JP2010196606A - Coal gasification combined power generation plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coal gasification combined power generation plant which effectively uses boil off gas generated from a liquefied carbon dioxide storage tank for storing liquefied carbon dioxide and can control release of the boil off gas into the atmosphere. <P>SOLUTION: In the coal gasification combined power generation plant, coal is subjected to partial combustion in a coal gasification device 14. The gasification gas generated therein under high pressure and temperature conditions is lead to a heat exchanger 20 and is cooled. The cooled gas is subjected to gas purification by a dust removal device 22 and a gas treatment device 24, from which carbon dioxide is removed and collected. The purified gas is then subjected to combustion, to thereby generate power with a gas turbine generator 40. Steam collected from the heat exchanger 20 is also used to generate power with a steam turbine generator 46. Boil off gas generated from a liquefied carbon dioxide storage tank 32 for storing the removed and collected carbon dioxide is used as seal gas of the coal gasification device 14. This allows the boil off gas to be used effectively and also allows a release of the boil off gas into the atmosphere to be controlled. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a coal gasification combined power plant that uses coal as a gasification fuel, and more particularly, to a coal gasification combined power plant that includes a carbon dioxide recovery facility that separates and recovers carbon dioxide.

  The coal gasification combined cycle plant is a power generation facility that is effective in preventing global warming because carbon dioxide (carbon dioxide) is less generated because coal can be used to generate power efficiently. The conventional combined coal gasification combined power plant is configured to partially burn coal in the coal gasifier and cool the gasified gas generated under high pressure and high temperature conditions to a heat exchanger, and further, dust removal equipment, gas processing equipment, etc. After purifying the gas, the gas turbine power generation facility burns and generates power, and the steam turbine power generation facility uses steam from the heat exchanger and the exhaust heat recovery boiler on the downstream side of the gas turbine. Furthermore, a system that separates and recovers carbon dioxide from the purified gasification gas has also been proposed (see, for example, Patent Document 1 and Patent Document 2).

Japanese Patent No. 2870929 JP-A-9-279163

  In a coal gasification combined power plant equipped with a facility for recovering carbon dioxide, the recovered carbon dioxide is liquefied and stored in a liquefied carbon dioxide storage tank, and then the liquefied carbon dioxide is transported and processed. Part of the liquefied carbon dioxide gas stored in the liquefied carbon dioxide gas storage tank is vaporized by heat input from the outside to become boil-off gas. Since the boil-off gas increases the pressure in the liquefied carbon dioxide storage tank, when the pressure in the liquefied carbon dioxide storage tank reaches a predetermined pressure, a part of the boil-off gas is released to the atmosphere to protect the tank. Since it is contrary to the original purpose to release the collected carbon dioxide into the atmosphere again, measures to prevent the boil-off gas from being released into the atmosphere as much as possible are required.

  If the storage time in the liquefied carbon dioxide storage tank is shortened and the liquefied carbon dioxide gas is discharged within a short period of time, the effect of heat input from the outside will be reduced and the amount of boil-off gas generated will be suppressed. Considering operations such as gas transportation and processing, there is a limit to shortening the storage time. Currently, in a coal gasification combined power plant equipped with a carbon dioxide gas recovery facility, a technology that effectively uses boil-off gas and a technology that can suppress release of the generated boil-off gas into the atmosphere have not been developed.

  An object of the present invention is to effectively utilize boil-off gas generated from a liquefied carbon dioxide storage tank that stores liquefied carbon dioxide and to suppress the release of boil-off gas to the atmosphere in a coal gasification combined power plant equipped with a carbon dioxide recovery facility. Is to provide a combined coal gasification combined power plant.

  The present invention according to claim 1 refines the coal gasification gas including a coal gasification device including a gasification furnace housed in a pressure vessel, which generates coal gasification gas from coal and a gasifying agent. Powered by steam from a gas turbine power generation facility that burns gas and generates power using the burned gas, a heat exchanger that recovers the heat of the gasification furnace, and an exhaust heat recovery boiler that recovers the exhaust heat of the gas turbine A steam turbine power generation facility for generating electricity, a carbon dioxide recovery facility having a liquefied carbon dioxide storage tank for recovering and storing carbon dioxide generated in the coal gasification gas generation step as liquefied carbon dioxide, and the liquefied carbon dioxide storage tank A coal gasifier seal gas supply means for supplying the generated boil-off gas to the coal gasifier as a seal gas of the coal gasifier. A coal gasification combined cycle power plant according to symptoms.

  According to a second aspect of the present invention, there is provided a combined coal gasification combined power plant according to the first aspect, wherein the coal gasification combined power plant is further installed in a downstream side of the coal gasification device to recover unburned char scattered from the gasification furnace. A dust device, and a return means for returning unburned char recovered by the dust removal device to the gasification furnace, and boil-off gas generated from the liquefied carbon dioxide storage tank is used as a transfer gas for the return means. It is characterized by comprising unburned char transfer gas supply means for supplying the return means.

  The present invention according to claim 3 is the combined coal gasification combined power plant according to claim 1 or 2, further comprising a coal hopper for storing coal supplied to the gasification furnace, from the liquefied carbon dioxide storage tank. Coal conveying gas supply means is provided for supplying the generated boil-off gas to the coal hopper as a conveying gas for supplying coal from the coal hopper to the gasifier.

  The present invention described in claim 4 is the coal gasification combined power plant according to any one of claims 1 to 3, further comprising a booster that boosts the boil-off gas generated from the liquefied carbon dioxide storage tank. A control device for controlling the booster and setting the boil-off gas to a predetermined pressure, and any one of the coal gasifier seal gas supply means, the unburned char transfer gas supply means, and the coal transfer gas supply means The above gas supply means supplies the boil-off gas boosted by the booster.

  The coal gasification combined power plant of the present invention is a coal gasifier seal gas supply means for supplying boil-off gas generated from a liquefied carbon dioxide storage tank for liquefying and storing recovered carbon dioxide as a seal gas for the coal gasifier. Therefore, the boil-off gas can be effectively used as the seal gas of the coal gasifier as a substitute gas for the nitrogen gas generally used as the seal gas. Thereby, the usage-amount of nitrogen gas can be reduced. In addition, even if boil-off gas supplied as sealing gas is mixed into gasification gas, it is collected again by the carbon dioxide gas recovery facility, so that release of boil-off gas into the atmosphere can be suppressed and effective in preventing global warming. Is.

  The coal gasification combined power plant of the present invention further supplies boil-off gas generated from a liquefied carbon dioxide storage tank for liquefying and storing the recovered carbon dioxide as a transport gas for returning unburned char to the gasification furnace. Since the unburned char transfer gas supply means is provided, the boil-off gas can be effectively used as the unburned char transfer gas as an alternative gas to the nitrogen gas. Thereby, the usage-amount of nitrogen gas can be reduced. In addition, the boil-off gas supplied as the unburned char carrier gas is mixed in the gasification gas, but is recovered again by the carbon dioxide recovery facility, so that the release of boil-off gas into the atmosphere can be suppressed, and global warming can be prevented. It is effective for countermeasures.

  Further, the combined coal gasification combined power plant of the present invention further uses boil-off gas generated from a liquefied carbon dioxide storage tank for liquefying and storing recovered carbon dioxide as a transport gas for supplying coal from a coal hopper to a gasifier. Since the coal transportation gas supply means is provided, boil-off gas can be effectively used as the coal transportation gas as an alternative gas of nitrogen gas. Thereby, the usage-amount of nitrogen gas can be reduced. In addition, although boil-off gas supplied as coal transportation gas is mixed into gasification gas, it is recovered again by the carbon dioxide gas recovery facility, so it is possible to suppress boil-off gas from being released into the atmosphere and to prevent global warming. It is effective against.

  The coal gasification combined power plant of the present invention includes a booster that boosts the boil-off gas generated from the liquefied carbon dioxide storage tank that liquefies and stores the recovered carbon dioxide, so that the pressure in the liquefied carbon dioxide storage tank is reduced to coal. Even when the pressure is lower than the pressure of the gasifier or the like, the boil-off gas can be effectively used as a seal gas or the like of the coal gasifier.

It is a process flow figure showing a schematic structure of coal gasification combined power plant 1 as a 1st embodiment of the present invention. It is a process flow figure showing a schematic structure of coal gasification combined power plant 3 as a 2nd embodiment of the present invention. It is a process flow figure showing a schematic structure of coal gasification combined power plant 5 as a 3rd embodiment of the present invention.

  FIG. 1 is a process flow diagram showing a schematic configuration of a combined coal gasification combined power plant 1 as a first embodiment of the present invention. The coal gasification combined power plant 1 includes a gasification facility, a gas purification facility, a power generation facility, a carbon dioxide recovery facility, and a boil-off gas supply facility.

  The gasification facility is a facility for gasifying coal to generate gasified gas, and is composed of a gasification furnace 10 and a pressure vessel 12 for gasifying coal, a coal gasifier 14, coal gas A coal hopper 16 for supplying coal to the gasifier 14, an air separator 18 for supplying oxygen to the coal gasifier 14, and a heat exchanger 20 for cooling the gasified gas and recovering heat as steam. Composed.

  The gas purification equipment is equipment for removing impurities in the gasification gas generated by the gasification equipment, and a dust removing device 22 and gas for purifying the gasification gas cooled by the heat exchanger 20. A processing device 24 is included.

  The carbon dioxide gas recovery equipment is equipment for recovering carbon dioxide from the gasification gas purified by the gas purification equipment, and is a carbon dioxide gas separation and recovery device 28 for recovering carbon dioxide gas from the purified gasification gas, carbon dioxide gas liquefaction. An apparatus 30 and a liquefied carbon dioxide storage tank 32 are included.

  The power generation facility includes a gas turbine power generation facility that generates power using purified gasified gas as fuel and a steam turbine power generation facility that uses steam generated by using the recovered heat as a power source. The gas turbine power generation facility includes a combustor 34, a gas turbine 36, an air compressor 38, a gas turbine generator 40, and an exhaust heat recovery boiler 42 that cools the combusted high-temperature gas and recovers steam. The steam turbine power generation facility is a power generation facility that uses steam generated in the heat exchanger 20 and the exhaust heat recovery boiler 42 as a power source, and includes a steam turbine 44 and a steam turbine generator 46.

The coal gasifier 14 is an apparatus for gasifying coal, and the gasification furnace 10 is installed in the pressure vessel 12. The gasification furnace 10 is a furnace for gasifying coal at a high temperature using a gasifying agent in which coal is mixed with oxygen or air and oxygen. The gasifier 10 is supplied with coal from a coal supply pipe 48 and supplied with a gasifying agent from a gasifying agent supply pipe 52. Coal supplied to the gasification furnace 10 comes into contact with oxygen in a high-pressure atmosphere to cause a partial combustion reaction, and hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), water vapor (H ₂ O ) Etc. are generated. The temperature of the gasification furnace 10 is maintained at a temperature higher than the melting point of the ash contained in the coal by a partial combustion reaction, and the ash melts. The molten ash is taken out from the lower part of the coal gasifier 14. Further, the gasification gas is guided to the heat exchanger 20.

  The pressure vessel 12 is a vessel provided with a gasification furnace 10 inside. The coal hopper 16 is a container for storing pulverized coal under high pressure conditions. Coal stored in the coal hopper 16 is supplied to the gasifier 10 through the coal supply pipe 48. The air separation device 18 includes a cryogenic separation device that separates air sent from the air supply pipe 50 mainly into oxygen and nitrogen. The separated oxygen is supplied from the gasifying agent supply pipe 52 to the gasifier 10.

  The heat exchanger 20 exchanges heat between the high-temperature gasification gas extracted from the gasification furnace 10 and water using a heat transfer tube or the like. The hot gasification gas is cooled in the heat exchanger 20, while water is recovered as steam or the like. The gasified gas leaving the heat exchanger 20 is guided to the dust removing device 22 and then to the gas processing device 24 for purification.

  The dedusting device 22 is a cyclone, a filter, or the like that collects unburned char that is not sufficiently gasified in the gasification furnace 10 and is scattered along with the gasification gas. The recovered unburned char is returned to the gasification furnace 10 through the unburned char extraction pipe 54. The gas processing device 24 is a device that removes hydrogen sulfide and the like contained in the gasification gas.

  Carbon dioxide is recovered from the gasified gas purified by the dust removing device 22 and the gas processing device 24.

  The carbon dioxide gas separation and recovery device 28 separates and recovers carbon dioxide from the gasification gas. The carbon dioxide gas liquefying device 30 is a device for compressing and cooling the recovered carbon dioxide to liquefy it, and the liquefied carbon dioxide gas is stored in the liquefied carbon dioxide gas storage tank 32. The liquefied carbon dioxide gas stored in the liquefied carbon dioxide gas storage tank 32 is vaporized by the heat of the outside air and becomes a boil-off gas, increasing the pressure in the tank. Therefore, an upper part of the liquefied carbon dioxide gas storage tank 32 is for protecting the tank. A pressure control valve 33 is provided.

  The gasified gas from which carbon dioxide has been separated and recovered is sent to a gas turbine power generation facility including a combustor 34, a gas turbine 36, an air compressor 38, and a gas turbine generator 40. The combustor 34 is a device that burns gasified gas under high pressure conditions. The high-temperature and high-pressure combustion gas is sent to the gas turbine 36. The gas turbine 36 expands the high-pressure and high-temperature gas combusted in the combustor 34, rotates the turbine blades with the power, and is mounted coaxially with the gas turbine 36. The air compressor 38 and the gas turbine generator 40 are rotationally driven to generate power.

  The combustion gas exiting the gas turbine 36 is sent to the exhaust heat recovery boiler 42 and then discharged from the chimney 56 to the atmosphere.

  The exhaust heat recovery boiler 42 is a boiler that cools the combustion gas and generates steam at the same time. The steam generated in the exhaust heat recovery boiler 42 and the steam generated from the heat exchanger 20 are merged and sent to the steam turbine 44. The steam turbine 44 rotates turbine blades using steam from the heat exchanger 20 and the exhaust heat recovery boiler 42 as a power source, and drives the steam turbine generator 46 coaxially to generate power.

  Of the coal gasification combined power plant 1 configured as described above, the gasification equipment, gas purification equipment, power generation equipment, and carbon dioxide recovery facility have the same basic configuration as that of a conventional coal gasification combined power plant. The coal gasification combined power plant 1 according to the present invention is greatly characterized in that it includes a boil-off gas supply facility described below, and constitutes a gasification facility, a gas purification facility, a power generation facility, a carbon dioxide recovery facility, and the like. The device is not limited to the above devices and devices.

  The boil-off gas supply facility includes a coal gasifier seal gas supply means, a booster 58, and a control device 60.

  The booster 58 is a device that boosts the boil-off gas generated in the liquefied carbon dioxide storage tank 32 to a predetermined pressure, and is connected to the liquefied carbon dioxide storage tank 32 via the boil-off gas extraction pipe 62.

  The coal gasifier seal gas supply means is a device for supplying the coal gasifier 14 with the boil-off gas boosted by the booster 58 as a seal gas, and the coal gasifier seal gas supply pipe 64 and the differential pressure. A detector 66 is included. The coal gasifier seal gas supply pipe 64 has one end connected to the booster 58 and the other end connected to the space area 68 of the coal gasifier 14, and the boil-off gas boosted by the booster 58 is converted into the coal gasifier. 14 seal gas is supplied to the space region 68 of the coal gasifier 14. The space region 68 is the upper part of the partition wall 70 between the gasification furnace 10 and the pressure vessel 12 of the coal gasifier 14. The differential pressure detector 66 detects a pressure difference between the space region 68 and the gasification furnace 10.

  The control device 60 takes in a signal from the differential pressure detector 66 so that the differential pressure between the space region 68 and the gasification furnace 10 is within a certain range, for example, the pressure in the space region 68 is compared with the pressure in the gasification furnace 10. The discharge flow rate of the booster 58 is controlled so as to be constantly increased by several hundred to several tens of thousands Pa. By maintaining the pressure in the space region 68 higher than the pressure in the gasification furnace 10, the high-temperature gasification gas generated in the gasification furnace 10 flows into the space region 68, and the temperature of the pressure vessel 12 rises and is included in the gasification gas. Corrosion of the pressure vessel 12 due to the corrosive gas generated can be prevented, and danger such as breakage of the pressure vessel 12 can be prevented.

  Further, when the boil-off gas boosted by the booster 58 is supplied to the coal gasifier 14 as a seal gas, in addition to the method of controlling the flow rate by directly controlling the drive of the booster 58, the coal gasifier seal gas supply A flow rate detector and a flow rate control valve may be provided in the middle of the pipe 64, and these may be controlled by the control device 60 to control the flow rate of the boil-off gas boosted by the booster 58. In the present embodiment, assuming that the pressure of the liquefied carbon dioxide gas storage tank 32 is low and the pressure of the generated boil-off gas is lower than the pressure of the space region 68 of the coal gasifier 14, the boil-off gas is increased to the booster 58. Although an example of supplying the gas as a seal gas for the coal gasifier 14 has been shown, if the pressure in the liquefied carbon dioxide storage tank 32 is higher than the pressure in the space region 68 of the coal gasifier 14, the pressure is increased. It goes without saying that the machine 58 is not necessary.

  In conventional coal gasification combined power plants, nitrogen gas is generally used as the seal gas for the coal gasifier 14, but the boil-off gas discharged from the liquefied carbon dioxide storage tank 32 is used as the coal gasifier 14. The boil-off gas can be effectively used as an alternative gas for the nitrogen gas. Thereby, the usage-amount of nitrogen gas can be reduced. In addition, even if boil-off gas supplied as sealing gas is mixed into gasification gas, it is recovered again by the carbon dioxide gas recovery facility, so that release of boil-off gas into the atmosphere can be suppressed, which is effective in preventing global warming. It is.

  FIG. 2 is a process flow diagram showing a schematic configuration of the coal gasification combined power plant 3 as the second embodiment of the present invention. The same components as those in the combined coal gasification combined power plant 1 shown in FIG.

  The unburned char recovered by the dust removing device 22 is returned to the gasification furnace 10 from the unburned char extraction pipe 54, which is a char return means, and is gasified. A carrier gas is used to return the unburned char to the gasification furnace 10. In the coal gasification combined power plant 3 shown in the second embodiment, in addition to the configuration of the coal gasification combined power plant 1 shown in the first embodiment, the boosted boil-off gas is used as unburned char carrier gas. It is characterized in that it is provided with a gas supply means for transporting unburned char supplied to the char extraction pipe 54.

  The unburned char transfer gas supply means includes an unburned char transfer gas supply pipe 82 that supplies a transfer gas to the unburned char discharge pipe 54, an unburned char transfer gas flow rate adjustment valve 84, and an unburned char transfer gas. And a flow rate detector 86. The unburned char transfer gas supply pipe 82 has one end connected to the coal gasifier seal gas supply pipe 64 and the other end connected to a transfer gas supply port (not shown) of the unburned char extraction pipe 54. . An unburned char transfer gas flow rate adjusting valve 84 is interposed in the middle of the unburned char transfer gas supply pipe 82, and the unburned char transfer gas flow rate adjusting valve 84 and the unburned char discharge pipe 54 are connected to each other. An unburned char transfer gas flow rate detector 86 is mounted in the middle of the pipeline connecting the transfer gas supply port.

  The control device 60 takes in a signal from the unburned char transfer gas flow rate detector 86, adjusts the unburned char transfer gas flow rate adjustment valve 84, and uses the booster 58 as a transfer gas to the unburned char discharge pipe 54. A boil-off gas whose pressure has been increased to a predetermined pressure is supplied. The boil-off gas supplied to the unburned char extraction pipe 54 returns the unburned char to the gasification furnace 10.

  When the boil-off gas is supplied to the unburned char extraction pipe 54 as a carrier gas, a booster capable of independently boosting and supplying the boil-off gas may be provided separately from the seal gas supplied to the coal gasifier 14. . In the present embodiment, assuming that the pressure of the liquefied carbon dioxide gas storage tank 32 is low and the pressure of the generated boil-off gas is lower than the pressure required for the unburned char transfer gas, the boil-off gas is increased to the booster 58. However, if the pressure in the liquefied carbon dioxide storage tank 32 is higher than the pressure required for the unburned char transport gas, the booster 58 is What is not necessary is the same as in the first embodiment.

  In the conventional coal gasification combined power plant, nitrogen gas is generally used as the unburned char carrier gas, but the boil-off gas discharged from the liquefied carbon dioxide storage tank 32 is used as the unburned char carrier gas. By using, boil-off gas can be effectively used as an alternative gas for nitrogen gas. Thereby, the usage-amount of nitrogen gas can be reduced. The boil-off gas, which is an unburned char carrier gas, is supplied to the gasification furnace 10 together with the char and mixed into the gasification gas. However, since the boil-off gas is recovered again by the carbon dioxide recovery facility, the boil-off gas is diffused to the atmosphere. It is effective in preventing global warming. In addition, when nitrogen gas is used as the unburned char carrier gas, nitrogen gas enters the gasification furnace 10 and is mixed into the gasification gas. Although the gas is converted to nitrogen oxides and pollutes the atmosphere, carbon dioxide is used as the unburned char carrier gas, so there is no such problem.

  FIG. 3 is a process flow diagram showing a schematic configuration of the coal gasification combined power plant 5 as the third embodiment of the present invention. The same components as those in the coal gasification combined power plant 1 and the coal gasification combined power plant 3 shown in FIG. 1 or FIG.

  Coal filled in the coal hopper 16 is supplied to the gasifier 10 through a coal supply pipe 48 that connects the coal hopper 16 and the gasifier 10. A transport gas is used for transporting the coal to the gasification furnace 10. In the combined coal gasification combined power plant 5 shown in the third embodiment, in addition to the configuration of the combined coal gasification combined power plant 3 shown in the second embodiment, the boosted boil-off gas is used as a coal transportation gas to supply a coal supply pipe 48. There is a feature in that it is provided with a gas supply means for transporting coal.

  The coal conveyance gas supply means includes a coal conveyance gas supply pipe 88 that supplies conveyance gas to the coal supply pipe 48, a coal conveyance gas flow rate adjustment valve 90, and a coal conveyance gas flow rate detector 92. . The coal conveyance gas supply pipe 88 is connected to a conveyance gas supply port (not shown) of the coal supply pipe 48. A coal conveyance gas flow rate adjustment valve 90 is interposed in the middle of the coal conveyance gas supply pipe 88 and connects the coal conveyance gas flow rate adjustment valve 90 to the conveyance gas supply port of the coal supply pipe 48. In the middle of the road, a coal conveying gas flow rate detector 92 is mounted.

  The control device 60 takes in a signal from the coal transport gas flow rate detector 92, adjusts the coal transport gas flow rate adjustment valve 90, and boosts the coal supply pipe 48 to a predetermined pressure by the booster 58 as transport gas. Supply boil-off gas. The carrier gas supplied to the coal supply pipe 48 sends coal to the gasification furnace 10.

  When supplying boil-off gas to the coal supply pipe 48 as a carrier gas, a booster capable of independently boosting and supplying the boil-off gas separately from the seal gas and unburned char carrier gas supplied to the coal gasifier 14 May be provided. In the present embodiment, it is assumed that the pressure of the liquefied carbon dioxide storage tank 32 is low, and the pressure of the generated boil-off gas is low as the coal carrier gas, and after boosting the boil-off gas with the booster 58, Although an example in which the gas is supplied as coal transportation gas is shown, if the pressure in the liquefied carbon dioxide storage tank 32 is higher than the pressure necessary as the coal transportation gas, it is the first or second that the booster 58 is not necessary. This is the same as in the second embodiment.

  In conventional coal gasification combined power plants, nitrogen gas is generally used as the coal carrier gas, but the boil-off gas discharged from the liquefied carbon dioxide storage tank 32 is used as the coal carrier gas. Thus, the boil-off gas can be effectively used as an alternative gas for the nitrogen gas. Thereby, the usage-amount of nitrogen gas can be reduced. Although the boil-off gas, which is a coal carrier gas, is supplied to the gasification furnace 10 together with the coal and mixed into the gasification gas, it is recovered again by the carbon dioxide recovery facility, so that the boil-off gas is not released to the atmosphere. It is effective in preventing global warming. In addition, when nitrogen gas is used as the coal transport gas, the nitrogen gas enters the gasification furnace 10 and is mixed into the gasification gas. Therefore, when the gasification gas is burned in the combustor 34, a part of the nitrogen gas is generated. Although it converts into nitrogen oxides and pollutes the atmosphere, carbon dioxide is used as the coal carrier gas, and there is no such problem.

  In the coal gasification combined power plant shown in the second and third embodiments, the boil-off gas is used for a plurality of applications at the same time, for example, in the coal gasification combined power plant 3 shown in the second embodiment, the coal gasification Although an example in which the gas is used as a sealing gas for the apparatus 14 and a gas for conveying unburned char has been shown, it goes without saying that these can be used alone. Further, in the coal gasification combined power plant according to the present invention, even when the boil-off gas is used for a plurality of applications at the same time, the pressure to be used is almost the same, so the apparatus configuration is very simple.

DESCRIPTION OF SYMBOLS 1 Coal gasification combined cycle plant 3 Coal gasification combined cycle plant 5 Coal gasification combined cycle plant 10 Gasification furnace 12 Pressure vessel 14 Coal gasifier 16 Coal hopper 20 Heat exchanger 32 Liquefied carbon dioxide storage tank 36 Gas turbine 40 Gas turbine generator 42 Waste heat recovery boiler 44 Steam turbine 46 Steam turbine generator 48 Coal supply pipe 54 Unburnt char extraction pipe 56 Chimney 58 Booster 60 Controller 64 Coal gasifier seal gas supply pipe 66 Differential pressure detector 68 Spatial region 70 Bulkhead 78 Coal gasifier seal gas flow rate adjustment valve 80 Coal gasifier seal gas flow rate detector 82 Unburned char transfer gas supply pipe 84 Unburned char transfer gas flow rate adjustment valve 86 Unburned char transfer gas Flow detector 88 Coal transport gas supply pipe 90 Coal transport gas flow control valve 92 Gas flow detector for coal transportation

Claims (4)

A coal gasifier including a gasification furnace housed in a pressure vessel, which generates coal gasification gas from coal and a gasifying agent;
A gas turbine power generation facility configured to burn a gas obtained by purifying the coal gasification gas, and to generate electric power using the burned gas as power
A steam turbine power generation facility that generates power using steam from a heat exchanger that recovers heat of the gasification furnace and an exhaust heat recovery boiler that recovers exhaust heat of the gas turbine; and
A carbon dioxide recovery facility having a liquefied carbon dioxide storage tank for recovering and storing carbon dioxide generated in the coal gasification gas generation step as liquefied carbon dioxide;
A coal gasifier seal gas supply means for supplying boil-off gas generated from the liquefied carbon dioxide storage tank to the coal gasifier as a seal gas of the coal gasifier;
A coal gasification combined cycle plant comprising: Further, a dedusting device that is installed on the downstream side of the coal gasifier and collects the unburned char scattered from the gasifier, and a return means for returning the unburned char recovered by the deduster to the gasifier And
2. The coal gas according to claim 1, further comprising unburned char transport gas supply means for supplying boil-off gas generated from the liquefied carbon dioxide storage tank to the return means as transport gas for the return means. Combined power plant. And a coal hopper for storing coal to be supplied to the gasifier,
A boil-off gas generated from the liquefied carbon dioxide storage tank is provided with a coal conveyance gas supply means for supplying the coal hopper as a conveyance gas for supplying coal from the coal hopper to the gasification furnace. Item 3. The coal gasification combined power plant according to Item 1 or 2. And a booster that boosts the boil-off gas generated from the liquefied carbon dioxide storage tank;
A control device for controlling the booster to bring the boil-off gas to a predetermined pressure;
One or more gas supply means of the coal gasifier seal gas supply means, the unburned char transfer gas supply means, and the coal transfer gas supply means supply the boil-off gas boosted by the booster. The coal gasification combined cycle power plant according to any one of claims 1 to 3 characterized by things.

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