A double-cycle IGCC power generation system and method based on solid absorbent

Abstract

The invention discloses a double-cycle IGCC power generation system and method based on solid absorbent, comprising a gasification reactor and a calcination reactor, wherein the gasification reactor and the calcination reactor form a gasification unit, wherein the gasification reactor is provided with a steam inlet and a coal inlet, wherein the gas outlet of the gasification reactor is connected to a coal gas waste heat boiler, wherein the coal gas waste heat boiler is connected to a waste heat boiler, and the waste heat boiler is used to drive a steam turbine to generate electricity; wherein the gas outlet of the coal gas waste heat boiler is connected to a gas turbine; wherein the calcination reactor is provided with an oxygen inlet and a solid absorbent inlet, wherein the gas outlet of the calcination reactor is connected to a flue gas turbine to generate electricity, wherein the outlet of the flue gas turbine is connected to a flue gas waste heat boiler, and wherein the flue gas waste heat boiler is connected to a waste heat boiler; wherein the gasification reactor performs an IGCC cycle, wherein the calcination reactor performs a flue gas-steam combined cycle, and wherein the gasification reactor and the calcination reactor perform a cycle through a solid absorbent. The system output power and efficiency can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of energy conservation and emission reduction, and in particular to a double-cycle IGCC power generation system and method based on solid absorbent. Background Art

[0002] The integrated gasification combined cycle (IGCC) power plant is an important clean coal power generation technology in the future. Its combination with CO2 capture technology is one of the current research hotspots in the energy field. IGCC power plants can remove carbon before combustion. The coal-to-gas produced by the gasifier enters the water-gas shift unit after purification, where the CO and water vapor undergo a water-gas shift reaction to generate CO2 and H2, increasing the CO2 content in the gas, and then the CO2 is separated. Compared with post-combustion capture, the volume of gas to be processed in pre-combustion capture is greatly reduced, and the CO2 concentration is significantly increased, thereby greatly reducing the energy consumption and equipment investment of the separation process. At the current technical level, pre-combustion decarbonization technology is regarded as one of the most promising decarbonization technologies in the future.

[0003] Common pre-combustion decarbonization processes include absorption and adsorption, which usually use chemical or physical absorbents to absorb or adsorb CO2 at low temperatures, and then the absorbent is regenerated after heating. Processes such as membrane separation and solid absorbent methods can absorb CO2 in a dry manner at higher temperatures, and have obvious advantages in reducing the reduction in IGCC system efficiency caused by the introduction of CO2 absorption.

[0004] In the traditional IGCC pre-combustion decarbonization process, the treatment process of the synthesis gas after coal gasification includes many processes such as coal gas purification, water-gas shift, desulfurization, and decarbonization. The process is long and energy-intensive. When IGCC adopts a wet low-temperature decarbonization process, the synthesis gas is required to be cooled before entering the decarbonization unit, and then heated after decarbonization before entering the combustion chamber. The energy loss caused by this process is large. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a double-cycle IGCC power generation system and method based on solid absorbent, which can effectively improve the system output power and efficiency.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A double-cycle IGCC power generation system based on solid absorbent, comprising a gasification reactor and a calcination reactor;

[0008] The gasification reactor and the calcination reactor form a gasification unit, the gasification reactor is provided with a steam inlet and a coal inlet, the gas outlet of the gasification reactor is connected to a coal gas waste heat boiler, the coal gas waste heat boiler is connected to a waste heat boiler, the waste heat boiler is used to drive a steam turbine to generate electricity; the gas outlet of the coal gas waste heat boiler is connected to a gas turbine;

[0009] The calcining reactor is provided with an oxygen inlet and a solid absorbent inlet, the gas outlet of the calcining reactor is connected to a flue gas turbine for power generation, the outlet of the flue gas turbine is connected to a flue gas waste heat boiler, and the flue gas waste heat boiler is connected to a waste heat boiler;

[0010] The gasification reactor performs an IGCC cycle, the calcination reactor performs a flue gas steam combined cycle, and the gasification reactor and the calcination reactor perform a cycle through a solid absorbent.

[0011] Preferably, the solid absorbent is CaO and / or CaCO3.

[0012] Preferably, an air separation device is further included, and the oxygen inlet of the calcining reactor is connected to the oxygen outlet of the air separation device.

[0013] Preferably, it further comprises a dust removal device, which is arranged on the gas passage between the gasification reactor and the coal gas waste heat boiler.

[0014] Preferably, it also includes a condenser, wherein the inlet of the condenser is connected to the gas outlet of the flue gas waste heat boiler, the gas outlet of the condenser is connected to the inlet of the waste heat boiler, and the liquid outlet of the condenser is connected to the outside.

[0015] Preferably, the gas outlet of the coal gas waste heat boiler is connected to the combustion chamber of the gas turbine, the inlet of the combustion chamber is connected to the outlet of the compressor, the combustion chamber outlet of the gas turbine is connected to the inlet of the turbine, and the outlet of the turbine is connected to the inlet of the waste heat boiler.

[0016] Preferably, the outlet gas product of the gasification reactor is high-temperature and high-pressure hydrogen-rich fuel gas, and the solid products are unreacted coke, ash and CaCO3.

[0017] Preferably, the outlet gas product of the calcination reactor is a high-temperature and high-pressure CO2-rich gas, and the solid products are ash and CaO.

[0018] A double cycle IGCC power generation method based on solid absorbent, comprising the following process:

[0019] The gas outlet of the gasification reactor outputs hydrogen-rich fuel gas, which enters the coal gas waste heat boiler to heat the hot water from the waste heat boiler, generates steam that returns to the waste heat boiler and drives the steam turbine to work after being overheated. The gas at the outlet of the coal gas waste heat boiler enters the combustion chamber of the gas turbine as fuel;

[0020] The gas outlet of the calcining reactor outputs CO2-rich gas, which enters the flue gas turbine to generate work. The gas from the flue gas turbine enters the flue gas waste heat boiler to heat hot water to generate steam. Part of the steam generated by the flue gas waste heat boiler is sent to the calcining reactor, and the other part is returned to the waste heat boiler of the gas turbine combined cycle.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] The present invention provides a double-cycle IGCC power generation system based on solid absorbent, which forms a gasification unit by setting up a gasification reactor and a calcination reactor, and the gasification reactor and the calcination reactor are circulated through a solid absorbent. By introducing a solid absorbent, the original IGCC gasifier is transformed into a gasification reactor + calcination reactor to achieve the source solidification of CO2; the present invention uses the calcination reactor as the source to construct a CO2 flue gas steam combined cycle, and couples it with the IGCC cycle through a solid absorbent and a water / water vapor cycle to construct a double-cycle IGCC system; by setting up a CO2 flue gas turbine, the pressure energy of the high-temperature and high-pressure flue gas at the outlet of the calcination reactor is recovered, which can effectively improve the total output power and efficiency of the system;

[0023] Compared with the existing IGCC pre-combustion carbon capture system, the present invention realizes one-step CO2 capture and integrates water-gas shift and CO2 absorption by introducing CO2 solid absorbent at the gasification source; the prepared hydrogen-rich fuel gas directly enters the gas turbine combustion chamber after dust removal and heat recovery, and there is no process of first cooling down and then heating up in the existing IGCC carbon capture system, thereby reducing energy loss in the heat transfer process; by adding a calcination reactor, a flue gas turbine, and a flue gas waste heat boiler, a flue gas-steam combined cycle is constructed, forming a double-cycle IGCC power generation system, which can effectively improve the system output power and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a double-cycle IGCC power generation system based on solid absorbent;

[0025] In the attached drawings: 1 is a gasification reactor; 2 is a dust removal device; 3 is a coal gas waste heat boiler; 4 is a combustion chamber; 5 is a compressor; 6 is a turbine; 7 is a steam turbine; 8 is a waste heat boiler; 9 is a condenser; 10 is a flue gas waste heat boiler; 11 is a flue gas turbine; 12 is a calcination reactor; and 13 is an air separation device. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0027] The present invention provides a double-cycle IGCC power generation system based on solid absorbent, including an IGCC cycle with a gasification reactor as the source and a flue gas steam combined cycle with a calcination reactor 12 as the source. The two cycles are coupled through the solid absorbent circulation between the gasification reactor 1 and the calcination reactor 12, and the water / steam integration between the waste heat boiler 8 and the flue gas waste heat boiler 10.

[0028] The gasification reactor 1 and the calcination reactor 12 form a gasification unit. The gasification reactor 1 is provided with a steam inlet and a coal inlet. The gas outlet of the gasification reactor 1 is connected to the coal gas waste heat boiler 3. The dust removal device 2 is provided on the gas passage between the gasification reactor 1 and the coal gas waste heat boiler 3. The gas outlet of the coal gas waste heat boiler 3 is connected to the combustion chamber 4 of the gas turbine. The inlet of the combustion chamber 4 is connected to the outlet of the compressor 5. The outlet of the combustion chamber 4 of the gas turbine is connected to the inlet of the turbine 6. The outlet of the turbine 6 is connected to the inlet of the waste heat boiler 8. The coal gas waste heat boiler 3 is connected to the waste heat boiler 8. The waste heat boiler 8 is used to drive the steam turbine 7 to generate electricity. The inlet of the condenser 9 is connected to the gas outlet of the flue gas waste heat boiler 10. The gas outlet of the condenser 9 is connected to the inlet of the waste heat boiler 8. The liquid outlet of the condenser 9 is connected to the outside. The gas outlet of the coal gas waste heat boiler 3 is connected to the gas turbine.

[0029] The calcining reactor 12 is provided with an oxygen inlet and a solid absorbent inlet, the gas outlet of the calcining reactor 12 is connected to the flue gas turbine 11 for power generation, and the oxygen inlet of the calcining reactor 12 is connected to the oxygen outlet of the air separation unit 13. The outlet of the flue gas turbine 11 is connected to the flue gas waste heat boiler 10, and the flue gas waste heat boiler 10 is connected to the waste heat boiler 8; the gasification reactor 1 performs an IGCC cycle, and the calcining reactor 12 performs a flue gas steam combined cycle, and the gasification reactor 1 and the calcining reactor 12 are circulated through the solid absorbent.

[0030] The capture and regeneration of CO2 is achieved by circulating solid absorbent (such as CaO / CaCO3) between the gasification reactor 1 and the calcination reactor 12. The feed of the gasification reactor 1 includes coal, CaO from the calcination reactor 12, and water vapor. Among them, the water vapor is extracted from the waste heat boiler 8. The outlet gas product of the gasification reactor 1 is a high-temperature and high-pressure hydrogen-rich fuel gas (the main component is H2), and the solid products are unreacted coke, ash, CaCO3, etc. The inlet materials of the calcination reactor 12 include solid products from the gasification reactor 1, supplementary fresh CaCO3, O2 from air separation, and water vapor. The outlet gas product of the calcination reactor 12 is a high-temperature and high-pressure CO2-rich gas, and the solid products are ash and CaO.

[0031] The present invention provides a double-cycle IGCC power generation method based on solid absorbent, comprising the following process:

[0032] The gas outlet of the gasification reactor 1 outputs hydrogen-rich fuel gas, which enters the coal gas waste heat boiler 3 after passing through the dust removal device 2 to heat the hot water from the waste heat boiler 8, and generates steam to return to the waste heat boiler 8 to drive the steam turbine 7 to do work after being overheated. The gas at the outlet of the coal gas waste heat boiler 3 enters the gas turbine combustion chamber 4 as fuel.

[0033] The outlet gas product of the calcination reactor 12 is a high-temperature and high-pressure CO2-rich gas. The CO2-rich gas enters the flue gas turbine 11 to generate work, and the gas of the flue gas turbine 11 enters the flue gas waste heat boiler 10 to heat hot water to generate steam. The outlet gas of the flue gas waste heat boiler 10 is condensed by the condenser 9 to condense the flue gas, and the water therein is condensed. The remaining gas is pure CO2, which can be used for compression and storage. Part of the steam generated by the flue gas waste heat boiler 10 is sent to the calcination reactor 12, and the other part is returned to the waste heat boiler 8 of the gas turbine combined cycle.

Claims

1. A double cycle IGCC power generation system based on solid absorbent, characterized in that: It comprises a gasification reactor (1) and a calcination reactor (12); The gasification reactor (1) and the calcination reactor (12) form a gasification unit. The gasification reactor (1) is provided with a steam inlet and a coal inlet. The gas outlet of the gasification reactor (1) is connected to a coal gas waste heat boiler (3). The coal gas waste heat boiler (3) is connected to a waste heat boiler (8). The waste heat boiler (8) is used to drive a steam turbine (7) to generate electricity. The gas outlet of the coal gas waste heat boiler (3) is connected to a gas turbine. The calcining reactor (12) is provided with an oxygen inlet and a solid absorbent inlet, the gas outlet of the calcining reactor (12) is connected to a flue gas turbine (11) for power generation, the outlet of the flue gas turbine (11) is connected to a flue gas waste heat boiler (10), and the flue gas waste heat boiler (10) is connected to a waste heat boiler (8); The gasification reactor (1) performs an IGCC cycle, the calcination reactor (12) performs a flue gas steam combined cycle, and a solid absorbent is used for circulation between the gasification reactor (1) and the calcination reactor (12); The solid absorbent is CaO and / or CaCO3; It also includes an air separation device (13), wherein the oxygen inlet of the calcining reactor (12) is connected to the oxygen outlet of the air separation device (13); It also comprises a dust removal device (2), wherein the dust removal device (2) is arranged on a gas passage between the gasification reactor (1) and the coal gas waste heat boiler (3); It also includes a condenser (9), wherein the inlet of the condenser (9) is connected to the gas outlet of the flue gas waste heat boiler (10), the gas outlet of the condenser (9) is connected to the inlet of the waste heat boiler (8), and the liquid outlet of the condenser (9) is connected to the outside; The gas outlet of the coal gas waste heat boiler (3) is connected to the combustion chamber (4) of the gas turbine, the inlet of the combustion chamber (4) is connected to the outlet of the compressor (5), the outlet of the combustion chamber (4) of the gas turbine is connected to the inlet of the turbine (6), and the outlet of the turbine (6) is connected to the inlet of the waste heat boiler (8); The outlet gas product of the gasification reactor (1) is a high-temperature and high-pressure hydrogen-rich fuel gas, and the solid products are unreacted coke, ash and CaCO3; The outlet gas product of the calcination reactor (12) is high-temperature and high-pressure CO2-rich gas, and the solid products are ash and CaO.

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