JPH11200886A - Gasifying combined power generation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasifying combined power generation equipment whereby kept energy of high pressure nitrogen from an air separator can be effectively applied without reducing residual oxygen concentration of exhaust gas supplied to a boiler equipment with high temperature exhaust gas of a gas turbine serving as an oxidizing agent. SOLUTION: In this gasifying combined power generation equipment provided with a gasifying equipment 1, gas turbine equipment 6, and a boiler equipment 10 to burn fuel in the boiler equipment with exhaust gas in the gas turbine equipment 6 serving as an oxidizing agent, a high pressure type air separator 7 liquefying pressure air separated into pressurized oxygen gas and nitrogen gas, nitrogen gas heaters 12, 14 heating separated nitrogen gas, and an oxygen gas compressing turbine compressor 16 further pressurizing separated oxygen gas by heated nitrogen gas are provided. In a nitrogen/air heat exchanger 12, by extraction air, and/or in a nitrogen/gasified gas heat exchanger 14, by gasified gas, separated nitrogen gas is heated to a high temperature (for instance, about 400 to 500 deg.C), and an expansion turbine of the turbine compressor 16 is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated gasification combined cycle system in which exhaust gas from a gas turbine facility is used as an oxidant to burn fuel in a boiler facility.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional integrated gasification combined cycle facility (I).
It is a flowchart of GCC: Integrated Gasification Combined Cycle. A hydrocarbon-based fuel such as coal or heavy oil is gasified in a gasification facility 1 using steam and oxygen gas to produce a crude gas, which is then dedusted by a dedusting device 2, and a crude gas cooler 3.
, And is desulfurized by the wet desulfurization facility 4 and supplied to the saturation facility 5, and the humidified fuel gas is supplied to the combustor 6 a of the gas turbine generator 6. On the other hand, the excess air of the gas turbine generator 6 is extracted and the air separator 7 (ASU:
Air separation unit), where oxygen and nitrogen are separated from the bleed air and the introduced air, and this oxygen is pressurized by the oxygen compressor 9b and supplied to the gasification equipment 1 for gasification and separated. Nitrogen is supplied to a combustor of a gas turbine.

In the gas turbine power generation facility 6, a compressor 6b
The fuel gas is burned by the compressed air pressurized by the above, the gas turbine 6c is driven by the combustion gas increased by the humidified steam and the nitrogen gas to generate power by the generator 6d, and the exhaust gas is discharged into the exhaust heat recovery boiler 8 (HRSG: HeatRecovery Steam Generator
), Heat is recovered from the exhaust gas, and the feed water is heated. A part of the heated feed water is supplied to the saturation equipment 5 and used for humidification.

The saturation equipment 5 comprises a multi-stage contact tower 5a in which gas and water come into contact with each other and a pump 5b for circulating hot water. To about 140 ° C., and humidify the steam to the saturation point at this temperature. In addition, saturation equipment is not necessarily required.

[0005]

As described above, in the conventional integrated gasification combined cycle system (IGCC), the nitrogen gas separated by the air separation unit 7 is pressurized by the nitrogen compressor 9c to form the gas turbine The gas was sent to the combustor 6a to increase the output of the gas turbine 6c and reduce NOx. Further, in combination with this, an air compressor that extracts excess surplus air compressed by the air compressor 6 b of the gas turbine power generation facility 6, sends it to the air separation device 7, and supplies compressed air to the air separation device 7 The power of 9a was reduced.

However, the waste heat recovery boiler 8 in the conventional integrated gasification combined cycle facility only recovers sensible heat from the high temperature exhaust gas (for example, 500 ° C. to 600 ° C.) of the gas turbine 6c, and therefore has low thermal efficiency. Therefore, especially when there is an existing boiler facility, the existing boiler facility is used effectively by using the existing boiler facility instead of the exhaust heat recovery boiler 8 and burning the fuel using the exhaust gas of the gas turbine as an oxidant. At the same time, it has been proposed to increase the total power generation amount of the integrated gasification combined cycle facility (referred to as repowering).

When performing repowering, as in the prior art,
When the nitrogen gas from the air separation device 7 is sent to the gas turbine power generation equipment 6, the oxygen concentration in the exhaust gas of the gas turbine may fall below a required concentration (1 to 4%). In this case, the nitrogen in the air separation device 7 must be discharged to the atmosphere without being sent to the gas turbine. In particular, when the air separation device 7 is of a high pressure type, the pressure of the separated nitrogen gas is 3 to 4ata
And waste that energy.

The present invention has been made to solve such a problem. That is, an object of the present invention is to effectively utilize the high-pressure nitrogen retained energy from an air separation device without reducing the residual oxygen concentration of exhaust gas supplied to a boiler facility using high-temperature exhaust gas of a gas turbine as an oxidant. An object of the present invention is to provide an integrated gasification combined cycle facility.

[0009]

According to the present invention, there is provided a gasification combined cycle power plant comprising a gasification facility, a gas turbine facility and a boiler facility, wherein the exhaust gas from the gas turbine facility is used as an oxidant to burn fuel in the boiler facility. A high-pressure air separation device that liquefies and separates pressurized air into oxygen gas and nitrogen gas that is pressurized, a nitrogen gas heater that heats the separated nitrogen gas, and a separation using heated nitrogen gas And a turbine compressor for compressing oxygen gas that further pressurizes the supplied oxygen gas.

According to a preferred embodiment of the present invention, the nitrogen gas heater uses bleed air from a gas turbine facility and / or gasified gas from a gasification facility as a heating source.

According to the configuration of the present invention, the nitrogen gas generated by the high-pressure air separation apparatus and pressurized to a high pressure (3 at least) is extracted with the extracted air and / or gasified gas at a high temperature (for example, about 400 After the temperature is raised to about 500 ° C.), the oxygen gas can be further pressurized by turning an expansion turbine of a turbine compressor for oxygen gas compression and used as high-pressure oxygen supplied to gasification equipment.

Therefore, the energy of the high-pressure nitrogen generated in the air separation device by the expansion turbine can be recovered, and the energy that has been conventionally released to the atmosphere can be effectively used. The compressor 9b and the nitrogen compressor 9c can be eliminated, and their equipment costs and operating power costs can be reduced. In addition, with this configuration, since the nitrogen generated in the air separation device is not mixed into the exhaust gas of the gas turbine, the residual oxygen concentration of the high-temperature exhaust gas can be kept high, and this exhaust gas is used as an oxidizing agent to effectively repower the boiler equipment. Can be done.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, common portions are denoted by the same reference numerals, and redundant description is omitted.
FIG. 2 is an overall configuration diagram of a conventional high-pressure air separation device. The high-pressure air separation device 7 shown in this figure is of a molecular sieve type, and has a molecular sieve adsorber 7a,
It is provided with an expander (expander) 7b, a distillation column 7c, an air cooler 7d, a main heat exchanger 7e, and the like. Compressed air pressurized by an air compressor (such as the air compressor 9a or 6b in FIG. 2) enters the molecular sieve adsorber 7a, and impurities such as moisture, carbon dioxide, and hydrocarbons contained in the air are adsorbed. Removed. Next, a part of the pressurized air is adiabatically expanded in the expander 7b to generate a cryogenic temperature, and the air cooler 7d
The remaining pressurized air is cooled and liquefied to a cryogenic temperature in the distillation column 7c.
To the lower tower. In the lower column of the distillation column 7c, the liquefied air is reduced in pressure to 12 to 13 ata (temperature of about -160
° C), vaporized nitrogen gas (GN) and liquefied air (LA)
Are separately cooled in the main heat exchanger 7e and supplied to the upper column of the distillation column 7c. The upper column of the distillation column 7c is decompressed to 4 to 5 data (temperature of about -170 ° C), and all of the liquefied air (LA) is gasified nitrogen (GN) and liquefied oxygen (L).
O) and heated by an air cooler 7d or a main heat exchanger 7e, respectively, to a pressure of about 3 to 4 ata, about 150
It is taken out at a temperature of ° C. The high-pressure air separation device 7 is not limited to the molecular sieve type, and may be, for example, a well-known reversing heat exchanger type or the like.

FIG. 1 is an overall flowchart of an integrated gasification combined cycle power plant according to the present invention. In this figure, the integrated gasification combined cycle system of the present invention includes a gasification facility 1, a gas turbine facility 6
And boiler equipment 10, and the boiler equipment 10 burns fuel using the exhaust gas of the gas turbine equipment 6 as an oxidant. The boiler facility 10 is an existing boiler facility, and is most suitably repowering that makes effective use of the boiler facility, but may be newly provided separately. Further, the boiler facility 10 may be a power generation facility provided with a steam power generation facility, or may be for other purposes.

As shown in FIG. 1, the combined gasification combined cycle system of the present invention comprises a high-pressure air separation device 7 for liquefying and separating pressurized air into pressurized oxygen gas and nitrogen gas. A nitrogen gas heater for heating the heated nitrogen gas; and a turbine compressor 16 for compressing the oxygen gas, which further pressurizes the oxygen gas separated by the heated nitrogen gas.

In this example, the nitrogen gas heater includes a nitrogen / air heat exchanger 12 using the extracted air of the gas turbine facility 6 as a heating source, and a nitrogen / gas heat source using the gasification gas of the gasification facility 1 as a heating source. Gas heat exchanger 14. With this configuration, the low-temperature and high-pressure (for example, about 15 ° C., about 3 to 4 ata) nitrogen gas separated by the high-pressure air separation device 7 shown in FIG. Reheat in the gas heat exchanger 14 to perform high temperature and high pressure (for example,
About 400 ° C., about 3 to 4 data). The nitrogen / air heat exchanger 12 and the nitrogen / gasification gas heat exchanger 14 may include only one of them.

That is, in the integrated gasification combined cycle system shown in FIG. 1, compared with the conventional integrated gasification combined cycle installation shown in FIG.
The compressors 9b and 9c are eliminated, and a turbine compressor 16 is provided instead. The nitrogen gas separated by the air separation device 7 is not supplied to the gas turbine equipment 6 but is supplied to the expansion turbine of the turbine compressor 16 after heating to generate power. Further, a boiler facility 10 is used instead of the conventional exhaust heat recovery boiler 8. Other configurations are the same as those in FIG.

According to the configuration of the present invention described above, the nitrogen gas generated in the high-pressure type air separation device 7 and pressurized to a high pressure (3 at least) is extracted air in the nitrogen / air heat exchanger 12 and / or Alternatively, the gasification gas in the nitrogen / gasification gas heat exchanger 14 is heated to a high temperature (for example, about 400 to 500
C.), the expansion turbine of the oxygen gas compression turbine compressor 16 is driven to further pressurize the oxygen gas, which can be used as high-pressure oxygen supplied to gasification equipment.

Therefore, the energy of the high-pressure nitrogen generated in the air separation device 7 by the expansion turbine can be recovered, and the energy that has been conventionally released to the atmosphere can be effectively used. The compressor 9b and the nitrogen compressor 9c can be eliminated, and their equipment costs and operating power costs can be reduced. Further, according to this configuration, since the nitrogen generated in the air separation device 7 is not mixed into the exhaust gas of the gas turbine, the residual oxygen concentration of the high-temperature exhaust gas can be kept high, and this exhaust gas is used as an oxidant to repower the boiler equipment. Can be done effectively.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0021]

As described above, the integrated gasification combined cycle power plant of the present invention can be used in an air separation device without reducing the residual oxygen concentration of exhaust gas supplied to a boiler facility using hot exhaust gas from a gas turbine as an oxidant. Of the high pressure nitrogen can be effectively utilized.

[Brief description of the drawings]

FIG. 1 is an overall flowchart of an integrated gasification combined cycle facility according to the present invention.

FIG. 2 is an overall configuration diagram of a conventional air separation device.

FIG. 3 is a flowchart of a conventional integrated gasification combined cycle facility.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gasification equipment 2 Dust removal device 3 Crude gas cooler 4 Wet desulfurization equipment 5 Saturation equipment 5a Multi-stage contact tower 5b Pump 6 Gas turbine generator 6a Combustor 6b Compressor 6c Gas turbine 6d Generator 7 Air separator 7a Molecular sieve adsorber 7b Expander (expander) 7c Distillation tower 7d Air cooler 7e Main heat exchanger 8 Waste heat recovery boiler 9a, 9b, 9c Compressor 10 Boiler equipment 12 Nitrogen / air heat exchanger 14 Nitrogen / gasification gas heat exchanger 16 Turbine compressor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02C 6/18 F02C 6/18 Z

Claims (2)

[Claims] A gasification combined cycle power plant comprising a gasification facility, a gas turbine facility, and a boiler facility, wherein the exhaust gas from the gas turbine facility is used as an oxidant to burn fuel in the boiler facility. A high-pressure air separation device that separates the separated oxygen gas and nitrogen gas, a nitrogen gas heater that heats the separated nitrogen gas, and an oxygen gas that further pressurizes the separated oxygen gas with the heated nitrogen gas An integrated gasification combined cycle facility comprising a turbine compressor for compression. 2. The gasification complex according to claim 1, wherein the nitrogen gas heater uses a bleed air of a gas turbine facility and / or a gasification gas of a gasification facility as a heating source. Power generation equipment.