Photo-thermal coupling methanol reforming hydrogen-electricity co-production system

Abstract

The invention discloses a photo-thermal coupling methanol reforming hydrogen-electricity co-production system which comprises a photo-thermal unit, a heat storage unit, a methanol reforming hydrogen production unit, a fuel cell unit and a steam turbine power generation unit, and the heat storage unit is connected with the photo-thermal unit, the methanol reforming hydrogen production unit, the fuel cell unit and the steam turbine power generation unit. The fuel cell unit is respectively connected with the methanol reforming hydrogen production unit and the steam turbine power generation unit; the photo-thermal unit stores heat energy of solar radiation in the heat storage unit, the heat storage unit supplies heat to the methanol reforming hydrogen production unit, methanol reforming reaction is carried out in the methanol reforming hydrogen production unit, prepared hydrogen is supplied to the fuel cell unit, the fuel cell unit generates power through the hydrogen and discharges high-temperature water vapor, and the fuel cell unit is connected with the heat storage unit. And the heat energy of the discharged high-temperature water vapor is directly supplied to the steam turbine power generation unit or stored in the heat storage unit and supplied to the steam turbine power generation unit through the heat storage unit. And high-efficiency and low-carbon methanol reforming hydrogen production and power generation can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of methanol hydrogen production, and specifically relates to a photothermal coupled methanol reforming hydrogen-electricity cogeneration system. Background Art

[0002] Methanol reforming hydrogen production technology is a process that converts methanol and water into hydrogen and carbon dioxide under the action of a catalyst. This process has the advantages of low cost, high hydrogen purity, simple equipment, and convenient storage and transportation. It has become one of the important sources of industrial hydrogen. With the refinement and improvement of the hydrogen energy industry, methanol reforming hydrogen production technology has greater development potential in small-scale flexible hydrogen production scenarios.

[0003] At present, China is the world's largest methanol producer and consumer, with an annual production capacity of more than 90 million tons, accounting for about 60% of the world's total methanol production, providing a solid industrial foundation for methanol reforming to produce hydrogen. In addition, methanol can be used as a steady-state carrier of hydrogen energy, which can safely, efficiently and cost-effectively transport hydrogen energy from the hydrogen production end to the hydrogen use end, greatly reducing storage and transportation costs, and improving the implementation and safety of hydrogen energy. As an important technical link at the hydrogen use end, methanol reforming hydrogen production technology helps to solve the problems of hydrogen energy in hydrogen production, storage, transportation and hydrogenation, and provides a safe and efficient path for the implementation of hydrogen energy.

[0004] Methanol-to-hydrogen power generation is an extended application of methanol-to-hydrogen production. The hydrogen obtained by methanol reforming is converted into electricity through fuel cells, which can realize the immediate use of hydrogen, avoid the need for large-scale hydrogen storage and long-distance hydrogen transportation, and simplify the hydrogen energy supply chain. In addition, the carbon dioxide produced in the process of methanol reforming hydrogen production can be discharged in a centralized manner, which is easy to capture and utilize, and helps reduce greenhouse gas emissions.

[0005] The following reactions mainly occur in the process of methanol reforming to produce hydrogen, among which methanol reforming is the main reaction and methanol cracking is the side reaction. The selectivity of methanol reforming is usually greater than 95%:

[0006] Methanol reforming: CH3OH(g)+H2O(g)→CO2(g)+3H2(g)+48.17kJ / mol

[0007] Methanol cracking: CH3OH(g)→CO(g)+2H2(g)+89.3kJ / mol

[0008] According to the above-mentioned methanol reforming and methanol cracking reactions, the products of the methanol reforming hydrogen production process are mainly hydrogen and carbon dioxide. However, due to the presence of carbon monoxide in the product, it is necessary to remove carbon monoxide through water gas shift or methanation reaction. The water gas shift and methanation reactions are as follows:

[0009] Water gas shift: CO(g)+H2O(g)→CO2(g)+H2(g)-41.2kJ / mol

[0010] Methanation: CO(g)+3H2(g)→CH4(g)+H2O(g)-204.7kJ / mol

[0011] From a material perspective, methanol reforming to produce hydrogen can produce three molecules of hydrogen for every molecule of carbon dioxide emitted, which is a relatively efficient and low-carbon way to produce hydrogen. However, from an energy perspective, methanol reforming to produce hydrogen is a net endothermic process that requires fuel combustion to provide energy, and the combustion or production process of fuels such as coal, methanol or hydrogen will emit additional carbon dioxide. Therefore, the carbon dioxide emissions generated by the current methanol reforming hydrogen production process are far higher than the theoretical value of its carbon dioxide emissions, making it difficult to achieve low-carbon hydrogen production and power generation. Summary of the invention

[0012] In view of the above-mentioned defects of the prior art, the present invention provides a photothermal coupled methanol reforming hydrogen-electricity cogeneration system, which can achieve efficient and low-carbon methanol hydrogen production and power generation.

[0013] The technical solution adopted by the present invention to solve its technical problem is:

[0014] A photothermal coupled methanol reforming hydrogen-electricity cogeneration system comprises a photothermal unit, a heat storage unit, a methanol reforming hydrogen production unit, a fuel cell unit and a steam turbine power generation unit, wherein the heat storage unit is respectively connected to the photothermal unit, the methanol reforming hydrogen production unit, the fuel cell unit and the steam turbine power generation unit, and the fuel cell unit is respectively connected to the methanol reforming hydrogen production unit and the steam turbine power generation unit; the photothermal unit is used to store the heat energy of solar radiation in the heat storage unit, the heat storage unit is used to supply heat to the methanol reforming hydrogen production unit, so that a methanol reforming reaction occurs in the methanol reforming hydrogen production unit and the produced hydrogen is supplied to the fuel cell unit, the fuel cell unit is used to convert the chemical energy of hydrogen and oxygen into electrical energy and discharge high-temperature water vapor, and is used to directly supply heat to the steam turbine power generation unit with the heat energy of the discharged high-temperature water vapor or store it in the heat storage unit and supply heat to the steam turbine power generation unit through the heat storage unit, so that the steam turbine power generation unit performs steam power generation.

[0015] Furthermore, the methanol reforming hydrogen production unit comprises an evaporator, a first tubular reactor, a second tubular reactor, a first heat exchanger, a first condenser and a pressure swing adsorption separator, wherein the gas outlet of the evaporator is connected to the gas inlet of the first tubular reactor, the gas outlet of the first tubular reactor is connected to the gas inlet of the second tubular reactor, the gas outlet of the second tubular reactor is connected to the gas inlet of the first heat exchanger, the gas outlet of the first heat exchanger is connected to the gas inlet of the first condenser, the gas outlet of the first condenser is connected to the gas inlet of the pressure swing adsorption separator, and the pressure swing adsorption separator The hydrogen outlet of the reactor is connected to the hydrogen inlet of the fuel cell unit; the evaporator is used to evaporate a mixed liquid of methanol and water, the first tubular reactor is used to produce a methanol gas-water vapor reforming reaction, the second tubular reactor is used to produce a methanation reaction, the first heat exchanger is used to reduce the gas at the outlet of the second tubular reactor to a certain temperature higher than normal temperature, the first condenser is used to reduce the gas at the outlet of the first heat exchanger to normal temperature and remove water, and the pressure swing adsorption separator is used to separate the gas at the outlet of the first condenser to obtain high-purity hydrogen and recover carbon dioxide.

[0016] Furthermore, the photothermal unit is a trough photothermal unit and includes a parabolic trough concentrator and a heat collecting tube. The parabolic trough concentrator is used to focus sunlight onto the heat collecting tube, and the low-temperature heat transfer oil in the heat storage unit is used to enter the heat collecting tube and absorb the heat energy of solar radiation and convert it into high-temperature heat transfer oil.

[0017] Further, the heat storage unit includes a high-temperature thermal oil tank, a low-temperature thermal oil tank, a high-temperature molten salt tank, a low-temperature molten salt tank, a high-temperature and high-pressure water tank, and a low-temperature water tank;

[0018] The oil outlet of the low-temperature thermal oil tank is connected to the oil inlet of the photothermal unit, and the oil outlet of the photothermal unit is connected to the oil inlet of the high-temperature thermal oil tank;

[0019] The oil outlet of the high-temperature heat-conducting oil tank is connected to the high-temperature oil inlet of the second heat exchanger, the low-temperature oil outlet of the second heat exchanger is connected to the oil inlet of the low-temperature heat-conducting oil tank, the oil outlet of the first tubular reactor is connected to the low-temperature oil inlet of the second heat exchanger, and the high-temperature oil outlet of the second heat exchanger is connected to the oil inlet of the first tubular reactor;

[0020] The oil outlet of the high-temperature heat-conducting oil tank is connected to the oil inlet of the second tubular reactor, and the oil outlet of the second tubular reactor is connected to the oil inlet of the high-temperature heat-conducting oil tank;

[0021] The oil outlet of the low-temperature heat-conducting oil tank is connected to the oil inlet of the first heat exchanger, and the oil outlet of the first heat exchanger is connected to the oil inlet of the high-temperature heat-conducting oil tank;

[0022] The water outlet of the low-temperature water tank is connected to the low-temperature water inlet of the first condenser, and the high-temperature water outlet of the first condenser is connected to the water inlet of the high-temperature and high-pressure water tank;

[0023] The water outlet of the high-temperature and high-pressure water tank is connected to the water inlet of the evaporator, and the water outlet of the evaporator is connected to the water inlet of the low-temperature water tank;

[0024] The exhaust port of the fuel cell unit is connected to the air inlet of the third heat exchanger, the air outlet of the third heat exchanger is connected to the air inlet of the fourth heat exchanger, the molten salt outlet of the low-temperature molten salt tank is connected to the molten salt inlet of the third heat exchanger, and the molten salt outlet of the third heat exchanger is connected to the molten salt inlet of the high-temperature molten salt tank;

[0025] The low-temperature water outlet of the fourth heat exchanger is connected to the water inlet of the water treatment device, the water outlet of the water treatment device is connected to the water inlet of the desalted water tank, the water outlet of the low-temperature water tank is connected to the low-temperature water inlet of the fourth heat exchanger, and the high-temperature water outlet of the fourth heat exchanger is connected to the water inlet of the high-temperature and high-pressure water tank;

[0026] The molten salt outlet of the high-temperature molten salt tank is connected to the molten salt inlet of the fifth heat exchanger, the molten salt outlet of the fifth heat exchanger is connected to the molten salt inlet of the low-temperature molten salt tank, the oil outlet of the low-temperature thermal oil tank is connected to the oil inlet of the fifth heat exchanger, and the oil outlet of the fifth heat exchanger is connected to the oil inlet of the high-temperature thermal oil tank.

[0027] Furthermore, the steam turbine power generation unit includes a steam turbine, a generator and a second condenser, the steam turbine is connected to the generator, and the exhaust port of the steam turbine is connected to the air inlet of the second condenser; the thermal energy of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is used to heat the water discharged from the low-temperature water outlet of the second condenser, or the thermal energy stored in the heat storage unit is used to heat the water discharged from the low-temperature water outlet of the second condenser.

[0028] Furthermore, the heat energy of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is used to supply heat to the water discharged from the low-temperature water outlet of the second condenser. Specifically: the exhaust port of the fuel cell unit is also connected to the high-temperature air inlet of the sixth heat exchanger, the low-temperature water outlet of the sixth heat exchanger is connected to the water inlet of the water treatment device, the low-temperature water inlet of the sixth heat exchanger is connected to the low-temperature water outlet of the second condenser, and in the case of insufficient water supply to the second condenser, the low-temperature water inlet of the sixth heat exchanger is also connected to the water outlet of the desalted water tank, and the high-temperature air outlet of the sixth heat exchanger is connected to the air inlet of the steam turbine.

[0029] Furthermore, the heat energy stored in the heat storage unit is used to supply heat to water discharged from the low-temperature water outlet of the second condenser. Specifically, the low-temperature water outlet of the second condenser is connected to the low-temperature water inlet of the seventh heat exchanger, and when the water supply to the second condenser is insufficient, the low-temperature water inlet of the seventh heat exchanger is also connected to the water outlet of the desalted water tank, the air outlet of the seventh heat exchanger is connected to the air inlet of the eighth heat exchanger, the water outlet of the high-temperature and high-pressure water tank is connected to the high-temperature water inlet of the seventh heat exchanger, and the seventh The low-temperature water outlet of the heat exchanger is connected to the water inlet of the low-temperature water tank; the oil outlet of the high-temperature thermal oil tank is connected to the oil inlet of the eighth heat exchanger, the oil outlet of the eighth heat exchanger is connected to the oil inlet of the low-temperature thermal oil tank, and the air outlet of the eighth heat exchanger is connected to the air inlet of the ninth heat exchanger; the molten salt outlet of the high-temperature molten salt tank is connected to the molten salt inlet of the ninth heat exchanger, the molten salt outlet of the ninth heat exchanger is connected to the molten salt inlet of the low-temperature molten salt tank, and the air outlet of the ninth heat exchanger is connected to the air inlet of the steam turbine.

[0030] Furthermore, the first heat exchanger is used to reduce the temperature of the gas at the gas outlet of the second tubular reactor to below 200°C.

[0031] Furthermore, the drain outlet of the first condenser is connected to the water inlet of the low-temperature water tank.

[0032] Furthermore, the reaction temperature of the methanol gas-steam reforming reaction occurring in the first tubular reactor is less than or equal to 280°C, the reaction temperature of the methanation reaction occurring in the second tubular reactor is less than or equal to 380°C, the gas temperature at the outlet of the second tubular reactor is less than or equal to 400°C, the external heating temperature of the photothermal unit is 390-400°C, the temperature of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is 750-800°C, the temperature of the high-temperature water vapor at the outlet of the third heat exchanger is 300±5°C, the temperature of the heat transfer oil in the high-temperature heat transfer oil tank is greater than or equal to 380°C, the temperature of the heat transfer oil in the low-temperature heat transfer oil tank is less than or equal to 160°C, the temperature of the molten salt in the high-temperature molten salt tank is 580±5°C, the temperature of the molten salt in the low-temperature molten salt tank is 290±5°C, the temperature of the high-temperature and high-pressure water in the high-temperature and high-pressure water tank is 180±5°C, and the temperature of the mixed gas of methanol gas and water vapor obtained by the evaporator is less than or equal to 140°C.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] The photothermal coupled methanol reforming hydrogen and electricity cogeneration system of the present invention includes a photothermal unit, a heat storage unit, a methanol reforming hydrogen production unit, a fuel cell unit and a steam turbine power generation unit, and the heat storage unit is respectively connected to the photothermal unit, the methanol reforming hydrogen production unit, the fuel cell unit and the steam turbine power generation unit, and the fuel cell unit is respectively connected to the methanol reforming hydrogen production unit and the steam turbine power generation unit. First, the energy required for methanol reforming hydrogen production is directly provided by the heat storage unit, and the energy of the heat storage unit is provided by the heat of the high-temperature water vapor discharged by the photothermal unit and the recovery fuel cell unit, thereby fundamentally eliminating the need for fuel combustion heating, so that the overall process of methanol reforming hydrogen production only emits carbon dioxide in the chemical reaction stoichiometric ratio, that is, for every 1 mole of methanol consumed, 3 moles of hydrogen and 1 mole of carbon dioxide are produced, thereby minimizing the carbon emissions of the process. Secondly, due to the addition of the heat storage unit, the system can work without sunlight to achieve continuous hydrogen production and power generation. In addition, the methanol reforming hydrogen production unit, the fuel cell unit and the steam turbine power generation unit can be operated independently or semi-independently through the heat storage unit, thereby achieving more flexible and wide-range operation. For example, after hydrogen is extracted, the hydrogen intake of the fuel cell unit is reduced and the power generation capacity is reduced. The heat storage unit can provide heat to generate more high-temperature and high-pressure water vapor to increase the output power of the steam turbine power generation unit, thereby ensuring the stability of the overall power generation capacity. For example, when the power generation capacity needs to be adjusted, the hydrogen intake of the fuel cell unit can be adjusted by adjusting the methanol feed rate, and the energy ratio recovered from the exhaust gas of the fuel cell unit to the heat storage unit can be changed to change the output power of the steam turbine power generation unit, thereby achieving a larger range of power generation capacity adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the photothermal coupled methanol reforming hydrogen-electricity cogeneration system of the present invention;

[0036] Figure 2 It is a schematic diagram of the specific layout of the photothermal coupled methanol reforming hydrogen-electricity cogeneration system in the present invention. DETAILED DESCRIPTION

[0037] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present invention, but not to limit the present invention.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] like Figure 1 As shown, a photothermal coupled methanol reforming hydrogen-electricity cogeneration system comprises a photothermal unit, a heat storage unit, a methanol reforming hydrogen production unit, a fuel cell unit and a steam turbine power generation unit, wherein the heat storage unit is respectively connected to the photothermal unit, the methanol reforming hydrogen production unit, the fuel cell unit and the steam turbine power generation unit, and the fuel cell unit is respectively connected to the methanol reforming hydrogen production unit and the steam turbine power generation unit; the photothermal unit is used to store the heat energy of solar radiation in the heat storage unit, and the heat storage unit is used to supply heat to the methanol reforming hydrogen production unit, so that a methanol reforming reaction occurs in the methanol reforming hydrogen production unit and the produced hydrogen is supplied to the fuel cell unit, and the fuel cell unit is used to convert the chemical energy of hydrogen and oxygen into electrical energy and discharge high-temperature water vapor, and is used to directly supply heat to the steam turbine power generation unit with the heat energy of the discharged high-temperature water vapor or store it in the heat storage unit and supply heat to the steam turbine power generation unit through the heat storage unit, so that the steam turbine power generation unit performs steam power generation.

[0040] First, the energy required for methanol reforming to produce hydrogen is directly provided by the heat storage unit, and the energy of the heat storage unit is provided by the heat of the high-temperature water vapor discharged by the photothermal unit and the recovery fuel cell unit, thus fundamentally eliminating the need for fuel combustion heating, so that the overall process of methanol reforming to produce hydrogen only emits carbon dioxide in the chemical reaction stoichiometric ratio, that is, for every 1 mole of methanol consumed, 3 moles of hydrogen and 1 mole of carbon dioxide are produced, thereby minimizing the carbon emissions of the process. Secondly, due to the addition of the heat storage unit, the system can work without sunlight, achieving continuous hydrogen production and power generation. In addition, the methanol reforming hydrogen production unit, the fuel cell unit and the steam turbine power generation unit can be operated independently or semi-independently through the heat storage unit, thereby achieving more flexible and wide-range operation. For example, after hydrogen is extracted, the hydrogen intake of the fuel cell unit is reduced and the power generation capacity is reduced. The heat storage unit can provide heat to generate more high-temperature and high-pressure water vapor to increase the output power of the steam turbine power generation unit, thereby ensuring the stability of the overall power generation capacity. For example, when the power generation capacity needs to be adjusted, the hydrogen intake of the fuel cell unit can be adjusted by adjusting the methanol feed rate, and the energy ratio recovered from the exhaust gas of the fuel cell unit to the heat storage unit can be changed to change the output power of the steam turbine power generation unit, thereby achieving a larger range of power generation capacity adjustment.

[0041] In one embodiment, Figure 2 As shown, the solar thermal unit is a trough type solar thermal unit and includes a parabolic trough concentrator and a heat collecting tube. The parabolic trough concentrator is used to focus sunlight onto the heat collecting tube, and the low-temperature heat transfer oil in the heat storage unit is used to enter the heat collecting tube and absorb the heat energy of solar radiation and convert it into high-temperature heat transfer oil.

[0042] In one embodiment, Figure 2 As shown, the methanol reforming hydrogen production unit includes an evaporator, a first tubular reactor, a second tubular reactor, a first heat exchanger, a first condenser and a pressure swing adsorption separator, the gas outlet of the evaporator is connected to the gas inlet of the first tubular reactor, the gas outlet of the first tubular reactor is connected to the gas inlet of the second tubular reactor, the gas outlet of the second tubular reactor is connected to the gas inlet of the first heat exchanger, the gas outlet of the first heat exchanger is connected to the gas inlet of the first condenser, the gas outlet of the first condenser is connected to the gas inlet of the pressure swing adsorption separator, and the drain outlet of the first condenser is connected to the water inlet of the low-temperature water tank. The hydrogen outlet of the pressure swing adsorption separator is connected to the hydrogen inlet of the fuel cell unit; the evaporator is used to evaporate the mixed liquid of methanol and water, the first tubular reactor is used to produce a methanol gas-water vapor reforming reaction, the second tubular reactor is used to produce a methanation reaction, the first heat exchanger is used to reduce the gas at the outlet of the second tubular reactor to a certain temperature higher than normal temperature, the first condenser is used to reduce the gas at the outlet of the first heat exchanger to normal temperature and remove water, and the pressure swing adsorption separator is used to separate the gas at the outlet of the first condenser to obtain high-purity hydrogen and recover carbon dioxide. In this way, the carbon dioxide emitted from the methanol reforming hydrogen production unit is concentrated at the carbon dioxide outlet of the pressure swing adsorption separator, which is conducive to the capture of carbon dioxide.

[0043] Among them, Figure 2 As shown, the heat storage unit includes a high-temperature thermal oil tank, a low-temperature thermal oil tank, a high-temperature molten salt tank, a low-temperature molten salt tank, a high-temperature and high-pressure water tank, and a low-temperature water tank;

[0044] The oil outlet of the low-temperature thermal oil tank is connected to the oil inlet of the photothermal unit, and the oil outlet of the photothermal unit is connected to the oil inlet of the high-temperature thermal oil tank. Preferably, the oil outlet of the low-temperature thermal oil tank is connected to the oil inlet of the heat collecting pipe, and the oil outlet of the heat collecting pipe is connected to the oil inlet of the high-temperature thermal oil tank;

[0045] The oil outlet of the high-temperature heat-conducting oil tank is connected to the high-temperature oil inlet of the second heat exchanger, the low-temperature oil outlet of the second heat exchanger is connected to the oil inlet of the low-temperature heat-conducting oil tank, the oil outlet of the first tubular reactor is connected to the low-temperature oil inlet of the second heat exchanger, and the high-temperature oil outlet of the second heat exchanger is connected to the oil inlet of the first tubular reactor, so that the low-temperature heat-conducting oil in the first tubular reactor can be heated by the high-temperature heat-conducting oil in the high-temperature heat-conducting oil tank in the second heat exchanger to provide the heat required for the methanol gas-steam reforming reaction in the first tubular reactor to be absorbed;

[0046] The oil outlet of the high-temperature heat-conducting oil tank is connected to the oil inlet of the second tubular reactor, and the oil outlet of the second tubular reactor is connected to the oil inlet of the high-temperature heat-conducting oil tank, so that the high-temperature heat-conducting oil in the high-temperature heat-conducting oil tank can provide a stable reaction temperature for the methanation reaction occurring in the second tubular reactor by entering and exiting the second tubular reactor;

[0047] The oil outlet of the low-temperature heat-conducting oil tank is connected to the oil inlet of the first heat exchanger, and the oil outlet of the first heat exchanger is connected to the oil inlet of the high-temperature heat-conducting oil tank, so that the gas at the gas outlet of the second tubular reactor can be reduced to a certain temperature higher than the normal temperature in the first heat exchanger, and the heat energy carried by the gas at the gas outlet of the second tubular reactor can be stored in the heat-conducting oil;

[0048] The water outlet of the low-temperature water tank is connected to the low-temperature water inlet of the first condenser, and the high-temperature water outlet of the first condenser is connected to the water inlet of the high-temperature and high-pressure water tank, so that the gas at the outlet of the first heat exchanger can be cooled to room temperature and dehydrated in the first condenser, and the heat carried by the gas at the outlet of the first heat exchanger can be stored in water, wherein the dehydration specifically involves condensing the water vapor in the gas discharged from the outlet of the first heat exchanger into water in the first condenser and passing it into the low-temperature water tank.

[0049] The water outlet of the high-temperature and high-pressure water tank is connected to the water inlet of the evaporator, and the water outlet of the evaporator is connected to the water inlet of the low-temperature water tank, so that the high-temperature water in the high-temperature and high-pressure water tank can be used in the evaporator to evaporate the mixed liquid of methanol and water;

[0050] The exhaust port of the fuel cell unit is connected to the air inlet of the third heat exchanger, the air outlet of the third heat exchanger is connected to the air inlet of the fourth heat exchanger, the molten salt outlet of the low-temperature molten salt tank is connected to the molten salt inlet of the third heat exchanger, and the molten salt outlet of the third heat exchanger is connected to the molten salt inlet of the high-temperature molten salt tank, so that the high-temperature water vapor discharged from the exhaust port of the fuel cell unit can be used to heat the low-temperature molten salt in the third heat exchanger;

[0051] The low-temperature water outlet of the fourth heat exchanger is connected to the water inlet of the water treatment device, the water outlet of the water treatment device is connected to the water inlet of the desalted water tank, the water outlet of the low-temperature water tank is connected to the low-temperature water inlet of the fourth heat exchanger, and the high-temperature water outlet of the fourth heat exchanger is connected to the water inlet of the high-temperature and high-pressure water tank, so that the high-temperature water vapor discharged from the gas outlet of the third heat exchanger can be used to heat water in the fourth heat exchanger;

[0052] The molten salt outlet of the high-temperature molten salt tank is connected to the molten salt inlet of the fifth heat exchanger, the molten salt outlet of the fifth heat exchanger is connected to the molten salt inlet of the low-temperature molten salt tank, the oil outlet of the low-temperature thermal oil tank is connected to the oil inlet of the fifth heat exchanger, and the oil outlet of the fifth heat exchanger is connected to the oil inlet of the high-temperature thermal oil tank, so that the high-temperature molten salt can be used to heat the low-temperature thermal oil in the fifth heat exchanger.

[0053] The heat storage unit has three heat storage sub-units with different thermal qualities, which can recover and utilize heat of different qualities in a graded manner to achieve higher energy utilization efficiency.

[0054] Preferably, if Figure 2 As shown, the steam turbine power generation unit includes a steam turbine, a generator and a second condenser, the steam turbine is connected to the generator, and the exhaust port of the steam turbine is connected to the air inlet of the second condenser, and the second condenser is used to cool the low-temperature water vapor discharged from the steam turbine; the heat energy of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is used to heat the water discharged from the low-temperature water outlet of the second condenser, and when the water supply of the second condenser is insufficient and does not meet the steam turbine operation conditions, the heat energy of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is also used to heat the water discharged from the water outlet of the desalted water tank to obtain high-temperature and high-pressure water vapor and pass it into the steam turbine to drive the generator to generate electricity; or the heat energy stored in the heat storage unit is used to heat the water discharged from the low-temperature water outlet of the second condenser, and when the water supply of the second condenser is insufficient and does not meet the steam turbine operation conditions, the heat energy stored in the heat storage unit is also used to heat the water discharged from the water outlet of the desalted water tank to obtain high-temperature and high-pressure water vapor and pass it into the steam turbine to drive the generator to generate electricity. The above two methods can drive the steam turbine power generation unit to generate electricity independently or together.

[0055] Preferably, the heat energy of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is used to heat the water discharged from the low-temperature water outlet of the second condenser, specifically: Figure 2As shown, the exhaust port of the fuel cell unit is also connected to the high-temperature air inlet of the sixth heat exchanger, the low-temperature water outlet of the sixth heat exchanger is connected to the water inlet of the water treatment device, the low-temperature water inlet of the sixth heat exchanger is connected to the low-temperature water outlet of the second condenser, and when the water supply to the second condenser is insufficient and does not meet the steam turbine operating conditions, the low-temperature water inlet of the sixth heat exchanger is also connected to the water outlet of the desalted water tank, and the high-temperature air outlet of the sixth heat exchanger is connected to the air inlet of the steam turbine. In this way, the high-temperature water vapor discharged from the exhaust port of the fuel cell unit can be directly used in the sixth heat exchanger to heat the water discharged from the low-temperature water outlet of the second condenser or heat the water discharged from the water outlet of the desalted water tank and convert it into high-temperature and high-pressure water vapor, and then pass it into the steam turbine to drive the generator to generate electricity.

[0056] Preferably, the heat energy stored in the heat storage unit is used to heat the water discharged from the low-temperature water outlet of the second condenser, specifically: Figure 2 As shown, the low-temperature water outlet of the second condenser is connected to the low-temperature water inlet of the seventh heat exchanger, and when the water supply to the second condenser is insufficient and does not meet the operating conditions of the steam turbine, the low-temperature water inlet of the seventh heat exchanger is also connected to the water outlet of the desalted water tank, the air outlet of the seventh heat exchanger is connected to the air inlet of the eighth heat exchanger, the water outlet of the high-temperature and high-pressure water tank is connected to the high-temperature water inlet of the seventh heat exchanger, and the low-temperature water outlet of the seventh heat exchanger is connected to the water inlet of the low-temperature water tank; the oil outlet of the high-temperature thermal oil tank is connected to the oil inlet of the eighth heat exchanger, the oil outlet of the eighth heat exchanger is connected to the oil inlet of the low-temperature thermal oil tank, and the air outlet of the eighth heat exchanger is connected to the air inlet of the ninth heat exchanger; the molten salt outlet of the high-temperature molten salt tank is connected to the molten salt inlet of the ninth heat exchanger, the molten salt outlet of the ninth heat exchanger is connected to the molten salt inlet of the low-temperature molten salt tank, and the air outlet of the ninth heat exchanger is connected to the air inlet of the steam turbine. In this way, high-temperature water can be used in the seventh heat exchanger to preheat the water vapor entering the eighth heat exchanger, and high-temperature heat transfer oil can be used in the eighth heat exchanger to preheat the water vapor entering the ninth heat exchanger. In the ninth heat exchanger, high-temperature molten salt can be used to heat the water vapor entering it and convert it into high-temperature and high-pressure water vapor, which is then passed into the steam turbine to drive the generator to generate electricity.

[0057] Wherein, the first heat exchanger is used to reduce the temperature of the gas at the gas outlet of the second tubular reactor to less than 200°C.

[0058] Among them, the reaction temperature of the methanol gas-steam reforming reaction occurring in the first tubular reactor is less than or equal to 280°C, the reaction temperature of the methanation reaction occurring in the second tubular reactor is less than or equal to 380°C, the gas temperature at the outlet of the second tubular reactor is less than or equal to 400°C, the external heating temperature of the photothermal unit can reach 390-400°C, the temperature of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is 750-800°C, the temperature of the high-temperature water vapor at the outlet of the third heat exchanger is 300±5°C, the temperature of the heat transfer oil in the high-temperature heat transfer oil tank is greater than or equal to 380°C, the temperature of the heat transfer oil in the low-temperature heat transfer oil tank is less than or equal to 160°C, the temperature of the molten salt in the high-temperature molten salt tank is 580±5°C, the temperature of the molten salt in the low-temperature molten salt tank is 290±5°C, the temperature of the high-temperature and high-pressure water in the high-temperature and high-pressure water tank is 180±5°C, and the temperature of the mixed gas of methanol gas and water vapor obtained by the evaporator is less than or equal to 140°C.

[0059] The direct current generated by the fuel cell unit is converted into alternating current through an AC-DC converter and transmitted externally.

[0060] In summary, the present photothermal coupled methanol reforming hydrogen-electricity cogeneration system recovers the heat energy of solar radiation and the heat energy of high-temperature water vapor at the exhaust port of the fuel cell unit, and utilizes this heat energy to provide the required heat absorption for the methanol reforming reaction, thereby achieving continuous and stable hydrogen production and power generation. By comprehensively utilizing different heat-conducting media, energy recovery of heat energy of different qualities and efficient cascade energy utilization are achieved. In addition, since no fuel combustion is required to provide heat for the methanol reforming hydrogen production process, the present invention can achieve efficient and low-carbon chemical hydrogen production and power generation.

[0061] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A photothermal coupled methanol reforming hydrogen-electricity cogeneration system, characterized by: It includes a photothermal unit, a heat storage unit, a methanol reforming hydrogen production unit, a fuel cell unit and a steam turbine power generation unit. The heat storage unit is connected to the photothermal unit, the methanol reforming hydrogen production unit, the fuel cell unit and the steam turbine power generation unit respectively, and the fuel cell unit is connected to the methanol reforming hydrogen production unit and the steam turbine power generation unit respectively; the photothermal unit is used to store the heat energy of solar radiation in the heat storage unit, and the heat storage unit is used to supply heat to the methanol reforming hydrogen production unit, so that a methanol reforming reaction occurs in the methanol reforming hydrogen production unit and the produced hydrogen is supplied to the fuel cell unit, and the fuel cell unit is used to convert the chemical energy of hydrogen and oxygen into electrical energy and discharge high-temperature water vapor, and is used to directly supply heat to the steam turbine power generation unit with the heat energy of the discharged high-temperature water vapor or store it in the heat storage unit and supply heat to the steam turbine power generation unit through the heat storage unit, so that the steam turbine power generation unit performs steam power generation.

2. A photothermal coupled methanol reforming hydrogen-electricity cogeneration system according to claim 1, characterized in that: The methanol reforming hydrogen production unit comprises an evaporator, a first tubular reactor, a second tubular reactor, a first heat exchanger, a first condenser and a pressure swing adsorption separator, wherein the gas outlet of the evaporator is connected to the gas inlet of the first tubular reactor, the gas outlet of the first tubular reactor is connected to the gas inlet of the second tubular reactor, the gas outlet of the second tubular reactor is connected to the gas inlet of the first heat exchanger, the gas outlet of the first heat exchanger is connected to the gas inlet of the first condenser, the gas outlet of the first condenser is connected to the gas inlet of the pressure swing adsorption separator, and the hydrogen of the pressure swing adsorption separator is connected to the gas outlet of the first tubular reactor. The gas outlet is connected to the hydrogen inlet of the fuel cell unit; the evaporator is used to evaporate a mixed liquid of methanol and water, the first tubular reactor is used to produce a methanol gas-water vapor reforming reaction, the second tubular reactor is used to produce a methanation reaction, the first heat exchanger is used to reduce the gas at the gas outlet of the second tubular reactor to a certain temperature higher than normal temperature, the first condenser is used to reduce the gas at the gas outlet of the first heat exchanger to normal temperature and remove water, and the pressure swing adsorption separator is used to separate the gas at the gas outlet of the first condenser to obtain high-purity hydrogen and recover carbon dioxide.

3. The photothermal coupled methanol reforming hydrogen-electricity cogeneration system according to claim 1, characterized in that: The photothermal unit is a trough photothermal unit and includes a parabolic trough concentrator and a heat collecting tube. The parabolic trough concentrator is used to focus sunlight onto the heat collecting tube. The low-temperature heat transfer oil in the heat storage unit is used to enter the heat collecting tube and absorb the heat energy of solar radiation and convert it into high-temperature heat transfer oil.

4. The photothermal coupled methanol reforming hydrogen-electricity cogeneration system according to claim 2, characterized in that: The heat storage unit includes a high-temperature heat transfer oil tank, a low-temperature heat transfer oil tank, a high-temperature molten salt tank, a low-temperature molten salt tank, a high-temperature and high-pressure water tank, and a low-temperature water tank; The oil outlet of the low-temperature thermal oil tank is connected to the oil inlet of the photothermal unit, and the oil outlet of the photothermal unit is connected to the oil inlet of the high-temperature thermal oil tank; The oil outlet of the high-temperature heat-conducting oil tank is connected to the high-temperature oil inlet of the second heat exchanger, the low-temperature oil outlet of the second heat exchanger is connected to the oil inlet of the low-temperature heat-conducting oil tank, the oil outlet of the first tubular reactor is connected to the low-temperature oil inlet of the second heat exchanger, and the high-temperature oil outlet of the second heat exchanger is connected to the oil inlet of the first tubular reactor; The oil outlet of the high-temperature heat-conducting oil tank is connected to the oil inlet of the second tubular reactor, and the oil outlet of the second tubular reactor is connected to the oil inlet of the high-temperature heat-conducting oil tank; The oil outlet of the low-temperature heat-conducting oil tank is connected to the oil inlet of the first heat exchanger, and the oil outlet of the first heat exchanger is connected to the oil inlet of the high-temperature heat-conducting oil tank; The water outlet of the low-temperature water tank is connected to the low-temperature water inlet of the first condenser, and the high-temperature water outlet of the first condenser is connected to the water inlet of the high-temperature and high-pressure water tank; The water outlet of the high-temperature and high-pressure water tank is connected to the water inlet of the evaporator, and the water outlet of the evaporator is connected to the water inlet of the low-temperature water tank; The exhaust port of the fuel cell unit is connected to the air inlet of the third heat exchanger, the air outlet of the third heat exchanger is connected to the air inlet of the fourth heat exchanger, the molten salt outlet of the low-temperature molten salt tank is connected to the molten salt inlet of the third heat exchanger, and the molten salt outlet of the third heat exchanger is connected to the molten salt inlet of the high-temperature molten salt tank; The low-temperature water outlet of the fourth heat exchanger is connected to the water inlet of the water treatment device, the water outlet of the water treatment device is connected to the water inlet of the desalted water tank, the water outlet of the low-temperature water tank is connected to the low-temperature water inlet of the fourth heat exchanger, and the high-temperature water outlet of the fourth heat exchanger is connected to the water inlet of the high-temperature and high-pressure water tank; The molten salt outlet of the high-temperature molten salt tank is connected to the molten salt inlet of the fifth heat exchanger, the molten salt outlet of the fifth heat exchanger is connected to the molten salt inlet of the low-temperature molten salt tank, the oil outlet of the low-temperature thermal oil tank is connected to the oil inlet of the fifth heat exchanger, and the oil outlet of the fifth heat exchanger is connected to the oil inlet of the high-temperature thermal oil tank.

5. The photothermal coupled methanol reforming hydrogen-electricity cogeneration system according to claim 4, characterized in that: The steam turbine power generation unit includes a steam turbine, a generator and a second condenser, the steam turbine is connected to the generator, and the exhaust port of the steam turbine is connected to the air inlet of the second condenser; the thermal energy of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is used to heat the water discharged from the low-temperature water outlet of the second condenser, or the thermal energy stored in the heat storage unit is used to heat the water discharged from the low-temperature water outlet of the second condenser.

6. A photothermal coupled methanol reforming hydrogen and power cogeneration system according to claim 5, characterized in that: The thermal energy of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is used to supply heat to the water discharged from the low-temperature water outlet of the second condenser. Specifically: the exhaust port of the fuel cell unit is also connected to the high-temperature air inlet of the sixth heat exchanger, the low-temperature water outlet of the sixth heat exchanger is connected to the water inlet of the water treatment device, the low-temperature water inlet of the sixth heat exchanger is connected to the low-temperature water outlet of the second condenser, and in the case of insufficient water supply to the second condenser, the low-temperature water inlet of the sixth heat exchanger is also connected to the water outlet of the desalted water tank, and the high-temperature air outlet of the sixth heat exchanger is connected to the air inlet of the steam turbine.

7. The photothermal coupled methanol reforming hydrogen and power cogeneration system according to claim 5, characterized in that: The heat energy stored in the heat storage unit is used to supply heat to the water discharged from the low-temperature water outlet of the second condenser, specifically: the low-temperature water outlet of the second condenser is connected to the low-temperature water inlet of the seventh heat exchanger, and when the water supply to the second condenser is insufficient, the low-temperature water inlet of the seventh heat exchanger is also connected to the water outlet of the desalted water tank, the air outlet of the seventh heat exchanger is connected to the air inlet of the eighth heat exchanger, the water outlet of the high-temperature and high-pressure water tank is connected to the high-temperature water inlet of the seventh heat exchanger, and the low-temperature water outlet of the seventh heat exchanger is connected to the water inlet of the low-temperature water tank; the oil outlet of the high-temperature thermal oil tank is connected to the oil inlet of the eighth heat exchanger, the oil outlet of the eighth heat exchanger is connected to the oil inlet of the low-temperature thermal oil tank, and the air outlet of the eighth heat exchanger is connected to the air inlet of the ninth heat exchanger; the molten salt outlet of the high-temperature molten salt tank is connected to the molten salt inlet of the ninth heat exchanger, the molten salt outlet of the ninth heat exchanger is connected to the molten salt inlet of the low-temperature molten salt tank, and the air outlet of the ninth heat exchanger is connected to the air inlet of the steam turbine.

8. The photothermal coupled methanol reforming hydrogen-electricity cogeneration system according to claim 2, characterized in that: The first heat exchanger is used to reduce the temperature of the gas at the gas outlet of the second tubular reactor to less than 200°C.

9. The photothermal coupled methanol reforming hydrogen-electricity cogeneration system according to claim 2, characterized in that: The drain outlet of the first condenser is connected to the water inlet of the low-temperature water tank.

10. The photothermal coupled methanol reforming hydrogen-electricity cogeneration system according to claim 4, characterized in that: The reaction temperature of the methanol gas-steam reforming reaction occurring in the first tubular reactor is less than or equal to 280°C, the reaction temperature of the methanation reaction occurring in the second tubular reactor is less than or equal to 380°C, the gas temperature at the gas outlet of the second tubular reactor is less than or equal to 400°C, the external heating temperature of the photothermal unit is 390-400°C, the temperature of the high-temperature water vapor discharged from the exhaust port of the fuel cell unit is 750-800°C, the temperature of the high-temperature water vapor at the gas outlet of the third heat exchanger is 300±5°C, the temperature of the heat transfer oil in the high-temperature heat transfer oil tank is greater than or equal to 380°C, the temperature of the heat transfer oil in the low-temperature heat transfer oil tank is less than or equal to 160°C, the temperature of the molten salt in the high-temperature molten salt tank is 580±5°C, the temperature of the molten salt in the low-temperature molten salt tank is 290±5°C, the temperature of the high-temperature and high-pressure water in the high-temperature and high-pressure water tank is 180±5°C, and the temperature of the mixed gas of methanol gas and water vapor obtained by the evaporator is less than or equal to 140°C.

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