A coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power

Abstract

The present invention discloses a coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power. The coastal coal-fired electricity-gas integrated energy production system for absorbing offshore wind power includes an offshore wind power generation system, a coastal hydrogen preparation system, a coastal coal-fired power generation system, a waste gas separation system, a methanogenic gas mixed preparation system, a gas storage system and an energy delivery system. The present invention solves the cost and system operation safety problems caused by the long-distance grid connection and absorption of wind power by utilizing offshore wind power to produce hydrogen. At the same time, the carbon-containing waste gas generated by traditional coal-fired power plants is separated and processed to form high-purity carbon monoxide and carbon dioxide gases, which are used together with hydrogen as raw materials for the production of methanogenic gas, reducing the carbon emissions of coal-fired power plants, improving the wind power absorption rate, reducing the overall system operation cost and improving the energy production efficiency. The overall system operation cost can be reduced and the energy production efficiency can be improved, and the comprehensive supply capacity of the regional energy system can be improved.

Description

Technical Field

[0001] The present invention relates to an energy production method, specifically a coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power, belonging to the technical field of low-carbon energy production. Background Art

[0002] In order to respond to global climate change and promote sustainable development of mankind, the global energy structure will be deeply adjusted in the context of the global era. The traditional energy structure dominated by fossil energy such as oil, coal, and natural gas can no longer meet the inherent requirements of sustainable development in various countries. Changing the energy structure and the way of energy utilization has become an important way. Clean energy such as solar energy, wind energy, hydropower, nuclear energy, and biomass energy has increasingly become the energy type that countries focus on supporting development. According to the International Energy Agency (IEA), by 2030, global renewable energy demand will account for 80% of the global electricity demand increase, of which wind power and photovoltaic power generation will account for nearly 30% from 8% in 2019.

[0003] At present, most traditional clean energy sources are produced independently, lacking a production model that allows for interactive interconnection between different energy sources. The cost of energy production and use is high, making it difficult to form a low-carbon, reliable, economical, and green energy supply method. Although with the continuous advancement of the construction of new power systems and re-electrification, offshore wind power and electrolysis hydrogen production have been invested in construction and use as the focus of industrial development, on the one hand, offshore wind farms have large fluctuations, and grid connection will have a certain impact on the large onshore power grid. Therefore, a large amount of flexible resources such as energy storage must be configured, which brings some technical and economic problems, and offshore wind power must also lay high-voltage submarine cables, which is costly; on the other hand, although electrolysis hydrogen production can realize offshore wind power consumption, the transportation of hydrogen energy is restricted by industry technology, the high density of hydrogen elements, and high transportation losses, which makes the additional costs and safety costs of hydrogen energy transportation high. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power, which can solve the problems of difficult long-distance transmission and absorption of offshore wind power and high carbon emissions of coal-fired power plants, and achieve the purpose of economically and efficiently absorbing renewable energy, reducing carbon emissions on the power generation side and comprehensive production of various energy sources.

[0005] To achieve the above-mentioned purpose, the coastal coal-fired electricity-gas integrated energy production system for absorbing offshore wind power includes an offshore wind power generation system, a coastal hydrogen preparation system, a coastal coal-fired power generation system, a waste gas separation system, a methanogenic gas mixing preparation system, a gas storage system and an energy delivery system; the flue gas emission outlet of the coastal coal-fired power generation system is connected to the input end of the waste gas separation system through a waste gas collection device, and the power output end of the coastal coal-fired power generation system is connected to the energy delivery system; the offshore wind power generation system includes an offshore wind power generator set, an offshore booster station, a submarine cable and an onshore step-down station that are electrically connected in sequence; the gas storage system includes an oxygen storage part, a hydrogen storage part and a carbon-rich relaxation gas storage part; the coastal hydrogen preparation system includes a seawater electrolysis part and a gas delivery part, The seawater electrolysis part is electrically connected to the onshore step-down station, the hydrogen output end of the gas transmission part is connected to the input end of the hydrogen storage part of the gas storage system, and the oxygen output end of the gas transmission part is connected to the input end of the oxygen storage part of the gas storage system; the output end of the waste gas separation system is connected to the input end of the carbon-rich relaxation gas storage part of the gas storage system; the methanogenic gas mixing preparation system includes a raw material input part, a methane gas preparation part and a residual carbon removal part connected in sequence, and the output end of the residual carbon removal part is connected to the energy transmission system; the output end of the hydrogen storage part and the output end of the carbon-rich relaxation gas storage part of the gas storage system are respectively connected to the raw material input part of the methanogenic gas mixing preparation system, and the output end of the oxygen storage part of the gas storage system is connected to the energy transmission system;

[0006] The electric energy generated by the Binhai coal-fired power generation system is sent to the energy transmission system for transmission. The harmful flue gas containing a large amount of carbides and sulfides generated by the Binhai coal-fired power generation system in the process of generating electric energy is collected by the exhaust gas collection device and sent to the exhaust gas separation system for treatment. The exhaust gas separation system separates the sulfur-containing harmful flue gas into carbon-rich relaxation gas including carbon monoxide and carbon dioxide, and enters the carbon-rich relaxation gas storage part of the gas storage system for storage;

[0007] At the same time, the electricity produced by the offshore wind power generating units of the offshore wind power generation system is consumed nearby, and after being boosted by the offshore booster station, it is transmitted via submarine cables, and after being reduced in pressure by the onshore step-down station, it is supplied to the coastal hydrogen preparation system, where a mixed gas containing hydrogen and oxygen is prepared by the water electrolysis hydrogen production method, and then separated to obtain high-concentration hydrogen and high-concentration oxygen. The high-concentration hydrogen enters the hydrogen storage part of the gas storage system for storage, and the high-concentration oxygen enters the oxygen storage part of the gas storage system for storage;

[0008] Then, according to the methane production demand, the output ends of the hydrogen storage part and the carbon-rich relaxation gas storage part of the gas storage system are controlled to adjust the gas transmission ratio, and the high-concentration hydrogen and carbon-rich relaxation gas are simultaneously transported to the methanation gas mixing preparation system to prepare methanation gas. The methane gas generated in the methanation gas preparation system is sent to the energy transmission system for delivery after residual carbon removal, and the oxygen in the oxygen storage part of the gas storage system is sent to the energy transmission system for delivery, thereby realizing the comprehensive energy production of electricity, oxygen and methane gas while absorbing offshore wind power.

[0009] As a further improvement of the present invention, the carbon-rich relaxation gas separated by the waste gas separation system has a concentration of carbon monoxide and carbon dioxide of more than 85%.

[0010] As a further improvement of the present invention, when the waste gas separation system separates the sulfur-containing harmful flue gas, the sulfur-containing harmful flue gas is pressurized to 1-1.3 MPa and then dry desulfurization is adopted.

[0011] As a further improvement of the present invention, dry desulfurization uses iron oxide desulfurization agent.

[0012] As a further improvement of the present invention, the methanation gas mixed preparation system prepares methanation gas by a pressurized fixed bed method.

[0013] As a further improvement of the present invention, when preparing methanogenic gas by a pressurized fixed bed method, the volume ratio of hydrogen to carbon-rich relaxation gas is 5:1, the temperature is controlled at 500-550°C, and the pressure is controlled at 4.2-4.5 MPa.

[0014] As a further improvement of the present invention, when the methane gas generated in the methanogenic gas preparation system is subjected to residual carbon removal treatment, the methane gas is pressurized to 9.5-10.5 MPa.

[0015] Compared with the existing technology, this coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power solves the cost and system operation safety problems caused by the long-distance grid connection and consumption of wind power by utilizing offshore wind power to produce hydrogen. At the same time, it separates and processes the carbon-containing waste gas produced by traditional coal-fired power plants to form high-purity carbon monoxide and carbon dioxide gases, which are used together with hydrogen as raw materials for the production of methanogenic gas, thereby reducing carbon emissions from coal-fired power plants, increasing the wind power consumption rate, reducing the overall operating cost of the system, and improving energy production efficiency. This coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power makes full use of traditional wind power hydrogen production and methanogenic gas preparation Based on the advantages of the technology, it can not only solve the problem of wind power consumption and the safety problems caused by hydrogen transmission, but also effectively utilize the carbon-containing gas produced by coal-fired power plants, improve the energy utilization rate per unit of carbon emissions, and reduce carbon emissions generated by energy production; use offshore wind power to produce hydrogen in the surrounding areas of coastal coal-fired power plants, and recycle the carbon-containing exhaust gas from coal-fired power plants to establish an integrated electricity-gas energy production method with coastal coal-fired power plants and offshore wind power hydrogen production systems as the core, giving full play to the flow characteristics of carbon between different energy substances, which can reduce the overall operating cost of the system, improve energy production efficiency, and improve the comprehensive supply capacity of the regional energy system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a coastal coal-fired electricity-gas integrated energy production system that absorbs offshore wind power;

[0017] Figure 2 is a flow chart of the present invention;

[0018] Figure 3 This is a diagram showing typical daily power generation and carbon emissions of a coal-fired power plant in a coastal area in each quarter according to an embodiment of the present invention;

[0019] Figure 4 1 is a diagram showing the transmission coefficient of a coal-fired power plant in a coastal area in different seasons according to an embodiment of the present invention;

[0020] Figure 5 This is a diagram showing the production of hydrogen and oxygen on a typical day in each season at a coal-fired power plant in a coastal area according to an embodiment of the present invention;

[0021] Figure 6 This is a diagram illustrating the carbon recycling situation in different seasons in a coal-fired power plant in a coastal area according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings (hereinafter referred to as Figure 1 The left side direction is described as the front).

[0023] like Figure 1 , Figure 2As shown, the coastal coal-fired electricity-gas integrated energy production system for absorbing offshore wind power includes an offshore wind power generation system, a coastal hydrogen preparation system, a coastal coal-fired power generation system, a waste gas separation system, a methanogenic gas mixing preparation system, a gas storage system and an energy delivery system;

[0024] The flue gas emission outlet of the coastal coal-fired power generation system is connected to the input end of the exhaust gas separation system through the exhaust gas collection device, and the power output end of the coastal coal-fired power generation system is connected to the energy transmission system; the offshore wind power generation system includes an offshore wind power generator set, an offshore booster station, a submarine cable and an onshore step-down station that are electrically connected in sequence; the gas storage system includes an oxygen storage part, a hydrogen storage part and a carbon-rich relaxation gas storage part; the coastal hydrogen preparation system includes a seawater electrolysis part and a gas transmission part, the seawater electrolysis part is electrically connected to the onshore step-down station, and the seawater is electrolyzed to prepare hydrogen and oxygen through the electricity generated by the offshore wind power generation system, and the hydrogen output end of the gas transmission part is connected to the gas storage system. The input end of the hydrogen storage part of the system is connected, and the oxygen output end of the gas transmission part is connected to the input end of the oxygen storage part of the gas storage system; the output end of the exhaust gas separation system is connected to the input end of the carbon-rich relaxation gas storage part of the gas storage system; the methanogenic gas mixing preparation system includes a raw material input part, a methane gas preparation part and a residual carbon removal part which are connected in sequence, and the output end of the residual carbon removal part is connected to the energy transmission system; the output end of the hydrogen storage part and the output end of the carbon-rich relaxation gas storage part of the gas storage system are respectively connected to the raw material input part of the methanogenic gas mixing preparation system, and the output end of the oxygen storage part of the gas storage system is connected to the energy transmission system.

[0025] During the production process of the coastal coal-fired electricity-gas integrated energy production system that absorbs offshore wind power, the electricity produced by the coastal coal-fired power generation system is sent to the energy delivery system for delivery. In the process of producing electricity, a large amount of harmful flue gas containing carbon and sulfide generated by the coastal coal-fired power generation system is collected uniformly by the waste gas collection device and sent to the waste gas separation system for treatment. The waste gas separation system pressurizes the sulfur-containing harmful waste gas to 1-1.3Mpa and then uses dry desulfurization to pass through an iron oxide desulfurizer to form a carbon-rich relaxation gas with a carbon monoxide and carbon dioxide concentration of more than 85%, and enters the carbon-rich relaxation gas storage part of the gas storage system for storage;

[0026] At the same time, the electricity produced by the offshore wind power generating units of the offshore wind power generation system is consumed nearby, and after being boosted by the offshore booster station, it is transmitted to the vicinity of the coastal coal-fired power plant via a submarine cable, and after being reduced in pressure by the onshore step-down station, it is supplied to the coastal hydrogen preparation system, where a mixed gas containing hydrogen and oxygen is prepared by the water electrolysis hydrogen production method, and then separated to obtain high-concentration hydrogen and high-concentration oxygen. The high-concentration hydrogen enters the hydrogen storage part of the gas storage system for storage, and the high-concentration oxygen enters the oxygen storage part of the gas storage system for storage;

[0027] Then, according to the methane production demand, the output ends of the hydrogen storage part and the carbon-rich relaxation gas storage part of the gas storage system are controlled, and the high-concentration hydrogen and carbon-rich relaxation gas are simultaneously transported to the methanation gas mixing preparation system, and the methanation gas is prepared by a pressurized fixed bed method, wherein the volume ratio of hydrogen to carbon-rich relaxation gas is 5:1, the temperature is controlled at 500-550°C, and the pressure is controlled at 4.2-4.5Mpa. The methane gas generated in the methanation gas preparation system is pressurized to 9.5-10.5MPa and then subjected to residual carbon removal treatment. It is then sent to the energy delivery system for delivery, and the oxygen in the oxygen storage part of the gas storage system is sent to the energy delivery system for delivery, thereby realizing the comprehensive energy production of electricity, oxygen and methane gas while absorbing offshore wind power.

[0028] Take a coal-fired power plant in a coastal area as an example. The power plant has 2*50MW generator sets. The typical daily power generation and carbon emissions of the power plant in each quarter are as follows: Figure 3 shown.

[0029] Required installed capacity of offshore wind turbines E w It can be expressed as

[0030] E w =η a k hc k vc c cg

[0031] Where: E w is the required installed capacity of offshore wind turbines, in MW; η a is the total electricity-hydrogen conversion ratio; k hc The hydrogen-to-carbon requirement ratio for methanogenic gas production; k vc is the carbon-containing gas conversion coefficient, unit mol / kgC; c cg is the total carbon emissions from coal-fired power plants, in kg·C.

[0032] The total conversion ratio of electricity to hydrogen is η a It can be expressed as

[0033] η a =k w k s k t G h

[0034] Where: k w is the wind power generation coefficient; k s k is the seasonal influence coefficient of wind turbines; t is the wind power transmission loss coefficient; G h It is the electricity-gas conversion coefficient, unit is mol / kWh.

[0035] The coefficients in the above formula are Figure 4 shown.

[0036] Through this coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power, it can be calculated that the power plant with 2*50MW generator sets needs to be equipped with 50MW offshore wind turbines. The typical daily hydrogen and oxygen production in each season is as follows Figure 5 As shown in Figure 2, the carbon recycling of coal-fired power plants in different seasons is as follows: Figure 6 It can be seen that the coastal coal-fired electricity-gas integrated energy production method that absorbs offshore wind power can effectively improve the carbon emission reuse rate of coal-fired power plants, give full play to the flow characteristics of carbon between different energy substances, improve the comprehensive supply capacity of the regional energy system, reduce the overall operation cost of the system and improve energy production efficiency.

Claims

1. A coastal coal-fired electricity-gas integrated energy production method for absorbing offshore wind power, characterized in that: The coastal coal-fired electricity-gas integrated energy production system that consumes offshore wind power includes an offshore wind power generation system, a coastal hydrogen preparation system, a coastal coal-fired power generation system, a waste gas separation system, a methanogenic gas mixing preparation system, a gas storage system and an energy transmission system; the flue gas emission outlet of the coastal coal-fired power generation system is connected to the input end of the waste gas separation system through a waste gas collection device, and the power output end of the coastal coal-fired power generation system is connected to the energy transmission system; the offshore wind power generation system includes an offshore wind power generator set, an offshore booster station, a submarine cable and an onshore step-down station that are electrically connected in sequence; the gas storage system includes an oxygen storage part, a hydrogen storage part and a carbon-rich relaxation gas storage part; the coastal hydrogen preparation system includes a seawater electrolysis part and a gas transmission part, and the seawater electrolysis part The gas transmission part is electrically connected to the onshore step-down station, the hydrogen output end of the gas transmission part is connected to the input end of the hydrogen storage part of the gas storage system, and the oxygen output end of the gas transmission part is connected to the input end of the oxygen storage part of the gas storage system; the output end of the waste gas separation system is connected to the input end of the carbon-rich relaxation gas storage part of the gas storage system; the methanogenic gas mixed preparation system includes a raw material input part, a methane gas preparation part and a residual carbon removal part which are connected in sequence, and the output end of the residual carbon removal part is connected to the energy transmission system; the output end of the hydrogen storage part and the output end of the carbon-rich relaxation gas storage part of the gas storage system are respectively connected to the raw material input part of the methanogenic gas mixed preparation system, and the output end of the oxygen storage part of the gas storage system is connected to the energy transmission system; The electric energy generated by the Binhai coal-fired power generation system is sent to the energy transmission system for transmission. The harmful flue gas containing a large amount of carbides and sulfides generated by the Binhai coal-fired power generation system in the process of generating electric energy is collected by the waste gas collection device and sent to the waste gas separation system for treatment. The waste gas separation system separates the sulfur-containing harmful flue gas into carbon-rich relaxation gas including carbon monoxide and carbon dioxide, and the concentration of carbon monoxide and carbon dioxide in the carbon-rich relaxation gas is above 85%, and enters the carbon-rich relaxation gas storage part of the gas storage system for storage; At the same time, the electricity produced by the offshore wind power generating units of the offshore wind power generation system is consumed nearby, and after being boosted by the offshore booster station, it is transmitted via submarine cables, and after being reduced in pressure by the onshore step-down station, it is supplied to the coastal hydrogen preparation system, where a mixed gas containing hydrogen and oxygen is prepared by the water electrolysis hydrogen production method, and then separated to obtain high-concentration hydrogen and high-concentration oxygen. The high-concentration hydrogen enters the hydrogen storage part of the gas storage system for storage, and the high-concentration oxygen enters the oxygen storage part of the gas storage system for storage; Then, according to the methane production demand, the output ends of the hydrogen storage part and the carbon-rich relaxation gas storage part of the gas storage system are controlled to adjust the gas transmission ratio, and the high-concentration hydrogen and carbon-rich relaxation gas are simultaneously transported to the methanation gas mixing preparation system to prepare methanation gas by a pressurized fixed bed method. When preparing methanation gas by the pressurized fixed bed method, the volume ratio of hydrogen to carbon-rich relaxation gas is 5:1, the temperature is controlled at 500-550°C, and the pressure is controlled at 4.2-4.5MPa. The methane gas generated in the methanation gas preparation system is subjected to residual carbon removal treatment and then sent to the energy transmission system for transmission. The oxygen in the oxygen storage part of the gas storage system is sent to the energy transmission system for transmission, thereby realizing the comprehensive energy production of electricity, oxygen and methane gas while absorbing offshore wind power.

2. The method for producing coastal coal-fired electricity and gas integrated energy for absorbing offshore wind power according to claim 1, characterized in that: When the waste gas separation system separates the sulfur-containing harmful flue gas, the sulfur-containing harmful flue gas is pressurized to 1-1.3MPa and then dry desulfurization is adopted.

3. The method for producing coastal coal-fired electricity and gas integrated energy for absorbing offshore wind power according to claim 2, characterized in that: Dry desulfurization uses iron oxide desulfurizer.

4. The method for producing coastal coal-fired electricity and gas integrated energy for absorbing offshore wind power according to claim 1, characterized in that: When the methane gas generated in the methanogenic gas preparation system is subjected to residual carbon removal treatment, the methane gas is pressurized to 9.5 to 10.5 MPa.

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