Note: Descriptions are shown in the official language in which they were submitted.
CA 02542552 2006-04-10
METHOD AND APPARATUS FOR COAL GASIFIER
FIELD
[0001] The present
disclosure relates generally to processing coal, and
particularly to forming a selected material from a coal precursor.
BACKGROUND
[0002] Since electricity and electrically powered systems are becoming
ubiquitous, it has become increasingly desirable to find sources of power. For
example, various systems may convert directly various petrochemical
compounds into electrical energy. Further, petrochemical compounds are used
to create various materials, such as steam, which are used to drive steam
powered turbines.
[0003] Various petrochemical compounds and forms, such as coal,
petroleum, and the like may be used to power various systems or produce heat
to
create steam. Various sources of certain compounds are expensive or difficult
to
extract and require complex machinery to process. Therefore, it is desirable
to
provide systems that are operable to produce various compounds, either
synthetics of generally known compounds or alternatives thereto to produce the
selected heat energy or electrical energy.
SUMMARY
[0004]
The present disclosure relates to a system to gasify coal in a
gasification process that provides for an efficient transfer of a coal heating
value
to a gas of similar heating value. For example, a system may be provided to
create at least a 90% or greater cold gas efficiency (CGE). Generally, CGE is
the
higher heating value (HHV) of the produced gas, such as synthesis gas, divided
by the HHV of the coal or petcoke. Synthesis gas may include hydrogen gas and
carbon monoxide and other compounds. The system may also produce a 93 %
or higher CGE according to various embodiments.
[0005] According to various embodiments a system to produce a
gaseous product from a solid starting material is disclosed. The system may
include a starting material supply, a first gasification subsystem, and a
second
CA 02542552 2006-04-10
gasification subsystem. Also, a pump system may provide a volume of the solid
starting material from the starting material supply and operable to form a dry
slurry of the solid starting material with a slurry material. A starting
material
recycling system may be used to increase the efficiency of the system or other
appropriate purposes. A cyclone separator interconnecting the first
gasification
subsystem and the second gasification subsystem may remove a volume of a
solid material from a stream of gas produced by the first gasification
subsystem
prior to the stream passing to the second gasification subsystem. The pump
increases a pressure of the solid starting material to a pressure greater than
an
ambient pressure.
[0006] According to various embodiments a system for forming a gas of
a solid material is disclosed. The system may include a pressurizing sub-
system
with a pump operable to form a dry slurry of the solid material with a slurry
material to pressurize the solid material and a solid material supply to
provide a
selected volume of the solid material to be pressurized in the pressurizing
system. Also a first sub-system to process the solid material to a first
product
having a temperature greater than about 1300 C may be used with a second
sub-system to process the first product to a second product having a
temperature
less than about 950 C. A separation system may remove a solid material from
the first product formed by the first subsystem. The system may also include a
solid material recycle subsystem that is operable to provide a portion of the
solid
material unprocessed in the first subsystem or second subsystem for
reprocessing in at least one of the first subsystem or the second subsystem.
[0007] According to various embodiments a method of forming a gas
from a solid material including a first and a second gasification system is
disclosed. The method may include pressurizing the solid material to a first
pressure that may be performed by forming a slurry of the solid material with
a
non-aqueous material to form a slurry to be pressurized. A first portion of
the
solid material may be gasified to form a product at a first temperature and
the
product may be processed to a second temperature. Adding a second portion of
the solid material may assist in forming the second temperature. Both a
selected
material and an unprocessed material may be removed from the product. The
unprocessed material may be gasified with a first portion of the solid
material.
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CA 02542552 2013-02-20
[0008] Further areas of applicability of the present teachings will
become
apparent from the description provided hereinafter. It should be understood
that the
description and various examples, while indicating various embodiments are
intended
for purposes of illustration only and are not intended to limit the scope of
the
teachings.
[0008.1] In accordance with one aspect of the present invention, there is
provided a system to produce a gaseous product from a solid starting material,
comprising: a first gasification subsystem; a second gasification subsystem;
and a
pump system connected in parallel and in series with the first gasification
subsystem
and the second gasification subsystem for providing a volume of the solid
starting
material to the first gasification subsystem and the second gasification
subsystem, the
pump system being operable to form a dry slurry of the solid starting material
with a
slurry material; and a cyclone separator interconnecting said first
gasification
subsystem and said second gasification subsystem; wherein said cyclone
separator
removes a volume of a solid material from a stream of gas produced by said
first
gasification subsystem prior to the stream passing to said second gasification
subsystem; wherein said pump system increases a pressure of the solid starting
material to a pressure greater than an ambient pressure.
[0008.2] In accordance with another aspect of the present invention, there is
provided a gasification system comprising: a high temperature gasifier for
operating at
a first temperature; a low temperature gasifier for operating at a second
temperature
that is lower than the first temperature, the low temperature gasifier being
located
downstream from the high temperature gasifier; a pump system connected in
parallel
and in series with the high temperature gasifier and the low temperature
gasifier; and
a cyclone separator connected between the high temperature gasifier and the
low
temperature gasifier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will become more fully understood from the
detailed description and the accompanying drawings, wherein:
[00010] Figure 1 is a detail view and partial cross-section of a two-stage
coal
gasifier; and
[00011] Figure 2 is a diagrammatic view of a coal gasification system.
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CA 02542552 2013-02-20
DESCRIPTION OF VARIOUS EMBODIMENTS
[00012] The following description of various embodiments is merely exemplary
in nature and is in no way intended to limit the present teachings, its
application, or
uses.
[00013] With reference to Figure 1, a two-stage coal gasifier and cyclone
separating the system (two-stage gasifier) 10 is illustrated. As described
herein, the
two-stage gasifier 10 may be used with a system to form a selected gas
product, such
as raw synthesis gas, at a selected pressure, temperature, and other physical
properties. It will be understood that synthesis gas may be a mixture of any
appropriate gas products, such as hydrogen (H2) gas and carbon monoxide (CO)
gas.
The hydrogen and carbon monoxide gas may be used for various purposes, such as
synthesizing selected petrochemicals, hydro-carbons, and the like. The gas
produced by the two-stage gasifier 10 may be used to power various systems,
such
as turbines. Also the properties of the produced gas itself may be used in a
more
direct way such as being expanded to provide a source of thermal heat and
other
appropriate energy sources.
[00014] The two-stage gasifier 10 generally includes a first stage gasifier
section 12. The first stage gasifier 12 allows for input of a selected
product, such as
coal, char (recycled coal), petcoke and other appropriate materials, such as
those described herein. In addition, various input compounds may further
include
steam or water and oxygen to assist in the first gasification stage. The first
stage
3a
CA 02542552 2013-02-20
gasifier 12, therefore, includes a plurality of inlets to offer input of the
various
components. In the first stage gasifier 12, various injectors may be used to
inject the
materials and provide a heat source to ignite the materials in the oxygen and
steam
atmosphere. In the first stage gasifier 12, it may be desirable to produce
various
temperatures and flow rates. Generally, the first stage gasifier may provide
an exit
temperature of about 1315 C to about 1760 C (about 2400 F to about 3200
F). It
will be understood that any appropriate temperature either above 3200 F or
below
2500 F may be formed in the first stage gasifier 12 as desired. Nevertheless,
various feed materials may degrade faster at a temperature higher than 3200 F
and
a selected amount of gasification may not occur below about 2500 F. Although,
the
two-stage gasifier 10 and a system into which it is incorporated may be
altered to
require or allow for temperatures outside of range of 2500 F to about 3200
F.
[00015] The first stage gasifier 12 has an outlet 14 into a cyclone
separator
16. The cyclone separator 16 allows for a moving or separation of the
materials
injected into the cyclone separator 16 from the first gasifier 12, such that
various
components may be removed from the stream. As described herein various
components or slag may exit through an outlet 18 to be recovered for various
uses.
The slag may include trace amounts of ungasified components of the char and
coal
input into the first gasifier 12 and other various byproducts that are not
carried further
through the system. Therefore, the slag may exit through the outlet 18 while
the
gasified components may move into a second stage gasifier 24. The cyclone 16
may
be protected through any appropriate materials, such as ceramic bricks an or
active
cooling systems 20, such as those described herein and in U.S. Patent No.
6,920,836, entitled "REGENERATIVELY COOLED SYNTHESIS GAS
GENERATOR". Various ceramic matrix composite (CMC) active cooling systems 20
may be used as a cyclone liner so that the slag may exit through the outlet 18
and
the gasified products enter the second gasifier 24 without compromising the
integrity
of the cyclone 16.
[00016] Nevertheless, once the gasified products enter the second
gasifier
24 additional inputs may be provided. For example, an additional volume or
mass of coal or petcoke may be added to the second gasifier stage 24. As is
4
CA 02542552 2006-04-10
understood in the art, this may cause a quenching of the gasifying process and
may cool the temperature of the second stage gasifier 24 to a temperature less
than that of the exit temperature of the first gasifier 12 and the cyclone 16.
For
example, the temperature of the material exiting the second stage gasifier 24
may be about 871 C to about 982 C (about 1600 F to about 1800 F), such as
about 954 C (about 1750 F). As discussed above, the temperatures of the
material exiting the second stage gasifier 24 may be any appropriate
temperature, and about 871 C to about 982 C is merely exemplary. For
example, various materials or systems may require or be advantageously
operated at temperatures either below or above this range. Further, the gas
exiting the second gasifier 24 may include various and selected components due
to the selected temperature range. For example, although the gas exiting the
first
gasifier stage 12 may be substantially carbon monoxide and hydrogen gas, such
as greater than about 85 vol%, temperatures of the gas below about or at about
1700 F may produce or allow a formation of methane at about 2% to about 10%,
or about 3%, of the volume of the gas. Therefore, various temperature ranges
may be formed in the gas flow stream to form a gas of a selected composition.
[0017] The two-stage gasifier 10 may be used in any appropriate
system to form a selected product, such as gasification of coal or petcoke
into a
material, such as synthesis gas. Although these systems using the two-stage
gasifier 10 may be any appropriate system, a system according to various
embodiments is diagrammatically illustrated in Figure 2. A coal gasification
or
synthesis gas production system 50 is illustrated in Figure 2. It will be
understood that the gasification system 50 is merely exemplary and is not
limiting. Further, the gasification production system 50 may be used in a
plant to
form a product having an efficiency of the CGE of the input coal to greater
than
about 90%.
[0018] The gasification system 50 may gasify any appropriate material,
such as coal. Any appropriate coal from various sources may be used in the
gasification system 50. Further, material such as petcoke and other solid
carbonateous materials may be used in the formation of the selected material,
such as the synthesis gas. The system 50 includes a coal or carbonateous
material hopper 52. It will be understood that the coal hopper 52 may hold any
5
CA 02542552 2013-02-20
appropriate material and include an outlet 54 for selectively providing the
material
held in the coal hopper 52 to the remaining portions of the system 50.
[00019] The coal from the coal hopper 52 can be provided along line 56 to
a
pump system 58. The line 56 is illustrated diagrammatically and will be
understood
to be any appropriate line system. Further, it will be understood that the
lines
described herein may be any appropriate lines to provide the material from its
origin
to a selected destination. Therefore, the line 56 is provided to exemplary
show an
interconnection between the coal hopper 52 and the pump system 58. The coal
may
be fed from the coal hopper 52 at any selected or appropriate rate produced by
the
coal pump system 58. For example, the coal may be fed at a rate of about 46
pounds per second. Although it will be understood that the coal may be
provided at
any appropriate rate, such as about five pounds per second to about two
hundred
pounds per second. Although any appropriate rate may be provided higher or
lower
than this range depending upon the system 50 and any portion to which it may
be
interconnected. Therefore, the flow rate of the coal from the coal hopper 52
is
merely exemplary and provided for the teachings herein.
[00020] The system 58 may include any appropriate coal pump system. For
example, the coal pump system may be a substantially dry system that forms a
dry
slurry of the coal from the coal hopper 52 with a volume of CO2. Therefore,
the coal
pump system 58 need not mix the coal with a liquid, such as water, to pump the
coal
into the remaining portions of the system 50 or to any portion of the system
50 to
which it may be connected. The coal pump system 58, including the CO2 slurry
system, may further include a CO2 header or supply 60. The CO2 from the CO2
supply may be provided along line 62 to the coal pump system 58 at any
appropriate
rate or pressure. For example, the CO2 may be provided from the CO2 supply 60
at
about one to about five pounds per second, and may be provided at about 2.7
pounds per second from the CO2 supply 60 to the coal pump system 58.
[00021] The coal pump system 58 may be any appropriate coal
pump system. For example, the coal pump system may be similar to the
system described in U.S. Patent No. 7,303,597, entitled "METHOD AND
APPARATUS FOR CONTINUOUSLY FEEDING AND PRESSURIZING A SOLID
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CA 02542552 2013-02-20
MATERIAL INTO A HIGH PRESSURE SYSTEM". Further systems that may be
provided as the coal pump system 58 may include the Stamet rotary disk pump
provided by Stamet, Inc. of North Hollywood, California. Regardless of the
specific
system provided for the coal pump 58, the coal pump 58 may move the coal from
the
coal hopper 52 in a selected slurry, such as a slurry of CO2, in a
substantially dry or
water free manner to the system 50. It will be understood that a selected
amount of
water or moisture may be provided in the coal or other portions of the system,
but the
pump system 58 may form a dry slurry of the coal from the hopper 52 and not
form a
water slurry with the coal. Further, an outlet 64 can be provided from the
coal pump
system 58.
[00022] The outlet 64 can provide or outlet the coal from the coal pump
system 58 in any appropriate physical conditions. For example, the coal slurry
may
exit the outlet 64 at a pressure of about 500 psia to about 1400 psia, such as
about
1200 psia. Further, the pressurization of the coal in the pump system 58 may
raise
the temperature of the coal slurry to about 87 C to about 93 C (about 190 F
to
about 200 F). It will be understood that any appropriate pressure may be
formed in
the pump system 58. For example, a plurality of pumps may be provided in
series to
sequentially increase the pressure of the coal slurry to a selected pressure
of, for
example, about 1200 psia. Regardless, it will be understood that any
appropriate
pressure of the coal slurry may be provided at the outlet 64 of the coal pump
system
58. Simply, the exemplary pressures are provided for the discussion herein.
[00023] For example, higher pressures may be used downstream to
power additional systems, such as expansion heaters or heat exchangers.
The higher pressures may be used to directly power various turbines. In
addition, higher pressures may be used to provide for easy transport of the
product formed by the system 50, such as synthesis gas. The higher pressures
may be commercially advantageous for such systems as supplying or
supplementing octane in fuels, forming alcohols, forming pure hydrogen gas,
and
other appropriate systems. Further, the high pressure product may be
selectively
7
CA 02542552 2006-04-10
depressurized to power various systems, such as heat exchangers, expansion
turbines, and the like. Therefore, the overall efficiency of the system 50 and
a
plant into which the system 50 may be provided can increase the efficiency of
the
plant
[0024] As discussed above, the two-stage gasifier 10 forms a part of
the system 50 for forming a gas from a selected component, such as coal that
may be provided from the coal hopper 52. The two-stage gasifier 10 includes
the
first stage gasification 12 and the second stage gasification 24
interconnected
through a cyclone separator 16. To be described further herein, char may be
formed during the gasification of the coal. The char can be recycled through
the
system to further remove and gasify material from the coal. Therefore, the
coal
from the coal pump 58 and char can mix in a mixing area or mixer 68.
[0025] The mixer 68 may be any appropriate pipe section. For
example, mixer 68 may include a powered mixing system to mix the new coal or
fresh coal from the coal pump 58 and the recycled char. Alternatively, or in
addition thereto, the mixing section 68 may simply provide an area for
collection
in non-active mixing of the fresh coal with the char. Regardless, the mixing
section 68 allows for intermingling and providing the char to the first stage
gasifier
12 with the fresh coal that is provided through the coal pump 58.
[0026] The fresh coal provided directly out of the coal pump 58 can
generally be provided at a flow rate of about 49 pounds per second through
line
70. A portion of the fresh feed from the pump 58 may be diverted through a
diversion or second stage feed line 72. In the second stage feed line, the
flow
may be about 20 to about 25 pounds per second, such as about 23 pounds per
second or even at about 22.6 pounds per second.
[0027]
In the mixing area 68, the remaining portion of the new or fresh
coal from the coal pump 58 is provided through a line 74, after it is mixed in
the
mixing section 68, with the char provided from line 76. The char in the line
76
may be provided at a flow rate of about 5 to about 9 pounds per second, such
as
about 7.8 pounds per second As discussed herein, the char can be pressurized
to the high system pressure of about 500 psia to about 1400 psia. Since the
char is already produced near the elevated gasifier pressure, the char recycle
feed 118 may be pressurized (after displacing the entrained synthesis gas with
8
= CA 02542552 2013-02-20
carbon dioxide) using a commercially available piston-diaphragm pump such as
the
GEHO pump manufactured by the Weir Group, Netherlands. The material in the
line
74 may then be provided at a flow rate of about 30 to about 37 pounds per
second,
such is about 34.2 pounds per second. As discussed above, the pressure from
the
pump 58 and the high pressure of the system 50 may provide that the coal
material,
including the new or fresh coal and the char, at a pressure through the line
74 at
about 500 psia to about 1400 psia.
[00028] Through a second inlet line oxygen may be provided from an
oxygen
supply 78. The oxygen provided from the oxygen supply 78 can be provided along
line 80. The oxygen along line 80 may be provided at any appropriate flow
rate, such
as about 25 to about 30 pounds per second, or such as about 28.5 pounds per
second. Further, the oxygen may be provided at any appropriate temperature,
such
as about 260 C to about 482 C (about 500 F to about 900 F). Further, the
oxygen provided through the line 80 may be pressurized to the pressure of the
system, such as about 500 psia to about 1400 psia. It will be understood,
however,
that the various flow rates, pressures, and temperatures of the oxygen
provided
through the line 80 may be altered depending upon the system 50 or the
operation of
the system 50 with another selected system.
[00029] Further, a mixing section 82 may be provided to mix with
the oxygen
provided from the oxygen supply 78 with steam provided from a steam mixer
84 through a steam line 86. As discussed herein, steam may be produced
in various areas of the system 50 or may provided by a boiler for injection
into the oxygen and steam line 77. The steam injected from the steam mixer
84 to the line 86, and provided to the mixing section 82, may be provided
at any appropriate flow rate. The flow rate of the steam may be about 25 to
about 29 pounds per second, and such as about 27.8 pounds per second.
The temperature of the steam provided in line 86 may be provided at about
537 C to about 760 C (about 1000 F to about 1400 F). Further, the pressure
of the steam in line 86 to the mixer 82 may be similar to the pressure of the
system, such as about 500 psia to about 1400 psia. It will be understood
that the flow rate, pressures, temperatures, and the like may be provided in
any
appropriate range or number to provide a result from the system 50 as
selected. For
9
CA 02542552 2006-04-10
example, the system 50 may be operated at a lower pressure for achieving
selected results or characteristics of the product. Alternatively, higher
pressures
and temperatures may be used to select a particular efficiency,
characteristic,
and the like for the system 50.
[0030] As discussed
above, the two-stage gasifier 10 includes the first
stage gasification system 12. The gasification system 12 may be any
appropriate
gasification system that is compact and produces a high speed (approximately
200 ft/sec) liquid/gas flow for connection to the inlet of the cyclone
separator.
The gasification system 12 may contain a liner (such as the CMC liner
described
in U.S. Patent Application No. 10/677,817) which is capable of withstanding
the
abrasive and corrosive environment of such as a high temperature and high
speed gas flow containing molten slag and sulfur gas compounds such as H2S
and COS. The gasification system 12 generally provides a mechanism and
environment to gasify the coal provided through the coal pump 58 and any char
provided through line 76. The operating temperatures of the first stage
gasifier
12 may be any appropriate temperature, such as those discussed above.
Regardless, it will be appreciated that the temperatures of the first stage 12
may
be greater than about 1204 C (about 2200 F). As discussed above, the
operating temperature of the first stage 12 may, however, be maintained below
about 1760 C (about 3200 F) for various operational reasons, such as
longevity.
[0031]
The gasified product or the product exiting the first stage
through the gasification outlet 14 enters the cyclone separator 16. In the
cyclone
separator 16, the molten slag, which can include metal oxides and silicates
(such
as alkali, alkali earth, and transition metal oxides and silicates), may be
emptied
from the outlet 18 to a molten slag holder 90. The molten slag holder 90 may
be
any appropriate system, such as a water quench or heat resistant container.
Generally, the slag exits the cyclone separator 16 at a rate of about 3 to
about 5
pounds per second, such as about 4.8 pounds per second. The molten slag can
be heated to a temperature, including any appropriate temperature, such as
greater than about 1204 C (about 2200 F). It is understood by one skilled in
the
art that the slag material may include various elements that may be contained
within a solidified ash product. By providing the molten slag at a temperature
CA 02542552 2006-04-10
above about 1204 C (about 2200 F) the molten slag provided to the molten slag
holder 90 may be used safely in various applications, such as landfill, road
bed
fill, and the like. Therefore, because the first gasification stage system 12
allows
for formation of temperatures greater than about 1204 C the molten slag
provided to the molten slag holder 90 is generally usable in selected
applications.
[0032] Further, the cyclone separator 16 provides a gas stream out of
the cyclone separator 16 to the inlet 92 of the second stage system 24 that is
generally about 99 wt% pure gas (corresponding to a slag removal efficiency of
90 wt%) from the gasification in the first gasification stage 12. It will be
understood that the gas provided to the second stage gasification system 24
may
include any appropriate percentage of slag, depending upon the operation of
various components and the efficiencies of the cyclone separator 16.
Regardless, the gas (that may include a fraction of slag) is provided to the
inlet
92 of the second stage gasification system 24 including less than about 1 wt%
slag.
[0033]
Further, as discussed above, fresh coal may be provided
through line 72 to the second stage gasification system 24. The provision of
the
coal to the second stage gasification system 24 may allow for a complete
gasification of the material provided to the second gasification stage system
24.
Further, the coal provided along line 72 may provide a quenching of the
material
in the second stage gasification system stage 24.
[0034]
The provision of the fresh coal may substantially cool the
temperature of the material provided to the inlet 92 of the second stage
gasification system 24. As discussed above, the material exiting the first
stage
gasification system 12 is generally greater than about 2200 F. The
temperature
of the material exiting an outlet 100 of the second stage gasification system
24,
however, may be provided at a temperature of about 815 C to about 1037 C
(about 1500 F to about 1900 F), such as about 954 C (about 1750 F).
Therefore, the quenching in the second stage gasification system 24 can
substantially cool the temperature of the material as it exits or before it
exits the
second stage gasification system 24. Regardless, the product exiting the
outlet
100 of the second stage gasification system 24 can still include a pressure of
about 500 psia to about 1200 psia, such as about 1000 psia. Further, the flow
of
11
CA 02542552 2006-04-10
the material from the outlet 100 may be about 100 to about 120 pounds per
second, such as about 108.2 pounds per second.
[0035] The material exiting the second stage gasification system 24 at
the outlet 100 may include substantially synthesis gas, which can have various
compositional breakdowns. Nevertheless, the product exiting the second stage
gasification system 24 through the outlet 100 may be about 85 to about 98%
synthesis gas, such as about 93% synthesis gas. The synthesis gas may include
a plurality of components, such as methane, hydrogen, water vapor, and other
various components. At the temperatures of the outlet 100, the synthesis gas
may include about two to about four volume percent of methane, such as about
3.26 volume percent methane. Further, carbon monoxide, carbon dioxide,
hydrogen gas and water may form a majority of the synthesis gas.
[0036]
It will be understood that the composition of the synthesis gas
exiting the outlet 100 may be exemplary and actual amounts may differ from the
theoretical calculations. Regardless, a portion of the synthesis gas provided
the
outlet 100 may include methane, carbon monoxide, carbon dioxide, and
hydrogen gas. Further, the char provided from the outlet 100 may include a
higher heat value (HHV) of about 9000 to about 10000 BTUs per pound, such as
about 9820 BTUs per pound. Note this char is produced from the coal provided
in the hopper 52 that may have an initial higher heat value of about 12360
BTUs
per pound. The chemical energy of the product synthesis gas exiting outlet 100
will retain over 90 % of the HHV of the coal in the gasification system 50,
according to various embodiments.
[0037] The material from the outlet 100 can be provided to a quencher
or heat exchanger 110 that is operable to cool the temperature of the material
a
selected amount. For example, the heat exchanger 110 may cool the material
from the exit temperature from the outlet 100 to a temperature of about 260 C
to
about 537 C (about 500 F to about 1000*F), such as about 426 C (about 800
F).
[0038] The quenched material may then be provided through a filter
112, such as a selected ceramic or metal filter. The filter 112 may be any
appropriate filter, such as the candle filter modules manufactured by the Pall
Corporation of Timonium, MD.
The filter 112 may allow for removal of various
12
. CA 02542552 2013-02-20
portions from the synthesis gas, such as the unreacted char produced from the
line
72 coal feed and the slag that was not removed from by cyclone 16. Therefore,
the
filters 112 may provide for a substantially purer or cleaner synthesis gas to
exit the
system 50 through outlet line 116. The gas stream may pass through a collector
117
where the back pressure through the filters may drive the char so that it may
be
recycled. The back pressure gas may be CO2 or any appropriate gas. Also, CO2
may be used in the collector to assist in removing any product gas caught in
the
interstices of the char particles. The CO2 may move the particles to allow for
release
of the product gas and not interfere with the recycle system for the char.
[00039] The raw gas exiting the system 50 may exit the system at
any
appropriate pressure and temperature. Nevertheless, the various systems may be
provided to allow for the exit of the raw synthesis gas through outlet line
116 at a flow
rate of about 98 pounds per second to about 102 pounds per second, such as
about
100 pounds per second. Further, a temperature of the raw gas exiting the line
116
may be about 315 C to about 537 C (about 600 F to about 1000 F), such as
about 426 C (about 800 F). Further, the raw material exiting the line 116
may have
a pressure of about 500 psia to about 1200 psia, such as about 1000 psia. As
discussed above, the pressure of the gas exiting the system 50 may be expanded
to
power various further generating systems or may be provided for various uses
at the
high pressure.
[00040] The filter 112 may be periodically cleared with a back
pressure of
CO2, which may be provided from the CO2 supply 60, or other appropriate
material.
The filters may be rotated between a primary and a cleaning filter, such that
the back
pressure may remove the particulates, such as the char and slag from the
filters.
The clearing may allow for efficient use of the primary filter and it may be
reinstalled
for efficient use thereof. Therefore, the filters 112 may be substantially non-
sacrificial
or non-reactive and be provided to remove the material from the gas produced
by the
system 50.
[00041] As discussed above, char may be provided in a recycle
system to
allow it to further be gasified in the two-stage gasifier 10 that may be part
of the
gasification system 50 if it is not gasified during its first pass. Therefore,
the char
may be provided first along line 118 to a char pump system 120. The char pump
13
CA 02542552 2006-04-10
system 120 may be any appropriate pump system, such as the pump system
used for the coal pump system 58. Regardless, the char pump system 120 may
provide the char through the line 76 to the mixing area 68 as discussed above.
[0042]
In addition to or as part of the gasification system 50 described
above, a cooling system and steam generation system may also be provided. It
will be understood that the cooling and steam generation system may be
substantially integral with the system 50. The cooling system may provide
steam
and water for the gasification system 50.
A water supply 94 provides water
along line 126 to the quench system 110. The quench system 110 may be a heat
exchange system to cool the material from the outlet 100 before it enters the
filters 112, thereby heating the water provided to the quench system 110
through
line 126. Therefore, the water may exit the quench system 110 at a heated
temperature.
[0043] The water may exit the quench system 110 to various lines to
provide cooling or steam to selected systems. The water may exit the quench
system 110 along a first line 128 to provide cooling to the outlet of the
second
stage gasification system 24. Further, water or steam may be provided along a
second line 130 to the outlet of the cyclone 16. Water or steam may also be
provided along line 132 to the outlet of the first stage gasification system
12.
Also, water or other coolant may travel though the coolant outlet lines which
are:
line 134 from the second stage system, line 136 from the first stage
gasification
system, and line 140 from the cyclone system. The coolant in these lines may
be
provided to the steam mixer 84 for injection into the first stage gasification
system 12.
[0044] As noted, the cyclone system 16 may include an active cooling
system. The active cooling system may be in addition to a heat shielding or
protection wall. The active cooling system may include channels or tubes in
the
cyclone 16. A coolant material may be provided in the tubes to actively cool
the
inner surface of the cyclone 16 to assist maintaining a structural integrity
of the
cyclone 16. The tubes may form a barrier between the interior of the cyclone
16
and the outer structural wall and be cooled with a coolant provided therein.
Various systems include tubes or channels formed of a ceramic matrix
composite (CMC) that may provide a circulation within the cyclone 16. Various
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CA 02542552 2013-02-20
CMC cooling systems include those disclosed in U.S. Patent No. 6,920,836,
entitled
"Regeneratively Cooled Synthesis Gas Generator", filed 10/02/2003.
[00045] The tubes formed of the CMC material may line the cyclone 16 and
a coolant, such as steam or water, may be passed therethrough to cool the
tubes
and not allow the external structure of the cyclone to reach various
temperatures.
The tubes may actually form the internal surface of the cyclone 16, such that
the
outer or super structure of the cyclone 16 does not reach a temperature, which
may
cause a structural heating.
[00046] It will be understood, however, that various other systems may be
provided to insulate the super-structure or outer structure of the cyclone 16
from the
heat of the material from the first gasification stage 12 after it enters the
cyclone 16.
For example, various heat resistant bricks or ceramic materials may be used to
line
the internal surface of the cyclone 16. Nevertheless, the CMC tubes may be
used to
not only cool the internal surface of the cyclone 16, but to provide a steam
along a
line 140 to the steam mixer 84 for injection into the first stage gasification
system 12.
Therefore, the system 50 may not only recycle char from the gasification
process, but
may also regeneratively create steam for use in the gasification process.
[00047] Further, as the material from the outlet 100 of the second stage
24
enters the quench system 110 it may be cooled with the water provided from the
water supply 94. During this cooling, the heat may be transferred to the water
through a heat change system and be provided along a line 144. The steam or
water
provided along the line 144 may be super heated steam and at a substantially
high
pressure due to the cooling of the material from the outlet 100. As discussed
above,
the heat exchange may cool the product material to about 427 C to about 538 C
(about 800 F to about 1000 F). Therefore, the water provided along line 144
may
be substantially super heated and at a high pressure. The water flowing along
line
144 may be provided at any appropriate flow rates and include a temperature
that
may be about 538 C to about 760 C (about 1000 F to about 1400 F), such as
about 649 C (about 1200 F). Further the water in the line 144 may be provided
at a
pressure of about 1000 psia to about 2500 psia, such as about 1200 psia.
CA 02542552 2013-02-20
[00048] The water or steam provided in the water line 144 may be used for
various purposes, such as powering steam powered turbines, and the like.
Therefore, the system 50 may provide not only the gas from the gasification of
the
coal or other appropriate product, but may also provide super heated steam for
export to various other generative prophecies. Again this may increase the
efficiency
of the system 50 or a plant efficiency, including the system 50.
[00049] The material provided in the gas line 116 from the system 50 may
be used for various appropriate purposes. The material in the line 116 may be
synthesis gas, which can be used to synthesize or form various products, such
as
petroleum or other materials that may be used for various powering purposes.
Regardless, the system 50 generally operates without forming a liquid slurry,
such as
a water slurry of the coal from the hopper 52. Also the substantially dry
slurry that is
formed with the CO2 allows for a substantially high percentage of CGE. With
the
high pressure system and the substantially dry slurry, the percentage CGE of
the
system 50 may be greater than about 90% and greater than about 93%. It will be
understood that various techniques for determining efficiencies and
formulating
systems are generally known in the art and are used to determine final
efficiencies in
systems. For example a program, including computer code, may be used to
calculate and verify kinetics in systems to ensure proper reaction times and
volumes
includes the article K.M. Sprouse. Modeling Pulverized Coal Conversion in
Entrained Flows, AlChE Journal, v. 26, p. 964 (1980). Also, generally known
programs may be used to assist in determining chemical and system equilibriums
and thermodynamics, such as Gordon, S. and McBride, B.J. Computer Program for
Calculation of Complicated Chemical Equilibrium Composition and Application,
NASA Ref. Pub. 1311, Glen Research Ctr., Cleveland, OH, (1994). Thus one
skilled
in the art will understand that systems may be modeled with generally accepted
techniques to determine outcomes of systems, such as those described above.
[00050] The description of the embodiments above is merely exemplary in
nature.
16
