Integrated system for methane hydrate exploitation, hydrogen production by natural gas reforming and carbon capture and storage

Abstract

The application discloses an integrated system for combustible ice mining, natural gas reforming hydrogen production and carbon capture and storage, which is arranged on an offshore operation platform and comprises a combustible ice mining unit, a natural gas combined heat and power unit, a reforming hydrogen production unit, an air separation unit, an ammonia production unit and a carbon storage unit. Compared with the prior art, the integrated system integrates the functions of combustible ice mining, hydrogen production, ammonia production, carbon dioxide capture and storage, and realizes in-situ utilization of combustible ice. The combustible ice and seawater required by the integrated system can be obtained in-situ, so that transportation cost is saved, and carbon emission caused by the transportation process is reduced. In addition, the carbon dioxide generated in the natural gas combustion process can be stored in the seabed in-situ, so that the carbon dioxide storage cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of energy utilization technology, and in particular to an integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage. Background Technology

[0002] Natural gas hydrate, commonly known as "combustible ice," is an ice-like substance formed by water and a guest gas, primarily composed of natural gas, under high pressure and low temperature conditions. Its reserves are enormous, and it is hailed as one of the most promising alternative energy sources of the 21st century. Currently, combustible ice requires transportation to a specific location via liquefied natural gas (LNG) before it can be utilized. Because hydrogen energy has the advantages of high calorific value and zero carbon emissions during its utilization, hydrogen production is an ideal secondary energy production method. In natural gas-to-hydrogen technology, reforming has high energy utilization efficiency, but it also involves significant carbon dioxide emissions. Therefore, "blue hydrogen," a technology combining natural gas-to-hydrogen production with carbon sequestration, is the mainstream practice. However, traditional "blue hydrogen" production methods are not adapted to local conditions, resulting in substantial resource consumption and carbon emissions during natural gas transportation and carbon dioxide emission reduction. Summary of the Invention

[0003] The purpose of this invention is to provide an integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage, which integrates combustible ice extraction, hydrogen and ammonia production, and carbon dioxide capture and storage functions into one system, so as to realize the on-site utilization of combustible ice with zero carbon emissions.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention discloses an integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage, which is installed on an offshore operating platform and includes a combustible ice extraction unit, a natural gas cogeneration unit, a reforming for hydrogen production unit, an air separation unit, an ammonia production unit, and a carbon storage unit.

[0006] The combustible ice extraction unit is used to extract natural gas hydrate to obtain natural gas; the natural gas cogeneration unit is connected to the combustible ice extraction unit and is used to generate heat energy and store electrical energy by burning natural gas; the reforming hydrogen production unit is connected to the combustible ice extraction unit and uses the natural gas obtained from the combustible ice extraction unit and the heat energy generated by the natural gas cogeneration unit to perform seawater evaporation and reforming to produce hydrogen; the separation unit uses the electrical energy stored in the natural gas cogeneration unit to separate nitrogen and oxygen from the air by cryogenic liquefaction and stores them separately; the ammonia production unit is connected to both the reforming hydrogen production unit and the separation unit and uses the heat energy generated by the natural gas cogeneration unit to produce ammonia; the carbon sequestration unit is connected to both the natural gas cogeneration unit and the hydrogen production unit and captures and stores carbon dioxide generated during the natural gas combustion and reforming hydrogen production processes.

[0007] Preferably, the combustible ice extraction unit includes a drilling and extraction device, a purification device, and a natural gas storage tank connected in sequence.

[0008] Preferably, the combustible ice extraction unit further includes an electrically controlled flow valve, the input end of which is connected to the natural gas storage tank, the first output end of which is connected to the natural gas cogeneration unit, and the second output end of which is connected to the reforming hydrogen production unit, so as to distribute natural gas to the natural gas cogeneration unit and the reforming hydrogen production unit as needed.

[0009] Preferably, the natural gas combined heat and power unit includes a power generation and heating gas turbine, a water removal device, a battery bank, a first heat exchanger, a second heat exchanger, and a third heat exchanger; the power generation and heating gas turbine is connected to the first output terminal of the electrically controlled flow valve to receive natural gas; the water removal device is used to filter out moisture after gas combustion; the battery bank is used to store the electrical energy obtained by the power generation and heating gas turbine; and the first, second, and third heat exchangers are all used to supply the heat energy generated by the power generation and heating gas turbine to other devices.

[0010] Preferably, the reforming hydrogen production unit includes an evaporator, a mixer, a reforming hydrogen production device, and a carbon dioxide capture device; the evaporator is used to evaporate seawater, and the first heat exchanger supplies heat to the evaporator; the two input terminals of the mixer are respectively connected to the second output terminal of the electrically controlled flow valve and the output terminal of the evaporator to mix the water vapor obtained from the seawater evaporation with natural gas; the input terminal of the reforming hydrogen production device is connected to the output terminal of the mixer to obtain hydrogen and carbon dioxide through reforming hydrogen production, and the second heat exchanger supplies heat to the reforming hydrogen production device; the carbon dioxide capture device is used to separate carbon dioxide and hydrogen from the output products of the reforming hydrogen production device.

[0011] Preferably, the air separation unit includes an air separation device, an oxygen storage tank, and a nitrogen storage tank. The air separation device separates nitrogen and oxygen from the air and injects them into the oxygen storage tank and the nitrogen storage tank, respectively. The oxygen storage tank is connected to the power generation and heating gas turbine to supply oxygen to the power generation and heating gas turbine.

[0012] Preferably, the ammonia production unit includes an ammonia production device, a hydrogen storage tank, and an ammonia storage tank. The hydrogen storage tank is connected to both the carbon dioxide capture device and the ammonia production device to receive hydrogen output from the carbon dioxide capture device and supply hydrogen to the ammonia production device. The nitrogen storage tank is connected to the ammonia production device to supply nitrogen to the ammonia production device. The ammonia production device is used to synthesize ammonia from hydrogen and nitrogen, and the third heat exchanger provides heat to the ammonia production device. The ammonia production device is connected to the ammonia storage tank to store the produced ammonia in the ammonia storage tank.

[0013] Preferably, the carbon sequestration unit includes a carbon dioxide storage tank and a carbon dioxide sequestration device. The carbon dioxide storage tank is connected to the dehydration device and the carbon dioxide capture device to receive carbon dioxide output from the dehydration device and the carbon dioxide capture device. The carbon sequestration device is connected to the carbon dioxide storage tank to sequester carbon dioxide.

[0014] Preferably, the integrated system for combustible ice mining, natural gas reforming for hydrogen production and carbon capture and storage further includes an ammonia conveying unit, which is used to convey ammonia from the ammonia storage tank to the shore.

[0015] Preferably, the ammonia transport unit includes at least one of a transport ship and a gas pipeline, wherein the transport ship is used to transport the ammonia storage tank to the shore, and the gas pipeline is used to transport only the ammonia in the ammonia storage tank to the shore.

[0016] The present invention achieves the following technical effects compared to the prior art:

[0017] This invention's integrated system combines the functions of methane hydrate extraction, hydrogen and ammonia production, and carbon dioxide capture and storage, enabling the on-site utilization of methane hydrate. The methane hydrate and seawater required for this integrated system can both be sourced locally, saving transportation costs and reducing carbon emissions during transport. Furthermore, the carbon dioxide produced during natural gas combustion can be stored on the seabed, lowering the cost of carbon dioxide storage. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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.

[0019] Figure 1 This is a schematic diagram of an integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage, according to an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached drawings: 11-Drilling and production equipment; 12-Purification equipment; 13-Natural gas storage tank; 14-Electrically controlled flow valve; 21-Power generation and heating gas turbine; 22-Water removal equipment; 23-Battery pack; 24-First heat exchanger; 25-Second heat exchanger; 26-Third heat exchanger; 31-Evaporation equipment; 32-Mixer; 33-Reforming hydrogen production unit; 34-Carbon dioxide capture unit; 41-Air separation unit; 42-Oxygen storage tank; 43-Nitrogen storage tank; 51-Ammonia production unit; 52-Hydrogen storage tank; 53-Ammonia storage tank; 61-Carbon dioxide storage tank; 62-Carbon dioxide sealing device; 71-Compressor. Detailed Implementation

[0021] 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.

[0022] The purpose of this invention is to provide an integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage, which integrates combustible ice extraction, hydrogen and ammonia production, and carbon dioxide capture and storage functions into one system, achieving zero-carbon emission on-site utilization of combustible ice.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Reference Figure 1 This embodiment provides an integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage, which is set on an offshore operating platform and includes a combustible ice extraction unit, a natural gas cogeneration unit, a reforming for hydrogen production unit, an air separation unit, an ammonia production unit, and a carbon storage unit.

[0025] The combustible ice extraction unit is used to extract natural gas from natural gas hydrates. The natural gas combined heat and power (CHP) unit is connected to the combustible ice extraction unit to generate heat and store electricity by burning natural gas. The reforming hydrogen production unit is connected to the combustible ice extraction unit, using the natural gas obtained from the extraction unit and the heat generated by the CHP unit for seawater evaporation and reforming to produce hydrogen. The separation unit uses the electricity stored in the CHP unit to separate nitrogen and oxygen from the air using cryogenic liquefaction and stores them separately. The ammonia production unit is connected to both the reforming hydrogen production unit and the separation unit, using the heat generated by the CHP unit to produce ammonia. The carbon sequestration unit is connected to both the CHP unit and the hydrogen production unit to capture and store carbon dioxide generated during natural gas combustion and reforming hydrogen production.

[0026] This integrated system combines the functions of methane hydrate extraction, reforming for hydrogen production, ammonia production, and carbon dioxide capture and storage, enabling the on-site utilization of methane hydrate. Both the methane hydrate and seawater required for this integrated system can be sourced locally, saving transportation costs and reducing carbon emissions during transport. Furthermore, the carbon dioxide produced during natural gas combustion can be stored on the seabed, lowering the cost of carbon dioxide storage.

[0027] As one possible example, a combustible ice extraction unit includes a drilling and extraction unit 11, a purification unit 12, and a natural gas storage tank 13 connected in sequence. The drilling and extraction unit 11 is used to extract combustible ice, the purification unit 12 is used to purify the extracted combustible ice to obtain natural gas, and the natural gas storage tank 13 is used for the natural gas.

[0028] Specifically, the drilling and production unit 11 can adopt a relatively mature depressurization production unit. This unit is based on deepwater drilling platform technology, which fractures the formation to the free gas layer of the hydrate deposit, and arranges structures such as casing, wellbore, and sand control netting to obtain natural gas through pumping. The purification unit 12 is suitable for removing impurities, water, and some liquid light hydrocarbons from the combustible ice to obtain natural gas.

[0029] As a possible example, the combustible ice extraction unit also includes an electrically controlled flow valve 14. The input end of the electrically controlled flow valve 14 is connected to the natural gas storage tank 13, the first output end of the electrically controlled flow valve 14 is connected to the natural gas cogeneration unit, and the second output end of the electrically controlled flow valve 14 is connected to the reforming hydrogen production unit, so as to distribute natural gas to the natural gas cogeneration unit and the reforming hydrogen production unit as needed, thereby playing the role of distributing the flow of natural gas.

[0030] As one possible example, a natural gas combined heat and power (CHP) unit includes a power generation and heating gas turbine 21, a dehydration device 22, a battery bank 23, a first heat exchanger 24, a second heat exchanger 25, and a third heat exchanger 26. The power generation and heating gas turbine 21 is connected to the first output terminal of an electrically controlled flow valve 14 to receive natural gas. The dehydration device 22 is used to filter out moisture after gas combustion. The battery bank 23 is used to store the electrical energy generated by the power generation and heating gas turbine 21. The first heat exchanger 24, the second heat exchanger 25, and the third heat exchanger 26 are all used to supply the heat energy generated by the power generation and heating gas turbine 21 to other devices.

[0031] The first heat exchanger 24 provides a temperature of over 100°C required by the evaporation unit 31. The second heat exchanger 25, after being pressurized by the compressor 71, provides a temperature of 900-1000°C required by the reforming hydrogen production unit 33. The third heat exchanger 26 provides a temperature of around 500°C required by the ammonia production unit 51.

[0032] As one possible example, the reforming hydrogen production unit includes an evaporator 31, a mixer 32, a reforming hydrogen production unit 33, and a carbon dioxide capture unit 34. The evaporator 31 evaporates seawater, and a first heat exchanger 24 heats the evaporator 31. The two inputs of the mixer 32 are connected to the second output of an electrically controlled flow valve 14 and the output of the evaporator 31, respectively, to mix the water vapor obtained from the seawater evaporation with natural gas. The input of the reforming hydrogen production unit 33 is connected to the output of the mixer 32 to obtain hydrogen and carbon dioxide through reforming, and a second heat exchanger 25 heats the reforming hydrogen production unit 33. The carbon dioxide capture unit 34 separates carbon dioxide and hydrogen from the output products of the reforming hydrogen production unit 33.

[0033] The ratio of natural gas to steam introduced into mixer 32 is 1:2, and the reforming hydrogen production unit 33 uses a membrane reactor and a nickel-supported alumina catalyst.

[0034] As one possible example, the air separation unit includes an air separation device 41, an oxygen storage tank 42, and a nitrogen storage tank 43. The air separation device 41 separates nitrogen and oxygen from the air and injects them into the oxygen storage tank 42 and the nitrogen storage tank 43, respectively. The oxygen storage tank 42 is connected to the power generation and heating gas turbine 21 to supply oxygen to the power generation and heating gas turbine 21.

[0035] The air separation device 41 uses the electrical energy of the battery pack 23 for cooling, liquefies the compressed air, and separates the air by distillation. The separated nitrogen and oxygen are stored in the nitrogen storage tank 43 and the oxygen storage tank 42, respectively.

[0036] As one possible example, the ammonia production unit includes an ammonia production device 51, a hydrogen storage tank 52, and an ammonia storage tank 53. The hydrogen storage tank 52 is connected to both a carbon dioxide capture device 34 and the ammonia production device 51 to receive hydrogen output from the carbon dioxide capture device 34 and supply hydrogen to the ammonia production device 51. A nitrogen storage tank 43 is connected to the ammonia production device 51 to supply nitrogen to the ammonia production device 51. The ammonia production device 51 is used to synthesize ammonia from hydrogen and nitrogen, and a third heat exchanger 26 provides heat to the ammonia production device 51. The ammonia production device 51 is connected to the ammonia storage tank 53 to store the produced ammonia.

[0037] As one possible example, the carbon sequestration unit includes a carbon dioxide storage tank 61 and a carbon dioxide sequestration device 62. The carbon dioxide storage tank 61 is connected to a dehydration device 22 and a carbon dioxide capture device 34 to receive carbon dioxide output from the dehydration device 22 and the carbon dioxide capture device 34. The carbon sequestration device is connected to the carbon dioxide storage tank 61 to sequester carbon dioxide.

[0038] Specifically, the carbon dioxide sequestration technology employs the carbon dioxide sequestration method described in patent publication number CN116255198A. The carbon sequestration unit sequesters the carbon dioxide generated from the on-site combustion of extracted natural gas on the seabed, thereby reducing sequestration costs.

[0039] As a possible example, an ammonia conveying unit is also included, which is used to convey ammonia from ammonia storage tank 53 to the shore.

[0040] As one possible example, the ammonia transport unit includes at least one of a transport ship and a gas pipeline. The transport ship is used to transport ammonia storage tank 53 to the shore, and the gas pipeline is used to transport only the ammonia in ammonia storage tank 53 to the shore. In actual operation, a receiving wharf can be constructed at the shore to improve the transshipment efficiency of ammonia storage tank 53.

[0041] It is understood that in this embodiment, a compressor 71 is installed at the inlet of each storage tank. The power source of the compressor 71 can be the electricity stored in the battery pack 23, or the kinetic energy of the power generation and heating gas turbine 21 can be transmitted to the compressor 71 through mechanical transmission.

[0042] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage, characterized in that, Located on an offshore operating platform, it includes a combustible ice extraction unit, a natural gas cogeneration unit, a reforming hydrogen production unit, an air separation unit, an ammonia production unit, and a carbon sequestration unit; The combustible ice extraction unit is used to extract natural gas hydrate to obtain natural gas; the natural gas cogeneration unit is connected to the combustible ice extraction unit and is used to generate heat energy and store electrical energy by burning natural gas; the reforming hydrogen production unit is connected to the combustible ice extraction unit and uses the natural gas obtained from the combustible ice extraction unit and the heat energy generated by the natural gas cogeneration unit to perform seawater evaporation and reforming to produce hydrogen; the air separation unit uses the electrical energy stored in the natural gas cogeneration unit to separate nitrogen and oxygen from the air by cryogenic liquefaction and store them separately; The ammonia production unit is connected to the reforming hydrogen production unit and the air separation unit respectively, and uses the heat energy generated by the natural gas cogeneration unit to produce ammonia; the carbon sequestration unit is connected to the natural gas cogeneration unit and the hydrogen production unit respectively, and captures and stores the carbon dioxide generated during the natural gas combustion process and the reforming hydrogen production process; The combustible ice extraction unit includes a drilling and extraction device, a purification device, and a natural gas storage tank connected in sequence. The combustible ice extraction unit also includes an electrically controlled flow valve. The input end of the electrically controlled flow valve is connected to the natural gas storage tank, the first output end of the electrically controlled flow valve is connected to the natural gas cogeneration unit, and the second output end of the electrically controlled flow valve is connected to the reforming hydrogen production unit, so as to distribute natural gas to the natural gas cogeneration unit and the reforming hydrogen production unit as needed. The natural gas combined heat and power (CHP) unit includes a power generation and heating gas turbine, a water removal device, a battery bank, a first heat exchanger, a second heat exchanger, and a third heat exchanger. The power generation and heating gas turbine is connected to the first output terminal of the electrically controlled flow valve to receive natural gas. The water removal device is used to filter out moisture after gas combustion. The battery bank is used to store the electrical energy obtained by the power generation and heating gas turbine. The first, second, and third heat exchangers are all used to supply the heat energy generated by the power generation and heating gas turbine to other devices. The reforming hydrogen production unit includes an evaporator, a mixer, a reforming hydrogen production unit, and a carbon dioxide capture device; the evaporator is used to evaporate seawater, and the first heat exchanger supplies heat to the evaporator; the two input terminals of the mixer are respectively connected to the second output terminal of the electrically controlled flow valve and the output terminal of the evaporator to mix the water vapor obtained from the seawater evaporation with natural gas; The input end of the reforming hydrogen production unit is connected to the output end of the mixer to obtain hydrogen and carbon dioxide through reforming. The second heat exchanger provides heat to the reforming hydrogen production unit. The carbon dioxide capture device is used to separate carbon dioxide and hydrogen from the output products of the reforming hydrogen production unit. The air separation unit includes an air separation device, an oxygen storage tank, and a nitrogen storage tank. The air separation device separates nitrogen and oxygen from the air and injects them into the oxygen storage tank and the nitrogen storage tank, respectively. The oxygen storage tank is connected to the power generation and heating gas turbine to supply oxygen to the power generation and heating gas turbine.

2. The integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage according to claim 1, characterized in that, The ammonia production unit includes an ammonia production device, a hydrogen storage tank, and an ammonia storage tank. The hydrogen storage tank is connected to both the carbon dioxide capture device and the ammonia production device to receive hydrogen output from the carbon dioxide capture device and supply hydrogen to the ammonia production device. The nitrogen storage tank is connected to the ammonia production device to supply nitrogen to the ammonia production device. The ammonia production device is used to synthesize ammonia from hydrogen and nitrogen, and the third heat exchanger provides heat to the ammonia production device. The ammonia production device is connected to the ammonia storage tank to store the produced ammonia in the ammonia storage tank.

3. The integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage according to claim 2, characterized in that, The carbon sequestration unit includes a carbon dioxide storage tank and a carbon dioxide sequestration device. The carbon dioxide storage tank is connected to the dehydration device and the carbon dioxide capture device to receive carbon dioxide output from the dehydration device and the carbon dioxide capture device. The carbon sequestration device is connected to the carbon dioxide storage tank to sequester carbon dioxide.

4. The integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage according to claim 3, characterized in that, It also includes an ammonia conveying unit, which is used to convey ammonia from the ammonia storage tank to the shore.

5. The integrated system for combustible ice extraction, natural gas reforming for hydrogen production, and carbon capture and storage according to claim 4, characterized in that, The ammonia transport unit includes at least one of a transport ship and a gas pipeline, wherein the transport ship is used to transport the ammonia storage tank to the shore, and the gas pipeline is used to transport only the ammonia in the ammonia storage tank to the shore.

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