Combined heat and power generation coupled natural gas reforming hydrogen production system and control method

Abstract

The invention relates to the technical field of fossil energy hydrogen production, and discloses a combined heat and power generation coupled natural gas reforming hydrogen production system and a control method. The combined heat and power generation coupled natural gas reforming hydrogen production system comprises a raw material pretreatment unit, a natural gas conversion unit, a combined heat and power generation unit, a medium and low temperature conversion unit and a gas separation unit, the combined heat and power generation coupling natural gas hydrogen production control method comprises the steps that the heat and power distribution ratio of combined heat and power generation is calculated and compared with the water vapor demand quantity under the steady-state working condition, operation selection is conducted according to the comparison result, the heat and power distribution ratio of combined heat and power generation is calculated, and the final distribution ratio of heat and power is obtained. And stable supply of steam and electric quantity of the combined heat and power generation unit is realized. The gradient utilization of energy is realized, the waste heat utilization diversity is increased, and the heat utilization efficiency of the natural gas hydrogen production process is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production from fossil energy, and in particular relates to a heat and power cogeneration coupled natural gas reforming hydrogen production system and a control method. Background Art

[0002] In the process of natural gas hydrogen production, the raw natural gas is desulfurized and enters the natural gas conversion unit to generate crude synthesis gas, and then medium and low temperature conversion reactions and hydrogen purification are carried out in sequence. Among them, the high-quality heat generated by the natural gas steam reforming hydrogen production process is often used for by-product steam, but the insufficient heat utilization leads to excessively high flue gas outlet temperature; at the same time, the heat quality of the medium and low temperature conversion unit is low, resulting in low energy utilization efficiency in the natural gas hydrogen production process. Cogeneration is a system that can provide both heat and electricity. It achieves energy saving by capturing heat that would otherwise be wasted and converting it into heat or electricity. However, in the coupling process of cogeneration and natural gas hydrogen production, the coordinated control of cogeneration and natural gas hydrogen production processes, through the dynamic allocation of heat and electricity, to achieve a stable supply of by-product steam and electricity, is a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the deficiencies of the prior art, the present invention provides a cogeneration coupled natural gas reforming hydrogen production system and control method, in which a cogeneration device is coupled to the existing natural gas hydrogen production system. After the cogeneration device is added, high-pressure and low-pressure steam turbines are used for power generation in sequence according to the quality of thermal energy, thereby improving the cascade utilization of heat in the natural gas hydrogen production process and realizing efficient utilization of energy in the natural gas hydrogen production process. In addition, the flow control valves inside the cogeneration system are connected in communication, and when the by-product steam does not match its preset amount, the saturated steam distribution amount can be adjusted in time, and the heat and electricity in the natural gas hydrogen production process are coordinated to control the thermal energy and electricity, so as to achieve a stable supply of steam and electricity.

[0004] (II) Technical solution

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a cogeneration coupled natural gas reforming hydrogen production system, the system comprising: a natural gas conversion unit, a cogeneration unit and a medium-low temperature conversion unit connected to the natural gas conversion unit, the inlets of the cogeneration unit and the medium-low temperature conversion unit are connected to the outlet of the natural gas conversion unit, the inlets of the natural gas conversion unit and the medium-low temperature conversion unit are connected to the outlet of the cogeneration unit, and the inlet of the cogeneration unit is connected to the outlet of the medium-low temperature conversion unit; a gas separation unit, the inlet of the gas separation unit is connected to the outlet of the medium-low temperature conversion unit.

[0006] Furthermore, the natural gas conversion unit comprises: a conversion preheater, a natural gas conversion furnace and an air blower, wherein the inlet of the conversion preheater is connected to the outlet of the desulfurization device, the outlet of the conversion preheater is connected to the inlet of the natural gas conversion furnace, the natural gas conversion furnace is provided with an air input pipeline, the air blower is located on the air input pipeline, and the outlet of the air blower is connected to the inlet of the natural gas conversion furnace;

[0007] The cogeneration unit comprises:

[0008] A waste heat boiler, wherein the inlet of the waste heat boiler is connected to the outlet of the natural gas reformer;

[0009] and a conversion preheater connected to the waste heat boiler, wherein the inlet of the conversion preheater is connected to the outlet of the waste heat boiler, and is used to transport the hot stream conversion gas at the outlet of the hot stream of the waste heat boiler to the conversion preheater;

[0010] A high-pressure steam turbine, wherein the high-pressure steam turbine inlet is connected to the cold stream outlet of the waste heat boiler, a heat exchanger is arranged at the high-pressure steam turbine outlet, and the high-pressure steam turbine outlet is connected to the heat exchanger inlet, a low-pressure steam turbine is arranged on the heat exchanger outlet pipeline, and the heat exchanger outlet is connected to the low-pressure steam turbine inlet;

[0011] A booster pump, wherein the booster pump outlet is connected to the waste heat boiler inlet, a condensate preheater is provided on the booster pump inlet pipeline, and the condensate preheater outlet is connected to the booster pump inlet, the condensate preheater inlet is connected to the low-pressure steam turbine outlet, and a condensate input pipeline is provided on the condensate preheater inlet;

[0012] A steam superheater, wherein the steam superheater inlet is connected to the waste heat boiler outlet, and the steam superheater outlet is provided with a steam delivery pipeline;

[0013] The medium-low temperature conversion unit comprises: the conversion preheater, the heat exchanger, and a medium-low temperature conversion device connected to the conversion preheater and the heat exchanger, wherein the medium-low temperature conversion device is arranged on the outlet pipeline of the conversion preheater, and the inlet of the medium-low temperature conversion device is connected to the outlet of the conversion preheater, and the outlet of the medium-low temperature conversion device is connected to the inlet of the heat exchanger;

[0014] The gas separation unit comprises: a cooler, wherein the cooler inlet is connected to the heat exchanger outlet;

[0015] A gas-liquid separator, wherein the gas-liquid separator is arranged at the outlet end of the cooler, and the inlet of the gas-liquid separator is communicated with the outlet of the cooler; a decarbonation tower, wherein the inlet of the decarbonation tower is communicated with the outlet at the top of the gas-liquid separator;

[0016] A pressure swing adsorption device is arranged at the top outlet of the decarbonation tower, and the inlet of the pressure swing adsorption device is connected to the top outlet of the decarbonation tower.

[0017] Furthermore, the steam superheater is connected to the waste heat boiler via a first high-pressure steam delivery pipeline, and a first by-product steam regulating valve is provided on the first high-pressure steam delivery pipeline;

[0018] The high-pressure steam turbine is connected to the waste heat boiler through a second high-pressure steam delivery pipeline, and a second by-product steam regulating valve is provided on the second high-pressure steam delivery pipeline and is in communication connection with the first by-product steam regulating valve;

[0019] The outlet of the low-pressure steam turbine is connected to a circulating condensate delivery pipeline, and a condensate discharge pipeline is arranged at the discharge outlet of the circulating condensate delivery pipeline. A fifth flow regulating valve is arranged on the condensate discharge pipe, and is in communication connection with the first byproduct steam regulating valve;

[0020] An external condensate delivery pipeline is provided at the inlet end of the condensate preheater. The external condensate delivery pipeline is provided with a sixth flow regulating valve and is communicatively connected with the first by-product steam regulating valve.

[0021] Furthermore, the natural gas reformer is composed of a combustion chamber and a reforming chamber, and an air delivery pipeline is provided at the outlet of the air blower, and the other end of the air delivery pipeline is connected to the combustion chamber of the natural gas reformer;

[0022] The natural gas conversion unit further includes: a mixed gas pipeline connected to the conversion preheater and a steam pipeline connected to the cogeneration unit, a natural gas raw material delivery pipeline and the steam pipeline are connected to the mixed gas pipeline, the natural gas raw material delivery pipeline delivers natural gas, and the steam pipeline delivers steam to the mixed gas pipeline, a fourth flow regulating valve is provided on the steam pipeline, and a second temperature detection point is provided on the mixed gas pipeline;

[0023] The fifth pipeline is connected to the natural gas reformer. The fifth pipeline is used to connect the conversion preheater and the reforming chamber of the natural gas reformer. The fifth pipeline is also provided with a flow controller.

[0024] Furthermore, the inlet of the waste heat boiler is connected to the reforming chamber of the natural gas reformer through a reforming gas delivery pipeline, the outlet of the waste heat boiler is connected to a sixth pipeline, a third temperature detection point is provided on the sixth pipeline, and the sixth pipeline is connected to the inlet of the medium and low temperature conversion unit;

[0025] The waste heat boiler is connected with a pressurized condensed water delivery pipeline, a first high-pressure steam delivery pipeline and a second high-pressure steam delivery pipeline, the pressurized condensed water delivery pipeline is provided with a fourth temperature detection point, the first high-pressure steam delivery pipeline is provided with a fifth temperature detection point, and the second high-pressure steam delivery pipeline is provided with a seventh temperature detection point;

[0026] The steam superheater is connected to the waste heat boiler through a first high-pressure steam delivery pipeline, the first high-pressure steam delivery pipeline is provided with a first by-product steam regulating valve, the steam superheater outlet is connected with a seventh pipeline and an eighth pipeline, the eighth pipeline is provided with a sixth temperature detection point and a first flow detection point, the seventh pipeline enters the natural gas conversion unit and is connected with the natural gas raw material delivery pipeline and the mixed gas pipeline;

[0027] The high-pressure steam turbine is connected to the waste heat boiler through a second high-pressure steam delivery pipeline, a second by-product steam regulating valve is provided on the second high-pressure steam delivery pipeline, and the second by-product steam regulating valve is communicatively connected, a seventh temperature detection point and a second pressure detection point are provided on the second high-pressure steam delivery pipeline, and a low-temperature steam delivery pipeline is provided at the outlet of the high-pressure steam turbine, and an eighth temperature detection point and a third pressure detection point are provided on the low-temperature steam delivery pipeline;

[0028] The heat exchanger is connected to the high-pressure steam turbine through a low-temperature steam delivery pipeline, one end of the low-temperature steam delivery pipeline is connected to the heat exchanger inlet, and the other end is connected to the high-pressure steam turbine outlet;

[0029] The low-pressure steam turbine inlet is provided with a low-pressure medium-temperature steam pipeline, the other end of the low-pressure medium-temperature steam pipeline is connected to the heat exchanger, the low-pressure medium-temperature steam pipeline is provided with a ninth temperature detection point and a fourth pressure detection point, the low-pressure steam turbine outlet is connected with a circulating condensate water delivery pipeline, the circulating condensate water delivery pipeline is provided with a tenth temperature monitoring point and a fifth pressure detection point, and the circulating water pipeline is connected to the circulating condensate water delivery pipeline;

[0030] The cogeneration unit further comprises:

[0031] A condensate delivery pipeline connected to the inlet of the condensate preheater, an external condensate delivery pipeline connected to the inlet end of the condensate delivery pipeline, the external condensate delivery pipeline is provided with a sixth flow regulating valve, and is in communication connection with the first by-product steam regulating valve, the circulating water pipeline and the external condensate delivery pipeline are connected to the condensate delivery pipeline, an eleventh temperature detection point is provided on the condensate delivery pipeline, the outlet of the condensate preheater is also connected to a hot desalted water delivery pipeline, and a twelfth temperature monitoring point and a sixth pressure detection point are respectively provided on the hot desalted water delivery pipeline;

[0032] The booster pump is connected to the condensate preheater through a hot desalted water delivery pipeline, the booster pump is also connected to a pressurized condensate delivery pipeline, a seventh pressure detection point is provided on the pressurized condensate delivery pipeline, and the booster pump is connected to the waste heat boiler through a pressurized condensate delivery pipeline;

[0033] The condensate discharge pipeline is arranged at the discharge outlet of the circulating condensate delivery pipeline. A fifth flow regulating valve is provided on the condensate discharge pipe. The fifth flow regulating valve is connected to a flow controller through a transmission line and is communicatively connected to the first by-product steam regulating valve.

[0034] Furthermore, the medium and low temperature conversion unit also includes:

[0035] a converter feed pipeline connected to the inlet of the medium-low temperature converter, the inlet of the medium-low temperature converter and the outlet of the converter preheater are connected through the converter feed pipeline, a fourth pressure regulating valve is provided on the converter feed pipeline, a pressure controller is connected to the fourth pressure regulating valve through a transmission line, and a thirteenth temperature detection point and a synthesis gas component collection and analysis point are also provided on the converter feed pipeline;

[0036] The medium and low temperature conversion device is also connected to a hydrogen-rich gas delivery pipeline, on which a fourteenth temperature detection point and a hydrogen-rich gas component collection and analysis point are respectively provided. The medium and low temperature conversion device is connected to the heat exchanger through the hydrogen-rich gas delivery pipeline, and a cooler feed pipe is provided at the outlet of the heat exchanger, on which a fifteenth temperature detection point is provided.

[0037] Furthermore, the cooler outlet is connected to a gas-liquid mixed delivery pipeline, the cooler inlet is connected to the heat exchanger outlet through a cooler feed pipe, a sixteenth temperature detection point and a fifth pressure regulating valve are provided on the gas-liquid mixed delivery pipeline, a pressure controller is connected to the fifth pressure regulating valve through a transmission line, and a component detection point is also provided on the gas-liquid mixed delivery pipeline;

[0038] The ninth pipeline connected to the top outlet of the gas-liquid separator 11, the liquid water discharge pipeline connected to the bottom outlet of the gas-liquid separator, the ninth pipeline is provided with a seventeenth temperature detection point, a first gas component detection point, a sixth pressure regulating valve, the pressure regulating valve is connected to a pressure controller via a transmission line, and the liquid water discharge pipe is provided with an eighteenth temperature detection point;

[0039] The top outlet of the decarbonation tower is connected to a decarbonation gas delivery pipeline, the bottom outlet of the decarbonation tower is connected to a CO2 discharge pipeline, the inlet of the decarbonation tower is connected to the outlet of the gas-liquid separator through a gas delivery pipeline, the decarbonation gas delivery pipeline is provided with a nineteenth temperature detection point, the decarbonation gas delivery pipe is also provided with a second gas component detection point and a seventh pressure regulating valve, the seventh pressure regulating valve is connected to a pressure controller through a transmission line, and the CO2 discharge pipeline is provided with a twentieth temperature detection point;

[0040] The top outlet of the pressure swing adsorption device is connected to a hydrogen product delivery pipeline, the bottom outlet of the pressure swing adsorption device is connected to a remaining gas delivery pipeline, the pressure swing adsorption device is connected to a carbon dioxide removal tower through a carbon removal gas delivery pipeline, the hydrogen product delivery pipeline is provided with a twenty-first temperature detection point, the hydrogen product delivery pipeline is also provided with a third gas component detection point and an eighth pressure regulating valve, the sixth pressure regulating valve is connected to a pressure controller via a transmission line, and the remaining gas delivery pipes are provided with a twenty-second temperature detection point.

[0041] Furthermore, the system further comprises a raw material pretreatment unit, the outlet of the raw material pretreatment unit is connected to the inlet of the natural gas conversion unit;

[0042] The raw material pretreatment unit includes: a liquefied natural gas gasifier;

[0043] A pump is arranged at a natural gas inlet end of the liquefied natural gas vaporizer and is in communication with the liquefied natural gas vaporizer;

[0044] The desulfurization device is arranged at the outlet end of the liquefied natural gas vaporizer, and the inlet is connected with the outlet of the liquefied natural gas vaporizer; the natural gas transmission pipeline at the outlet of the desulfurization device is connected with the inlet of the natural gas conversion unit.

[0045] Furthermore, the pump inlet is connected to a liquefied natural gas feed pipe, the pump outlet is connected to a first pipeline, the liquefied natural gas feed pipe is provided with a first flow regulating valve, and the first pipeline is provided with a second flow regulating valve;

[0046] The liquefied natural gas vaporizer is in communication with the pump through a first pipeline, and a first pressure detection point and a first pressure regulating valve are also provided on the first pipeline for controlling the fluid pressure in the pipeline, and a pressure controller is connected to the first pressure regulating valve through a transmission line;

[0047] The desulfurization device is connected to the liquefied natural gas gasifier through a second pipeline, the second pipeline is connected to a first temperature detection point, a natural gas sampling point and a second pressure regulating valve, and the desulfurization device is also connected to a third pipeline and a fourth pipeline;

[0048] The third pipeline is provided with a third flow regulating valve, and the seventh pipeline enters the natural gas conversion unit and is connected with the third pipeline and the mixed gas pipeline.

[0049] A method for controlling cogeneration of heat and power coupled with natural gas hydrogen production, the method is implemented based on a cogeneration of heat and power coupled with natural gas hydrogen production system, and comprises the following steps:

[0050] S401: Calculate the condensed water demand and the amount of steam used for cogeneration based on material balance, heat balance, water vapor demand under steady-state conditions, and heat provided by natural gas conversion and medium- and low-temperature shift reactors, and calculate the heat and electricity distribution ratio of cogeneration under the conditions;

[0051] S402: collecting the amount of by-product steam and comparing it with the water vapor demand under the first step of steady-state conditions; collecting the amount of by-product steam through the first by-product steam regulating valve and comparing it with the water vapor demand under the steady-state conditions;

[0052] S403: Select an operation based on the comparison result:

[0053] If the by-product steam volume is the same as the water vapor demand, the operating conditions meet the steam demand under the production scale, and the steam valve opening will not be changed;

[0054] If the amount of byproduct steam is greater than the amount of water vapor demand, the water vapor generated under the current operating conditions is too much and greater than the actual steam demand, it is necessary to reduce the opening of the first byproduct steam regulating valve, increase the opening of the second byproduct steam regulating valve, increase the opening of the fifth flow regulating valve, and close the sixth flow regulating valve;

[0055] If the amount of byproduct steam is less than the amount of water vapor demand, the water vapor generated under the current operating conditions is too little and less than the actual steam demand, it is necessary to increase the opening of the first byproduct steam regulating valve, reduce the opening of the second byproduct steam regulating valve, close the fifth flow regulating valve, and increase the opening of the sixth flow regulating valve;

[0056] The opening / closing degree of the first by-product steam regulating valve, the second by-product steam regulating valve, the fifth flow regulating valve and the sixth flow regulating valve is determined according to the ratio of the collected by-product steam volume to the water vapor demand.

[0057] The formula for determining the opening / closing degree of the first byproduct steam regulating valve (403) is:

[0058]

[0059] The formula for determining the opening / closing degree of the second byproduct steam regulating valve (406) is:

[0060]

[0061] The formula for determining the opening / closing degree of the fifth flow control valve (410) is:

[0062]

[0063] The formula for determining the opening / closing degree of the sixth flow control valve (412) is:

[0064]

[0065] Where: F represents the flow rate, the subscript max represents the maximum flow rate corresponding to each valve fully open, Δκ represents the opening / closing degree of each valve. If the calculation result is positive, it means that the valve opening needs to be increased, and if the calculation result is negative, it means that the valve opening needs to be reduced.

[0066] S404: Calculate the heat and electricity distribution ratio b of the cogeneration according to the valve opening adjustment amount, the heat and electricity steady-state distribution ratio 热 / 电 =F 403 / F 406 ;

[0067] S405: According to the calculation result of step S404, the final distribution ratio of heat and electricity is obtained to achieve a stable supply of steam and electricity for the cogeneration unit.

[0068] Compared with the prior art, the present invention provides a cogeneration system and control method for hydrogen production by natural gas reforming, which has the following beneficial effects:

[0069] High efficiency of energy utilization: In the process of hydrogen production from natural gas, the low-quality heat in the process of hydrogen production from natural gas is recovered and utilized through the system integration of the cogeneration system, waste heat boiler, and medium and low temperature conversion unit. The cascade utilization of energy is achieved through the heating, gasification, power generation, and condensation of desalted water, thereby improving the efficiency of energy utilization.

[0070] Diversity of waste heat utilization: The present invention couples the cogeneration system, utilizing the high-quality heat of the natural gas conversion unit and the low-quality heat of the medium and low-temperature conversion unit to simultaneously generate electrical energy and low-temperature thermal energy.

[0071] Energy production stability: The internal flow regulating valves of the cogeneration system of the present invention are communicated and connected. When the by-product steam does not match its preset amount, the saturated steam distribution amount can be adjusted in time, and the heat and electricity in the natural gas hydrogen production process can be coordinated to control the stable supply of steam and electricity.

[0072] System flexibility: The coupling of the cogeneration system and the natural gas hydrogen production system enables the system to have flexible integration capabilities. The energy utilization and power generation scale can be adjusted according to actual needs and resource conditions to achieve the best energy utilization efficiency.

[0073] Environmental friendliness: As an energy-saving technology, cogeneration can use the cogeneration system to provide electricity and heating, achieving efficient use of energy, reducing carbon emissions and environmental impacts, and playing a positive role in mitigating climate change.

[0074] Economical: The low-temperature waste heat generated by the cogeneration system can be used for heating, cooling or industrial processes, which can improve the economic benefits of the natural gas hydrogen production system, thereby reducing the demand for other energy sources and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Attached Figure 1 A diagram showing the connection relationship between the various units for hydrogen production from natural gas reforming provided by the present invention, wherein the dotted line represents desalted water;

[0076] Attached Figure 2 A flow chart of the combined heat and power generation and natural gas hydrogen production coupling system provided by the present invention;

[0077] Attached Figure 3 A flow chart of the equipment for the control method of the combined heat and power generation and natural gas hydrogen production coupling system provided by the present invention;

[0078] Attached Figure 4 A flow chart of a method for producing hydrogen from natural gas by coupling heat and power cogeneration provided by the present invention;

[0079] Attached Figure 5 A schematic diagram of the pipeline and ancillary equipment of the raw material pretreatment unit provided for this application;

[0080] Attached Figure 6 Schematic diagram of pipelines and ancillary equipment for natural gas conversion, cogeneration unit and medium and low temperature conversion unit provided for this application;

[0081] Attached Figure 7 Schematic diagram of the pipeline and ancillary equipment of the gas separation unit provided in this application.

[0082] In the figure: pump 1, liquefied natural gas feed pipe 101, first pipeline 103, first flow regulating valve 102, second flow regulating valve 104, liquefied natural gas gasifier 2, first pressure detection point 1031, first pressure regulating valve 105, desulfurization device 3, second pipeline 106, first temperature detection point 1061, natural gas sampling point 1062, second pressure regulating valve 107, third pipeline 108, fourth pipeline 109, seventh pipeline 201, mixed gas pipeline 204, third flow regulating valve 202, fourth flow regulating valve 203, second temperature detection point 2041, conversion preheater 4, fifth pipeline 205, natural gas reformer 5, flow controller 206, air blower 19, air delivery pipeline 209, waste hot boiler 6, reforming gas delivery pipeline 207, sixth pipeline 208, third temperature detection point 2081, pressurized condensate delivery pipe 401, first high-pressure steam delivery pipeline 402, second high-pressure steam delivery pipeline 405, first byproduct steam regulating valve 403, fourth temperature detection point 4011, fifth temperature detection point 4021, steam superheater 14, eighth pipeline 404, sixth temperature detection point 4041, first flow detection point 4042, seventh temperature detection point 4051, second byproduct steam regulating valve 406, high-pressure steam turbine 15, low-temperature steam delivery pipeline 407, eighth temperature detection point 4071, second pressure detection point 4052, third pressure detection point 4072, medium and low temperature conversion device 8, heat exchanger 9, low medium-pressure steam pipeline 408, ninth temperature detection point 4081, fourth pressure detection point 4082, low-pressure steam turbine 16, circulating condensate water delivery pipeline 409, tenth temperature detection point 4091, fifth pressure detection point 4092, circulating water pipeline 416, condensate removal pipeline 415, fifth flow regulating valve 410, external condensate delivery pipeline 411, sixth flow regulating valve 412, condensate delivery pipeline 413, eleventh temperature detection point 4132, condensate preheater 17, hot desalted water delivery pipeline 414, twelfth temperature detection point 4141, sixth pressure detection point 4142, booster pump 18, seventh pressure detection point 4012, conversion device feed pipeline 301, fourth pressure regulating valve 302, tenth The third temperature detection point 3011, the synthesis gas component collection and analysis point 3012, the hydrogen-rich gas delivery pipe 303, the fourteenth temperature detection point 3031, the hydrogen-rich gas component collection and analysis point 3032, the cooler feed pipe 304, the fifteenth temperature detection point 3041, the cooler 10, the sixteenth temperature detection point 5011, the fifth pressure regulating valve 502, the gas-liquid mixed delivery pipeline 501, the component detection point 5012, the gas-liquid separator 11, the ninth pipeline 503, the liquid water discharge pipeline 504, the seventeenth temperature detection point 5031, the eighteenth temperature detection point 5041, the first gas component detection point 5032, the sixth pressure regulating valve 505, the carbon dioxide removal tower 12, the carbon removal gas delivery pipeline 506, the CO2 discharge pipeline 507,The nineteenth temperature detection point 5061, the twentieth temperature detection point 5071, the second gas component detection point 5062, the seventh pressure regulating valve 508, the pressure swing adsorption device 13, the hydrogen product delivery pipeline 509, the remaining gas delivery pipelines 510, the twenty-first temperature detection point 5091, the twenty-second temperature detection point 5101, the third gas component detection point 5092, and the eighth pressure regulating valve 511. DETAILED DESCRIPTION

[0083] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0084] See also Figure 1 The present invention provides a technical solution for a combined heat and power generation coupled with natural gas reforming hydrogen production system:

[0085] It comprises: a raw material pretreatment unit and a natural gas conversion unit, wherein the outlet of the raw material pretreatment unit is connected to the inlet of the natural gas conversion unit;

[0086] A cogeneration unit and a medium-low temperature conversion unit, wherein the inlets of the cogeneration unit and the medium-low temperature conversion unit are connected to the outlet of the natural gas conversion unit, the inlets of the natural gas conversion unit and the medium-low temperature conversion unit are connected to the outlet of the cogeneration unit, and the inlet of the cogeneration unit is connected to the outlet of the medium-low temperature conversion unit;

[0087] A gas separation unit, wherein the inlet of the gas separation unit is connected to the outlet of the medium and low temperature conversion unit.

[0088] As an implementation, please refer to Figure 2 as well as Figure 5 , the raw material pretreatment unit comprises:

[0089] The liquefied natural gas vaporizer 2, the pump 1 is arranged at the natural gas inlet end of the liquefied natural gas vaporizer 2 and is communicated with the liquefied natural gas vaporizer 2;

[0090] The desulfurization device 3 is arranged at the outlet end of the liquefied natural gas vaporizer 2, and the inlet is connected to the outlet of the liquefied natural gas vaporizer 2, and the outlet of the desulfurization device 3 is connected to the inlet of the natural gas conversion unit.

[0091] Furthermore, the pump 1 inlet is connected to a liquefied natural gas feed pipe 101, the pump 1 outlet is connected to a first pipeline 103, the liquefied natural gas feed pipe 101 is provided with a first flow regulating valve 102, the first pipeline 103 is provided with a second flow regulating valve 104, the first flow regulating valve 102 and the second flow regulating valve 104 are used to control the flow of the liquefied natural gas pipeline;

[0092] The liquefied natural gas (LNG) vaporizer 2 is connected to the pump 1 through a first pipeline 103. The first pipeline 103 is also provided with a first pressure detection point 1031 and a first pressure regulating valve 105 for controlling the fluid pressure in the pipeline. The first pressure regulating valve 105 is connected to a pressure controller through a transmission line.

[0093] The desulfurization device 3 is connected to the liquefied natural gas (LNG) gasifier 2 through a second pipeline 106. The second pipeline 106 is provided with a first temperature detection point 1061, a natural gas sampling point 1062 and a second pressure regulating valve 107 for monitoring the gas composition and state in the pipeline. The outlet end of the desulfurization device 3 is also connected to a third pipeline 108 and a fourth pipeline 109, which are natural gas transmission pipelines.

[0094] As an implementation, please refer to Figure 2 as well as Figure 6 , the natural gas conversion unit comprises:

[0095] The conversion preheater 4, the natural gas reformer 5 and the air blower 19,

[0096] The inlet of the conversion preheater 4 is connected to the outlet of the desulfurization device 3, and the outlet of the conversion preheater 4 is connected to the inlet of the natural gas reformer 5. The natural gas reformer 5 is provided with an air input pipeline, and the air blower 19 is located on the air input pipeline, and the outlet of the air blower 19 is connected to the inlet of the natural gas reformer 5, for inputting air into the natural gas reformer 5;

[0097] Furthermore, the third pipeline 108 is connected to the steam pipeline 201 and the mixed gas pipeline 204, and the fourth pipeline 109 is connected to the natural gas reformer 5;

[0098] Furthermore, the natural gas reformer 5 is composed of a combustion chamber 5-1 and a reforming chamber 5-2. The fourth pipeline 109 is connected to the combustion chamber 5-1 and is used to transport natural gas to the combustion chamber 5-1. The outlet of the air blower 19 is provided with an air delivery pipeline 209. The other end of the air delivery pipeline 209 is connected to the combustion chamber 5-1 of the natural gas reformer 5. The air passes through the air blower 19 and then through the air delivery pipeline 209 to the combustion chamber 5-1 of the natural gas reformer 5. The fuel natural gas burns in the combustion chamber 5-1 under air conditions to generate heat, and the heat is transferred to the reforming chamber 5-2 through the pipe wall.

[0099] Furthermore, the natural gas conversion unit further comprises:

[0100] The mixed gas pipeline 204 connected to the conversion preheater 4 and the steam pipeline 201 connected to the cogeneration unit, the third pipeline 108 and the steam pipeline 201 are connected to the mixed gas pipeline 204, the third pipeline 108 transports natural gas, and the steam pipeline 201 transports steam to the mixed gas pipeline 204, the third pipeline 108 is provided with a third flow regulating valve 202, and the steam pipeline 201 is provided with a fourth flow regulating valve 203, which is used to control the flow of the third pipeline 108 and the steam pipeline 201 fluid to ensure that the natural gas and water vapor are evenly mixed in a volume ratio of 1:3; the mixed gas pipeline 204 is provided with a second temperature detection point 2041, which is used to detect the temperature of the mixed gas;

[0101] The fifth pipeline 205 connected to the natural gas converter 5 is used to connect the conversion preheater 4 and the conversion chamber 5-2 of the natural gas converter 5. The mixed gas in the mixed gas pipeline 204 is heated by the conversion preheater 4 and then sent into the conversion chamber 5-2 of the natural gas converter 5 through the fifth pipeline 205. The mixed gas undergoes a natural gas conversion reaction in the conversion chamber 5-2. The fifth pipeline 205 is also provided with a flow controller 206 for regulating the flow.

[0102] Furthermore, the cogeneration unit comprises:

[0103] The waste heat boiler 6, the inlet of the waste heat boiler 6 is connected to the reforming chamber 5-2 of the natural gas reformer 5 through the reforming gas delivery pipeline 207, which is used to deliver the hot stream reforming gas to the waste heat boiler 6; the outlet of the waste heat boiler 6 is connected to the sixth pipeline 208, and the sixth pipeline 208 is provided with a third temperature detection point 2081, which is used to detect the temperature of the synthesis gas; the outlet synthesis gas temperature of the natural gas reformer 5 is greater than 700°C, and after cooling, it is delivered to the medium and low temperature conversion unit through the sixth pipeline 208; the hot stream inlet of the waste heat boiler 6 is connected to the outlet of the natural gas reformer 5;

[0104] And connected to the waste heat boiler 6:

[0105] A conversion preheater 7, wherein the inlet of the conversion preheater 7 is connected to the outlet of the waste heat boiler 6, and is used for conveying the hot stream conversion gas at the outlet of the hot stream of the waste heat boiler 6 to the conversion preheater 7;

[0106] A high-pressure steam turbine 15, wherein the inlet of the high-pressure steam turbine 15 is connected to the outlet of the cold stream of the waste heat boiler 6, and the outlet of the high-pressure steam turbine 15 is connected to the inlet of the heat exchanger 9, for converting thermal energy into electrical energy;

[0107] A pressure pump 18 is used to pressurize the heated condensate to supplement the pressure lost in the high-pressure steam turbine 15 and the low-pressure steam turbine 16. The outlet of the pressure pump 18 is connected to the inlet of the waste heat boiler 6. A condensate preheater 17 is provided on the inlet pipeline of the pressure pump 18, and the outlet of the condensate preheater 17 is connected to the inlet of the pressure pump 18. The inlet of the condensate preheater 17 is connected to the outlet of the low-pressure steam turbine 16, and a condensate input pipeline is provided on the inlet of the condensate preheater 17;

[0108] A steam superheater 14, wherein the inlet of the steam superheater 14 is connected to the outlet of the waste heat boiler 6, and a steam delivery pipeline is provided at the outlet of the steam superheater 14 for heating the by-product saturated steam into superheated steam;

[0109] Furthermore, the waste heat boiler 6 is connected with a pressurized condensed water delivery pipeline 401, a first high-pressure steam delivery pipeline 402 and a second high-pressure steam delivery pipeline 405. The pressurized condensed water delivery pipeline 401 is provided with a fourth temperature detection point 4011, the first high-pressure steam delivery pipeline 402 is provided with a fifth temperature detection point 4021, and the second high-pressure steam delivery pipeline 405 is provided with a seventh temperature detection point 4051, which are used to detect the temperature of the fluid in each pipeline to determine the degree of gasification of the desalted water. The pressurized desalted water enters the waste heat boiler 6 through the pressurized condensed water delivery pipe 401, and is heated by the synthesis gas at the outlet of the natural gas reformer 5 to produce saturated steam as a by-product.

[0110] Furthermore, the steam superheater 14 is connected to the waste heat boiler 6 through a first high-pressure steam delivery pipeline 402, and a first by-product steam regulating valve 403 is provided on the first high-pressure steam delivery pipeline 402 for adjusting the flow rate of steam. The outlet of the steam superheater 14 is connected with a seventh pipeline 201 and an eighth pipeline 404, and a sixth temperature detection point 4041 and a first flow detection point 4042 are provided on the eighth pipeline 404. The seventh pipeline 201 enters the natural gas conversion unit and is connected to the third pipeline 108 and the mixed gas pipeline 204, and the steam provides heat to the entire natural gas hydrogen production network through the eighth pipeline 404;

[0111] The high-pressure steam turbine 15 is connected to the waste heat boiler 6 through a second high-pressure steam delivery pipeline 405. The second high-pressure steam delivery pipeline 405 is provided with a second by-product steam regulating valve 406, and is in communication connection with the first by-product steam regulating valve 403, for regulating the steam flow entering the cogeneration. The second high-pressure steam delivery pipeline 405 is provided with a second pressure detection point 4052. The outlet of the high-pressure steam turbine 15 is provided with a low-temperature steam delivery pipeline 407, and the low-temperature steam delivery pipeline 407 is provided with an eighth temperature detection point 4071 and a third pressure detection point 4072;

[0112] The heat exchanger 9 is connected to the high-pressure steam turbine 15 via a low-temperature steam delivery pipeline 407. One end of the low-temperature steam delivery pipeline 407 is connected to the inlet of the heat exchanger 9, and the other end is connected to the outlet of the high-pressure steam turbine 15, and is used to heat the low-temperature steam in the low-temperature steam delivery pipeline 407;

[0113] The inlet of the low-pressure steam turbine 16 is provided with a low-pressure medium-temperature steam pipeline 408, and the other end of the low-pressure medium-temperature steam pipeline 408 is connected to the heat exchanger 9, and is used to transport the low-pressure medium-temperature steam to the low-pressure steam turbine 16; the low-pressure medium-temperature steam pipeline 408 is provided with a ninth temperature detection point 4081 and a third pressure detection point 4082; the outlet of the low-pressure steam turbine 16 is connected with a circulating condensed water delivery pipeline 409, and the circulating condensed water delivery pipeline 409 is provided with a tenth temperature monitoring point 4091 and a fourth pressure detection point 4092;

[0114] Further: the cogeneration unit also includes:

[0115] An external condensate delivery pipeline 411 is used to input external condensate. The external condensate delivery pipeline 411 is arranged at the inlet end of the condensate preheater 17. The external condensate delivery pipeline 411 is provided with a sixth flow regulating valve 412 and is in communication connection with the first byproduct steam regulating valve 403.

[0116] A circulating water pipeline 416, wherein the circulating water pipeline 416 is in communication with the circulating condensed water delivery pipeline 409 and is used to deliver the circulating water delivered by the circulating condensed water delivery pipeline 409;

[0117] The inlet of the condensate preheater 17 is provided with a condensate delivery pipeline 413, and the circulating water pipeline 416 and the external condensate delivery pipeline 411 are connected to the condensate delivery pipeline 413, so as to deliver the circulating water of the circulating water pipeline 416 and the condensate of the external condensate delivery pipeline 411 to the condensate preheater 17; the eleventh temperature detection point 4132 is provided on the condensate delivery pipeline 413 to detect the condensate temperature in real time;

[0118] The outlet of the condensate preheater 17 is also connected to a hot desalted water delivery pipeline 414, on which a twelfth temperature monitoring point 4141 and a sixth pressure detection point 4142 are respectively provided for data collection for subsequent heat exchange optimization;

[0119] The booster pump 18 is connected to the condensate preheater 17 through the hot desalted water delivery pipeline 414, and the booster pump 18 is also connected to a pressurized condensate delivery pipeline 401, and a seventh pressure detection point 4012 is provided on the pressurized condensate delivery pipeline 401. The booster pump 18 is connected to the waste heat boiler 6 through the pressurized condensate delivery pipeline 401, and is used to deliver pressurized condensate to the waste heat boiler 6;

[0120] The condensate discharge pipeline 415 is used to discharge condensate. The condensate discharge pipeline 415 is arranged at the discharge outlet of the circulating condensate delivery pipeline 409. The condensate discharge pipe 415 is provided with a fifth flow regulating valve 410. The fifth flow regulating valve 410 is connected to a flow controller through a transmission line and is communicatively connected to the first by-product steam regulating valve 403.

[0121] As an implementation, please refer to Figure 2 as well as Figure 6 , the medium and low temperature conversion unit comprises:

[0122] A conversion preheater 7, a heat exchanger 9, and a medium-low temperature conversion device 8 connected to the conversion preheater 7 and the heat exchanger 9, wherein the medium-low temperature conversion device 8 is arranged on the outlet pipeline of the conversion preheater 7, and the inlet of the medium-low temperature conversion device 8 is connected to the outlet of the conversion preheater 7, and the outlet of the medium-low temperature conversion device 8 is connected to the inlet of the heat exchanger 9, for subjecting the synthesis gas to medium-low temperature conversion reaction to produce more hydrogen, and at the same time supplying heat to the low-temperature steam through the heat exchanger 9.

[0123] Furthermore, the medium and low temperature conversion unit also includes:

[0124] A converter feed pipeline 301 connected to the inlet of the medium-low temperature converter 8, the inlet of the medium-low temperature converter 8 and the outlet of the converter preheater 7 are connected through the converter feed pipeline 301, a fourth pressure regulating valve 302 is provided on the converter feed pipeline 301, a pressure controller is connected to the fourth pressure regulating valve 302 through a transmission line, and a thirteenth temperature detection point 3011 and a synthesis gas component collection and analysis point 3012 are also provided on the converter feed pipeline 301 for monitoring the composition and state of the natural gas conversion reaction product;

[0125] The medium-low temperature conversion device 8 is also connected to a hydrogen-rich gas delivery pipeline 303, and the hydrogen-rich gas delivery pipeline 303 is respectively provided with a fourteenth temperature detection point 3031 and a hydrogen-rich gas component collection and analysis point 3032 for monitoring the composition and state of the hydrogen-rich gas; the medium-low temperature conversion device 8 is connected to the heat exchanger 9 through the hydrogen-rich gas delivery pipeline 303, and a cooler feed pipe 304 is provided at the outlet of the heat exchanger 9, which is used to allow the hydrogen-rich gas to enter the gas separation unit through the cooler feed pipe 304 after being cooled by the heat exchanger 9, and the cooler feed pipe 304 is provided with a fifteenth temperature detection point 3041.

[0126] As an implementation, please refer to Figure 2 and Figure 7 , the gas separation unit comprises:

[0127] A cooler 10, wherein the inlet of the cooler 10 is connected to the outlet 9 of the heat exchanger, and is used to cool the hydrogen-rich gas. After the hydrogen-rich gas is cooled, the water in the hydrogen-rich gas is condensed into a liquid phase;

[0128] A gas-liquid separator 11, wherein the gas-liquid separator 11 is disposed at the outlet of the cooler 10, and the inlet of the gas-liquid separator 11 is connected to the outlet of the cooler 10, and is used for separating the liquid water and gas phase components of the gas-liquid mixture;

[0129] A decarbonation tower 12, wherein the inlet of the decarbonation tower 12 is connected to the top outlet of the gas-liquid separator 11, and is used for removing carbon dioxide;

[0130] The pressure swing adsorption device 13 is arranged at the top outlet of the decarbonation tower 12, and the inlet of the pressure swing adsorption device 13 is connected to the top outlet of the decarbonation tower 12, and is used for hydrogen purification.

[0131] Furthermore, the outlet of the cooler 10 is connected to a gas-liquid mixed delivery pipeline 501, the inlet of the cooler 10 is connected to the outlet of the heat exchanger 9 through a cooler feed pipe 304, a sixteenth temperature detection point 5011 and a fifth pressure regulating valve 502 are provided on the gas-liquid mixed delivery pipeline 501, and a pressure controller is connected to the fifth pressure regulating valve 502 through a transmission line for regulating pressure; a component detection point 5012 is also provided on the gas-liquid mixed delivery pipeline 501 for monitoring the composition of the hydrogen-rich gas;

[0132] The ninth pipeline 503 connected to the top outlet of the gas-liquid separator 11, the liquid water discharge pipeline 504 connected to the bottom outlet of the gas-liquid separator 11, the ninth pipeline 503 is provided with a seventeenth temperature detection point 5031, a first gas component detection point 5032, and a sixth pressure regulating valve 505, the pressure regulating valve 505 is connected to a pressure controller via a transmission line, and the liquid water discharge pipe 504 is provided with an eighteenth temperature detection point 5041;

[0133] The top outlet of the decarbonation tower 12 is connected to a decarbonation gas delivery pipeline 506, and the bottom outlet of the decarbonation tower 12 is connected to a CO2 discharge pipeline 507 for discharging CO2. The inlet of the decarbonation tower 12 is connected to the outlet of the gas-liquid separator 11 through a gas delivery pipeline 503. The decarbonation gas delivery pipeline 506 is provided with a nineteenth temperature detection point 5061. The decarbonation gas delivery pipeline 506 is also provided with a second gas component detection point 5062 and a seventh pressure regulating valve 508. The seventh pressure regulating valve 508 is connected to a pressure controller through a transmission line, and the CO2 discharge pipeline 507 is provided with a twentieth temperature detection point 5071;

[0134] The top outlet of the pressure swing adsorption device 13 is connected to a hydrogen product delivery pipeline 509, and the bottom outlet of the pressure swing adsorption device 13 is connected to a remaining gas delivery pipe 510. The pressure swing adsorption device 13 is connected to the carbon dioxide removal tower 12 through a decarbonation gas delivery pipeline 506. The hydrogen product delivery pipe 509 is provided with a twenty-first temperature detection point 5091. The hydrogen product delivery pipeline 509 is also provided with a third gas component detection point 5092 and an eighth pressure regulating valve 511. The sixth pressure regulating valve 511 is connected to a pressure controller through a transmission line, and the remaining gas delivery pipe 510 is provided with a twenty-second temperature detection point 5101.

[0135] As an implementation, please refer to Figure 3 and Figure 4 A method for controlling cogeneration of heat and power coupled with natural gas to produce hydrogen is provided. The method is implemented based on the above cogeneration of heat and power coupled with natural gas to produce hydrogen system, and comprises the following steps:

[0136] S401: Calculate the condensed water demand and the amount of steam used for cogeneration based on material balance, heat balance, water vapor demand under steady-state conditions, and heat provided by natural gas conversion and medium- and low-temperature shift reactors, and calculate the heat and electricity distribution ratio of cogeneration under the conditions;

[0137] S402: Collect the amount of byproduct steam and compare it with the water vapor demand under the first step of steady-state operation. Collect the amount of byproduct steam through the first byproduct steam regulating valve 403 and compare it with the water vapor demand under steady-state operation.

[0138] S403: Select an operation based on the comparison result:

[0139] If the by-product steam volume is the same as the water vapor demand, the operating conditions meet the steam demand under the production scale, and the steam valve opening will not be changed;

[0140] If the amount of byproduct steam is greater than the amount of water vapor demand, the water vapor generated under the current operating conditions is too much and greater than the actual steam demand, it is necessary to reduce the opening of the first byproduct steam regulating valve 403, increase the opening of the second byproduct steam regulating valve 406, increase the opening of the fifth flow regulating valve 410, and close the sixth flow regulating valve 412;

[0141] If the amount of byproduct steam is less than the amount of water vapor demanded, the water vapor generated under the current operating conditions is too little and less than the actual steam demand, it is necessary to increase the opening of the first byproduct steam regulating valve 403, reduce the opening of the second byproduct steam regulating valve 406, close the fifth flow regulating valve 410, and increase the opening of the sixth flow regulating valve 412;

[0142] The opening / closing degree of the first byproduct steam regulating valve 403, the second byproduct steam regulating valve 406, the fifth flow regulating valve 410 and the sixth flow regulating valve 412 is determined according to the ratio of the collected byproduct steam amount to the water vapor demand.

[0143] The formula for determining the opening / closing degree of the first byproduct steam regulating valve (403) is:

[0144]

[0145] The formula for determining the opening / closing degree of the second byproduct steam regulating valve (406) is:

[0146]

[0147] The formula for determining the opening / closing degree of the fifth flow control valve (410) is:

[0148]

[0149] The formula for determining the opening / closing degree of the sixth flow control valve (412) is:

[0150]

[0151] Where: F represents the flow rate, the subscript max represents the maximum flow rate corresponding to each valve fully open, Δκ represents the opening / closing degree of each valve. If the calculation result is positive, it means that the valve opening needs to be increased, and if the calculation result is negative, it means that the valve opening needs to be reduced.

[0152] S404: Calculate the heat and electricity distribution ratio b of the cogeneration according to the valve opening adjustment amount, the heat and electricity steady-state distribution ratio 热 / 电 =F 403 / F 406 ;

[0153] S405: According to the calculation result of step S404, the final distribution ratio of heat and electricity is obtained to achieve a stable supply of steam and electricity for the cogeneration unit.

[0154] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0155] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A cogeneration system for producing hydrogen by natural gas reforming, characterized in that: The system comprises: A natural gas conversion unit, a heat and power cogeneration unit connected to the natural gas conversion unit, and a medium and low temperature conversion unit, The inlets of the cogeneration unit and the medium and low temperature conversion unit are connected to the outlet of the natural gas conversion unit, the inlets of the natural gas conversion unit and the medium and low temperature conversion unit are connected to the outlet of the cogeneration unit, and the inlet of the cogeneration unit is connected to the outlet of the medium and low temperature conversion unit; Gas separation unit, The inlet of the gas separation unit is communicated with the outlet of the medium and low temperature conversion unit.

2. The cogeneration and natural gas reforming hydrogen production system according to claim 1 is characterized by: The natural gas conversion unit comprises: A conversion preheater (4), a natural gas reformer (5) and an air blower (19), wherein the inlet of the conversion preheater (4) is connected to the outlet of the desulfurization device (3), the outlet of the conversion preheater (4) is connected to the inlet of the natural gas reformer (5), the natural gas reformer (5) is provided with an air input pipeline, the air blower (19) is located on the air input pipeline, and the outlet of the air blower (19) is connected to the inlet of the natural gas reformer (5); The cogeneration unit comprises: a waste heat boiler (6), the inlet of the waste heat boiler (6) being connected to the outlet of the natural gas reformer (5); and connected to the waste heat boiler (6): a conversion preheater (7), wherein the inlet of the conversion preheater (7) is connected to the outlet of the waste heat boiler (6), and is used to transport the hot stream conversion gas at the hot stream outlet of the waste heat boiler (6) to the conversion preheater (7); A high-pressure steam turbine (15), wherein the inlet of the high-pressure steam turbine (15) is connected to the outlet of the cold stream of the waste heat boiler (6), a heat exchanger (9) is arranged at the outlet end of the high-pressure steam turbine (15), and the inlet of the high-pressure steam turbine (15) is connected to the inlet of the heat exchanger (9), a low-pressure steam turbine (16) is arranged on the outlet pipeline of the heat exchanger (9), and the outlet of the heat exchanger (9) is connected to the inlet of the low-pressure steam turbine (16); A booster pump (18), wherein the outlet of the booster pump (18) is connected to the inlet of the waste heat boiler (6), a condensate preheater (17) is provided on the inlet pipeline of the booster pump (18), and the outlet of the condensate preheater (17) is connected to the inlet of the booster pump (18), the inlet of the condensate preheater (17) is connected to the outlet of the low-pressure steam turbine (16), and a condensate input pipeline is provided at the inlet of the condensate preheater (17); a steam superheater (14), wherein the inlet of the steam superheater (14) is connected to the outlet of the waste heat boiler (6), and the outlet of the steam superheater (14) is provided with a steam delivery pipeline; The medium-low temperature conversion unit comprises: the conversion preheater (7), the heat exchanger (9), and a medium-low temperature conversion device (8) connected to the conversion preheater (7) and the heat exchanger (9), wherein the medium-low temperature conversion device (8) is arranged on the outlet pipeline of the conversion preheater (7), and the inlet of the medium-low temperature conversion device (8) is connected to the outlet of the conversion preheater (7), and the outlet of the medium-low temperature conversion device (8) is connected to the inlet of the heat exchanger (9); The gas separation unit comprises: A cooler (10), wherein an inlet of the cooler (10) is connected to an outlet of the heat exchanger (9); A gas-liquid separator (11), wherein the gas-liquid separator (11) is arranged at the outlet end of the cooler (10), and the inlet of the gas-liquid separator (11) is connected to the outlet of the cooler (10); a decarbonation tower (12), wherein the inlet of the decarbonation tower (12) is connected to the top outlet of the gas-liquid separator (11); A pressure swing adsorption device (13) is provided at the top outlet of the decarbonation tower (12), and an inlet of the pressure swing adsorption device (13) is connected to the top outlet of the decarbonation tower (12).

3. The cogeneration system for producing hydrogen by natural gas reforming according to claim 2 is characterized in that: The steam superheater (14) is connected to the waste heat boiler (6) via a first high-pressure steam delivery pipeline (402), and a first by-product steam regulating valve (403) is provided on the first high-pressure steam delivery pipeline (402); The high-pressure steam turbine (15) is in communication with the waste heat boiler (6) via a second high-pressure steam delivery pipeline (405); a second by-product steam regulating valve (406) is provided on the second high-pressure steam delivery pipeline (405) and is in communication connection with the first by-product steam regulating valve (403); The outlet of the low-pressure steam turbine (16) is connected to a circulating condensed water delivery pipeline (409), and a condensed water discharge pipeline (415) is arranged at the discharge outlet of the circulating condensed water delivery pipeline (409). The condensed water discharge pipe (415) is provided with a fifth flow control valve (410) and is in communication connection with the first byproduct steam control valve (403); An external condensate delivery pipeline (411) is provided at the inlet end of the condensate preheater (17), and the external condensate delivery pipeline (411) is provided with a sixth flow regulating valve (412) and is communicatively connected with the first byproduct steam regulating valve (403).

4. The cogeneration and natural gas reforming hydrogen production system according to claim 2 is characterized by: The natural gas reformer (5) is composed of a combustion chamber (5-1) and a reforming chamber (5-2); an air delivery pipeline (209) is provided at the outlet of the air blower (19); and the other end of the air delivery pipeline (209) is connected to the combustion chamber (5-1) of the natural gas reformer (5); The natural gas conversion unit further comprises: a mixed gas pipeline (204) connected to the conversion preheater (4) and a steam pipeline (201) connected to the cogeneration unit, The natural gas raw material transmission pipeline and the steam pipeline (201) are connected to the mixed gas pipeline (204); the natural gas raw material transmission pipeline transmits natural gas, and the steam pipeline (201) transmits steam to the mixed gas pipeline (204); a fourth flow regulating valve (203) is provided on the steam pipeline (201); and a second temperature detection point (2041) is provided on the mixed gas pipeline (204); a fifth pipeline (205) connected to the natural gas reformer (5), The fifth pipeline (205) is used to connect the conversion preheater (4) and the conversion chamber (5-2) of the natural gas conversion furnace (5). The fifth pipeline (205) is also provided with a flow controller (206).

5. The cogeneration and natural gas reforming hydrogen production system according to claim 2 is characterized by: The inlet of the waste heat boiler (6) is connected to the reforming chamber (5-2) of the natural gas reformer (5) via a reforming gas delivery pipeline (207); the outlet of the waste heat boiler (6) is connected to a sixth pipeline (208); a third temperature detection point (2081) is provided on the sixth pipeline (208); and the sixth pipeline (208) is connected to the inlet of the medium and low temperature conversion unit; The waste heat boiler (6) is connected to a pressurized condensed water delivery pipeline (401), a first high-pressure steam delivery pipeline (402) and a second high-pressure steam delivery pipeline (405); the pressurized condensed water delivery pipeline (401) is provided with a fourth temperature detection point (4011), the first high-pressure steam delivery pipeline (402) is provided with a fifth temperature detection point (4021), and the second high-pressure steam delivery pipeline (405) is provided with a seventh temperature detection point (4051); The steam superheater (14) is connected to the waste heat boiler (6) via a first high-pressure steam delivery pipeline (402); a first by-product steam regulating valve (403) is provided on the first high-pressure steam delivery pipeline (402); a seventh pipeline (201) and an eighth pipeline (404) are connected to the outlet of the steam superheater (14); a sixth temperature detection point (4041) and a first flow detection point (4042) are provided on the eighth pipeline (404); the seventh pipeline (201) enters the natural gas conversion unit and is connected to the natural gas raw material delivery pipeline and the mixed gas pipeline (204); The high-pressure steam turbine (15) is connected to the waste heat boiler (6) via a second high-pressure steam delivery pipeline (405); a second by-product steam regulating valve (406) is provided on the second high-pressure steam delivery pipeline (405), and the second by-product steam regulating valve (403) is communicatively connected; a seventh temperature detection point (4051) and a second pressure detection point (4052) are provided on the second high-pressure steam delivery pipeline (405); a low-temperature steam delivery pipeline (407) is provided at the outlet of the high-pressure steam turbine (15); an eighth temperature detection point (4071) and a third pressure detection point (4072) are provided on the low-temperature steam delivery pipeline (407); The heat exchanger (9) is connected to the high-pressure steam turbine (15) via a low-temperature steam delivery pipeline (407), one end of the low-temperature steam delivery pipeline (407) is connected to the inlet of the heat exchanger (9), and the other end is connected to the outlet of the high-pressure steam turbine (15); The inlet of the low-pressure steam turbine (16) is provided with a low-pressure medium-temperature steam pipeline (408), the other end of the low-pressure medium-temperature steam pipeline (408) is connected to the heat exchanger (9), the low-pressure medium-temperature steam pipeline (408) is provided with a ninth temperature detection point (4081) and a fourth pressure detection point (4082), the outlet of the low-pressure steam turbine (16) is connected with a circulating condensate water delivery pipeline (409), the circulating condensate water delivery pipeline (409) is provided with a tenth temperature monitoring point (4091) and a fifth pressure detection point (4092), and the circulating water pipeline (416) is connected to the circulating condensate water delivery pipeline (409); The cogeneration unit further comprises: A condensate delivery pipeline (413) is connected to the inlet of the condensate preheater (17); an external condensate delivery pipeline (411) is connected to the inlet of the condensate delivery pipeline (413); the external condensate delivery pipeline (411) is provided with a sixth flow control valve (412) and is in communication connection with the first by-product steam control valve (403); the circulating water pipeline (416) and the external condensate delivery pipeline (411) are connected to the condensate delivery pipeline (413); an eleventh temperature detection point (4132) is provided on the condensate delivery pipeline (413); the outlet of the condensate preheater (17) is also connected to a hot desalted water delivery pipeline (414); and the hot desalted water delivery pipeline (414) is provided with a twelfth temperature monitoring point (4141) and a sixth pressure detection point (4142); The booster pump (18) is connected to the condensate preheater (17) via a hot desalted water delivery pipeline (414); the booster pump (18) is also connected to a pressurized condensate delivery pipeline (401); a seventh pressure detection point (4012) is provided on the pressurized condensate delivery pipeline (401); and the booster pump (18) is connected to the waste heat boiler (6) via the pressurized condensate delivery pipeline (401); The condensate discharge pipe (415) is arranged at the discharge outlet of the circulating condensate delivery pipe (409), and a fifth flow regulating valve (410) is provided on the condensate discharge pipe (415). The fifth flow regulating valve (410) is connected to a flow controller via a transmission line and is communicatively connected to the first by-product steam regulating valve (403).

6. The cogeneration and natural gas reforming hydrogen production system according to claim 2 is characterized by: The medium and low temperature conversion unit also includes: a conversion device feed pipeline (301) connected to the inlet of the medium and low temperature conversion device (8), The inlet of the medium-low temperature conversion device (8) and the outlet of the conversion preheater (7) are connected via the conversion device feed pipeline (301), the conversion device feed pipeline (301) is provided with a fourth pressure regulating valve (302), the fourth pressure regulating valve (302) is connected to a pressure controller via a transmission line, and the conversion device feed pipeline (301) is also provided with a thirteenth temperature detection point (3011) and a synthesis gas component collection and analysis point (3012); The medium-low temperature conversion device (8) is also connected to a hydrogen-rich gas delivery pipeline (303), and the hydrogen-rich gas delivery pipeline (303) is respectively provided with a fourteenth temperature detection point (3031) and a hydrogen-rich gas component collection and analysis point (3032). The medium-low temperature conversion device (8) is connected to the heat exchanger (9) through the hydrogen-rich gas delivery pipeline (303), and a cooler feed pipe (304) is provided at the outlet of the heat exchanger (9), and a fifteenth temperature detection point (3041) is provided on the cooler feed pipe (304).

7. The cogeneration and natural gas reforming hydrogen production system according to claim 2 is characterized by: The outlet of the cooler (10) is connected to a gas-liquid mixed transport pipeline (501); the inlet of the cooler (10) is connected to the outlet of the heat exchanger (9) via a cooler feed pipe (304); a sixteenth temperature detection point (5011) and a fifth pressure regulating valve (502) are provided on the gas-liquid mixed transport pipeline (501); a pressure controller is connected to the fifth pressure regulating valve (502) via a transmission line; and a component detection point (5012) is also provided on the gas-liquid mixed transport pipeline (501); a ninth pipeline (503) connected to the top outlet of the gas-liquid separator (11), a liquid water discharge pipeline (504) connected to the bottom outlet of the gas-liquid separator (11), the ninth pipeline (503) being provided with a seventeenth temperature detection point (5031), a first gas component detection point (5032), and a sixth pressure regulating valve (505), the pressure regulating valve (505) being connected to a pressure controller via a transmission line, and the liquid water discharge pipe (504) being provided with an eighteenth temperature detection point (5041); The top outlet of the decarbonation tower (12) is connected to a decarbonation gas delivery pipeline (506), the bottom outlet of the decarbonation tower (12) is connected to a CO2 discharge pipeline (507), the inlet of the decarbonation tower (12) is connected to the outlet of the gas-liquid separator (11) via a gas delivery pipeline (503), the decarbonation gas delivery pipeline (506) is provided with a nineteenth temperature detection point (5061), the decarbonation gas delivery pipeline (506) is also provided with a second gas component detection point (5062) and a seventh pressure regulating valve (508), the seventh pressure regulating valve (508) is connected to a pressure controller via a transmission line, and the CO2 discharge pipeline (507) is provided with a twentieth temperature detection point (5071); The top outlet of the pressure swing adsorption device (13) is connected to a hydrogen product delivery pipeline (509), and the bottom outlet of the pressure swing adsorption device (13) is connected to a remaining gas delivery pipeline (510). The pressure swing adsorption device (13) is connected to the carbon dioxide removal tower (12) via a decarbonation gas delivery pipeline (506). The hydrogen product delivery pipeline (509) is provided with a twenty-first temperature detection point (5091). The hydrogen product delivery pipeline (509) is also provided with a third gas component detection point (5092) and an eighth pressure regulating valve (511). The sixth pressure regulating valve (511) is connected to a pressure controller via a transmission line. The remaining gas delivery pipeline (510) is provided with a twenty-second temperature detection point (5101).

8. The cogeneration system for producing hydrogen through natural gas reforming according to any one of claims 1 to 7, characterized in that: The system further comprises a feedstock pretreatment unit, wherein an outlet of the feedstock pretreatment unit is in communication with an inlet of the natural gas conversion unit; The raw material pretreatment unit comprises: a liquefied natural gas gasifier (2); A pump (1) is arranged at the natural gas inlet end of the liquefied natural gas vaporizer (2) and is in communication with the liquefied natural gas vaporizer (2); The desulfurization device (3) is arranged at the outlet end of the liquefied natural gas vaporizer (2), and the inlet is connected to the outlet of the liquefied natural gas vaporizer (2); the outlet of the desulfurization device (3) is connected to the inlet of the natural gas conversion unit through a natural gas transmission pipeline.

9. The cogeneration and natural gas reforming hydrogen production system according to claim 8, characterized in that: The inlet of the pump (1) is connected to a liquefied natural gas feed pipe (101), the outlet of the pump (1) is connected to a first pipeline (103), the liquefied natural gas feed pipe (101) is provided with a first flow regulating valve (102), and the first pipeline (103) is provided with a second flow regulating valve (104); The liquefied natural gas vaporizer (2) is in communication with the pump (1) via a first pipeline (103); the first pipeline (103) is also provided with a first pressure detection point (1031) and a first pressure regulating valve (105) for controlling the fluid pressure in the pipeline; the first pressure regulating valve (105) is connected to a pressure controller via a transmission line; The desulfurization device (3) is connected to the liquefied natural gas vaporizer (2) via a second pipeline (106); the second pipeline (106) is connected to a first temperature detection point (1061), a natural gas sampling point (1062) and a second pressure regulating valve (107); the desulfurization device (3) is also connected to a third pipeline (108) and a fourth pipeline (109); The third pipeline (108) is provided with a third flow regulating valve (202), and the seventh pipeline (201) enters the natural gas conversion unit and is connected with the third pipeline (108) and the mixed gas pipeline (204).

10. A method for controlling cogeneration of heat and power coupled with natural gas hydrogen production, the method being implemented based on the cogeneration of heat and power coupled with natural gas hydrogen production system according to claim 2, comprising the following steps: S401: Calculate the condensed water demand and the amount of steam used for cogeneration based on material balance, heat balance, water vapor demand under steady-state conditions, and heat provided by natural gas conversion and medium- and low-temperature shift reactors, and calculate the heat and electricity distribution ratio of cogeneration under the conditions; S402: collecting the amount of byproduct steam and comparing it with the water vapor demand under the first step of steady-state operation; collecting the amount of byproduct steam through the first byproduct steam regulating valve (403) and comparing it with the water vapor demand under steady-state operation; S403: Select an operation based on the comparison result: If the by-product steam volume is the same as the water vapor demand, the operating conditions meet the steam demand under the production scale, and the steam valve opening will not be changed; If the amount of byproduct steam is greater than the amount of water vapor demanded, the water vapor generated under the current operating conditions is too much and greater than the actual steam demand, it is necessary to reduce the opening of the first byproduct steam regulating valve (403), increase the opening of the second byproduct steam regulating valve (406), increase the opening of the fifth flow regulating valve (410), and close the sixth flow regulating valve (412); If the amount of byproduct steam is less than the amount of water vapor demanded, the water vapor generated under the current operating conditions is too little and less than the actual steam demand, it is necessary to increase the opening of the first byproduct steam regulating valve (403), reduce the opening of the second byproduct steam regulating valve (406), close the fifth flow regulating valve (410), and increase the opening of the sixth flow regulating valve (412); The opening / closing degree of the first byproduct steam regulating valve (403), the second byproduct steam regulating valve (406), the fifth flow regulating valve (410) and the sixth flow regulating valve (412) is determined according to the ratio of the collected byproduct steam amount to the water vapor demand. The formula for determining the opening / closing degree of the first byproduct steam regulating valve (403) is: The formula for determining the opening / closing degree of the second byproduct steam regulating valve (406) is: The formula for determining the opening / closing degree of the fifth flow control valve (410) is: The formula for determining the opening / closing degree of the sixth flow control valve (412) is: Where: F represents the flow rate, the subscript max represents the maximum flow rate corresponding to each valve fully open, Δκ represents the opening / closing degree of each valve. If the calculation result is positive, it means that the valve opening needs to be increased, and if the calculation result is negative, it means that the valve opening needs to be reduced. S404: Calculate the heat and electricity distribution ratio b of the cogeneration according to the valve opening adjustment amount, the heat and electricity steady-state distribution ratio 热 / 电 =F 403 / F 406 ; S405: According to the calculation result of step S404, the final distribution ratio of heat and electricity is obtained to achieve a stable supply of steam and electricity for the cogeneration unit.

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