Water electrolysis hydrogen production waste heat recovery heat pump energy saving system and method
By adopting a heat pump energy-saving system in the alkaline electrolytic hydrogen production technology, the waste heat in the process of electrolytic hydrogen production is recovered and converted, which solves the problem of hot and cold energy inability to match, and improves the energy conversion rate and system energy efficiency.
Patent Information
- Application Number
- CN202510092655.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2025-04-11
AI Technical Summary
In alkaline electrolytic hydrogen production technology, hot and cold energy cannot match each other, resulting in low energy conversion rate and high production cost.
The heat pump energy-saving system is adopted, and the waste heat recovery and conversion utilization is achieved through a hydrogen-oxygen liquid separation unit, a hydrogen cooler and a hydrogen dryer, combined with a heat pump compressor, a steam generator, an expander, a refrigerator and a heat pump heat absorber.
It improves the energy recovery and conversion utilization of the hydrogen production process of electrolytic water, reduces energy consumption, and improves the energy efficiency of the system.
Smart Images
Figure CN119802889A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of hydrogen production by electrolysis of water, and relates to a heat pump energy-saving system and method for recovering waste heat from hydrogen production by electrolysis of water. Background Art
[0002] Hydrogen energy is considered to be a clean and efficient energy carrier, and the use of renewable electricity to produce hydrogen is considered an important way to improve the comprehensive utilization rate of energy. Alkaline water electrolysis hydrogen production technology is currently the most mature and commercially applied water electrolysis hydrogen production technology. However, it still has problems such as low energy conversion rate and high production cost, which restricts its application.
[0003] At present, the reasons for the low energy conversion rate of alkaline electrolyzed water technology are as follows: 1. During the process of electrolyzing water to produce hydrogen, part of the electrical energy is converted into the chemical energy of hydrogen while generating unnecessary heat energy. The waste heat generally needs to be removed by circulating cooling water; 2. After deoxygenation, hydrogen needs to be cooled before entering the drying tower. A hydrogen cooler is used to cool the hydrogen. The hydrogen cooler consumes a cold source. A water chiller is generally used for the hydrogen cooler. 3. The regeneration process of the hydrogen drying tower requires heating and regeneration before it can be recycled. The heating process usually uses an electric heater, which consumes heat energy.
[0004] In summary, the heat and cold energy required by the three processes, namely, the waste heat treatment process of water electrolysis to produce hydrogen, the cooling process after hydrogen deoxygenation, and the hydrogen drying process, cannot match each other, and the energy consumption of each part leads to a low energy conversion rate in the water electrolysis to produce hydrogen process. Summary of the invention
[0005] The purpose of the present invention is to provide a heat pump energy-saving system and method for recovering waste heat from water electrolysis to produce hydrogen, so as to solve the technical problems that the cold and hot energies in the alkaline water electrolysis technology cannot match each other and the energy conversion rate in the water electrolysis hydrogen production process is low. The present invention realizes the recovery and conversion utilization of energy in the water electrolysis hydrogen production process, which is beneficial to reducing the energy consumption in the water electrolysis hydrogen production process.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The invention discloses a heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production, comprising a hydrogen-oxygen-liquid separation unit, a hydrogen cooler and a hydrogen dryer connected in sequence; It also includes a heat pump compressor, a steam generator, an expander, a refrigerator and a heat pump absorber; The hydrogen and oxygen liquid separation unit is connected to the heat pump absorber through a circulating cooling water pipeline, the hydrogen cooler is connected to the refrigerator through a refrigerant pipeline, and the hydrogen dryer is connected to the steam generator through a hot water pipeline and a steam pipeline respectively; The outlet of the heat pump compressor is sequentially connected to the steam generator, the expander, the refrigerator, the heat pump absorber and the inlet of the heat pump compressor through a heat pump working medium circuit.
[0007] Furthermore, it also includes a feed pipeline, an electrolyzer and a power distribution module, the inlet of the hydrogen and oxygen liquid separation unit is connected to the outlet of the electrolyzer through a crude product pipeline, the inlet of the electrolyzer is connected to the feed pipeline, and the electrolyzer is electrically connected to the power distribution module.
[0008] Furthermore, the feed pipeline is connected to the hydrogen and oxygen liquid separation unit through a condensed water pipeline.
[0009] Furthermore, an oxygen pipeline is provided on the hydrogen-oxygen liquid separation unit.
[0010] Furthermore, it also includes a hydrogen deoxidizer, and the hydrogen-oxygen liquid separation unit is connected to the hydrogen deoxidizer and the hydrogen cooler in sequence through a hydrogen pipeline.
[0011] Furthermore, it also includes a hydrogen downstream unit, and the outlet of the hydrogen dryer is connected to the hydrogen downstream unit.
[0012] Furthermore, the heat pump compressor and the expander are coaxial.
[0013] Furthermore, the heat pump compressor is electrically connected to a power distribution module.
[0014] Furthermore, the heat pump compressor and the expander are electrically connected to a power distribution module respectively.
[0015] Based on the above method, the present invention also discloses a method for using a heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production, comprising the following steps: S1, separating hydrogen, oxygen and condensed water by the hydrogen-oxygen-liquid separation unit; S2, the separated hydrogen is cooled by the hydrogen cooler, and the cooled hydrogen enters the hydrogen dryer for drying; S3, during the hydrogen cooling process, the refrigerator provides coldness to the hydrogen cooler through the refrigerant pipeline to cool the hydrogen, and at the same time, the refrigerator transfers the heat released by the refrigerant pipeline to the heat pump working fluid circuit; S4, during the hydrogen drying process, the steam generator provides high-temperature steam to the hydrogen dryer through the steam pipeline to dry the hydrogen, and at the same time, the steam is cooled into hot water in the hydrogen dryer, and the hot water flows back to the steam generator through the hot water pipeline to be reheated into steam; S5, using the circulating cooling water pipeline to take away the waste heat generated by water electrolysis to produce hydrogen from the hydrogen-oxygen-liquid separation unit, and using the heat pump heat absorber to transfer the heat of the circulating cooling water pipeline to the heat pump working medium circuit; S6, compressing the heat pump working fluid through the heat pump compressor and sending it to the steam generator through the heat pump working fluid loop to provide heat energy for the steam generator, and the heat pump working fluid releases heat in the steam generator and then flows into the expander; S7, the expander expands the inflowing heat pump working fluid to do work and generate cold energy, and the expanded heat pump working fluid enters the refrigerator, the heat pump heat absorber and the inlet of the heat pump compressor in sequence through the heat pump working fluid circuit to form a heat pump cycle.
[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The hydrogen and oxygen liquid separation unit of the present invention is used to separate the hydrogen and oxygen generated in the process of water electrolysis to ensure the purity and efficiency of subsequent treatment. The hydrogen cooler is used to cool the hydrogen and reduce its temperature to prepare for the subsequent drying process. The hydrogen dryer is used to further remove moisture and residual impurities in the hydrogen to improve the dryness and purity of the hydrogen. The heat pump compressor is used to increase the temperature of the heat pump working fluid. The expander is used to reduce the temperature of the heat pump working fluid and perform work externally. The heat in the hydrogen and oxygen liquid separation unit is transferred to the heat pump heat absorber through the circulating cooling water in the circulating cooling water pipeline, and this part of the heat is transferred to the heat pump working fluid circuit in the heat pump heat absorber to realize the recovery and utilization of the waste heat inside the hydrogen and oxygen liquid separation unit. The refrigerant in the refrigerant pipeline is used to cool the hydrogen and absorb the waste heat of the hydrogen deoxygenation process. Then, through the refrigerator, the refrigerant transfers the heat to the heat pump working fluid circuit to realize the recovery and utilization of heat in the hydrogen cooling process. The hot water in the hot water pipeline is heated into steam in the steam generator, and the steam is sent to the hydrogen dryer through the steam pipeline to dry the hydrogen. During the circulation of the heat pump working fluid in the heat pump working fluid loop, the waste heat of the water electrolysis hydrogen production process is recovered through the circulating cooling water and the heat pump heat absorber, the waste heat of the hydrogen deoxidizer is recovered through the refrigerant and the refrigerator, and the heat generated by the heat pump compressor in the heat pump cycle is used for hydrogen drying, and the cold generated by the expander in the heat pump cycle is used for hydrogen cooling. The present invention realizes the conversion and utilization of energy in the three processes of waste heat treatment process of hydrogen production by water electrolysis, cooling process after hydrogen deoxygenation, and hydrogen drying process, which is conducive to reducing the energy consumption of hydrogen coolers and hydrogen dryers.
[0017] 2. The condensed water generated by the hydrogen and oxygen liquid separation unit of the present invention is recovered to the feed pipeline through the condensed water pipeline for repeated use.
[0018] 3. The heat pump compressor and the expander of the present invention are coaxial, and the axial power generated by the expander is recovered, thereby reducing the dependence of the heat pump compressor on external energy, thereby improving the energy efficiency of the entire system.
[0019] 4. The method of the present invention separates hydrogen, oxygen and condensed water through a hydrogen-oxygen liquid separation unit; the deoxygenated hydrogen is cooled by a hydrogen cooler, and the cooled hydrogen enters a hydrogen dryer for drying; during the hydrogen cooling process, the refrigerator provides cooling capacity to the hydrogen cooler through a refrigerant pipeline to cool the hydrogen, and at the same time, the refrigerator transfers the heat released by the refrigerant pipeline to the heat pump working medium circuit; during the hydrogen drying process, the steam generator provides high-temperature steam to the hydrogen dryer through a steam pipeline to dry the hydrogen, and at the same time, the steam is cooled into hot water in the hydrogen dryer, and the hot water is returned to the heat pump through a hot water pipeline. Flow to the steam generator and reheat it into steam; use the circulating cooling water pipeline to take away the heat generated by water electrolysis to produce hydrogen, and use the heat pump heat absorber to transfer the heat of the circulating cooling water pipeline to the heat pump working fluid circuit; compress the heat pump working fluid through the heat pump compressor, and send it into the steam generator through the heat pump working fluid circuit to provide thermal energy for the steam generator. The heat pump working fluid releases heat in the steam generator and flows into the expander; the expander expands the inflowing heat pump working fluid and produces cold energy. The expanded heat pump working fluid enters the inlet of the refrigerator, the heat pump heat absorber and the heat pump compressor in turn through the heat pump working fluid circuit to form a heat pump cycle. The present invention efficiently recovers the waste heat generated by water electrolysis to produce hydrogen through the circulating cooling water pipeline and the heat pump heat absorber, and transfers it to the heat pump working fluid circuit. This not only reduces the waste of energy, but also improves the energy efficiency of the entire system. Heat recovery in the hydrogen cooling process is achieved through the refrigerator and the refrigerant pipeline. The recovered heat is used to dry the hydrogen, thus realizing the energy recovery and conversion utilization of the process of hydrogen production by electrolysis of water, and reducing the energy consumption of the process of hydrogen production by electrolysis of water. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 is a system structure diagram of an embodiment of the present invention; Figure 2 is a system structure diagram of another embodiment of the present invention; Figure 3 The present invention is a flow chart of the method.
[0021] Among them: 1. Feed pipeline; 2. Crude product pipeline; 3. Circulating cooling water pipeline; 4. Oxygen pipeline; 5. Hydrogen pipeline; 6. Condensate pipeline; 7. Hot water pipeline; 8. Steam pipeline; 9. Refrigerant pipeline; 10. Heat pump working fluid circuit; 11. Electrolyzer; 12. Hydrogen and oxygen liquid separation unit; 21. Hydrogen deoxygenator; 22. Hydrogen cooler; 23. Hydrogen dryer; 24. Hydrogen downstream unit; 31. Heat pump compressor; 32. Steam generator; 33. Expander; 34. Refrigerator; 35. Heat pump absorber; 41. Power distribution module. DETAILED DESCRIPTION
[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.
[0023] It should be noted that the terms "including" and "having" and any variations thereof in the specification of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.
[0024] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1 , the present invention discloses a heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production, comprising a hydrogen-oxygen-liquid separation unit 12, a hydrogen cooler 22 and a hydrogen dryer 23 connected in sequence; It also includes a heat pump compressor 31, a steam generator 32, an expander 33, a refrigerator 34 and a heat pump absorber 35; The hydrogen-oxygen liquid separation unit 12 is used to perform preliminary separation of hydrogen, oxygen and water produced during the electrolysis of water to ensure the purity and efficiency of subsequent processing. The hydrogen cooler 22 is used to cool the hydrogen and reduce its temperature in preparation for the subsequent drying process. The hydrogen dryer 23 is used to further remove moisture and residual impurities in the hydrogen to improve the dryness and purity of the hydrogen. The heat pump compressor 31 is used to increase the temperature of the heat pump working fluid. The expander 33 is used to reduce the temperature of the heat pump working fluid.
[0025] The hydrogen-oxygen liquid-liquid separation unit 12 is connected to the heat pump absorber 35 through the circulating cooling water pipeline 3. The heat in the hydrogen-oxygen liquid-liquid separation unit 12 is transferred to the heat pump absorber 35 through the circulating cooling water in the circulating cooling water pipeline 3. The heat in the hydrogen-oxygen liquid-liquid separation unit 12 comes from the water electrolysis process. In the heat pump absorber 35, this part of heat is transferred to the heat pump working medium circuit 10, so as to realize the recovery and utilization of the waste heat inside the hydrogen-oxygen liquid-liquid separation unit 12. The hydrogen cooler 22 is connected to the refrigerator 34 through the refrigerant pipeline 9. The refrigerant in the refrigerant pipeline 9 cools the hydrogen and absorbs the heat of the hydrogen deoxygenation process. Then, through the refrigerator 34, the refrigerant transfers the heat to the heat pump working medium circuit 10, so as to realize the recovery and utilization of the heat in the hydrogen cooling process. The hydrogen dryer 23 is connected to the steam generator 32 through the hot water pipeline 7 and the steam pipeline 8 respectively. The hot water in the hot water pipeline 7 is heated into steam in the steam generator 32, and the steam is sent to the hydrogen dryer 23 through the steam pipeline 8 to dry the hydrogen.
[0026] The outlet of the heat pump compressor 31 is connected to the steam generator 32, the expander 33, the refrigerator 34, the heat pump absorber 35 and the inlet of the heat pump compressor 31 in sequence through the heat pump working medium circuit 10. During the cycle, the waste heat of the cooling process after hydrogen deoxygenation is recovered by the refrigerator 34, the waste heat of the water electrolysis hydrogen production process is recovered by the heat pump absorber 35, and the hydrogen is dried by the absorbed waste heat. The present invention realizes the conversion and utilization of energy in the three processes of waste heat treatment process of hydrogen production by water electrolysis, cooling process after hydrogen deoxygenation and hydrogen drying process, which is conducive to reducing the energy consumption of the hydrogen cooler 22 and the hydrogen dryer 23.
[0027] In summary, the present invention realizes the recovery and conversion of energy in the process of producing hydrogen by electrolysis of water, which is beneficial to reducing the energy consumption of the process of producing hydrogen by electrolysis of water.
[0028] Embodiment 1: See also Figure 1 This embodiment discloses a heat pump energy-saving system for recovering waste heat from water electrolysis to produce hydrogen. It includes a hydrogen-oxygen-liquid separation unit 12, a hydrogen cooler 22 and a hydrogen dryer 23 which are connected in sequence; It also includes a heat pump compressor 31, a steam generator 32, an expander 33, a refrigerator 34 and a heat pump absorber 35; The hydrogen and oxygen liquid separation unit 12 is connected to the heat pump absorber 35 through the circulating cooling water pipeline 3, the hydrogen cooler 22 is connected to the refrigerator 34 through the refrigerant pipeline 9, and the hydrogen dryer 23 is connected to the steam generator 32 through the hot water pipeline 7 and the steam pipeline 8 respectively; The outlet of the heat pump compressor 31 is connected to the steam generator 32 , the expander 33 , the refrigerator 34 , the heat pump absorber 35 and the inlet of the heat pump compressor 31 in sequence through the heat pump working medium circuit 10 .
[0029] Preferably, the inlet of the hydrogen-oxygen liquid-liquid separation unit 12 is connected to the outlet of the electrolyzer 11 through the crude product pipeline 2, the inlet of the electrolyzer 11 is connected to the feed pipeline 1, and the electrolyzer 11 is electrically connected to the power distribution module 41. The required electrolyte solution is provided to the electrolyzer 11 through the feed pipeline 1, and the power distribution module 41 provides the required electrical energy to the electrolyzer 11, driving the electrodes inside the electrolyzer 11 to perform an electrolysis reaction to decompose water molecules into hydrogen and oxygen. The hydrogen and oxygen mixed gas generated by the electrolyzer 11 enters the hydrogen-oxygen liquid-liquid separation unit 12 through the crude product pipeline 2.
[0030] Preferably, the feed pipeline 1 is connected to the hydrogen-oxygen-liquid separation unit 12 via a condensed water pipeline 6. Condensed water generated by the hydrogen-oxygen-liquid separation unit 12 is recycled to the feed pipeline 1 via the condensed water pipeline 6 for reuse.
[0031] Preferably, the hydrogen-oxygen-liquid separation unit 12 is provided with an oxygen pipeline 4 for discharging the oxygen separated by the hydrogen-oxygen-liquid separation unit 12 for subsequent treatment.
[0032] Preferably, the hydrogen-oxygen liquid separation unit 12 is sequentially connected to a hydrogen deoxidizer 21 and a hydrogen cooler 22 via a hydrogen pipeline 5. The hydrogen deoxidizer 21 is used to further remove oxygen in the hydrogen to improve the purity of the hydrogen.
[0033] Preferably, the outlet of the hydrogen dryer 23 is connected to the hydrogen downstream unit 24 .
[0034] Preferably, the heat pump compressor 31 and the expander 33 are coaxial, and the dependence of the heat pump compressor 31 on external energy is reduced by recovering the shaft work generated by the expander 33, thereby improving the energy efficiency of the entire system.
[0035] Preferably, the heat pump compressor 31 is electrically connected to the power distribution module 41 .
[0036] Embodiment 2: See also Figure 2 The present embodiment discloses a heat pump energy-saving system for recovering waste heat from water electrolysis to produce hydrogen. The difference between the present embodiment and the first embodiment is that the heat pump compressor 31 and the expander 33 of the present embodiment are not coaxial, and the heat pump compressor 31 and the expander 33 are electrically connected to the power distribution module 41 respectively, that is, the heat pump compressor 31 and the expander 33 can work separately, and the output power of the heat pump compressor 31 and the expander 33 can be flexibly adjusted according to system requirements, which helps to improve the adaptability and response speed of the system, so that it can better meet the needs under different environments and working conditions.
[0037] Embodiment three: See also Figure 1 , this embodiment discloses a heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production, which specifically includes a water electrolysis hydrogen production module, a hydrogen drying and purification module, a heat pump module and a power distribution module; The water electrolysis hydrogen production module comprises an electrolyzer 11, a hydrogen-oxygen-liquid separation unit 12 and an inlet and outlet pipeline; the electrolyzer 11 is used for electrolyzing water, the hydrogen-oxygen-liquid separation unit 12 is connected to the electrolyzer 11, and the hydrogen-oxygen-liquid separation unit 12 is used for separating and roughly treating the hydrogen and oxygen produced by the electrolyzer 11; The hydrogen drying and purification module is connected to the hydrogen-oxygen liquid-liquid separation unit 12, and the hydrogen drying and purification module includes a hydrogen deoxidizer 21, a hydrogen cooler 22, a hydrogen dryer 23, and the hydrogen deoxidizer 21, the hydrogen cooler 22, the hydrogen dryer 23 and the hydrogen downstream unit 24 are connected in sequence; The heat pump module is connected to the water electrolysis hydrogen production module and the hydrogen drying and purification module respectively, and the heat pump module includes a heat pump compressor 31, a steam generator 32, an expander 33, a refrigerator 34 and a heat pump heat absorber 35, and the heat pump compressor 31, the steam generator 32, the expander 33, the refrigerator 34 and the heat pump heat absorber 35 are connected in sequence to form a heat pump working medium loop 10, wherein the heat pump compressor 31 is connected to the heat pump heat absorber 35, and the heat pump working medium circulates in the heat pump working medium loop 10 in sequence; The heat pump compressor 31 is used to compress the heat pump working fluid and increase the temperature and energy grade of the heat pump working fluid; The steam generator 32 is used for heating water to absorb the heat of the heat pump working fluid at the outlet of the heat pump compressor 31 and generate steam, and the generated steam is used to provide heat for the hydrogen dryer 23; The steam generator 32 is connected to the hydrogen dryer 23 via a hot water pipeline 7 and a steam pipeline 8; The expander 33 is used to expand the heat pump working fluid to do work and generate cold energy; The refrigerator 34 is used for the refrigerant to absorb the cold energy of the heat pump working fluid at the outlet of the expander 33, heat the heat pump working fluid, and provide cold energy for the hydrogen cooler 22; The refrigerator 34 is connected to the hydrogen cooler 22 via a refrigerant pipeline 9; The heat pump absorber 35 is used to circulate cooling water to further heat the heat pump working fluid at the outlet of the refrigerator 34, while reducing the temperature of the circulating cooling water. The circulating cooling water is used to provide cooling for the hydrogen and oxygen liquid separation unit 12; The heat pump absorber 35 is connected to the hydrogen and oxygen liquid separation unit 12 through a circulating cooling water pipeline 3; The distribution module 41 is connected to the electrolytic water hydrogen production module and the heat pump module through cables respectively, and supplies electric energy to each module.
[0038] See Figure 1 , the expander 33 can be coaxial with the heat pump compressor 31 to recover shaft work and save the energy consumption of the heat pump compressor; See Figure 2 , the expander 33 and the heat pump compressor 31 can also be arranged non-coaxially.
[0039] In this embodiment, taking the electrolytic cell 11 with a capacity of 1000 Nm 3 / h as an example, after the products generated by the electrolysis of the electrolytic cell 11 are transported to the hydrogen-oxygen gas-liquid separation unit 12, the heat of the hydrogen-oxygen gas-liquid separation unit 12 is removed by the circulating cooling water pipeline 3. The flow rate of the circulating cooling water in the circulating cooling water pipeline 3 is 150 t / h, the pressure of the circulating cooling water is 0.4 MPa, the temperature of the circulating cooling water entering the hydrogen-oxygen gas-liquid separation unit 12 is 65 °C, and the temperature of the circulating cooling water discharged from the hydrogen-oxygen gas-liquid separation unit 12 is 80 °C, realizing energy recovery. In the prior art, the circulating cooling water needs to be re-cooled to 65 °C by a cooling tower for recycling, and the heat during the cooling process of the circulating cooling water is dissipated to the environment, resulting in waste. The present invention uses air as the heat pump working medium, and by additionally consuming 7.06 MW of energy, it can provide cold energy as low as -28.6 °C for the hydrogen cooler 22 and heat energy as high as 315.1 °C for the hydrogen dryer 23. The available energies are 2.77 MW and 12.45 MW respectively. It saves the energy consumption of the system and significantly improves the efficiency. [Remainder 1] Based on the above structure, the present invention also discloses a use method of a heat pump energy-saving system for recovering waste heat from electrolytic water hydrogen production. See Figure 3 , including the following steps: S1, separating hydrogen and oxygen through the hydrogen-oxygen gas-liquid separation unit 12; S2, after the separated hydrogen is deoxidized, it is cooled by the hydrogen cooler 22, and the cooled hydrogen enters the hydrogen dryer 23 for drying treatment, further removing the moisture in the hydrogen, improving the purity and quality of the hydrogen, and providing better conditions for the storage and use of hydrogen.
[0040] S3, during the hydrogen cooling process, the refrigerator 34 provides cold energy to the hydrogen cooler 22 through the refrigerant pipeline 9 to cool the hydrogen, and at the same time, the refrigerator 34 transfers the heat released by the refrigerant pipeline 9 to the heat pump working medium circuit 10; the refrigerator 34 not only provides the required cold energy for the hydrogen cooler, but also effectively transfers the heat it releases to the heat pump working medium circuit 10, realizing the recovery and reuse of heat.
[0041] S4, during the hydrogen drying process, the steam generator 32 provides high-temperature steam to the hydrogen dryer 23 through the steam pipeline 8 to dry the hydrogen. At the same time, the steam is cooled into hot water in the hydrogen dryer 23, and the hot water flows back to the steam generator 32 through the hot water pipeline 7 to be reheated into steam, thereby realizing the recycling of energy and improving the energy efficiency of the system; S5, using the circulating cooling water pipeline 3 to take away the waste heat generated by water electrolysis from the hydrogen-oxygen liquid separation unit 12, and using the heat pump heat absorber 35 to transfer the heat of the circulating cooling water pipeline 3 to the heat pump working medium loop 10, which helps to improve the overall energy efficiency of the heat pump system and reduces the dependence on external energy; S6, compressing the heat pump working fluid through the heat pump compressor 31 and sending it to the steam generator 32 through the heat pump working fluid loop 10 to provide heat energy for the steam generator 32. The heat pump working fluid releases heat in the steam generator 32 and then flows into the expander 33; S7, the expander 33 expands the inflowing heat pump working fluid to generate cold energy, and the expanded heat pump working fluid enters the refrigerator 34, the heat pump absorber 35 and the inlet of the heat pump compressor 31 in sequence through the heat pump working fluid circuit 10, forming a heat pump cycle.
[0042] The present invention efficiently recovers the waste heat generated by water electrolysis and hydrogen production from the hydrogen and oxygen liquid separation unit 12 through the circulating cooling water pipeline 3 and the heat pump heat absorber 35, and transfers it to the heat pump working medium circuit 10. This not only reduces the waste of energy, but also improves the energy efficiency of the entire system. The heat recovery in the hydrogen cooling process is achieved through the refrigerator 34 and the refrigerant pipeline 9. The recovered heat is used for drying the hydrogen, realizing the recovery and conversion utilization of energy in the water electrolysis and hydrogen production process, and reducing the energy consumption of the water electrolysis and hydrogen production process.
[0043] Embodiment 4: See also Figure 3 The present invention discloses a method for using a heat pump energy-saving system for recovering waste heat from water electrolysis to produce hydrogen. The specific steps are as follows: The feed pipeline 1 delivers the reactants into the electrolytic cell 11, and the power of the electrolytic cell 11 is provided by the power distribution module 41; The crude product after electrolysis is sent to the hydrogen-oxygen-liquid separation unit 12 through the crude product pipeline 2 for cooling and washing, and hydrogen and water are separated, and oxygen and water are separated. The cooling capacity of the hydrogen-oxygen-liquid separation unit 12 is provided by the circulating cooling water of the circulating cooling water pipeline 3; The oxygen at the outlet of the hydrogen-oxygen liquid separation unit 12 is discharged through the oxygen pipeline 4 and can be discharged to the atmosphere after post-treatment. The condensed water can be reused and the condensed water is re-discharged into the feed pipeline 1 through the condensed water pipeline 6. The hydrogen enters the hydrogen deoxygenator 21, the hydrogen cooler 22, the hydrogen dryer 23 and the hydrogen downstream unit 24 in sequence through the hydrogen pipeline 5; The hydrogen cooler 22 cools the hydrogen to meet the conditions for entering the hydrogen dryer 23, and this part of the cooling capacity is provided in whole or in part by the refrigerant in the refrigerant pipeline 9; The hydrogen dryer 23 dries the hydrogen until it meets the conditions for entering the hydrogen downstream unit 24. The heat is provided in whole or in part by the high-temperature steam in the steam pipeline 8. The steam after heating is condensed into hot water, which is returned to the steam generator 32 through the hot water pipeline 7. The heat pump working fluid enters the heat pump compressor 31 through the heat pump working fluid circuit 10 to be pressurized and heated, and the electric energy of the heat pump compressor 31 is supplied by the power distribution module 41; The heat pump working fluid after being pressurized and heated by the heat pump compressor 31 enters the steam generator 32, heats the hot water returning from the hot water pipeline 7 to above the boiling point and becomes steam, and the steam is transported to the hydrogen dryer 23 through the steam pipeline 8; After heat exchange in the steam generator 32, the heat pump working fluid enters the expander 33 through the heat pump working fluid circuit 10 to expand and perform work. In this embodiment, the expander 33 is coaxial with the heat pump compressor 31 to reduce the power consumption of the power distribution module 41; After the heat pump working fluid has been depressurized and cooled by the expander 33, it enters the refrigerator 34 to cool the refrigerant 9 and increase the temperature of the heat pump working fluid itself; The heat pump working fluid then enters the heat pump absorber 35 through the heat pump working fluid loop 10, and the heat pump working fluid absorbs the heat of the circulating cooling water in the heat pump absorber 35 to further increase the temperature, meet the conditions for entering the heat pump compressor 31, and realize the cooling of the circulating cooling water in the circulating cooling water pipeline 3.
[0044] In summary, the beneficial effects of the present invention are: using heat pump working fluid to recover waste heat generated in the water electrolysis process, producing steam to heat the hydrogen dryer 23, and the cold energy after the heat pump working fluid expands and works is used for the hydrogen cooler. The present invention utilizes the heat pump system in series with the cold and hot energy units required for the water electrolysis hydrogen production technology, realizes the comprehensive utilization of energy, improves energy utilization, and reduces operating costs.
[0045] The above contents are only for explaining the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention.
Claims
1. A heat pump energy-saving system for recovering waste heat from water electrolysis to produce hydrogen, characterized in that: It comprises a hydrogen-oxygen-liquid separation unit (12), a hydrogen cooler (22) and a hydrogen dryer (23) which are connected in sequence; It also includes a heat pump compressor (31), a steam generator (32), an expander (33), a refrigerator (34) and a heat pump absorber (35); The hydrogen and oxygen liquid separation unit (12) is connected to the heat pump absorber (35) via a circulating cooling water pipeline (3), the hydrogen cooler (22) is connected to the refrigerator (34) via a refrigerant pipeline (9), and the hydrogen dryer (23) is connected to the steam generator (32) via a hot water pipeline (7) and a steam pipeline (8), respectively; The outlet of the heat pump compressor (31) is connected in sequence to the steam generator (32), the expander (33), the refrigerator (34), the heat pump absorber (35), and the inlet of the heat pump compressor (31) via a heat pump working medium circuit (10).
2. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 1, characterized in that: It also comprises a feed pipeline (1), an electrolyzer (11) and a power distribution module (41), wherein the inlet of the hydrogen-oxygen liquid separation unit (12) is connected to the outlet of the electrolyzer (11) via a crude product pipeline (2), the inlet of the electrolyzer (11) is connected to the feed pipeline (1), and the electrolyzer (11) is electrically connected to the power distribution module (41).
3. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 2, characterized in that: The feed pipeline (1) is connected to the hydrogen-oxygen liquid separation unit (12) via a condensed water pipeline (6).
4. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 1, characterized in that: The hydrogen-oxygen-liquid separation unit (12) is provided with an oxygen pipeline (4).
5. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 1, characterized in that: It also includes a hydrogen deoxidizer (21), and the hydrogen-oxygen liquid-gas separation unit (12) is sequentially connected to the hydrogen deoxidizer (21) and the hydrogen cooler (22) via a hydrogen pipeline (5).
6. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 1, characterized in that: It also includes a hydrogen downstream unit (24), and the outlet of the hydrogen dryer (23) is connected to the hydrogen downstream unit (24).
7. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 1, characterized in that: The heat pump compressor (31) and the expander (33) are coaxial.
8. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 7, characterized in that: The heat pump compressor (31) is electrically connected to the power distribution module (41).
9. A heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production according to claim 1, characterized in that: The heat pump compressor (31) and the expander (33) are respectively electrically connected to a power distribution module (41).
10. A method for using the heat pump energy-saving system for recovering waste heat from water electrolysis hydrogen production as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: S1, separating hydrogen, oxygen and condensed water by the hydrogen-oxygen liquid separation unit (12); S2, the separated hydrogen is cooled by the hydrogen cooler (22), and the cooled hydrogen enters the hydrogen dryer (23) for drying; S3, during the hydrogen cooling process, the refrigerator (34) provides cooling capacity to the hydrogen cooler (22) through the refrigerant pipeline (9) to cool the hydrogen, and at the same time, the refrigerator (34) transfers heat released by the refrigerant pipeline (9) to the heat pump working fluid circuit (10); S4, during the hydrogen drying process, the steam generator (32) provides high-temperature steam to the hydrogen dryer (23) through the steam pipeline (8) to dry the hydrogen, and at the same time, the steam is cooled into hot water in the hydrogen dryer (23), and the hot water flows back to the steam generator (32) through the hot water pipeline (7) to be reheated into steam; S5, using the circulating cooling water pipeline (3) to remove waste heat generated by water electrolysis to produce hydrogen from the hydrogen-oxygen-liquid separation unit (12), and using the heat pump heat absorber (35) to transfer the heat of the circulating cooling water pipeline (3) to the heat pump working medium circuit (10); S6, compressing the heat pump working fluid through the heat pump compressor (31), and sending the heat pump working fluid into the steam generator (32) through the heat pump working fluid circuit (10), thereby providing heat energy for the steam generator (32), and the heat pump working fluid releases heat in the steam generator (32) and then flows into the expander (33); S7, the expander (33) expands the inflowing heat pump working fluid to perform work and generate cold energy, and the expanded heat pump working fluid enters the refrigerator (34), the heat pump heat absorber (35) and the inlet of the heat pump compressor (31) in sequence through the heat pump working fluid circuit (10), forming a heat pump cycle.