A system and method for producing hydrogen from carbon-based energy using high-temperature supercritical water gasification

Abstract

The present invention discloses a high-temperature supercritical water gasification carbon-based energy hydrogen production system and method, which belongs to the field of clean and efficient energy conversion and utilization. After the solid-liquid-gas separation of the gasification product, the residual carbon in the solid-liquid phase is reused to carry out supercritical hydrothermal combustion in a supercritical hydrothermal combustion reactor, and the chemical energy of carbon-based energy such as coal is fully utilized. The high temperature generated further increases the temperature of the supercritical fluid, and directly undergoes molecular contact mixing and preheating with the coal slurry to be gasified in the supercritical water gasifier, breaking through the temperature resistance limit of the structural alloy of the indirect heat exchange high-pressure equipment, achieving a higher temperature supercritical water gasification reaction, and maximizing the hydrogen production efficiency. The present invention makes full use of the heat generated in the hydrogen production process, reduces energy consumption, and realizes the direct and efficient conversion of carbon-based energy such as coal into hydrogen energy by coupling supercritical hydrothermal combustion and supercritical water gasification, combined with a variety of heat energy reuse measures such as a regenerator, while meeting environmental protection requirements and not emitting any harmful gases such as nitrogen oxides.

Description

Technical Field

[0001] The present invention belongs to the technical field of clean and efficient conversion and utilization of energy, and in particular relates to a system and method for producing hydrogen from carbon-based energy by gasification of high-temperature supercritical water. Background Art

[0002] Hydrogen energy is regarded as the clean energy with the greatest development potential in the 21st century. In the context of global warming and energy transformation, hydrogen energy has been included in the national energy strategic deployment of many countries because of its diverse sources, clean and low-carbon, flexible and efficient, and rich application scenarios. Hydrogen is a secondary energy source. There is no free hydrogen in nature, but it exists in the form of compounds such as hydrocarbons, water and biomass. Therefore, although the reserves are abundant and considerable, it is almost impossible to obtain it directly from nature. Today, the technology of hydrogen production, storage and use is also developing and improving. About 48% of hydrogen in the world comes from natural gas, 30% from oil, 18% from coal, and the rest from water and biomass. The product of hydrogen produced by water electrolysis is clean, but its cost is high, far exceeding fossil fuels, so it is not suitable for large-scale industrial production. my country is a country with coal as its main energy source. Using coal as raw material to produce hydrogen for end users and centrally treating hazardous waste to reduce pollution to the lowest level is a relatively environmentally friendly hydrogen production route. Although the traditional coal gasification hydrogen production process is mature, its disadvantages such as high investment cost, requirement of pure oxygen, high gas separation cost, low hydrogen production efficiency, large CO2 emissions and incomplete utilization of coal chemical energy have hindered large-scale industrial promotion.

[0003] The flame produced by supercritical hydrothermal combustion in water above the critical point is called a hydrothermal flame, which is a more violent oxidation reaction. The local high temperature of more than 1000℃ produced by the hydrothermal flame can accelerate the removal rate and removal rate of organic matter. At the same time, the additional heat released by the combustion can be used as a heat source to maintain its own reaction, without the need for additional heating to maintain the supercritical state. Supercritical gasification technology uses the special physical and chemical properties of water when the temperature and pressure reach or exceed the critical point of water (374.3℃, 22.1MPa) to gasify the carbon, hydrogen, and oxygen elements in coal into hydrogen and carbon dioxide. At the same time, part of the supercritical water is thermochemically decomposed to produce hydrogen, and the chemical energy of coal is directly and efficiently converted into hydrogen energy. Compared with the traditional "burning coal with one fire", the efficiency of power generation and hydrogen production of this technology is significantly improved, and the one-time investment and operating costs after large-scale are significantly reduced. The gasification products can generate electricity, heat, and steam, and can also produce high-value-added chemical products, realizing the efficient, clean, and pollution-free conversion and utilization of coal energy. However, due to the temperature resistance limit of high-pressure reactors and preheater materials, the current supercritical water gasification process is mostly carried out at a temperature of 400-500°C, the hydrogen production efficiency is low, and a considerable part of the energy in the coal is concentrated in the solid phase product after the reaction. Secondly, the low gasification temperature will also lead to the inability to completely degrade the polycyclic aromatic hydrocarbons in the material, and the reaction products need to be further processed, which increases the system process and equipment cost. Therefore, how to increase the operating temperature of the supercritical water gasification process without consuming additional external energy and make full use of the energy contained in the coal is a key issue to further enhance the industrial prospects of the supercritical water gasification process. Summary of the invention

[0004] In order to overcome the shortcomings of the above-mentioned prior art, rationally utilize coal, especially further release considerable energy in the solid phase product after gasification, increase the gasification temperature, improve the hydrogen production efficiency, and reduce the cost of hydrogen production, the purpose of the present invention is to provide a high-temperature supercritical water gasification carbon-based energy hydrogen production system and method with residual carbon water phase combustion internal heat-mineralized residue self-separation function, which can realize efficient and clean production of hydrogen from coal and other carbon-based energy.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A high-temperature supercritical water gasification carbon-based energy hydrogen production system, comprising a cyclonic supercritical water thermal combustion reactor 10 and a supercritical water gasification reactor 3, wherein a coal slurry input pipe 1 is connected to the cold fluid side inlet of a regenerator 2, a hot fluid side outlet of the regenerator 2 is connected to a plurality of gasification nozzles 24 in the supercritical water gasification reactor 3, an outlet of the supercritical water gasification reactor 3 is connected to the hot fluid side inlet of the regenerator 2, a cold fluid side outlet of the regenerator 2 is connected to the inlet of a gas phase separator A5 via a temperature and pressure regulator A4, and a top outlet of the gas phase separator A5 is connected to a To the hydrogen separation and purification unit 6, the bottom outlet is connected to the temperature and pressure regulator B7, the outlet of the temperature and pressure regulator B7 is connected to the inlet of the gas phase separator B8, the bottom outlet of the gas phase separator B8 is connected to the hydrothermal flame nozzle 14 installed on the upper part of the cyclone supercritical hydrothermal combustion reactor 10 through the booster unit 9, the bottom center of the cyclone supercritical hydrothermal combustion reactor 10 is connected to the supercritical water gasification reactor 3 through the supercritical hot fluid guide cone 22; a slurry outlet 23 is provided on the bottom side of the cyclone supercritical hydrothermal combustion reactor 10.

[0007] The supercritical hot fluid guide cone 22 is located at the top of the supercritical water gasification reactor 3 , and a plurality of gasification nozzles 24 are evenly distributed at the same level on the upper side of the supercritical water gasification reactor 3 .

[0008] The hydrothermal flame nozzle 14 is located at the upper side of the supercritical hydrothermal combustion reactor 10 . The hydrothermal flame nozzle 14 has two input ports, one of which is connected to the high-pressure oxidant input pipe 13 , and the other is connected to the outlet of the booster unit 9 .

[0009] The supercritical thermal fluid guide cone 22 is in the shape of a truncated cone, which matches the concave contour at the bottom of the supercritical water thermal combustion reactor 10. The connecting port between the supercritical water gasification reactor 3 and the cyclonic supercritical water thermal combustion reactor 10 is at the center of the truncated cone.

[0010] The pressure-bearing wall A25 of the supercritical water gasification reactor 3 is wrapped by a high-efficiency cooling jacket A20, and the pressure-bearing wall B17 of the supercritical water thermal combustion reactor 10 is wrapped by a high-efficiency cooling jacket B16. The high-efficiency cooling jacket A20 is provided with a coolant inlet 19 and a coolant outlet 21, and the high-efficiency cooling jacket B16 is provided with a coolant inlet 15 and a coolant outlet 18. The structures of the high-efficiency cooling jacket A20 and the high-efficiency cooling jacket B16 can be a jacket, a single-layer spiral channel or a multi-layer spiral channel, etc.

[0011] The slurry outlet 23 is connected to the waste heat recovery and subsequent processing unit 12 via the flow control valve 11 .

[0012] The present invention also provides a hydrogen production method based on the high-temperature supercritical water gasification carbon-based energy hydrogen production system, wherein the product discharged from the supercritical water gasification reactor 3 flows back to the regenerator 2 to preheat the new coal slurry material in the coal slurry input pipe 1, and the preheated new coal slurry is sprayed into the supercritical water gasification reactor 3 through a plurality of gasification nozzles 24 for gasification;

[0013] The product after heat exchange changes its temperature and pressure state in the temperature-regulating and pressure-regulating device A4, and hydrogen separation is achieved in the gas phase separator A5. The remaining product is continuously transported to the temperature-regulating and pressure-regulating device B7 to adjust the temperature and pressure, so as to separate the gas mainly composed of carbon dioxide from the product. The solid phase product mainly composed of residual carbon is pressurized in the boosting unit 9, and then injected into the supercritical hydrothermal combustion reactor 10 together with the oxidant of the high-pressure oxidant inlet pipe 13 through the hydrothermal flame nozzle 14. After ignition, the carbon-based energy is completely released, providing heat for the supercritical thermal fluid required for the subsequent supercritical water gasification, and maintaining the continued reaction in the supercritical water gasification reactor 3.

[0014] When performing the operation of removing the burnt ember slurry, first reduce the flow rate of coal slurry and air to one third of the stable operating flow rate, and then control the flow rate of the burnt ember slurry through the flow control valve 11 to prevent the outflow from being too fast and affecting the outflow stability of the product of the supercritical thermal fluid guide cone 22. The discharged burnt ember slurry enters the waste heat recovery and subsequent treatment unit for further operation.

[0015] The regenerator 2 preheats the new coal slurry material in the coal slurry input pipe 1 to 300-450°C;

[0016] The temperature and pressure state are changed in the thermostat A4, specifically to a temperature range of 80-150°C and a pressure range of 6-10MPa, and the specific values ​​are determined by the flow rate. The thermostat B7 adjusts the temperature and pressure, specifically to a temperature range of 20-60°C and a pressure range of 0.1-3MPa. The booster unit 9 increases the pressure to 25-30MPa.

[0017] The oxidant may be liquid oxygen, oxygen or air, etc., and the coolant may be water, air, heat transfer oil, organic slurry or oxidant, etc.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention couples supercritical hydrothermal combustion and supercritical water gasification, and utilizes the high-temperature supercritical thermal fluid generated by the hydrothermal combustion of the solid phase product after gasification to directly mix and preheat the coal slurry to be gasified in a molecular contact manner, thereby breaking through the temperature resistance limitation of the structural alloy of indirect heat exchange high-pressure equipment, and can achieve a higher temperature supercritical water gasification reaction, thereby maximizing the hydrogen production efficiency.

[0020] 2. The present invention adopts a cyclonic supercritical hydrothermal combustion reactor to ensure cyclonic flow in the reactor. The burnt slag slurry after hydrothermal combustion relies on inertia to be deposited around a supercritical hot fluid guide cone with a special structure, and then flows out through the slurry outlet for further waste heat recovery for subsequent treatment.

[0021] 3. The present invention preheats the new coal slurry through the use of a regenerator, fully recovers the high-quality thermal energy of the gasification product, and achieves the goal of fully increasing the temperature of supercritical water gasification and improving the hydrogen yield without introducing external energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0023] Among them, 1. coal slurry input pipe; 2. regenerator; 3. supercritical water gasification reactor; 4. temperature and pressure regulator A; 5. gas phase separator A; 6. hydrogen separation and purification unit; 7. temperature and pressure regulator B; 8. gas phase separator B; 9. booster unit; 10. cyclone supercritical hydrothermal combustion reactor; 11. flow control valve; 12. waste heat recovery and subsequent treatment unit; 13. high-pressure oxidant input pipe; 14. hydrothermal flame nozzle; 15. coolant inlet; 16. high-efficiency cooling jacket B; 17. pressure wall B; 18. coolant outlet; 19. coolant inlet; 20. high-efficiency cooling jacket A; 21. coolant outlet; 22. supercritical thermal fluid guide cone; 23. slurry outlet; 24. gasification nozzle; 25. pressure wall A. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0025] See also Figure 1 The outlet of the supercritical water gasification reactor 3 is connected to the inlet of the heat fluid side of the regenerator 2, the outlet of the heat fluid side of the regenerator 2 is connected to the inlet of the gas phase separator A5 through the temperature regulating and pressure regulating device A4, the top outlet of the gas phase separator A5 is connected to the hydrogen separation and purification unit 6, and the bottom outlet is connected to the temperature regulating and pressure regulating device B7, the outlet of the temperature regulating and pressure regulating device B7 is connected to the gas phase separator B8, and the bottom outlet of the gas phase separator B8 is connected to the high temperature oxidant inlet pipe 13 through the booster unit 9 installed on the cyclone supercritical water thermal combustion The hydrothermal flame nozzle 14 is at the top of the supercritical hydrothermal combustion reactor 10, and the bottom center of the swirl supercritical hydrothermal combustion reactor 10 is connected to the supercritical water gasification reactor 3 through the supercritical hot fluid guide cone 22; a slurry outlet 23 is provided on the bottom side of the swirl supercritical hydrothermal combustion reactor 10, which is connected to the waste heat recovery and subsequent treatment unit 12 through the flow control valve 11; the coal slurry input pipe 1 is connected to the cold fluid side inlet of the regenerator 2, and the hot fluid side outlet of the regenerator 2 is connected to a plurality of gasification nozzles 24.

[0026] During operation, the product discharged from the supercritical water gasification reactor 3 flows back to the regenerator 2 to preheat the new coal slurry material in the coal slurry input pipe 1. The preheated new coal slurry is sprayed into the supercritical water gasification reactor 3 through a plurality of gasification nozzles 24 at the same horizontal height on the upper side of the supercritical water gasification reactor 3 for gasification. The product after heat exchange further changes the temperature and pressure state in the temperature and pressure regulator A4, and hydrogen separation is achieved in the gas phase separator A5. The remaining product continues to be transported to the temperature and pressure regulator B7 to further adjust the temperature and pressure, so that the gas mainly composed of carbon dioxide is separated from the product. Therefore, after the solid phase of the product mainly composed of residual carbon is pressurized to 25MPa in the booster unit 9, it is re-injected into the supercritical hydrothermal combustion reactor 10 together with the oxidant of the high-pressure oxidant input pipe 13 through the hydrothermal flame nozzle 14, and after ignition, the carbon-based energy is further fully released, providing heat for the supercritical thermal fluid required for subsequent supercritical water gasification, and maintaining the continuation of the reaction in the supercritical water gasification reactor 3. During operation, high-efficiency cooling jacket A20 and high-efficiency cooling jacket B16 remain open to prevent wall overheating.

[0027] After a period of stable operation, the composition of the outflow from the burnt slag slurry outlet 23 is observed to determine whether to remove the burnt slag slurry. When the device removes the burnt slag slurry, the flow rate of the coal slurry and the air is first reduced to one-third of the stable operation flow rate to avoid additional waste caused by insufficient reaction. The flow rate of the burnt slag slurry is then controlled by the flow control valve 11 to prevent the outflow from being too fast and affecting the stability of the product outflow of the supercritical thermal fluid guide cone 22. The discharged burnt slurry enters the waste heat recovery and subsequent treatment unit for further operation. The high-efficiency cooling jacket A20 and the high-efficiency cooling jacket B16 are kept open to prevent the wall from overheating.

[0028] In summary, the present invention has the function of self-separation of the residual carbon water phase combustion internal heat and mineralized residue. After the solid-liquid-gas separation of the gasification product, the residual carbon in the solid and liquid phases is reused to carry out supercritical hydrothermal combustion in a supercritical hydrothermal combustion reactor, and the chemical energy of carbon-based energy such as coal is fully utilized. The high temperature generated further increases the temperature of the supercritical fluid, and directly undergoes molecular contact mixing and preheating with the coal slurry to be gasified in the supercritical water gasification reactor, breaking through the temperature resistance limit of the structural alloy of the indirect heat exchange high-pressure equipment, achieving a higher temperature supercritical water gasification reaction, and maximizing the hydrogen production efficiency. The entire process flow includes the use of a regenerator and a waste heat recovery and post-processing unit, which fully utilizes the heat generated in the hydrogen production process and reduces energy consumption. The present invention achieves the direct and efficient conversion of carbon-based energy such as coal into hydrogen energy by coupling supercritical hydrothermal combustion and supercritical water gasification, combined with a variety of heat energy reuse measures such as a regenerator, while meeting environmental protection requirements and not emitting any harmful gases such as nitrogen oxides.

Claims

1. A high-temperature supercritical water gasification carbon-based energy hydrogen production system, comprising a cyclonic supercritical water thermal combustion reactor (10) and a supercritical water gasification reactor (3), characterized in that: The coal slurry input pipe (1) is connected to the cold fluid side inlet of the regenerator (2), the hot fluid side outlet of the regenerator (2) is connected to a plurality of gasification nozzles (24) in the supercritical water gasification reactor (3), the outlet of the supercritical water gasification reactor (3) is connected to the hot fluid side inlet of the regenerator (2), the cold fluid side outlet of the regenerator (2) is connected to the inlet of the gas phase separator A (5) through the temperature regulating and pressure regulating device A (4), the top outlet of the gas phase separator A (5) is connected to the hydrogen separation and purification unit (6), and the bottom outlet is connected to the temperature regulating and pressure regulating device B ( 7), the outlet of the temperature and pressure regulator B (7) is connected to the inlet of the gas phase separator B (8), the bottom outlet of the gas phase separator B (8) is connected to the water thermal flame nozzle (14) installed on the upper part of the cyclone type supercritical hydrothermal combustion reactor (10) through the booster unit (9), and the bottom center of the cyclone type supercritical hydrothermal combustion reactor (10) is connected to the supercritical water gasification reactor (3) through the supercritical hot fluid guide cone (22); the bottom side of the cyclone type supercritical hydrothermal combustion reactor (10) is provided with a slurry outlet (23); The supercritical hot fluid guide cone (22) is located at the top of the supercritical water gasification reactor (3), and a plurality of gasification nozzles (24) are evenly distributed at the same horizontal height on the upper side of the supercritical water gasification reactor (3); the hydrothermal flame nozzle (14) is located on the upper side of the supercritical hydrothermal combustion reactor (10), and the hydrothermal flame nozzle (14) has two input ports, one of which is connected to the high-pressure oxidant input pipe (13) and the other is connected to the outlet of the booster unit (9).

2. The high temperature supercritical water gasification carbon-based energy hydrogen production system according to claim 1 is characterized in that: The supercritical thermal fluid guide cone (22) is in the shape of a truncated cone, matching the concave contour of the bottom of the supercritical water thermal combustion reactor (10), and the connecting port between the supercritical water gasification reactor (3) and the cyclonic supercritical water thermal combustion reactor (10) is at the center of the truncated cone.

3. The high temperature supercritical water gasification carbon-based energy hydrogen production system according to claim 1 is characterized in that: The pressure-bearing wall A (25) of the supercritical water gasification reactor (3) is wrapped by a high-efficiency cooling jacket A (20), and the pressure-bearing wall B (17) of the supercritical water thermal combustion reactor (10) is wrapped by a high-efficiency cooling jacket B (16). The high-efficiency cooling jacket A (20) is provided with a coolant inlet (19) and a coolant outlet (21), and the high-efficiency cooling jacket B (16) is provided with a coolant inlet (15) and a coolant outlet (18). The structures of the high-efficiency cooling jacket A (20) and the high-efficiency cooling jacket B (16) are jackets, single-layer spiral channels, or multi-layer spiral channels.

4. The high temperature supercritical water gasification carbon-based energy hydrogen production system according to claim 3 is characterized in that: The slurry outlet (23) is connected to the waste heat recovery and subsequent processing unit (12) via a flow control valve (11).

5. The hydrogen production method based on the high-temperature supercritical water gasification carbon-based energy hydrogen production system according to claim 1 is characterized in that: The product discharged from the supercritical water gasification reactor (3) flows back to the regenerator (2) to preheat the new coal slurry material in the coal slurry input pipe (1); the preheated new coal slurry is sprayed into the supercritical water gasification reactor (3) through a plurality of gasification nozzles (24) for gasification; The product after heat exchange changes its temperature and pressure state in the temperature and pressure regulator A (4), and hydrogen is separated in the gas phase separator A (5). The remaining product is continuously transported to the temperature and pressure regulator B (7) to adjust the temperature and pressure, so as to separate the gas mainly composed of carbon dioxide from the product. The solid phase product mainly composed of residual carbon is pressurized in the booster unit (9), and then injected into the supercritical hydrothermal combustion reactor (10) together with the oxidant from the high-pressure oxidant inlet pipe (13) through the hydrothermal flame nozzle (14). After ignition, the carbon-based energy is completely released, providing heat for the supercritical thermal fluid required for the subsequent supercritical water gasification, thereby maintaining the continuation of the reaction in the supercritical water gasification reactor (3).

6. The method for producing hydrogen according to claim 5, characterized in that: When the operation of removing the burnt ember slurry is performed, the flow rates of the coal slurry and the air are first reduced to one third of the stable operating flow rate, and then the flow rate of the burnt ember slurry is controlled by the flow control valve (11) to prevent the outflow from being too fast and affecting the outflow stability of the product of the supercritical thermal fluid guide cone (22). The discharged burnt ember slurry enters the waste heat recovery and subsequent treatment unit for further operation.

7. The method for producing hydrogen according to claim 5, characterized in that: The regenerator (2) preheats the new coal slurry material in the coal slurry input pipe (1) to 300-450°C; the temperature and pressure state are changed in the temperature and pressure regulator A (4) to a temperature range of 80-150°C and a pressure range of 6-10MPa; the temperature and pressure regulator B (7) adjusts the temperature and pressure to a temperature range of 20-60°C and a pressure range of 0.1-3MPa; and the booster unit (9) increases the pressure to 25-30MPa.

8. The method for producing hydrogen according to claim 5, characterized in that: The oxidant is oxygen or air, and the coolant is water, air or heat transfer oil.

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