A coupled oxygen-rich combustion power generation and CO 2 A new type of electricity-chemical cogeneration system for catalytic hydrogenation process

Abstract

The present invention discloses a novel electricity-chemical co-production system coupling oxy-fuel combustion power generation and CO2 catalytic hydrogenation process. The novel electricity-chemical co-production system includes an oxy-fuel combustion power generation system, a CO2 catalytic hydrogenation to methanol system, and a new energy electrolytic water system. The new energy electrolytic water system is connected to the oxy-fuel combustion power generation system and the CO2 catalytic hydrogenation to methanol system through pipelines respectively. The CO2-rich flue gas discharged from the oxy-fuel combustion power generation system and the H2 generated by the new energy electrolytic water system are used as raw materials for the CO2 catalytic hydrogenation to methanol system. The O2 generated by the new energy electrolytic water system is used as the raw material for oxy-fuel combustion power generation, replacing the air separator required for preparing O2 in conventional oxy-fuel combustion power generation. The oxy-fuel combustion power generation system provides heat and power consumption for the CO2 catalytic hydrogenation to methanol system, and the CO2 catalytic hydrogenation to methanol system provides heat for the oxy-fuel combustion power generation system. The present invention realizes the co-production of electric energy and methanol, and improves the energy utilization efficiency of the coupling system.

Description

Technical Field

[0001] The present invention relates to a novel electricity-chemical cogeneration system, in particular to a coupling oxygen-enriched combustion power generation and CO 2 A new type of electricity-chemical cogeneration system for catalytic hydrogenation process, belonging to CO 2 Capture and resource utilization field. Background Art

[0002] In the past few decades, fossil fuels have provided nearly 80% of energy supply and have made great contributions to social and economic development around the world. However, the direct combustion of these fossil fuels emits a large amount of CO 2 , exacerbating environmental problems such as global warming.

[0003] CO 2 Emission reduction technologies mainly include CO 2 Capture and storage (CO 2 Capture and Storage, CCS) and CO 2 Capture and resource utilization (CO 2 Compared with CCS technology, CCU technology can capture more CO 2 Converting into high calorific value fuel or chemicals has a brighter future for industrial applications. Among the many CCU technologies, new energy liquid / gas fuel technology, namely Power to Liquid / Power to Gas (PTL / PTG) technology, has received widespread attention. PTL / PTG technology includes three parts: (1) capturing CO2 emitted by industrial 2 ; (2) New energy water electrolysis hydrogen production; (3) CO 2 Catalytic hydrogenation to hydrocarbons.

[0004] CO from coal-fired power plants 2 Capture methods can be divided into pre-combustion CO 2 CO capture and post-combustion 2 CO capture and oxyfuel combustion 2 Capture. Among them, oxygen-enriched combustion CO 2 The capture technology uses pure O 2 The mixture of recycled flue gas replaces air and coal combustion, increasing the CO content in the product flue gas. 2 concentration and partial pressure, reducing CO 2 Difficulty of capture. Oxygen-enriched combustion CO 2 Capture technology has the advantages of high combustion efficiency and low pollution emissions, but this technology can produce pure O 2 An additional air separator is required, increasing the energy consumption and cost of the technology.

[0005] For CO 2 Hydrogenation to produce hydrocarbons, PTL technology refers to the use of CO 2 Catalytic hydrogenation to produce liquid fuels, PTG technology refers to the use of CO through the Sabatier reaction 2 Catalytic hydrogenation produces gaseous fuels. Compared with gaseous combustion, liquid fuels have higher energy density and are easier to store and transport. 2 Catalytic hydrogenation to methanol technology is considered an important way to achieve clean energy and carbon emission reduction in the future. Methanol is an important intermediate raw material in the agricultural, chemical, pharmaceutical and automotive industries. With the continuous growth of methanol demand, CO 2 Catalytic hydrogenation to methanol is expected to become an important method to replace traditional fossil fuels in synthesizing methanol in the future.

[0006] However, coal-fired power plants CO 2 Capture and CO 2 The relevant research on catalytic hydrogenation to hydrocarbons is usually carried out separately, and there are few reports on the coupling of the two processes. If the two processes can be efficiently coupled through a thermal integration method, it will be very useful in achieving CO 2 Under the premise of capture and resource utilization, significant energy-saving and emission reduction effects will inevitably be achieved. Summary of the invention

[0007] Purpose of the invention: The purpose of the present invention is to provide a coupling oxygen-enriched combustion power generation and CO 2 A new type of electricity-chemical cogeneration system for catalytic hydrogenation process.

[0008] Technical solution: The present invention relates to a method for coupling oxygen-rich combustion power generation and CO 2 A novel electric-chemical cogeneration system for catalytic hydrogenation process, the novel electric-chemical cogeneration system comprising an oxygen-enriched combustion power generation system, a CO 2 Catalytic hydrogenation methanol system and new energy water electrolysis system, the new energy water electrolysis system is connected to the oxygen-enriched combustion power generation system and the CO 2 The catalytic hydrogenation methanol system is connected, and the CO2-rich gas emitted by the oxygen-enriched combustion power generation system 2 Flue gas for CO 2 The raw materials of the catalytic hydrogenation system for producing methanol, the H generated by the new energy water electrolysis system 2 For CO 2 The raw materials of the catalytic hydrogenation methanol system; the O generated by the new energy water electrolysis system 2 Raw materials for oxygen-enriched combustion power generation, replacing conventional oxygen-enriched combustion power generation to produce O 2 The required air separator realizes the co-production of electricity and methanol (electricity-chemical co-generation). At the same time, the oxygen-enriched combustion power generation system is CO 2 Catalytic hydrogenation to methanol system provides low-grade heat and electricity consumption, CO2 The catalytic hydrogenation methanol system provides high-grade heat for the oxygen-enriched combustion power generation system.

[0009] Furthermore, the oxygen-enriched combustion power generation system includes a boiler combustion unit and a steam-water power generation unit.

[0010] Furthermore, the boiler combustion unit includes a furnace, a tail flue, a circulating fan and a purification device connected by a pipeline, the furnace is connected to the tail flue through a pipeline, the tail flue is connected to the circulating fan and the purification device through pipelines, and the first outlet of the purification device is connected to the CO 2 The catalytic hydrogenation methanol production system is connected, the second outlet of the purification device is connected to the outside of the system, and the furnace is connected to the new energy electrolysis water system through a pipeline.

[0011] Furthermore, the steam-water power generation unit includes a second heat exchanger and a third heat exchanger connected by a pipeline, the cold end of the second heat exchanger is connected to the cold end of the third heat exchanger through a pipeline, and the cold end of the third heat exchanger is connected to the tail flue through a pipeline.

[0012] Furthermore, the CO 2 The catalytic hydrogenation methanol system includes a CO2 multistage compressor, an H2 multistage compressor, a methanol reactor, a high-pressure separator, a fourth heat exchanger and a fifth heat exchanger; the CO2 multistage compressor is connected to the first outlet of the purification device through a pipeline, the hot end of the fourth heat exchanger is installed between the CO2 multistage compressors to absorb waste heat, the CO2 multistage compressor, the H2 multistage compressor, the cold end of the fourth heat exchanger and the cold end of the fifth heat exchanger are all connected to the methanol reactor through pipelines, the hot end of the second heat exchanger is respectively connected to the methanol reactor and the high-pressure separator through pipelines, the hot end of the fifth heat exchanger is installed between the H2 multistage compressors to absorb waste heat, and the hot end of the third heat exchanger is arranged inside the methanol reactor.

[0013] Furthermore, the new energy water electrolysis system is connected to the furnace and the H2 multi-stage compressor through pipelines respectively.

[0014] Furthermore, the methanol reactor and the high-pressure separator are connected to the hot end of the second heat exchanger through a pipeline.

[0015] Furthermore, the steam-water power generation unit also includes a high-pressure steam turbine, a medium-pressure steam turbine, a low-pressure steam turbine, a back-pressure steam turbine, a condenser, a first feedwater pump, a second feedwater pump and a first heat exchanger; the high-pressure steam turbine is connected to the furnace and the tail flue through pipelines, respectively, the medium-pressure steam turbine is connected to the furnace, the low-pressure steam turbine and the back-pressure steam turbine through pipelines, respectively, the low-pressure steam turbine is connected to the condenser and the first feedwater pump in sequence through pipelines, the back-pressure steam turbine is connected to the first heat exchanger and the second feedwater pump in sequence through pipelines, the first feedwater pump and the second feedwater pump are both connected to the cold end of the second heat exchanger and the cold end of the third heat exchanger in sequence through pipelines, and the cold end of the third heat exchanger is connected to the tail flue through a pipeline.

[0016] Furthermore, the CO 2 The catalytic hydrogenation methanol system also includes a low-pressure separator; the low-pressure separator is connected to the high-pressure separator through a pipeline, and the high-pressure separator and the low-pressure separator are both connected to the cold end of the fourth heat exchanger and the cold end of the fifth heat exchanger through pipelines.

[0017] Furthermore, CO 2 The catalytic hydrogenation methanol system also includes a methanol distillation tower; the low-pressure separator is connected to the methanol distillation tower through a pipeline, and the cold end of the first heat exchanger is arranged inside the methanol distillation tower.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0019] (1) The method of coupling oxygen-enriched combustion power generation and CO 2 The new electricity-chemical cogeneration system of the catalytic hydrogenation process realizes the energy cascade utilization of the new system through efficient system integration: (1) The heat of the methanol distillation tower is provided by the exhaust steam of the back-pressure steam turbine of the oxygen-enriched combustion power generation system, and the CO 2 Multistage compressor and H 2 The power consumption of the multi-stage compressor is provided by the coal-fired power plant; (2) CO 2 and H 2 The low temperature waste heat from multi-stage compression cooling is used to preheat CO 2 The circulating reaction gas of the catalytic hydrogenation system to produce methanol saves the high-grade heat released by the methanol reactor; (3) The heat released by the methanol reactor and the sensible heat of the gas products of the methanol reactor are used to heat the feed water of the oxygen-enriched combustion power generation system. The extraction steam originally used by the oxygen-enriched combustion power generation system to heat the feed water can be saved and enter the steam turbine to do work, thereby increasing the power generation of the system.

[0020] (2) The method of coupling oxygen-enriched combustion power generation and CO 2The new power-to-chemical cogeneration system for catalytic hydrogenation is based on the concept of "power to liquid (PTL)" and combines oxygen-enriched combustion of CO 2 Capture, CO 2 The process of catalytic hydrogenation to produce methanol and new energy electrolysis of water to produce hydrogen, using H generated by coal and new energy 2 and O 2 As raw materials, electricity and methanol co-production (electricity-chemical co-production) is achieved.

[0021] (3) The present invention couples oxygen-enriched combustion power generation, CO 2 Catalytic hydrogenation to produce methanol and new energy water electrolysis power generation technology realizes the co-production of electricity and methanol (electricity-chemical co-production), and based on the principle of energy cascade utilization, improves the energy utilization efficiency of the coupled system, with good innovation and practical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the process of the novel power-chemical cogeneration system of the present invention. Among them, 1-furnace, 2-tail flue, 3-circulation fan, 4-purification device, 5-high-pressure steam turbine, 6-medium-pressure steam turbine, 7-low-pressure steam turbine, 8-back-pressure steam turbine, 9-condenser, 10-first feed water pump, 11-second feed water pump, 12-first heat exchanger, 13-second heat exchanger, 14-third heat exchanger, 15-CO 2 Multistage compressor, 16-H 2 Multi-stage compressor, 17-methanol reactor, 18-high-pressure separator, 19-low-pressure separator, 20-methanol distillation tower, 21-fourth heat exchanger, 22-fifth heat exchanger, 23-new energy water electrolysis system. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0024] Example 1

[0025] like Figure 1 As shown, the invention relates to a method for coupling oxygen-rich combustion power generation and CO 2 A new type of electricity-chemical cogeneration system for catalytic hydrogenation process, including oxygen-enriched combustion power generation system, CO 2 Catalytic hydrogenation methanol system and new energy water electrolysis system. The new energy water electrolysis system is connected to the oxygen-enriched combustion power generation system and CO 2 The catalytic hydrogenation methanol system is connected, and the oxygen-enriched combustion power generation system emits CO2-rich 2 Flue gas for CO 2 The raw materials of catalytic hydrogenation to methanol system and the H produced by new energy water electrolysis system 2 For CO 2The raw materials of the catalytic hydrogenation system for producing methanol; the byproduct O produced by the new energy electrolysis system 2 Raw materials for oxygen-enriched combustion power generation, replacing conventional oxygen-enriched combustion power generation to produce O 2 The required air separator realizes the co-production of electricity and methanol. At the same time, the oxygen-enriched combustion power generation system is CO 2 Catalytic hydrogenation to methanol system provides low-grade heat and electricity consumption, CO 2 The catalytic hydrogenation methanol system provides high-grade heat for the oxygen-enriched combustion power generation system.

[0026] in:

[0027] The oxygen-enriched combustion power generation system includes a boiler combustion unit and a steam-water power generation unit. The boiler combustion unit includes a furnace 1, a tail flue 2, a circulating fan 3 and a purification device 4. The furnace 1 is connected to the tail flue 2 through a pipeline, and the tail flue 2 is connected to the circulating fan 3 and the purification device 4 through pipelines. The steam-water power generation unit includes a high-pressure steam turbine 5, a medium-pressure steam turbine 6, a low-pressure steam turbine 7, a back-pressure steam turbine 8, a condenser 9, a first feedwater pump 10, a second feedwater pump 11, a first heat exchanger 12, a second heat exchanger 13 and a third heat exchanger 14. The high-pressure steam turbine 5 is connected to the furnace 1 and the tail flue 2 through pipelines, respectively. The medium-pressure steam turbine 6 is connected to the furnace 1, the low-pressure steam turbine 7 and the back-pressure steam turbine 8 through pipelines, respectively. The low-pressure steam turbine 7 is connected to the condenser 9 and the first feedwater pump 10 in sequence through pipelines, and the back-pressure steam turbine 8 is connected to the first heat exchanger 12 and the second feedwater pump 11 in sequence through pipelines. The first feedwater pump 10 and the second feedwater pump 11 are connected to the cold end of the second heat exchanger 13 and the cold end of the third heat exchanger 14 in sequence, and the cold end of the third heat exchanger 14 is connected to the tail flue 2 through a pipeline. The first outlet of the purification device 4 is connected to the CO 2 through a pipeline. 2 The catalytic hydrogenation methanol system is connected, and the second outlet of the purification device 4 is connected to the outside of the system. The furnace 1 is connected to the new energy electrolysis water system through a pipeline.

[0028] CO 2 Catalytic hydrogenation to methanol system includes CO 2 Multistage compressor 15, H 2 A multi-stage compressor 16, a methanol reactor 17, a high-pressure separator 18, a low-pressure separator 19, a methanol rectification column 20, a fourth heat exchanger 21 and a fifth heat exchanger 22. 2 Multistage compressor 15, H 2 The multi-stage compressor 16, the cold end of the fourth heat exchanger 21 and the cold end of the fifth heat exchanger 22 are connected to the methanol reactor 17 through pipelines. 2 The multi-stage compressor 15 is connected to the first outlet of the purification device 4 through a pipeline. 2The multistage compressor 16 is connected to the new energy electrolysis water system 23 through a pipeline, the methanol reactor 17 and the high-pressure separator 18 are connected to the hot end of the second heat exchanger 13 through a pipeline, the high-pressure separator 18 and the low-pressure separator 19 are both connected to the cold end of the fourth heat exchanger 21 and the cold end of the fifth heat exchanger 22 through a pipeline, the high-pressure separator 18 is connected to the low-pressure separator 19 through a pipeline, and the low-pressure separator 19 is connected to the methanol distillation tower 20 through a pipeline. The hot end of the third heat exchanger 14 is arranged inside the methanol reactor 17. The cold end of the first heat exchanger 12 is arranged inside the methanol distillation tower 20. The hot end of the second heat exchanger 13 is connected to the methanol reactor 17 and the high-pressure separator 18 through a pipeline. The hot end of the fourth heat exchanger 21 is installed between the CO2 multistage compressor 15 to absorb waste heat, and the hot end of the fifth heat exchanger 22 is installed between the H2 multistage compressor 16 to absorb waste heat.

[0029] The new energy electrolysis water system is connected to furnace 1 and H through pipelines. 2 The multi-stage compressor 16 is in communication.

[0030] For the boiler combustion unit, the flue gas generated by the combustion of coal and oxidant passes through the furnace 1 and the tail flue 2 in turn, heating the feed water and low-temperature reheat steam to superheated steam and high-temperature reheat steam respectively; the flue gas leaving the tail flue 2 is divided into two paths, one of which passes through the circulating fan 3 and the O generated by the new energy water electrolysis hydrogen production process. 2 The mixed gas is returned to the furnace 1 as an oxidant, and the other is discharged into the purification device 4 as exhaust gas to obtain high-purity CO 2 ; High purity CO at the outlet of purification device 4 2 It is divided into two routes, one of which is used as raw material to enter CO from the first outlet 2 Catalytic hydrogenation to methanol system, the other route is collected and leaves the system from the second outlet.

[0031] For the steam-water power generation unit, the feed water enters the furnace 1 and the tail flue 2 and is heated to become superheated steam, and the superheated steam enters the high-pressure steam turbine 5 to perform work; the low-temperature reheated steam at the outlet of the high-pressure steam turbine 5 returns to the furnace 1 and the tail flue 2 and is heated to become high-temperature reheated steam, and the high-temperature reheated steam enters the medium-pressure steam turbine 6 to perform work; the outlet steam of the medium-pressure steam turbine 6 is divided into two paths, one path enters the low-pressure steam turbine 7, the outlet steam of the low-pressure steam turbine 7 enters the hot end inlet of the condenser 9, and the other path enters the back-pressure steam turbine 8, The steam at the outlet of the back-pressure turbine 8 enters the hot end inlet of the first heat exchanger 12; the saturated water at the hot end outlet of the condenser 9 enters the first feedwater pump 10, and the saturated water at the hot end outlet of the first heat exchanger 12 enters the second feedwater pump 11; the feedwater at the outlets of the first feedwater pump 10 and the second feedwater pump 11 are mixed and enter the cold end inlet of the second heat exchanger 13, and the feedwater at the cold end outlet of the second heat exchanger 13 enters the cold end inlet of the third heat exchanger 14, and the feedwater at the cold end outlet of the third heat exchanger 14 returns to the furnace 1 and the tail flue 2.

[0032] High-purity CO generated by oxygen-enriched combustion power generation system 2 Enter CO 2 Multi-stage compressor 15, H produced by the new energy water electrolysis hydrogen production process 2 Enter H 2 Multistage compressor 16, CO 2 High-pressure CO at the outlet of the multi-stage compressor 15 2 , H 2 The high pressure H at the outlet of the multistage compressor 16 2 The mixture is mixed with the circulating reaction gas at the cold end outlet of the fourth heat exchanger 21 and the fifth heat exchanger 22 and enters the methanol reactor 17 as the reaction gas; the hot end of the third heat exchanger 14 is arranged inside the methanol reactor 17 to absorb the reaction heat; the gas product at the outlet of the methanol reactor 17 enters the hot end inlet of the second heat exchanger 13, and the gas product at the hot end outlet of the second heat exchanger 13 enters the high-pressure separator 18; the liquid at the lower end outlet of the high-pressure separator 18 enters the low-pressure separator 19 after passing through the throttle valve, and the liquid at the lower end outlet of the low-pressure separator 19 enters the methanol distillation tower 20; the gas at the upper end outlet of the high-pressure separator 18 is mixed with the gas at the upper end outlet of the low-pressure separator 19 and is divided into two paths, one of which is used as the circulating reaction gas to enter the cold end inlet of the fourth heat exchanger 21 and the fifth heat exchanger 22, and the other is used as the purge gas discharge system; the circulating reaction gas at the cold end outlet of the fourth heat exchanger 21 and the fifth heat exchanger 22 is mixed with CO 2 High-pressure CO at the outlet of the multi-stage compressor 15 2 , H 2 The high pressure H at the outlet of the multistage compressor 16 2 The mixture enters the methanol reactor 17 as a reaction gas; the cold end of the first heat exchanger 12 is arranged inside the methanol distillation tower 20 to provide the heat required for the methanol distillation process, and the high-purity methanol separated by the methanol distillation tower 20 is stored as a product.

[0033] Based on the novel electricity-chemical cogeneration system described in the present invention, during material transfer, the CO2-rich gas emitted by the oxygen-enriched combustion power generation system is 2 Flue gas and H generated by new energy water electrolysis system 2 Used as CO 2 The raw material of the catalytic hydrogenation system to produce methanol is used to achieve CO 2 Capture and resource utilization, byproduct O generated by the new energy electrolysis water system 2 Used as a raw material for oxygen-enriched combustion power generation, replacing oxygen-enriched combustion power generation to produce O 2 Air separator required; in heat transfer, oxygen-enriched combustion power generation system is CO 2 The catalytic hydrogenation methanol system provides the low-grade heat and CO required by the methanol distillation tower. 2 and H 2 The power consumption of the multi-stage compressor, CO 2The high-grade heat released by the catalytic hydrogenation to methanol system is used to heat the feed water of the oxy-combustion power generation system, thereby increasing the power generation of the system through efficient thermal integration.

[0034] A conventional 600MW supercritical coal-fired power plant was selected, and oxygen-enriched combustion was transformed based on wet flue gas recirculation. The elemental analysis of the selected coal was C=35.60%, H=2.24%, O=13.29%, N=0.77%, S=1.14%, water=33.40%, ash=13.56%. CO 2 The catalytic hydrogenation process for methanol production adopts a one-step methanol production process, and the catalyst uses a Cu-based catalyst. The operating pressure and temperature of the methanol reactor are 6.5 MPa and 300 °C respectively. 2 / H 2 The molar ratio is 1:3, single CO 2 The conversion rate of hydrogenation to methanol is 30%. The new energy electrolysis process uses electricity generated by solar or wind power, combined with alkaline water electrolysis technology, to produce H 2 and O 2 , O in the water electrolysis process 2 / H 2 The molar ratio is 1:2.

[0035] Thermodynamic calculations show that: (1) Based on material balance, for a 600MW oxyfuel combustion coal-fired power plant, the elemental analysis of coal shows that the required O 2 is 0.034 kmol / kg (coal). Since the coal consumption of a 600MW oxygen-enriched combustion coal-fired power plant is 395.0 t / h, the required O 2 is 13430.0 kmol / h; when the O 2 / H 2 The molar ratio is 1:2, and the H produced during the electrolysis of water 2 is 26860.0 kmol / h; CO 2 CO from catalytic hydrogenation to methanol 2 / H 2 The molar ratio is 1:3, so CO 2 CO required for catalytic hydrogenation to methanol 2 The actual CO in oxygen-enriched combustion coal-fired power plants is 8953.3 kmol / h. 2 The emission is 11716.8 kmol / h, so CO 2 The resource utilization rate reached 76.41%, which means that nearly 80% of the CO captured by the oxygen-enriched combustion power generation system is recycled. 2 Can be used for CO 2 Catalytic hydrogenation to produce methanol has a good material matching effect. The coupling of oxygen-enriched combustion power generation and CO 2A novel power-to-chemical cogeneration system for catalytic hydrogenation processes enables large-scale CO 2 (2) According to the energy balance, the design exhaust pressure of the back pressure turbine 8 is 0.14 MPa, and the corresponding saturated steam temperature is 109°C. The first heat exchanger 12 releases heat to the methanol distillation tower 20 to meet the low-grade heat required for its operation; the fourth heat exchanger 21 and the fifth heat exchanger 22 are used to recover CO 2 Stage compressor 15 and H 2 The low temperature waste heat generated by the multi-stage compressor 16 converts CO 2 The circulating reaction gas of the catalytic hydrogenation methanol system is heated from 30°C to 160°C, saving the high-grade heat released by the methanol reactor 17; the gas product and the high-grade heat released by the methanol reactor heat the feed water from 52°C to 275°C through the second heat exchanger 13 and the third heat exchanger 14; therefore, although the steam-water system extracts part of the steam for use in the methanol distillation tower 20, the recovered high-grade waste heat saves the eight-stage heat recovery steam extraction of the original coal-fired power plant steam-water system, which increases the gross power generation of the coal-fired power plant from 600MW to 695MW, that is, under the premise of the same methanol production (283.6t / h), the gross power generation considering energy coupling is increased by 15.8%, and the energy saving and emission reduction effect is very significant. (3) For the net power generation of the coal-fired power plant, although CO 2 The gas compression process of the catalytic hydrogenation methanol system consumes a certain amount of electricity (147.2MW), but the O generated by water electrolysis 2 The power required for oxygen production by the air separator (106.0MW) is saved, so the coupling of oxygen-enriched combustion power generation and CO 2 The new type of electricity-chemical cogeneration system of the catalytic hydrogenation process still maintains a high net power generation efficiency and has good application prospects.

Claims

1. A novel power-chemical cogeneration system coupling oxygen-enriched combustion power generation and CO2 catalytic hydrogenation process, characterized in that: The novel electricity-chemical cogeneration system comprises an oxygen-enriched combustion power generation system, a CO2 catalytic hydrogenation to methanol system and a new energy water electrolysis system. The new energy water electrolysis system is connected to the oxygen-enriched combustion power generation system and the CO2 catalytic hydrogenation to methanol system through pipelines, respectively. The CO2-rich flue gas discharged by the oxygen-enriched combustion power generation system is used as a raw material for the CO2 catalytic hydrogenation to methanol system, and the H2 generated by the new energy water electrolysis system is used as a raw material for the CO2 catalytic hydrogenation to methanol system; the O2 generated by the new energy water electrolysis system is used as a raw material for oxygen-enriched combustion power generation, replacing the air separator required for conventional oxygen-enriched combustion power generation to prepare O2, thereby realizing the cogeneration of electricity and methanol. At the same time, the oxygen-enriched combustion power generation system provides low-grade heat and power consumption for the CO2 catalytic hydrogenation to methanol system, and the CO2 catalytic hydrogenation to methanol system provides high-grade heat for the oxygen-enriched combustion power generation system; The oxygen-enriched combustion power generation system comprises a boiler combustion unit and a steam-water power generation unit. The boiler combustion unit comprises a furnace (1), a tail flue (2), a circulating fan (3) and a purification device (4) which are connected by pipelines. The furnace (1) is connected to the tail flue (2) by pipelines. The tail flue (2) is connected to the circulating fan (3) and the purification device (4) by pipelines. The first outlet of the purification device (4) is connected to the CO2 catalytic hydrogenation to methanol system by pipelines. The second outlet of the purification device (4) is connected to the outside of the system. The furnace (1) is connected to the new energy electrolysis water system by pipelines. The steam-water power generation unit comprises a second heat exchanger (13) and a third heat exchanger (14) which are connected by pipelines. The cold end of the second heat exchanger (13) is connected to the cold end of the third heat exchanger (14) through a pipeline, and the cold end of the third heat exchanger (14) is connected to the tail flue (2) through a pipeline. The CO2 catalytic hydrogenation system for producing methanol comprises a CO2 multistage compressor (15), an H2 multistage compressor (16), a methanol reactor (17), a high-pressure separator (18), a fourth heat exchanger (21) and a fifth heat exchanger (22); the CO2 multistage compressor (15) is connected to the first outlet of the purification device (4) through a pipeline, and the hot end of the fourth heat exchanger (21) is installed between the CO2 multistage compressor (15) to absorb waste heat. The CO2 multistage compressor (15), the H2 multistage compressor (16), the fourth heat exchanger (21) ) and the cold end of the fifth heat exchanger (22) are both connected to the methanol reactor (17) through pipelines, the hot end of the second heat exchanger (13) is connected to the methanol reactor (17) and the high-pressure separator (18) through pipelines, the hot end of the fifth heat exchanger (22) is installed between the H2 multi-stage compressor (16) to absorb waste heat, the hot end of the third heat exchanger (14) is arranged inside the methanol reactor (17), the new energy water electrolysis system is connected to the furnace (1) and the H2 multi-stage compressor (16) through pipelines, and the steam-water power generation unit also includes a high-pressure steam turbine (5), a medium-pressure steam turbine (6), a low-pressure steam turbine (7), a back-pressure steam turbine (8), a condenser (9), a first feed water pump (10), and a second feed water pump (11) and a first heat exchanger (12); the high-pressure steam turbine (5) is connected to the furnace (1) and the tail flue (2) respectively through pipelines, the medium-pressure steam turbine (6) is connected to the furnace (1), the low-pressure steam turbine (7) and the back-pressure steam turbine (8) respectively through pipelines, the low-pressure steam turbine (7) is connected to the condenser (9) and the first feedwater pump (10) in sequence through pipelines, the back-pressure steam turbine (8) is connected to the first heat exchanger (12) and the second feedwater pump (11) in sequence through pipelines, the first feedwater pump (10) and the second feedwater pump (11) are both connected to the cold end of the second heat exchanger (13) and the cold end of the third heat exchanger (14) in sequence through pipelines, and the CO2 catalytic hydrogenation system to produce methanol also includes a low-pressure separator (19);The low-pressure separator (19) is connected to the high-pressure separator (18) through a pipeline, and the high-pressure separator (18) and the low-pressure separator (19) are both connected to the cold end of the fourth heat exchanger (21) and the cold end of the fifth heat exchanger (22) through pipelines. The CO2 catalytic hydrogenation system for producing methanol further includes a methanol distillation tower (20); the low-pressure separator (19) is connected to the methanol distillation tower (20) through a pipeline, and the cold end of the first heat exchanger (12) is arranged inside the methanol distillation tower (20). ;

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