Integrated coal gasification combined power generation process with zero carbon emission

Abstract

The present disclosure relates to the technical field of coal chemical industry, and particularly discloses an integrated coal gasification combined power generation process with zero carbon emission, the process comprising: pressurizing air for performing air separation to obtain liquid oxygen and liquid nitrogen, wherein the liquid oxygen is used for gasification and power generation, the liquid nitrogen is applied as the coolant for the gasification and power generation, the liquid nitrogen and a part of liquid oxygen stored during the valley period with low electricity load are provided for use during the peak period with high electricity load; the pulverized coal delivered under pressure and high-pressure oxygen enter a coal gasification furnace for gasification, so as to generate high-temperature fuel gas, which subjects to heat exchange and purification, and then the high-pressure fuel gas enters into a combustion gas turbine along with oxygen and recyclable CO.sub.2 for burning and driving an air compressor and a generator to rotate at a high speed; the air compressor compresses the air to a pressure of 0.40.8 MPa, and the generator generates electricity; the high-temperature combustion flue gas performs the supercritical CO.sub.2 power generation, its coolant is liquid oxygen or liquid nitrogen; the heat exchanged combustion fuel gas subsequently perform heat exchange with liquid nitrogen, the liquid nitrogen vaporizes to drive a nitrogen turbine generator for generating electricity, the cooled flue gas is dehydrated and distilled to separate CO.sub.2, a part of CO.sub.2 is used for circulation and temperature control, and another portion of CO.sub.2 is sold outward as liquid CO.sub.2 product. The power generation process provided by the present disclosure not only solves the difficult problems of high water consumption, low power generation efficiency and small range of peak load adjustment capacity of the existing IGCC technology; but also can compress air with high unit volume for energy storage with a high conversion efficiency, and greatly reduce load of the air compressor, thereby perform CO.sub.2 capture and utilization with low-cost, zero NO.sub.x emission and discharging fuel gas at a normal temperature, and significantly improve the power generation efficiency.

Claims

1. An integrated coal gasification combined power generation process with zero carbon emission, the process comprising: 1) introducing pressurized air with a pressure 0.4 to 0.8 MPa into an air separation facility for performing air separation to obtain liquid oxygen and liquid nitrogen; 2) performing heat exchange at a first cooler between at least a part of the liquid oxygen and high-temperature CO.sub.2 from an outlet of a first supercritical CO.sub.2 generator, so as to generate high-pressure vaporized oxygen and recyclable CO.sub.2; 3) subjecting at least a part of the high-pressure vaporized oxygen and pulverized coal to a gasification reaction in a coal gasification furnace to obtain a high-temperature and high pressure fuel gas, carrying out heat exchange of the high-temperature and high-pressure fuel gas in a first CO.sub.2 waste heat boiler to perform a first supercritical CO.sub.2 power generation; 4) purifying high-pressure fuel gas obtained by the heat exchange in step 3) to obtain high-pressure purified fuel gas; 5) pumping the high-pressure vaporized oxygen remaining after step 3) and the high-pressure purified fuel gas jointly into a combustion gas turbine for burning and swelling to drive an air compressor and a generator to generate electricity and to obtain a high-temperature combustion flue gas; 6) subjecting the high-temperature combustion flue gas obtained in step 5) to heat exchange in a second CO.sub.2 waste heat boiler to perform a second supercritical CO.sub.2 power generation, and coolant of the second supercritical CO.sub.2 power generation is at least part of the liquid oxygen and/or at least part of the liquid nitrogen; 7) performing heat exchange of heat exchanged combustion flue gas obtained in step 6) with at least part of the liquid nitrogen through a vaporizer to obtain a staged cooled flue gas, wherein the vaporization of liquid nitrogen drives a nitrogen turbine generator to generate electricity.

2. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the power generation process further comprises: dehydrating the staged cooled flue gas obtained in step 7), and sending the dehydrated flue gas to a flue gas distillation tower to separate and recover CO.sub.2.

3. The integrated coal gasification combined power generation process with zero carbon emission according to claim 2, wherein at least a part of the recovered CO.sub.2 is recycled to the step 5) and enters the combustion gas turbine in conjunction with the high-pressure vaporized oxygen and the high-pressure purified fuel gas.

4. The integrated coal gasification combined power generation process with zero carbon emission according to claim 3, wherein the mass ratio of the high-pressure vaporized oxygen from an inlet of the combustion gas turbine relative to the recyclable CO.sub.2 is 1:2 to 1:12.

5. The integrated coal gasification combined power generation process with zero carbon emission according to claim 4, wherein the mass ratio of the high-pressure vaporized oxygen from an inlet of the combustion gas turbine relative to the recyclable CO.sub.2 is 1:5 to 1:8.

6. The integrated coal gasification combined power generation process with zero carbon emission according to claim 2, wherein at least a part of recovered CO.sub.2 is used for replenishing working medium in the first supercritical CO.sub.2 power generation in step 3) and/or the second supercritical CO.sub.2 power generation in step 6).

7. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the air separation is a cryogenic air separation, a cascade air separation combined with pressure swing adsorption separation and cryogenic separation or a cascade air separation combined with membrane separation and cryogenic separation.

8. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the first supercritical CO.sub.2 power generation and the second supercritical CO.sub.2 power generation are one of a supercritical CO.sub.2 power generation mode of a recompression cycle, a segment expansion cycle, a preload cycle, and a partial cooling cycle, respectively.

9. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the first supercritical CO.sub.2 power generation according to step 3) comprises: pressurizing supercritical CO.sub.2 with a first CO.sub.2 compressor, and then performing heat exchange with the high-temperature and high-pressure fuel gas in step 3) in a first CO.sub.2 waste heat boiler to form a heat exchanged working medium; the heat exchanged working medium enters the first supercritical CO.sub.2 generator for performing the first supercritical CO.sub.2 power generation; high-temperature CO.sub.2 from an outlet of the first supercritical CO.sub.2 generator subjects to a heat exchange in the first cooler with a part of the liquid oxygen, the recyclable CO.sub.2 is delivered to the first CO.sub.2 compressor; the supercritical CO.sub.2 pressure is within a range of 7 to 40 MPa.

10. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the second supercritical CO.sub.2 power generation in step 6) comprises: pressurizing the supercritical CO.sub.2 by a second CO.sub.2 compressor, and then performing heat exchange in the second CO.sub.2 compressor with the high-temperature combustion flue gas obtained in step 5) to form a heat exchanged working medium; pumping the heat exchanged working medium into a second supercritical CO.sub.2 generator to carry out the second supercritical CO.sub.2 power generation; subjecting the high-temperature CO.sub.2 from an outlet of the second supercritical CO.sub.2 generator to a heat exchange in a second cooler with at least part of the liquid nitrogen to form recyclable CO.sub.2, the recyclable CO.sub.2 is delivered to the second CO.sub.2 compressor; the supercritical CO.sub.2 pressure is within a range of 7 to 40 MPa.

11. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the coal gasification furnace of step 3) is an entrained flow bed gasification furnace, a circulating fluidized bed gasification furnace or a staged pyrolysis gasification composite furnace.

12. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the pressure of the gasification reaction in step 3) is within a range of 1 to 10 MPa.

13. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the purification in step 4) comprises: subjecting the high-pressure fuel gas to dust removal, desulfurization, dechlorination and removal of heavy metals so as to prepare the high-pressure purified fuel gas.

14. The integrated coal gasification combined power generation process with zero carbon emission according to claim 1, wherein the air inhaled from the outside is compressed to a pressure of 0.4 to 0.8 MPa by the air compressor in step 5) to obtain the pressurized air with a pressure 0.4 to 0.8 MPa as described in step 1).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings provide reference to facilitate further understanding of the present disclosure, and constitute a part of the description, it serves to illustrate the present disclosure along with the following specific embodiments, but the drawings do not impose limitation on the present disclosure. In the drawings:

(2) FIG. 1 is a schematic diagram of an integrated coal gasification combined power generation process with zero carbon emission according to an embodiment of the present disclosure.

DESCRIPTION OF THE REFERENCE SIGNS

(3) TABLE-US-00001 1. air separation 2. coal bunker 3. coal gasification facility furnace 4. first CO.sub.2 waste 5. first supercritical 6. first cooler heat boiler CO.sub.2 generator 7. first CO.sub.2 8. purifier 9. combustion gas compressor turbine 10. vaporizer 11. nitrogen turbine 12. flue gas distillation generator tower 13. air compressor 14. second CO.sub.2 waste 15. second supercritical heat boiler CO.sub.2 generator 16. second cooler 17. second CO.sub.2 18. generator compressor

DETAILED DESCRIPTION

(4) The terminals and any value of the ranges disclosed herein are not limited to the precise ranges or values, such ranges or values shall be comprehended as comprising the values adjacent to the ranges or values. As for numerical ranges, the endpoint values of the various ranges, the endpoint values and the individual point value of the various ranges, and the individual point values may be combined with one another to produce one or more new numerical ranges, which should be deemed have been specifically disclosed herein.

(5) As illustrated in FIG. 1, the present disclosure provides an integrated coal gasification combined power generation process with zero carbon emission, the process comprising:

(6) 1) introducing pressurized air with a pressure 0.40.8 MPa into an air separation facility for performing air separation to obtain liquid oxygen and liquid nitrogen;

(7) 2) performing heat exchange at a first cooler between at least a part of the liquid oxygen and the high-temperature CO.sub.2 from an outlet of a first supercritical CO.sub.2 generator, so as to generate high-pressure vaporized oxygen and recyclable CO.sub.2;

(8) 3) subjecting at least a part of the high-pressure vaporized oxygen and pulverized coal to a gasification reaction in a coal gasification furnace, carrying out heat exchange of the obtained high-temperature and high-pressure fuel gas in a first CO.sub.2 waste heat boiler to perform the first supercritical CO.sub.2 power generation;

(9) 4) purifying the high-pressure fuel gas obtained by the heat exchange in step 3) to obtain the high-pressure purified fuel gas;

(10) 5) pumping the remaining part of the high-pressure vaporized oxygen and the high-pressure purified fuel gas jointly into a combustion gas turbine for burning and swelling to drive an air compressor and a generator to generate electricity;

(11) 6) subjecting the high-temperature combustion flue gas obtained in step 5) to a heat exchange in a second CO.sub.2 waste heat boiler to perform a second supercritical CO.sub.2 power generation, and the coolant of the second supercritical CO.sub.2 power generation is at least part of the liquid oxygen and/or at least part of the liquid nitrogen;

(12) 7) performing heat exchange of the heat exchanged combustion flue gas obtained in step 6) with at least part of the liquid nitrogen through a vaporizer, the vaporization of liquid nitrogen drives a nitrogen turbine generator to generate electricity.

(13) According to the present disclosure, the air separation is preferably a cryogenic air separation, a cascade air separation combined with pressure swing adsorption separation and cryogenic separation or a cascade air separation combined with membrane separation and cryogenic separation. The specific operation of the air separation may be carried out according to the conventional techniques in the art, and the present disclosure does not impose a particular limitation hereto.

(14) At least a part of the pumped liquid oxygen is used for heat exchange and cooling of the supercritical CO.sub.2 power generation, at least a part of the liquid oxygen subjects to a heat exchange in a first cooler with the high-temperature CO.sub.2 from the first supercritical CO.sub.2 generator outlet for the first supercritical CO.sub.2 power generation, so as to produce the high-pressure vaporized oxygen and recyclable CO.sub.2.

(15) According to the present disclosure, a part of the high-pressure vaporized oxygen is used for gasification of the pulverized coal. Specifically, at least a part of the high-pressure vaporized oxygen and pulverized coal subject to a gasification reaction in a coal gasification furnace to obtain the high-temperature and high-pressure (HTHP) gas. Preferably, the coal gasification furnace of step 3) is an entrained flow bed gasification furnace, a circulating fluidized bed gasification furnace or a staged pyrolysis gasification composite furnace. The conditions of the gasification reaction in the present disclosure are not particularly limited, as long as the pulverized coal can be gasified. Preferably, the pressure of the gasification reaction in step 3) is within a range of 110 MPa, and more preferably 2.86.4 MPa. In particular, the pulverized coal may be provided by a pulverized coal storage unit, such as a coal bunker.

(16) The HTHP fuel gas is subjected to waste heat recovery in a first CO.sub.2 waste heat boiler. Specifically, the HTHP fuel gas subjects to a heat exchange in a first CO.sub.2 waste heat boiler to perform first supercritical CO.sub.2 power generation. According to the present disclosure, in particular, the process the HTHP fuel gas subjects to a heat exchange in a first CO.sub.2 waste heat boiler to perform first supercritical CO.sub.2 power generation refers to that the supercritical CO.sub.2 pressurized by a first CO.sub.2 compressor exchanges heat with the HTHP fuel gas in a first CO.sub.2 waste heat boiler, and the heat exchanged working medium enters a first supercritical CO.sub.2 generator to carry out the first supercritical CO.sub.2 power generation.

(17) Each of the first supercritical CO.sub.2 power generation and the second supercritical CO.sub.2 power generation according to the present disclosure may be independently the variety of power generation modes conventionally used in the art, preferably, the first supercritical CO.sub.2 power generation and the second supercritical CO.sub.2 power generation are one of a supercritical CO.sub.2 power generation mode of a recompression cycle, a segment expansion cycle, a preload cycle, and a partial cooling cycle, respectively.

(18) According to a preferred embodiment of the present disclosure, the first supercritical CO.sub.2 power generation according to step 3) comprises: pressurizing the supercritical CO.sub.2 with a first CO.sub.2 compressor, and then performing heat exchange with the HTHP fuel gas in step 3) in a first CO.sub.2 waste heat boiler; the heat exchanged working medium enters the first supercritical CO.sub.2 generator for performing the first supercritical CO.sub.2 power generation; the high-temperature CO.sub.2 from an outlet of the first supercritical CO.sub.2 generator subjects to a heat exchange in the first cooler with at least a part of the liquid oxygen, the obtained recyclable CO.sub.2 is delivered to the first CO.sub.2 compressor.

(19) According to the power generation process provided by the present disclosure, preferably, the supercritical CO.sub.2 pressure is within a range of 740 MPa, and further preferably, the supercritical CO.sub.2 pressure is within a range of 1225 MPa.

(20) According to the present disclosure, in the step 3), the HTHP fuel gas is subjected to a waste heat recovery in a first CO.sub.2 waste heat boiler to obtain the high-pressure fuel gas, which subject to a purification process to prepare a high-pressure purified fuel gas. The present disclosure does not impose a particular limitation on the purification process in step 4), the purification may be carried out in accordance with the conventional technical means in the art. Preferably, the purification in step 4) comprises: subjecting the high-pressure fuel gas to the dust removal, desulfurization, dechlorination and removal of heavy metals so as to prepare the high-pressure purified fuel gas. The specific operations of the dust removal, desulfurization, dechlorination and removal of heavy metals may be implemented according to conventional means in the art.

(21) A part of the high-pressure vaporized oxygen is used for gasification of pulverized coal, and another part of the high-pressure vaporized oxygen and the aforementioned high-pressure purified fuel gas jointly enter a combustion gas turbine for burning and swelling to drive an air compressor and a generator to generate electricity. The specific distribution ratio of the aforementioned high-pressure vaporized oxygen is not particularly limited in the present disclosure, and the skilled person in the art may appropriately distribute and select the ratio according to the specific circumstance.

(22) According to a specific embodiment of the present disclosure, the air inhaled from the outside is compressed to a pressure of 0.40.8 MPa by the air compressor in step 5) to obtain the pressurized air with a pressure 0.40.8 MPa as described in step 1). The power generation process provided by the present disclosure does not need to pressurize the air to a high-pressure of 2.8 MPa, thereby reduce energy consumption. Specifically, the compressor may be an axial flow compressor, and the air compressor in step 5) inhales air from the external atmospheric environment and stepwise pressurizes the air to a pressure of 0.40.8 MPa through the axial flow compressor.

(23) According to the present disclosure, the high-pressure purified gas is subjected to work by the combustion gas turbine to obtain high-temperature combustion flue gas, and the high-temperature combustion flue gas subjects to a heat exchange in the second CO.sub.2 waste heat boiler to perform a second supercritical CO.sub.2 power generation, wherein the coolant of the second supercritical CO.sub.2 power generation is at least part of the liquid oxygen and/or at least part of the liquid nitrogen. That is, when the coolant of the second supercritical CO.sub.2 power generation is at least part of the liquid oxygen, a part of the liquid oxygen obtained in step 1) is used as the coolant of the first supercritical CO.sub.2 power generation in step 2), the remaining part of the liquid oxygen is used as a coolant of the second supercritical CO.sub.2 power generation in step 6); the specific operations of using the remaining part of the liquid oxygen as a coolant of the second supercritical CO.sub.2 power generation in step 6) may be as follows: the remaining part of the liquid oxygen performs heat exchange in a second cooler with the high-temperature CO.sub.2 from an outlet of the second supercritical CO.sub.2 generator; when the coolant of the second supercritical CO.sub.2 power generation is at least part of the liquid nitrogen, a part of liquid nitrogen obtained in step 1) is used as a coolant of the second supercritical CO.sub.2 power generation, a remaining part of liquid nitrogen is used in step 7), which performs heat exchange through a vaporizer with the heat exchanged combustion flue gas obtained in step 6), the vaporization of liquid nitrogen drives a nitrogen turbine generator to generate electricity. Preferably in step 6), the coolant used for the second supercritical CO.sub.2 power generation is at least part of the liquid nitrogen. Preferably, the liquid oxygen obtained in step 1) is completely used in step 2), and it subjects to heat exchange in a first cooler with the high-temperature CO.sub.2 from an outlet of the first supercritical CO.sub.2 generator.

(24) According to a preferred embodiment of the present disclosure, the second supercritical CO.sub.2 power generation in step 6) comprises: pressurizing the supercritical CO.sub.2 by a second CO.sub.2 compressor, and then performing heat exchange in a second CO.sub.2 compressor with the high-temperature combustion flue gas obtained in step 5); pumping the heat exchanged working medium into a second supercritical CO.sub.2 generator to carry out the second supercritical CO.sub.2 power generation; subjecting the high-temperature CO.sub.2 from the second supercritical CO.sub.2 generator outlet to a heat exchange in a second cooler with at least part of the liquid nitrogen, the obtained recyclable CO.sub.2 is delivered to the second CO.sub.2 compressor. Preferably, the supercritical CO.sub.2 pressure is within a range of 740 MPa, and further preferably, the supercritical CO.sub.2 pressure is 1225 MPa.

(25) The specific proportion of liquid nitrogen obtained in step 1) of the present disclosure is not particularly limited, and the skilled person in the art may appropriately select the ratio according to the practical condition.

(26) According to the present disclosure, the liquid nitrogen obtained in step 1) may be stored during the valley period with low electricity load (e.g., at nighttime), and then during the peak period with high electricity load (e.g., in the daytime), the heat exchange of the heat exchanged combustion flue gas obtained in step 6) with at least part of the liquid nitrogen may be performed through a vaporizer, the vaporization of liquid nitrogen drives a nitrogen turbine generator to generate electricity. The power generation process provided by the present disclosure can perform peak shaving and power generation.

(27) According to a preferred embodiment of the present disclosure, the power generation process further comprises: dehydrating the staged cooled flue gas obtained in step 7), and sending the dehydrated flue gas to a flue gas distillation tower to separate and recover CO.sub.2. The staged cooled flue gas refers to the flue gas obtained by means of performing heat exchange (first stage cooling) of the high-temperature combustion flue gas in the second CO.sub.2 waste heat boiler, and subjecting the combustion flue gas after the heat exchange to a heat exchange (second stage cooling) by the vaporizer with at least part of the liquid nitrogen. The manner of the dehydration in the present disclosure is not particularly limited, and dehydration may be carried out according to a variety of technical means conventionally used in the art.

(28) According to a preferred embodiment of the present disclosure, at least a part of the recovered CO.sub.2 is recycled to the combustion gas turbine in step 5) and enters the combustion gas turbine in conjunction with the high-pressure vaporized oxygen and the high-pressure purified fuel gas. At least a portion of the recovered CO.sub.2 is returned to the combustion gas turbine as a feed material for circulation and temperature control.

(29) According to a preferred embodiment of the present disclosure, the mass ratio of the high-pressure vaporized oxygen from an inlet of the combustion gas turbine relative to the recyclable CO.sub.2 is 1:(212), further preferably 1:(58).

(30) According to a preferred embodiment of the present disclosure, at least a part of recovered CO.sub.2 is used for replenishing working medium in the first supercritical CO.sub.2 power generation in step 3) and/or the second supercritical CO.sub.2 power generation in step 6). The present disclosure does not impose a particular limitation on the specific amount of recovered CO.sub.2 used in the supercritical CO.sub.2 power generation for the replenishment of the working medium, and the skilled person in the art can make a suitable choice according to the specific operation conditions.

(31) The recovered CO.sub.2 can also be sold outward as a liquid CO.sub.2 product.

(32) According to a specific embodiment of the present disclosure, the integrated coal gasification combined power generation process with zero carbon emission provided by the present disclosure comprises: introducing pressurized air with a pressure 0.40.8 MPa into an air separation facility for performing air separation to obtain liquid oxygen and liquid nitrogen; the pumped pressurized liquid oxygen is used for heat exchange, vaporization and power generation; the pumped pressurized liquid nitrogen is used as a coolant to perform heat exchange and used to vaporize and generate electricity; the liquid nitrogen and a part of the liquid oxygen separated at night are stored for use during a peak period with high electricity load at daytime; the pulverized coal transported under pressure from a coal bunker performs a gasification reaction in a coal gasification furnace with at least a part of the high-pressure vaporized oxygen, the obtained high-temperature and high-pressure fuel gas subjects to waste heat recovery through a first CO.sub.2 waste heat boiler, and carries out a purification process of dust removal, desulfurization, dechlorination and removal of heavy metals in a purifier, thereby obtain the high-pressure purified fuel gas. The high-temperature supercritical CO.sub.2 following a heat exchange by the first CO.sub.2 waste heat boiler enters the first supercritical CO.sub.2 generator to carry out the first supercritical CO.sub.2 power generation, and it is cooled through a heat exchange in the first cooler with at least a part of the liquid oxygen, and is compressed by the first CO.sub.2 compressor, and then be delivered to the first CO.sub.2 waste heat boiler to perform heat exchange and circulation. The high-pressure purified fuel gas, the remaining part of the high-pressure vaporized oxygen, and the high-pressure recyclable CO.sub.2 jointly enter the combustion gas turbine to swell and drive the air compressor and the generator to rotate at a high speed, the air compressor compresses the air to a pressure of 0.40.8 MPa (obtaining the pressurized air in step 1) with a pressure of 0.40.8 MPa), the generator produces electricity. The obtained high-temperature combustion flue gas is further subjected to heat exchange by a second CO.sub.2 waste heat boiler for a second supercritical CO.sub.2 power generation, the coolant of the second supercritical CO.sub.2 power generation is at least a part of the liquid nitrogen, and the supercritical CO.sub.2 following a cooling process is compressed by the second CO.sub.2 compressor, and is then transported to the second CO.sub.2 waste heat boiler to perform heat exchange and circulation. The combustion flue gas after the heat exchange further performs heat exchange with at least a part of the liquid nitrogen through the vaporizer, vaporization of the liquid nitrogen promotes the nitrogen turbine generator to generate electricity; the flue gas following a staged cooling is dehydrated, the obtained liquid flue gas passes through a distillation tower for separating and recovering CO.sub.2, a part of the CO.sub.2 is returned to the combustion gas turbine as a feed material for circulation and temperature control, a part of CO.sub.2 is used in the supercritical CO.sub.2 power generation for replenishing work medium, and a remaining part of CO.sub.2 is sold outward as liquid CO.sub.2 product. During the peak period of power grid operation with high electricity load during the daytime, the liquid nitrogen stored at nighttime and separated during the daytime is pumped and pressurized, and then subjects to heat exchange and vaporization for power generation; the liquid oxygen stored at nighttime and separated during the daytime is pumped and pressurized, and then subjects to heat exchange and vaporization for use in a coal gasification furnace and a combustion gas turbine to perform peak shaving and power generation in response to the load fluctuation.

(33) The present disclosure will be described in detail below with reference to examples.

Example 1

(34) 1) As shown in FIG. 1, the air compressor (13) inhales air from the outside atmospheric environment and pressurizes the air to a pressure of 0.40.8 MPa; the pressurized air with a pressure of 0.40.8 MPa enters an air separation facility (1) for performing air separation to obtain liquid oxygen and liquid nitrogen;
2) the liquid oxygen is used for the first supercritical CO.sub.2 heat exchange, specifically, the liquid oxygen and the high-temperature CO.sub.2 from an outlet of a first supercritical CO.sub.2 generator (5) for carrying out the first supercritical CO.sub.2 power generation perform heat exchange in a first cooler (6), thereby obtain high-pressure vaporized oxygen and recyclable CO.sub.2, the coolant in the first cooler (6) is liquid oxygen;
3) at least a part of the high-pressure vaporized oxygen and the pulverized coal provided by the coal bunker (2) are subjected to a gasification reaction in a coal gasification furnace (3) (pressure within a range of 110 MPa), and the obtained high-temperature and high-pressure (HTHP) fuel gas performs heat exchange in the first CO.sub.2 waste heat boiler (4) in order to perform the first supercritical CO.sub.2 power generation, the first supercritical CO.sub.2 power generation comprising: pressurizing the supercritical CO.sub.2 with a first CO.sub.2 compressor (7), and then performing heat exchange in a first CO.sub.2 waste heat boiler (4) with the HTHP fuel gas; the heat exchanged working medium enters the first supercritical CO.sub.2 generator (5) for performing the first supercritical CO.sub.2 power generation; the high-temperature CO.sub.2 from an outlet of the first supercritical CO.sub.2 generator (5) subjects to a heat exchange in the first cooler (6) with the liquid oxygen, the obtained recyclable CO.sub.2 is delivered to the first CO.sub.2 compressor (7), and the supercritical CO.sub.2 pressure is within a range of 740 MPa;
4) the high-pressure fuel gas obtained by the heat exchange in step 3) is subjected to a purification process of dust removal, desulfuration, dechlorination and removal of heavy metals in a purifier (8) to obtain high-pressure purified fuel gas;
5) the remaining part of the high-pressure vaporized oxygen, the high-pressure purified fuel gas and the recyclable CO.sub.2 jointly enter the combustion gas turbine (9) for burning and swelling to drive the air compressor (13) and the generator (18) to rotate at a high speed, the air compressor (13) compresses the air to a pressure of 0.40.8 MPa (to obtain the pressurized air in step 1) with a pressure of 0.40.8 MPa), the generator (18) generates electricity, and the mass ratio of the high-pressure vaporized oxygen from an inlet of the combustion gas turbine (9) relative to the recyclable CO.sub.2 is 1:(212);
6) the high-temperature combustion flue gas obtained in step 5) is subjected to heat exchange in a second CO.sub.2 waste heat boiler (14) to perform a second supercritical CO.sub.2 power generation, and a coolant of the second supercritical CO.sub.2 power generation is at least a part of the liquid nitrogen; the second supercritical CO.sub.2 power generation comprises: pressurizing the supercritical CO.sub.2 with a second CO.sub.2 compressor (17), and then performing heat exchange in a second CO.sub.2 waste heat boiler (14) with the high-temperature combustion flue gas obtained in step 5); the heat exchanged working medium enters the second supercritical CO.sub.2 generator (15) for performing the second supercritical CO.sub.2 power generation; the high-temperature CO.sub.2 from an outlet of the first supercritical CO.sub.2 generator (5) subjects to a heat exchange in the second cooler (16) with at least a part of the liquid nitrogen, the obtained recyclable CO.sub.2 is delivered to the second CO.sub.2 compressor (17), and the supercritical CO.sub.2 pressure is within a range of 740 MPa;
7) the heat exchanged combustion flue gas obtained in step 6) is subjected to heat exchange with the remaining part of liquid nitrogen through a vaporizer (10), the vaporization of the liquid nitrogen drives a nitrogen turbine generator (11) to generate electricity.

(35) The staged cooled flue gas is dehydrated, and the dehydrated liquid flue gas is sent to the flue gas distillation tower (12) for separating and recovering CO.sub.2, a part of the recovered CO.sub.2 is returned to the combustion gas turbine (9) as a feed material for circulation and temperature control, a part of the recovered CO.sub.2 is used for replenishing working medium of the supercritical CO.sub.2 power generation, and a remaining part of the recovered CO.sub.2 is sold outward as a liquid CO.sub.2 product.

(36) The liquid nitrogen and a part of the liquid oxygen obtained from air separation may be stored during the valley period with low electricity load (e.g., at nighttime) so as to be supplied in use during the peak period with high electricity load in the daytime. Specifically, during the peak period of power grid operation with high electricity load (e.g., the daytime), the liquid nitrogen stored at nighttime and separated during the daytime may be pumped and pressurized, and then subjects to heat exchange and vaporization in a vaporizer (10) for power generation; the liquid oxygen stored at nighttime and separated during the daytime is pumped and pressurized, and then subjects to heat exchange and vaporization for use in a coal gasification furnace (3) and a combustion gas turbine (9) to perform peak shaving and power generation in response to the load fluctuation.

(37) The integrated coal gasification combined power generation process with zero carbon emission provided by the present disclosure can be used for shaving peak and generating electricity. According to an Aspen simulation result, the power generation process provided by the present disclosure uses an air separation facility to pump and pressurize the liquid oxygen and liquid nitrogen with a low energy consumption, the pressure of the air compressor is reduced from the current level of about 2.8 MPa to 0.40.8 MPa, which makes the energy consumption ratio of the combustion gas turbine for the air compressor is reduced from 30%40% to around 10%; the high-temperature and high-pressure fuel gas from the gasification of pulverized coal first utilizes the supercritical CO.sub.2 to perform heat exchange and power generation, and then subjects to purification and sends to a combustion gas turbine for power generation, such the arrangement may reasonably and stepwise utilize the sensible heat and chemical energy of the fuel gas, thereby reduce the cycle ratio of high-pressure CO.sub.2 and the difficulty of gas purification, improve the power generation efficiency of the fuel gas; the flue gas uses supercritical CO.sub.2 power generation, the vaporization of liquid nitrogen and power generation by a nitrogen turbine generator to form the IGCC system, the temperature of exhaust flue gas is lowered from about 140 C. in the prior art to about 30 C., the energy recovery rate is greatly improved, the flue gas can be easily dehydrated and separated to obtain CO.sub.2, and the energy consumption of CO.sub.2 capture is significantly reduced; the water consumption of this process is greatly reduced due to the CO.sub.2 circulation and temperature control of the combustion gas turbine, the supercritical CO.sub.2 is applied as a work medium of waste heat power generation, the dehydration of flue gas at a low temperature and a recyclable utilization of the dehydrated water, in combination with coal gasification and dry slagging, the water-saving rate will be as high as 95%, the process is especially suitable for water-deficient areas; in addition, the high-pressure fuel gas is subjected to a precise purification process of dust removal, desulfurization, dechlorination and removal of heavy metals in advance, the combustion gas turbine uses oxygen to aid combustion, and the CO.sub.2 subjects to circulation and temperature control, it avoids an emission of the NO.sub.x in the flue gas from the existing coal-fired power plants, greatly reduces the emission of smoke dust and SOx, and achieves clean power generation of the coal; moreover, the air separation components are separately utilized, the liquid nitrogen is used for energy storage and peak shaving, the demand of gas storage volume is greatly reduced, the air storage energy consumption is reduced by more than 20 times, the energy storage efficiency is high, which satisfies the demand of the peak shaving and valley filling of the IGCC basic load power plant in the future.

(38) The above content describes in detail the preferred embodiments of the present disclosure, but the present disclosure is not limited thereto. A variety of simple modifications can be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure, including a combination of individual technical features in any other suitable manner, such simple modifications and combinations thereof shall also be regarded as the content disclosed by the present disclosure, each of them falls into the protection scope of the present disclosure.