Coal-to-natural gas and new energy coupling energy supply system

Abstract

The present application belongs to the field of coal gasification, and relates to an energy supply system coupling coal gasification and new energy; the system can reasonably utilize renewable energy, complement the defects of the coal gasification system and the photoelectric and / or wind power system, reduce the generation cost, and improve the product competitiveness; the technical scheme comprises a cogeneration unit, a coal gas preparation unit, a hydrogen gas preparation unit, and a natural gas preparation unit; the cogeneration unit is configured to provide superheated steam; the coal gas preparation unit is in communication with the cogeneration unit, and is configured to receive the superheated steam from the cogeneration unit and generate coal gas; the hydrogen gas preparation unit adopts wind power and / or photoelectric power to electrolyze water and generate hydrogen gas; the natural gas preparation unit is in communication with the coal gas preparation unit and the hydrogen gas preparation unit, and is configured to receive the coal gas from the coal gas preparation unit and the hydrogen gas from the hydrogen gas preparation unit and generate natural gas.

Description

Technical Field

[0001] This invention belongs to the field of coal-to-gas and relates to an energy supply system that couples coal-to-natural gas with new energy sources. Background Technology

[0002] Coal-to-natural gas (SNG) typically refers to the production of synthetic natural gas (SNG) from mined raw coal through a gasification process.

[0003] my country has abundant coal resources. Converting coal into natural gas at coal-producing areas can reduce coal transportation and air pollution caused by coal combustion.

[0004] In current technologies, the coal-to-natural-gas process requires a large amount of hydrogen. Currently, hydrogen production generally uses water electrolysis. To ensure hydrogen production volume and cost, water electrolysis for hydrogen production requires a large amount of electricity but is inexpensive.

[0005] my country has abundant wind and solar power resources. However, wind and solar power are affected by natural conditions, resulting in unstable power generation and poor power stability. Therefore, they need to be processed through rectification, transformation, and inversion before being uploaded to the power grid, which increases the cost of wind and solar power and causes a large amount of power loss during the processing. Summary of the Invention

[0006] To overcome the shortcomings of the aforementioned related technologies, this invention proposes an energy supply system that couples coal-to-natural gas with new energy sources; it can make reasonable use of renewable energy, complement the shortcomings of coal-to-natural gas systems and photovoltaic and / or wind power systems, reduce production costs, and improve product competitiveness.

[0007] Some embodiments of the present invention provide an energy supply system coupling coal-to-natural gas and new energy sources. The coal-to-natural gas and new energy supply system includes: a combined heat and power (CHP) unit, a coal gas production unit, a hydrogen production unit, and a natural gas production unit. The CHP unit is configured to provide superheated steam. The coal gas production unit is connected to the CHP unit and is configured to receive superheated steam from the CHP unit and generate coal gas. The hydrogen production unit uses wind power and / or photovoltaic power to electrolyze water and generate hydrogen. The natural gas production unit is connected to both the coal gas production unit and the hydrogen production unit and is configured to receive coal gas from the coal gas production unit and hydrogen from the hydrogen production unit and generate natural gas.

[0008] Preferably, the combined heat and power (CHP) unit includes a steam boiler powered by fossil fuels, and the steam boiler is also connected to the gasification unit. The gasification unit further includes a gasifier, a cooling device, and a low-temperature methanol washing device. The superheated steam and part of the exhaust gas from the steam boiler enter the gasifier to generate hydrogen, carbon monoxide, carbon dioxide, and water vapor, and the generated gases are sequentially introduced into the cooling device and the low-temperature methanol washing device. The gasification unit also includes a CO2 capture device connected to the exhaust port of the low-temperature methanol washing device. The CO2 capture device is configured to collect the gas emitted from the low-temperature methanol washing device and collect carbon dioxide from the emitted gas. The CO2 capture device is also connected to the natural gas preparation unit, which is further configured to receive carbon dioxide from the CO2 capture device and react it with hydrogen to generate natural gas.

[0009] Preferably, the natural gas production unit includes a first methanation reactor and a second methanation reactor. The first methanation reactor is connected to the coal gas production unit and the hydrogen production unit, and receives coal gas and hydrogen to produce natural gas. The second methanation reactor is connected to the CO2 capture device and the hydrogen production unit, and receives CO2 and hydrogen to produce natural gas.

[0010] Preferably, the CO2 capture device is also connected to the outside environment. A first valve is installed on the pipeline connecting the CO2 capture device to the outside environment, and a second valve is installed on the pipeline connecting the CO2 capture device to the second methanation reactor. The first valve and the second valve are linked to maintain a stable total flow rate.

[0011] Preferably, the hydrogen production unit further includes an electrolyzer and a hydrogen storage tank. The electrolyzer is connected to the hydrogen storage tank, and the hydrogen produced by the electrolyzer is guided into the hydrogen storage tank. A gas flow sensor is installed on the pipeline between the electrolyzer and the hydrogen storage tank. The controller of the second valve is also electrically connected to the gas flow sensor, and the opening amplitude of the second valve is inversely proportional to the value of the gas flow sensor.

[0012] The beneficial effects of this invention are as follows:

[0013] This invention employs a hydrogen production unit that can use wind power or solar power to electrolyze water to produce hydrogen, which can reduce the processing of wind power or solar power, achieve low-cost and high-efficiency utilization of wind power or solar power, and further increase the product competitiveness of coal-to-natural gas.

[0014] This invention utilizes wind power or solar power. Due to the instability of wind power or solar power, this invention also employs a first methanation reactor and a second methanation reactor. The second methanation reactor can adjust the natural gas production rate according to the impact of wind power or solar power on hydrogen production, thereby achieving coupling between the coal-to-natural gas system and the new energy system. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a structural diagram of the present invention;

[0017] Figure 2 This is another structural diagram of the present invention;

[0018] Figure 3 This is a structural flow diagram of the natural gas preparation unit of the present invention. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0022] like Figures 1 to 3 As shown, some embodiments of the present invention provide an energy supply system coupling coal-to-natural gas and new energy sources. The coal-to-natural gas and new energy coupled production system includes: a combined heat and power (CHP) unit 1, a coal gas preparation unit 2, a hydrogen preparation unit 3, and a natural gas preparation unit 4. The CHP unit 1 is configured to provide superheated steam. The coal gas preparation unit 2 is connected to the CHP unit 1 and is configured to receive the superheated steam from the CHP unit 1 and generate coal gas. The hydrogen preparation unit 3 uses wind power and / or photovoltaic power to electrolyze water and generate hydrogen. The natural gas preparation unit 4 is connected to the coal gas preparation unit 2 and the hydrogen preparation unit 3 and is configured to receive coal gas from the coal gas preparation unit 2 and hydrogen from the hydrogen preparation unit 3 and generate natural gas.

[0023] In this application, the gas production process of unit 2 involves passing superheated steam through high-temperature coal to generate water gas. To avoid the adverse effects of water gas on the catalyst formation in unit 4, the water gas needs to undergo desulfurization and denitrification treatment, carbon dioxide absorption treatment, and drying treatment before being converted into coal gas.

[0024] The hydrogen production unit 3 also needs to dry the generated hydrogen before it enters the natural gas production unit 4.

[0025] Preferably, the combined heat and power (CHP) unit 1 includes a steam boiler 11, which uses fossil fuels. In this application, the CHP unit 1 generates superheated steam, which can be directly supplied to the gas production unit 2. Excess superheated steam can be used by a turbine generator set to generate hydrogen in the hydrogen production unit 3 when the grid price is at a low point, and can be uploaded to the grid when the grid price is at a high point.

[0026] The combined heat and power (CHP) unit 1 includes a steam boiler 11, which uses fossil fuels and is also connected to the gasification unit 2. The gasification unit 2 further includes a gasifier 21, a cooling device 22, and a low-temperature methanol washing device 23. The superheated steam and part of the exhaust gas from the steam boiler enter the gasifier 21 and generate hydrogen, carbon monoxide, carbon dioxide, and water vapor. The generated gases are then sequentially introduced into the cooling device 22 and the low-temperature methanol washing device 23. The gasification unit 2 also includes a CO2 capture device 24, which is connected to the exhaust port of the low-temperature methanol washing device 23. The CO2 capture device 24 is configured to collect the gas emitted from the low-temperature methanol washing device 23 and collect the carbon dioxide in the emitted gas. The CO2 capture device 24 is also connected to the natural gas preparation unit 4 via a raw material gas-liquid separator and a desulfurization tank. The natural gas preparation unit 4 is further configured to receive carbon dioxide from the CO2 capture device 24 and react it with hydrogen to generate natural gas.

[0027] Preferably, the natural gas preparation unit 4 includes a first methanation reactor 41 and a second methanation reactor 42. The first methanation reactor 41 is connected to the coal gas preparation unit 2 and the hydrogen preparation unit 3. After the coal gas and hydrogen have passed through a raw material gas-liquid separator and a desulfurization tank, the first methanation reactor 41 receives the coal gas and hydrogen and generates natural gas. This natural gas is then processed by a methane reactor and a gas-liquid separator before being sent to the first station, ultimately providing gaseous natural gas to users. The second methanation reactor 42 is connected to the CO2 capture device 24 and the hydrogen preparation unit 3. The second methanation reactor 42 receives CO2 and hydrogen and generates natural gas. This natural gas is also processed by a methane reactor and a gas-liquid separator before being sent to the first station, ultimately providing gaseous natural gas to users.

[0028] In this application, there may be multiple first methanation reactors 41, which are connected in series. For example, multiple first methanation reactors 41 may include three, which are connected in series to achieve the full reaction of CO2 and hydrogen to produce methane.

[0029] There can be multiple second methanation reactors 42, which are connected in parallel. Each second methanation reactor 42 is connected to the CO2 capture device 24. Hydrogen production adapts accordingly to changes in electricity output. To ensure stable natural gas production, hydrogen can be preferentially supplied to the first methanation reactor 41. Excess hydrogen can be supplied to multiple second methanation reactors 42 based on their demand. This means that the number of second methanation reactors supplied can be controlled based on the amount of excess hydrogen. This satisfies natural gas production requirements while adapting to unstable power generation due to external factors affecting solar and / or wind power, maximizing the utilization of new energy sources such as wind and solar power. This avoids electricity waste and enhances the competitiveness of coal-to-natural gas.

[0030] The natural gas production unit 4 described in this application may further include a third methanation reactor 43, with each second methanation reactor 42 connected to a third methanation reactor 43, and each third methanation reactor 43 receiving gas discharged from the second methanation reactor 42. Further catalytic reactions can be performed on the gas discharged from the second methanation reactor 42 to improve the methane purity of the generated natural gas.

[0031] Preferably, the CO2 capture device 24 is also connected to the outside world. A first valve 25 is installed on the pipeline connecting the CO2 capture device 24 to the outside world, and a second valve 14 is installed on the pipeline connecting the CO2 capture device 24 to the second methanation reactor 42. The first valve 25 and the second valve 14 are linked to maintain a stable total flow rate.

[0032] In this application, each second methanation reactor 42 is equipped with a second valve 14 on the pipeline connected to the CO2 capture device 24. The second valve 14 is electrically connected to the controller. The second valve 14 can be opened according to the hydrogen production. That is, when the hydrogen production meets the production rate of the second methanation reactor 42, the second valve 14 is opened accordingly. In other words, the opening data of the second valve 14 is consistent with the hydrogen production rate that meets the normal production rate of the second methanation reactor 42.

[0033] Preferably, the hydrogen production unit 3 further includes an electrolytic cell 31 and a hydrogen storage tank 32. The electrolytic cell 31 is connected to the hydrogen storage tank 32. The hydrogen produced by the electrolytic cell 31 is treated by the scrubber of the separator and then guided into the hydrogen storage tank 32. The scrubber provides circulating water to the hydrogen storage tank 32 through a water tank and a circulating water pump. A gas flow sensor is installed on the pipeline between the electrolytic cell 31 and the hydrogen storage tank 32. The controller of the second valve 14 is also electrically connected to the gas flow sensor, and the opening degree of the second valve 14 is inversely proportional to the value of the gas flow sensor.

[0034] In this application, the number of closed or open valves 14 can be controlled according to the hydrogen production. Specifically, when the hydrogen production meets the production needs of several second methanation reactors 42, the corresponding number of second valves 14 are opened. For example, when the hydrogen production can meet the production needs of one second methanation reactor 42, one second valve 14 is opened; when the hydrogen production can meet the production needs of two second methanation reactors 42, two second valves 14 are opened.

[0035] The above control methods can accommodate the instability of new energy power generation, while reducing excessive processing of new energy power, thereby reducing power waste, improving power utilization efficiency, effectively reducing product production costs, and enhancing product competitiveness.

[0036] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0037] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An energy supply system coupling coal-to-natural gas and new energy sources, characterized in that, include: A combined heat and power (CHP) unit, the CHP unit being configured to provide superheated steam; A gas preparation unit is connected to the cogeneration unit, and the gas preparation unit is configured to receive superheated steam from the cogeneration unit and generate gas. The hydrogen production unit uses wind power and / or photovoltaic power to electrolyze water and generate hydrogen. A natural gas production unit is connected to the coal gas production unit and the hydrogen production unit, and the natural gas production unit is configured to receive coal gas from the coal gas production unit and hydrogen from the hydrogen production unit and generate natural gas. The combined heat and power unit includes a steam boiler that uses fossil fuels and is also connected to the gas production unit. The gas preparation unit also includes a gasification furnace, a cooling device, and a low-temperature methanol washing device. The superheated steam and part of the tail gas from the steam boiler enter the gasification furnace and generate hydrogen, carbon monoxide, carbon dioxide, and water vapor. The generated gases are then sequentially introduced into the cooling device and the low-temperature methanol washing device. The gas preparation unit also includes a CO2 capture device, which is connected to the exhaust port of the low-temperature methanol washing device. The CO2 capture device is configured to collect the gas emitted from the low-temperature methanol washing device and collect carbon dioxide from the gas emitted from the low-temperature methanol washing device. The CO2 capture device is also connected to the natural gas production unit, which is further configured to receive carbon dioxide from the CO2 capture device and react it with hydrogen to produce natural gas. The natural gas production unit includes: A first methanation reactor is connected to the coal gas preparation unit and the hydrogen preparation unit. The first methanation reactor receives coal gas and hydrogen to generate natural gas. Multiple second methanation reactors are configured and connected in parallel. Each second methanation reactor is connected to the CO2 capture device and the hydrogen production unit. The second methanation reactor receives CO2 and hydrogen to generate natural gas. The hydrogen produced by the hydrogen production unit is preferentially supplied to the first methanation reactor, and the excess hydrogen after meeting the production needs of the first methanation reactor is supplied to multiple second methanation reactors. The CO2 capture device is also connected to the outside world. A first valve is installed on the pipeline connecting the CO2 capture device to the outside world, and a second valve is installed on the pipeline connecting the CO2 capture device to the second methanation reactor. The first valve and the second valve are linked to keep the total flow of the first valve and the second valve stable; The hydrogen production unit further includes an electrolytic cell and a hydrogen storage tank. The electrolytic cell is connected to the hydrogen storage tank, and the hydrogen produced by the electrolytic cell is guided into the hydrogen storage tank. A gas flow sensor is installed on the pipeline between the electrolytic cell and the hydrogen storage tank. The controller of the second valve is also electrically connected to the gas flow sensor, and the opening degree of the second valve is inversely proportional to the value of the gas flow sensor.

2. The energy supply system coupling coal-to-natural gas and new energy sources according to claim 1, characterized in that, There are multiple first methanation reactors, which are connected in series to allow carbon dioxide and hydrogen in the coal gas to react fully to produce methane.

3. The energy supply system coupling coal-to-natural gas and new energy sources according to claim 1, characterized in that, The natural gas production unit further includes a third methanation reactor, and each second methanation reactor is connected to one of the third methanation reactors. Each third methanation reactor receives the gas discharged from the corresponding second methanation reactor and further catalyzes the reaction to improve the methane purity of the generated natural gas.

Images