfer. The short sight length also helps heat transfer in the radiant
cooler because slag-containing gas is generally opaque. Furthermore the short sight
length helps eliminate a colder zone next to the membrane water walls.
.0036] In embodiments in which gasifier 12 is separate from, i.e.. not
contained within syngas cooler 31, further advantages of the above-described
embodiments include using only a minimal size increase in the syngas cooler 3 1 to
achieve cooling, without using an additional cooling system (i.e.. pumps piping, steam
drums) in syngas cooler 31. thus reducing costs and improving availability.
Furthermore, because of the water cooling, gasifier refractory life is extended, even at
higher operating temperatures. Thus, carbon conversion efficiency per pass is
improved and the cost of handling fine slag is reduced.
.0037] In embodiments in which gasifier 12 is contained within
syngas cooler 31, further advantages include the elimination of a need for a transfer
line and convective syngas cooler. Although the radiant syngas cooler 3 1 height is
increased, lower cost tubes can be used for the reduced temperature service. The
savings from the reduction in footprint and the equipment reduction can more than
offset the incremental cost increase of the radiant syngas cooler. In addition, lower
alloy tubes can be used for approximately half of the heat transfer surface area, therebyreducing
cost and allowing more fabrication options because there is an inner high
alloy bundle and an outer low alloy bundle and pressure vessel. Furthermore, all raw
syngas is on the shell side in the water tube configuration and all heal transfer surfaces
are vertical, thereby reducing or eliminating issues concerning cooler plugging and
deposition. Also, there is a low differential pressure on the tubes in the scrubbed
syngas section of the syngas cooler, thereby allowing the use of thinner tubes to reduce
cost, weight, and heat transfer surface requirements.
[0038] When introducing elements of the present invention or
preferred embodiments thereof, the articles "a", "an", "the", and "said" are intended to
mean that there are one or more of the elements. The terms "comprising", "including",
and "having" are intended to be inclusive and mean that there ma be additional
elements other than the listed elements.
1003 As various changes could be made in the above constructions
and methods without departing from the scope of the invention, it is intended that all
matter contained in the above description and shown in the accompanying drawings
shall be interpreted as illustrative and not in a limiting sense.
10040] Exemplary embodiments of a system and method for cooling
syngas produced from a gasifier are described above in detail. The system and
methods are not limited to the specific embodiments described herein, but rather,
components of the apparatus and/or steps of the methods may be utilized
independently and separately from other components and/or steps described herein.
For example, the methods may also be used in combination with other gasifiers and
methods, and are not limited to practice with only the syngas cooler system as
described herein. Rather, the exemplary embodiment can be implemented and
utilized in connection with many other syngas cooling applications.
|0041 | Although specific features of various embodiments of the
invention may be shown in some drawings and not in others, this is for convenience
only. In accordance with the principles of the invention, any feature of a drawing
may be referenced and or claimed in combination with any feature of any other
drawing.
[0042] While the methods and systems described herein have been
described in terms of various specific embodiments, those skilled in the art will
recognize that the methods and systems described herein can be practiced with
modification within the spirit and scope of the appended claims.

WHAT IS CLAIMED IS:
1. A syngas cooler comprising:
an outer wall defining a cavity:
a first membrane water wall positioned within said cavity; and
a thermal siphon positioned between said first membrane water wall
and said outer wall, said thermal siphon configured to channel a flow of syngas
therethrough to facilitate cooling the channeled syngas.
2. A syngas cooler in accordance with Claim 1 further comprising:
a second membrane water wall substantially concentrically aligned
with said first membrane water wall; and
a third membrane water wall substantially concentrically aligned with
said second membrane water wall, wherein said second membrane water wall is
between said first membrane water wall and said third membrane water wall.
3 . A syngas cooler in accordance with Claim 2 further comprising a
lockhopper coupled to said outer wall for collecting slag contained in the injected
syngas.
4 . A syngas cooler in accordance with Claim 2 further comprising a
first angled wal extending inward from said first membrane water wall, and a second
angled wall coupled to said first angled wall, said first angled wall and said second
angled wall are configured to promote recirculation of the syngas.
5. A syngas cooler in accordance with Claim 2 further comprising first
radial wing walls coupled between said first membrane water wall and said second
membrane water wall, and second radial wing walls coupled between said third
membrane water wall and said second membrane water wall.
6. A syngas cooler in accordance with Claim 2 further comprising a
ramming mix refractor*' coating layer coupled to a top section of said first membrane
water wall.
7 L syngas cooler in accordance with Claim 2 further comprising at
least one half pipe coupled to an inner surface of said third membrane water wall
wherein said half pipe comprises a low alloy half pipe and a SiC coating.
8. A syngas cooler in accordance with Claim 2 further comprising at
least one entry coupled to at least one of said first membrane water wall, said second
membrane water wall, and said third membrane water wall for channeling a flow of
cooling fluid therethrough.
9 . A syngas cooler in accordance with Claim 1 further comprising a
gasifier positioned within a top portion of said first membrane water wall and
configured to channel hot syngas downward inside said first membrane water wall.
10. A syngas cooler in accordance with Claim 2 further comprising a
quench wall coupled to said third membrane water wall for channeling the sygnas
from the thermal siphon to a quench chamber, wherein said quench chamber
facilitates rapidly cooling the syngas.
11. A gas turbine engine system comprising:
a compressor:
a combustor in flow communication with said compressor to receive at
least some of the air discharged by said compressor; and
a syngas cooler coupled in flow communication with said combustor
for channeling a flow of syngas to said combustor, said syngas cooler comprising.
an outer wall defining a cavity;
a first membrane water wall positioned within said cavity; and
a thermal siphon positioned between said first membrane water wall
and said outer wall said thermal siphon configured to channel the s gas
therethrough to facilitate cooling the channeled syngas.
12. L gas turbine engine system in accordance with Claim 1, wherein
said syngas cooler further comprises:
a second membrane water wall substantially concentrically aligned
with said first membrane water wall; and
a third membrane water wall substantially concentrically aligned with
said second membrane water wall wherein said second membrane water wall is
positioned between said first membrane water wall and said third membrane water
a l.
13. A gas turbine engine system in accordance with Claim 1 wherein
said syngas cooler further comprises a gasifier positioned within a top portion of said
first membrane water wall and configured to channel hot syngas downward inside
said first membrane water wall.
14. A gas turbine engine system in accordance with Claim 12, wherein
said syngas cooler further comprises a quench wall coupled to said third membrane
water wall for channeling the sygnas from the thermal siphon to a quench chamber
wherein said quench chamber facilitates rapidly cooling the syngas.
15. A gas turbine engine system in accordance with Claim 11, further
comprising a heat exchanger coupled between said syngas cooler and a syngas
scrubber, wherein said syngas cooler channels a first flow of syngas to said heat
exchanger, said syngas scrubber channels a second flow of syngas to said heat
exchanger for transferring heat from said first flow of syngas to said second flow of
syngas.
1 . A method for cooling syngas produced in a gasifier and separating
slag and particulate matter from the syngas, the method comprising:
surrounding a flow of syngas with three concentric vertically oriented
membrane water walls inside a syngas cooling unit;
channeling cooling fluid through the three concentric membrane water
walls:
passing the syngas down through a first of the three membrane water
walls to partially cool the syngas and separate slag and particulate matter from the
syngas; and
utilizing a thermal siphon to pass the partially cooled syngas up
between the first of the three membrane water walls and a second of the three
membrane water walls and then down between the third of the three membrane water
walls and the second of the three membrane water walls to produce cooled output
syngas.
17. A method in accordance with Claim 16 further comprising using
the cooled output syngas to generate electrical power.
1 . A method in accordance with Claim 17 wherein using the syngas
to generate electrical power comprises burning the cooled output syngas to produce
hot, high pressure gas.
19. A method in accordance with Claim wherein using the syngas
to generate electrical power further comprises channeling the hot, high pressure gas
and compressed air from a compressor over a turbine to power a first electrical
generator.
20. A method in accordance with Claim 19 further comprising
operating a second generator using waste heat from the turbine