Methane cracking hydrogen production system utilizing pressure energy of natural gas gate station

Abstract

The utility model relates to the field of hydrogen production systems, in particular to a methane cracking hydrogen production system utilizing pressure energy of a natural gas gate station. The hydrogen production system comprises a control valve group, a control valve group A, a natural gas expansion generator set, a control valve group B, a purifier, a heat regenerator A, an electric heater, a natural gas cracking furnace, a heat regenerator B and a hydrogen separator, and the gas inlet end of the control valve group and the gas inlet end of the control valve group A are both connected to a gas inlet pipeline; the gas outlet end of the control valve set A, the natural gas expansion generator set and the heat regenerator A are all connected to the heat regenerator B. The heat regenerator A and the electric heater are both connected to the natural gas cracking furnace. Pressure energy of natural gas is utilized to generate power, electric energy is converted into heat energy to be input into the natural gas cracking system, chemical energy in the natural gas is converted into hydrogen energy, the overall energy utilization efficiency of the system is improved, the hydrogen production cost is reduced, and meanwhile, cracking products contain solid carbon, so that the hydrogen production system has lower carbon emission compared with other hydrogen production processes.

Description

Technical Field

[0001] The utility model relates to the field of hydrogen production systems, especially a methane cracking hydrogen production system that utilizes the pressure energy of natural gas gate stations. Background Technique

[0002] With the continuous increase in the global demand for clean energy, hydrogen energy, as a new type of energy with characteristics such as high efficiency and cleanliness, has gradually received wide attention. In the process of hydrogen production, natural gas cracking has become a promising method due to its high efficiency and potential economy, but a large amount of energy input is required during the natural gas cracking process. A natural gas gate station is an important link in the natural gas transmission pipeline network, mainly used to adjust the pressure and flow rate of natural gas to meet the needs of downstream users. In the traditional natural gas transmission system, high-pressure natural gas is reduced in pressure at the gate station to a pressure suitable for downstream users. However, during this process, a large amount of pressure energy carried by the natural gas is not fully utilized, resulting in energy waste. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is: To solve the technical problems described in the background technique, the utility model provides a methane cracking hydrogen production system that utilizes the pressure energy of natural gas gate stations. The pressure energy of natural gas is used to generate electricity, and the electric energy is converted into heat energy and input into the natural gas cracking system, converting the chemical energy in the natural gas into hydrogen energy, improving the overall energy utilization efficiency of the system, reducing the hydrogen production cost. At the same time, since the cracking product contains solid carbon, it has lower carbon emissions compared to other hydrogen production processes.

[0004] The technical solution adopted by the utility model to solve its technical problems is:

[0005] A methane cracking hydrogen production system that utilizes the pressure energy of natural gas gate stations includes a control valve group, control valve group A, a natural gas expansion power generation unit, control valve group B, a purifier, regenerator A, an electric heater, a natural gas cracking furnace, regenerator B, and a hydrogen separator. The inlet ends of the control valve group and control valve group A are both connected to the inlet pipeline. The outlet end of control valve group A, the natural gas expansion power generation unit, and regenerator A are all connected to regenerator B. Regenerator A and the electric heater are both connected to the natural gas cracking furnace. Regenerator A and regenerator B are both connected to the hydrogen separator. Regenerator A and the electric heater are connected to each other. The natural gas expansion power generation unit and control valve group B are both connected to the control valve group. Control valve group B and the purifier are connected. The purifier and regenerator A are connected.

[0006] Specifically, the control valve group includes a heating furnace, an emergency cut-off valve, a pressure reducing valve, a manual valve, and a gas flow meter 1. The heating furnace and the gas flow meter 1 are connected by two pipelines. An emergency cut-off valve and a pressure reducing valve are sequentially installed on one pipeline, and a manual valve is installed on the other pipeline.

[0007] Specifically, the control valve group A includes an emergency cut-off valve A, a gas flow regulating valve A, a manual valve A, and a gas flowmeter II. The intake pipeline is connected to the gas flowmeter II through two pipelines. An emergency cut-off valve A and a gas flow regulating valve A are sequentially installed on one pipeline, and a manual valve A is installed on the other pipeline.

[0008] Specifically, the control valve group B includes an emergency cut-off valve B, a gas flow regulating valve B, a manual valve B, and a gas flowmeter B. The natural gas expansion power generation unit is connected to the gas flowmeter B through two pipelines. An emergency cut-off valve B and a gas flow regulating valve B are sequentially installed on one pipeline, and a manual valve B is installed on the other pipeline.

[0009] Specifically, the natural gas expansion power generation unit includes an expander and a generator. The generator is connected to the expander, and the structure of the expander is a twin-screw type or a centrifugal type.

[0010] Specifically, the natural gas cracking furnace is a fluidized bed vertical cracking furnace.

[0011] Specifically, the hydrogen separator is a vertical cylindrical methane adsorption tower.

[0012] The beneficial effects of the present utility model are as follows: The present utility model provides a methane cracking hydrogen production system that utilizes the pressure energy of a natural gas gate station. The pressure energy of natural gas is used to generate electricity, and the electrical energy is converted into heat energy and input into the natural gas cracking system, converting the chemical energy in natural gas into hydrogen energy, improving the overall energy utilization efficiency of the system, reducing the hydrogen production cost. At the same time, since the cracking product contains solid carbon, it has lower carbon emissions compared to other hydrogen production processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0014] Figure 1 is a schematic structural diagram of the present utility model;

[0015] In the figure, 3. Natural gas expansion power generation unit, 5. Purifier, 6. Regenerator A, 7. Electric heater, 8.

[0016] Natural gas cracking furnace, 9. Regenerator B, 10. Hydrogen separator, 11. Heating furnace, 12. Emergency cut-off valve, 13. Pressure reducing valve, 14. Manual valve, 15. Gas flowmeter I. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The present utility model will now be further described in detail in conjunction with the drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present utility model in a schematic manner, so they only show the components related to the present utility model.

[0018] Figure 1 It is a schematic structural diagram of the present utility model.

[0019] As shown in the Figure 1 accompanying drawings, a methane cracking hydrogen production system utilizing the pressure energy of a natural gas gate station includes a control valve group, control valve group A, natural gas expansion power generation unit 3, control valve group B, purifier 5, regenerator A 6, electric heater 7, natural gas cracking furnace 8, regenerator B 9, and hydrogen separator 10. The inlet ends of the control valve group and control valve group A are both connected to the inlet pipeline. The outlet end of control valve group A, natural gas expansion power generation unit 3, and regenerator A 6 are all connected to regenerator B 9. Regenerator A 6 and electric heater 7 are both connected to natural gas cracking furnace 8. Regenerator A 6 and regenerator B 9 are both connected to hydrogen separator 10. Regenerator A 6 and electric heater 7 are connected to each other. Natural gas expansion power generation unit 3 and control valve group B are both connected to control valve group 1. Control valve group B and purifier 5 are connected. Purifier 5 and regenerator A 6 are connected.

[0020] Natural gas from the high-pressure pipe network is input through the inlet pipeline and enters regenerator B 9 for heat recovery after passing through control valve group A, then enters natural gas expansion power generation unit 3 to do work, converting the pressure energy into electric energy and outputting it to electric heater 7 and natural gas cracking furnace 8 as energy consumption. A part of the low-pressure natural gas after expansion work enters the low-pressure pipe network, and another part of the low-pressure natural gas enters purifier 5 through control valve group B to remove CO2 and moisture impurities. The purified natural gas enters electric heater 7 and is preheated to 600 °C. The high-temperature natural gas enters natural gas cracking furnace 8, where it is cracked into carbon atoms and hydrogen molecules under the catalytic action of a catalyst. The carbon atoms produce carbon nanotubes on the surface of the catalyst. The un-cracked methane and hydrogen are discharged and enter the interior of regenerator A 6, where they exchange heat with the low-pressure natural gas after expansion work. The cooled cracking tail gas enters hydrogen separator 10. The separated methane is pressurized and then returns to regenerator A 6 for heat recovery and then enters natural gas cracking furnace 8 again for cracking. The separated hydrogen is transported to end users.

[0021] The control valve group includes a heating furnace 11, an emergency cut-off valve 12, a pressure reducing valve 13, a manual valve 14, and a gas flowmeter 1 15. There are two pipelines connecting heating furnace 11 and gas flowmeter 1 15. An emergency cut-off valve 12 and a pressure reducing valve 13 are sequentially installed on one pipeline, and a manual valve 14 is installed on the other pipeline.

[0022] Control valve group A includes an emergency cut-off valve A 21, a gas volume regulating valve A 22, a manual valve A 23, and a gas flowmeter 2 24. There are two pipelines connecting the inlet pipeline and gas flowmeter 2 24. An emergency cut-off valve A 21 and a gas volume regulating valve A 22 are sequentially installed on one pipeline, and a manual valve A 23 is installed on the other pipeline.

[0023] The control valve group B includes an emergency cut-off valve B41, a gas flow regulating valve B42, a manual valve B43, and a gas flowmeter B44. There are two pipelines connecting the natural gas expansion power generation unit 3 and the gas flowmeter B44. An emergency cut-off valve B41 and a gas flow regulating valve B42 are installed in sequence on one pipeline, and a manual valve B43 is installed on the other pipeline.

[0024] The natural gas expansion power generation unit 3 includes an expander and a generator. The generator is connected to the expander, and the structure of the expander is twin-screw type or centrifugal type. The expander drives the generator to output electric energy.

[0025] The natural gas cracking furnace 8 is a fluidized bed vertical cracking furnace, and is filled with an iron-nickel catalyst supported by alumina in the form of micron-sized powder.

[0026] The hydrogen separator 10 is a vertical cylindrical methane adsorption tower, and realizes the separation of hydrogen and methane by the pressure swing adsorption principle.

[0027] Example:

[0028] A part of the high-pressure natural gas (4.0 MPa, 20 °C) in the high-pressure pipe network enters the low-pressure pipe network after being reduced in pressure by the control valve group to low-pressure natural gas (0.8 MPa, 5 °C). Another part of the high-pressure natural gas (4.0 MPa, 20 °C) in the high-pressure pipe network enters the regenerator B9 through the control valve group A, performs heat regeneration with the cracking tail gas and is heated up to 60 °C, and then enters the natural gas expansion power generation unit 3 to do work, converting the pressure energy into electric energy and outputting it to the electric heater 7 and the natural gas cracking furnace 8 as energy consumption. A part of the low-pressure natural gas (0.8 MPa, 5 °C) after expansion work enters the low-pressure pipe network, and another part of the low-pressure natural gas (0.8 MPa, 5 °C) enters the purifier 5 through the control valve group B to remove CO2 and moisture impurities. The purified natural gas enters the electric heater 7 and is preheated to 600 °C, enters the interior of the natural gas cracking furnace 8, and is cracked into carbon atoms and hydrogen molecules under the catalytic action of the catalyst. The carbon atoms produce carbon nanotubes on the surface of the catalyst. The un-cracked methane and hydrogen are discharged and enter the regenerator A6, where they perform heat exchange with another part of the low-pressure natural gas (0.8 MPa, 5 °C) after expansion work. The cracked tail gas after heat exchange enters the regenerator B9 to continue heat exchange with the high-pressure natural gas (4.0 MPa, 20 °C), and the cracked tail gas cooled to 25 °C enters the hydrogen separator 10. The separated methane is pressurized and returned to the regenerator A6 for heating, and then enters the natural gas cracking furnace 8 again for cracking. The hydrogen with a purity of more than 99.9% after separation is transported to the client through pipelines or high-pressure hydrogen tank trucks.

[0029] This system generates electricity using the pressure energy of natural gas, converts the electrical energy into heat energy and inputs it into the natural gas cracking system, converts the chemical energy in natural gas into hydrogen energy, improves the overall energy utilization efficiency of the system, reduces the hydrogen production cost. At the same time, since the cracking products contain solid carbon, it has lower carbon emissions compared to other hydrogen production processes.

[0030] This system has the advantages of low carbon emissions, high production efficiency, and high economic benefits, and can effectively solve the problems of high carbon emissions, high energy consumption, low production efficiency, and poor economic benefits faced by the development of existing hydrogen production processes.

[0031] Inspired by the above ideal embodiments of the present utility model, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this utility model. The technical scope of this utility model is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A methane cracking hydrogen production system utilizing the pressure energy of a natural gas gate station, characterized in that, It includes a control valve group, control valve group A, a natural gas expansion power generation unit (3), control valve group B, a purifier (5), regenerator A (6), an electric heater (7), a natural gas cracking furnace (8), regenerator B (9), and a hydrogen separator (10). The intake ends of the control valve group and control valve group A are both connected to the intake pipeline. The outlet end of control valve group A, the natural gas expansion power generation unit (3), and regenerator A (6) are all connected to regenerator B (9). Regenerator A (6) and the electric heater (7) are both connected to the natural gas cracking furnace (8). Regenerator A (6) and regenerator B (9) are both connected to the hydrogen separator (10). Regenerator A (6) and the electric heater (7) are connected to each other. The natural gas expansion power generation unit (3) and control valve group B are both connected to the control valve group (1). Control valve group B and the purifier (5) are connected. The purifier (5) and regenerator A (6) are connected.

2. The methane cracking hydrogen production system using the pressure energy of a natural gas gate station according to claim 1, wherein: The control valve group includes a heating furnace (11), an emergency cut-off valve (12), a pressure reducing valve (13), a manual valve (14), and a gas flowmeter 1 (15). The heating furnace (11) and the gas flowmeter 1 (15) are connected by two pipelines. An emergency cut-off valve (12) and a pressure reducing valve (13) are sequentially installed on one pipeline, and a manual valve (14) is installed on the other pipeline.

3. The methane cracking hydrogen production system using the pressure energy of a natural gas gate station according to claim 1, wherein: The control valve group A includes an emergency cut-off valve A (21), a gas volume regulating valve A (22), a manual valve A (23), and a gas flowmeter 2 (24). The intake pipeline and the gas flowmeter 2 (24) are connected by two pipelines. An emergency cut-off valve A (21) and a gas volume regulating valve A (22) are sequentially installed on one pipeline, and a manual valve A (23) is installed on the other pipeline.

4. The methane cracking hydrogen production system using the pressure energy of a natural gas gate station according to claim 1, wherein: The control valve group B includes an emergency cut-off valve B (41), a gas volume regulating valve B (42), a manual valve B (43), and a gas flowmeter B (44). The natural gas expansion power generation unit (3) and the gas flowmeter B (44) are connected by two pipelines. An emergency cut-off valve B (41) and a gas volume regulating valve B (42) are sequentially installed on one pipeline, and a manual valve B (43) is installed on the other pipeline.

5. The methane cracking hydrogen production system using the pressure energy of a natural gas gate station according to claim 1, characterized in that: The natural gas expansion power generation unit (3) includes an expander and a generator. The generator is connected to the expander. The structure of the expander is a twin-screw type or a centrifugal type.

6. The methane cracking hydrogen production system using the pressure energy of a natural gas gate station according to claim 1, characterized in that: The natural gas cracking furnace (8) is a fluidized bed vertical cracking furnace.

7. The methane cracking hydrogen production system using the pressure energy of a natural gas gate station according to claim 1, wherein: The hydrogen separator (10) is a vertical cylindrical methane adsorption tower.

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