JPH11200885A - Gasifying combined power generation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gasifying combined power generation equipment whereby kept energy of extraction air supplied to a low pressure type air separator can be effectively applied without reducing residual oxygen concentration of exhaust gas supplied to a boiler equipment, in the case of providing the 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 10 with exhaust gas in the gas turbine equipment 6 serving as an oxidizing agent, a low pressure type air separator 7 liquefying pressure air separated in low pressure oxygen gas and nitrogen gas and an oxygen gas compressor 16 (for instance, turbine compressor) further pressurizing oxygen gas separated by high pressure extraction air from the gas turbine equipment 6 are provided. The high pressure extraction air, after its temperature is increased to a high value (for instance, about 500 to 600 deg.C), is supplied to the oxygen gas compressor 16, and oxygen gas is further pressurized therein, to be supplied to the gasifying equipment 1.

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 addition, saturation equipment is not necessarily required.

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.

[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. In combination with this, the excess air compressed by the air compressor 6b of the gas turbine power generation equipment 6 is extracted and sent to the high-pressure air separation device 7 to supply compressed air to the air separation device 7. The power of the air compressor 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 high-pressure type air separation device 7 is sent to the gas turbine power generation equipment 6, the oxygen concentration in the gas turbine exhaust gas may fall below the 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 4a
There is also ta, and the stored energy is wasted.

On the other hand, the air separation device 7 is of a low pressure type in addition to the high pressure type, and the low pressure type air separation device 7 has a higher separation efficiency than the high pressure type, and the pressure of the separated nitrogen gas is 1 to 1.
2ata, which is characterized by little loss even if released as it is. However, when the low-pressure air separation device 7 is used, since the pressure of the bleed air from the air compressor 6b is high (for example, about 15 ata), it is necessary to expand the pressure to about 4 to 5 ata, which is the low-pressure maximum operating pressure. Energy is wasted.

The present invention has been made in order to solve such a problem. That is, an object of the present invention is to provide a low-pressure type air separation device without reducing the residual oxygen concentration of exhaust gas supplied to the boiler equipment when a boiler equipment using high-temperature exhaust gas of a gas turbine as an oxidant is provided. It is an object of the present invention to provide a combined gasification and power generation facility that can effectively utilize the energy possessed by bleed air.

[0010]

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 low-pressure air separation device that liquefies and separates pressurized air into low-pressure oxygen gas and nitrogen gas, and an oxygen gas compression device that further pressurizes the oxygen gas separated by high-pressure bleed air from gas turbine equipment. The combined gasification combined cycle equipment provided with these is provided.

According to a preferred embodiment of the present invention, there is provided an air heater for heating the high-pressure bleed air with gasification gas of a gasification facility.

According to the configuration of the present invention, the high-pressure bleed air supplied from the gas turbine power generation facility is preferably heated to a high temperature (for example, about 500
After the temperature is raised to about 600 ° C.), the oxygen gas is supplied to an oxygen gas compression device (preferably, a turbine compressor), and the oxygen gas is further pressurized by the compression device and can be used as high-pressure oxygen supplied to a gasification facility.

Therefore, when a low-pressure air separation device is used, the stored energy that has been expanded to its operating pressure and wasted can be recovered and effectively used by the oxygen gas compression device. Thereby, the oxygen compressor and the expander which have been conventionally required can be eliminated, and the equipment cost and the operating power cost thereof can be reduced. Also, with this configuration, nitrogen generated in the air separation device is
Since it is not mixed with the exhaust gas of the gas turbine, the residual oxygen concentration of the high-temperature exhaust gas can be kept high, and the re-powering of the boiler equipment can be effectively performed using the exhaust gas as an oxidant.

[0014]

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 low-pressure air separation device. The low-pressure air separation device 7 shown in this figure is of a molecular sieve type, and 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. 4 compressed by an air compressor (such as the air compressor 9a or 6b in FIG. 2).
Compressed air of ~ 5ata is molecular sieve adsorber 7a
And impurities such as moisture, carbon dioxide, and hydrocarbons contained in the air are removed by adsorption. Next, a part of the pressurized air is adiabatically expanded in the expander 7b to generate an extremely low temperature,
The remaining pressurized air is cooled and liquefied to an extremely low temperature by the air cooler 7d and supplied to the lower column of the distillation column 7c. In the lower column of the distillation column 7c, the liquefied air is reduced in pressure to 4 to 5 ata, and the gasified nitrogen (GN) and the liquefied air (LA) are separately cooled in the main heat exchanger 7e. It is supplied to the upper tower. The upper column of the distillation column 7c is decompressed to 2-3 ata, where all of the liquefied air (LA) is gasified nitrogen (G
N) and liquefied oxygen (LO), and are heated by an air cooler 7d or a main heat exchanger 7e, respectively, to about 1-2 at.
It is taken out at the pressure of a. The low-pressure air separation device 7 is not limited to the molecular sieve type, but may be, for example, a well-known reversing heat exchanger type or the like.

FIG. 1 is an overall flow chart of an integrated gasification combined cycle system 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, in the integrated gasification combined cycle system of the present invention, the pressurized air is liquefied and separated to a low pressure (for example, 1 to 2).
The apparatus is provided with a low-pressure air separation device 7 for separating oxygen gas and nitrogen gas of ata) and an oxygen gas compression device 16 for further pressurizing the oxygen gas separated by high-pressure bleed air from the gas turbine equipment 6. Further, this facility further includes an air heater 14 for heating the high-pressure bleed air with the gasification gas of the gasification facility 1.

In this example, the oxygen gas compressor 16
Is a turbine compressor, which drives a turbine with high-pressure bleed air to drive a compressor for oxygen gas directly connected to the turbine. The present invention is not limited to this configuration. For example, a turbine and a compressor may be separately installed, a generator may be driven by the turbine, and the compressor may be driven by the generated power.

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 high-pressure bleed air from the gas turbine power generation facility 6 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. Further, the nitrogen gas separated by the air separation device 7 is not supplied to the gas turbine equipment 6, but is discharged as it is because of the low pressure, or supplied to other equipment.
Other configurations are the same as those in FIG.

According to the configuration of the present invention described above, after the high-pressure bleed air supplied from the gas turbine power plant 6 is heated to a high temperature (for example, about 500 to 600 ° C.), the oxygen gas compression device 16 (turbine Compressor)
The oxygen gas can be further pressurized by the compression device 16 and used as high-pressure oxygen supplied to the gasification facility 1. Therefore, when using a low-pressure air separation device, the retained energy that was expanded to its operating pressure and wasted wastefully,
The oxygen gas can be recovered and effectively used by the oxygen gas compression device 16, thereby eliminating the need for an oxygen compressor and an expander, which are conventionally required, and reducing the equipment cost and operating power cost thereof. . 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.

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 system of the present invention reduces the residual oxygen concentration of the exhaust gas supplied to the boiler facility when the boiler facility uses the high-temperature exhaust gas of the gas turbine as an oxidant. Without having such an advantage, it is possible to effectively utilize the energy possessed by the extracted air supplied to the low-pressure air separation device.

[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 14 Air heater 16 Oxygen gas compressor (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] 1. A gasification combined cycle power plant comprising a gasification facility, a gas turbine facility and a boiler facility, wherein the exhaust gas of the gas turbine facility is used as an oxidant to burn fuel in the boiler facility. Gasification characterized by comprising: a low-pressure air separation device for separating oxygen gas and nitrogen gas from each other; and an oxygen gas compression device for further pressurizing the oxygen gas separated by high-pressure bleed air from gas turbine equipment. Combined power generation facility. 2. The integrated gasification combined cycle system according to claim 1, further comprising an air heater for heating the high-pressure bleed air with a gasification gas from a gasification facility.