A low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system and method

Abstract

The present invention belongs to the technical field of water electrolysis hydrogen production, and relates to a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system and method. It includes a hydrogen-oxygen liquid-liquid separation unit, a heat pump compressor and an expander, wherein the hydrogen-oxygen liquid-liquid separation unit is connected to a hydrogen dryer through a hydrogen cooler; the hydrogen-oxygen liquid-liquid separation unit is connected to a heat pump heat absorber through a circulating cooling water pipeline, the hydrogen cooler is connected to a refrigerator through a refrigerant pipeline, and the hydrogen dryer is connected to a steam generator through a hot water pipeline and a steam pipeline respectively; the outlet of the heat pump compressor is connected to the steam generator and the inlet of the expander in sequence through a hot heat pump working fluid pipeline, and the outlet of the expander is connected to the refrigerator, the heat pump heat absorber and the inlet of the heat pump compressor in sequence through a cold heat pump working fluid pipeline; the hot heat pump working fluid pipeline and the cold heat pump working fluid pipeline are both connected to a heat regenerator. The present invention is conducive to reducing the pressure ratio of the heat pump compressor, enriching the selection range of the heat pump working fluid, and improving the energy utilization rate of the system.

Description

Technical Field

[0001] The invention belongs to the technical field of water electrolysis hydrogen production, and relates to a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system and method. Background Art

[0002] Water electrolysis hydrogen production technology is an effective means to improve the utilization rate of new energy electricity and is also a means of energy storage. The energy carrier of this technology is green hydrogen, which can be used as a clean fuel to supply road transportation, ships and aerospace.

[0003] As a clean and efficient form of energy, hydrogen energy has received widespread attention and development around the world in recent years. With the continuous progress of the hydrogen energy industry, the construction of hydrogen energy infrastructure has also been increasingly improved. Among them, alkaline electrolyzers, as one of the key technologies for hydrogen production by electrolysis of water, occupy an important position in the hydrogen energy industry due to their compact structure, safe and reliable operation, and long service life.

[0004] During operation, the alkaline electrolyzer produces hydrogen and oxygen by electrolyzing water. Its hydrogen production efficiency can usually reach more than 60%, which means that most of the input electrical energy is effectively converted into hydrogen energy, but at least 30% of the electrical energy is still converted into heat energy, causing energy loss in the system. The crude hydrogen and oxygen at the outlet of the electrolyzer need to be cooled by circulating cooling water and separated from the gas and liquid before entering the downstream process. Although these treatment processes are necessary, they will also increase the complexity and energy consumption of the system. In addition, the hydrogen after electrolysis must also undergo deoxygenation, cooling, drying and other processes to make the product dew point reach below -50°C before it can be stored and transported. This process further consumes energy and reduces the efficiency of the entire system.

[0005] The heat pump system can be used to recover the heat generated by the electrolysis process and provide steam and cold for the drying and purification process of hydrogen products. However, the heat pump system for cooling and heating has the problem of high pressure ratio of the heat pump compressor. Summary of the invention

[0006] The purpose of the present invention is to provide a low-pressure ratio energy-optimized heat pump system and method for producing hydrogen by electrolysis of water, so as to solve the technical problem that the heat pump system for cooling and heating has a high pressure ratio of the heat pump compressor. The present invention is conducive to reducing the pressure ratio of the heat pump compressor, enriching the selection range of the heat pump working fluid, and improving the energy utilization rate of the system.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The invention discloses a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, comprising a hydrogen-oxygen-liquid separation unit, a hydrogen cooler and a hydrogen dryer connected in sequence;

[0009] It also includes a heat pump compressor, a steam generator, an expander, a refrigerator and a heat pump absorber;

[0010] 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;

[0011] The outlet of the heat pump compressor is sequentially connected to the steam generator and the inlet of the expander through a hot heat pump working medium pipeline, and the outlet of the expander is sequentially connected to the refrigerator, the heat pump absorber and the inlet of the heat pump compressor through a cold heat pump working medium pipeline;

[0012] The hot heat pump working medium pipeline and the cold heat pump working medium pipeline are both connected to the regenerator;

[0013] On the heat pump working medium pipeline, the regenerator is located between the steam generator and the expander;

[0014] On the working medium pipeline of the cold and hot pump, the regenerator is located between the heat pump absorber and the heat pump compressor.

[0015] Furthermore, the heat pump compressor and the expander are coaxial.

[0016] Furthermore, the heat pump compressor and the expander are not coaxial.

[0017] Furthermore, it also includes a feed pipeline, an electrolyzer, a crude product pipeline and a power distribution module, the inlet of the hydrogen and oxygen liquid separation unit is connected to the outlet of the electrolyzer through the 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.

[0018] Furthermore, a condensed water pipeline is provided on the hydrogen-oxygen-liquid separation unit, and the hydrogen-oxygen-liquid separation unit is connected to the feed pipeline via the condensed water pipeline.

[0019] Furthermore, an oxygen pipeline is provided on the hydrogen-oxygen liquid separation unit.

[0020] 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.

[0021] Furthermore, it also includes a hydrogen downstream unit, and the outlet of the hydrogen dryer is connected to the hydrogen downstream unit.

[0022] Furthermore, the heat pump compressor is electrically connected to the power distribution module.

[0023] Based on the above method, the present invention also discloses a method for using a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, comprising the following steps:

[0024] S1, separating hydrogen, oxygen and water by the hydrogen-oxygen-liquid separation unit;

[0025] S2, the separated hydrogen is cooled by the hydrogen cooler, and the cooled hydrogen enters the hydrogen dryer for drying;

[0026] 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 cold and heat pump working medium pipeline;

[0027] 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;

[0028] 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 cold and heat pump working medium pipeline;

[0029] 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 pipeline 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;

[0030] S7, the expander expands the inflowing heat pump working fluid and generates cold energy. 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 cold and hot pump working fluid pipeline, forming a heat pump cycle. The hot heat pump working fluid pipeline heats the heat pump working fluid in the cold and hot pump working fluid pipeline through the regenerator.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The hydrogen-oxygen liquid-liquid separation unit of the present invention is used to separate hydrogen, oxygen and water generated in the process of water electrolysis. The hydrogen cooler is used to cool the separated hydrogen. The hydrogen dryer is used to dry the cooled hydrogen. The heat pump compressor compresses the heat pump working fluid and increases the temperature and pressure of the heat pump working fluid. The expander is used to expand the heat pump working fluid to do work and reduce the temperature and pressure of the heat pump working fluid. The heat of the hydrogen-oxygen liquid-liquid separation unit is taken away by the circulating cooling water pipeline, and the heat of the circulating cooling water pipeline is transferred to the cold and hot pump working fluid pipeline by the heat pump absorber to realize the recovery of waste heat. The refrigerant pipeline transports the low-temperature refrigerant in the refrigerator to the hydrogen cooler to facilitate the cooling of hydrogen. The hot water is heated by the steam generator to become high-temperature water vapor, and the high-temperature water vapor is transported to the hydrogen dryer through the steam pipeline for drying hydrogen. The high-temperature water vapor is cooled in the hydrogen dryer and then re-input into the steam generator through the hot water pipeline to realize the recovery of waste heat. The outlet of the heat pump compressor is connected to the steam generator and the inlet of the expander in sequence through the hot heat pump working fluid pipeline, and the outlet of the expander is connected to the refrigerator, the heat pump heat absorber and the inlet of the heat pump compressor in sequence through the cold heat pump working fluid pipeline to form a heat pump cycle. During the cycle, the heat pump working fluid absorbs the heat of the hydrogen cooler and the hydrogen and oxygen liquid separation unit in sequence to achieve the recycling and conversion of heat energy, which is conducive to reducing the compression ratio of the heat pump compressor and improving the energy utilization rate of the system. Before the heat pump working fluid enters the heat pump compressor, the heat of the working fluid in the hot heat pump working fluid pipeline is recovered through the regenerator, which increases the working fluid temperature entering the heat pump compressor and reduces the temperature difference when the heat pump compressor heats the heat pump working fluid to the temperature required by the steam generator, which is conducive to reducing the compression ratio of the heat pump compressor, enriching the selection range of heat pump working fluids, and improving the energy utilization rate of the system.

[0033] The heat pump compressor and the expander of the present invention are coaxial, which is beneficial to reducing the overall size and floor space of the system. At the same time, by recovering the shaft work generated by the expander, the heat pump compressor's dependence on external energy is reduced, thereby improving the energy efficiency of the entire system.

[0034] The hydrogen-oxygen-liquid separation unit of the present invention is provided with a condensed water pipeline, and the hydrogen-oxygen-liquid separation unit is connected to a feed pipeline via the condensed water pipeline to achieve recycling of materials.

[0035] The hydrogen and oxygen liquid separation unit of the present invention is connected to a hydrogen deoxidizer and a hydrogen cooler in sequence through a hydrogen pipeline. The provision of the hydrogen deoxidizer is beneficial to improving the purity of hydrogen.

[0036] The method of the present invention separates hydrogen, oxygen and water through a hydrogen-oxygen liquid separation unit; the separated hydrogen is cooled by a hydrogen cooler, and the cooled hydrogen enters a hydrogen dryer for drying; in the hydrogen cooling process, a refrigerator provides cooling capacity to the hydrogen cooler through a refrigerant pipeline to cool the hydrogen, and at the same time, the refrigerator exchanges heat from the hydrogen in the refrigerant pipeline to a cold and heat pump working fluid pipeline to realize energy recovery and utilization. During the hydrogen drying process, the steam generator provides high-temperature steam to the hydrogen dryer through the steam pipeline to dry the hydrogen. 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, thereby realizing the recycling of energy. The heat of the hydrogen, oxygen and liquid separation unit is taken away by the circulating cooling water pipeline, and the heat pump absorber is used to transfer the heat of the circulating cooling water pipeline to the cold and hot pump working fluid pipeline, thereby effectively utilizing the heat generated in the hydrogen, oxygen and liquid separation process. Through the cooperation of the circulating cooling water and the heat pump absorber, this part of the heat is transferred to the heat pump system, thereby realizing energy recovery and reuse, and increasing the temperature of the heat pump working fluid before entering the heat pump compressor, which is beneficial to reducing the compression ratio of the heat pump compressor. The heat pump working fluid is compressed by the heat pump compressor and sent to the steam generator through the hot heat pump working fluid pipeline to provide heat 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 incoming heat pump working fluid and generates cold energy. The expanded heat pump working fluid enters the refrigerator, heat pump heat absorber and heat pump compressor in turn through the cold heat pump working fluid pipeline to form a heat pump cycle. The hot heat pump working fluid pipeline heats the heat pump working fluid in the cold heat pump working fluid pipeline through the regenerator, and the heat of the working fluid in the hot heat pump working fluid pipeline is recovered through the regenerator, which further reduces the compression ratio of the heat pump compressor, which is conducive to enriching the selection range of heat pump working fluids and improving the energy utilization rate of the system. The refrigerator uses the cold energy generated by the expander to cool the refrigerant in the refrigerant pipeline to provide cold energy for hydrogen cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0038] Figure 2 This is a schematic diagram of the structure of the heat pump compressor and expander of the present invention in a non-coaxial design;

[0039] Figure 3 The figure is a flow chart of the method of the present invention.

[0040] 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. Regenerator; 34. Expander; 35. Refrigerator; 36. Heat pump absorber; 41. Power distribution module; 101. Hot heat pump working fluid pipeline; 102. Cold and hot pump working fluid pipeline. DETAILED DESCRIPTION

[0041] 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.

[0042] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims 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.

[0043] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0044] See also Figure 1 , the present invention discloses a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, comprising a hydrogen-oxygen liquid separation unit 12, a hydrogen cooler 22 and a hydrogen dryer 23 connected in sequence;

[0045] It also includes a heat pump compressor 31, a steam generator 32, an expander 34, a refrigerator 35 and a heat pump absorber 36; the hydrogen-oxygen liquid separation unit 12 is used to separate the hydrogen, oxygen and water generated during the electrolysis of water. The hydrogen cooler 22 is used to cool the separated hydrogen. The hydrogen dryer 23 is used to dry the cooled hydrogen. The heat pump compressor 31 compresses the heat pump working fluid and increases the temperature and pressure of the heat pump working fluid. The expander 34 is used to expand the heat pump working fluid to do work and reduce the temperature and pressure of the heat pump working fluid.

[0046] The hydrogen and oxygen liquid-liquid separation unit 12 is connected to the heat pump absorber 36 through the circulating cooling water pipeline 3, and the heat of the hydrogen and oxygen liquid-liquid separation unit 12 is taken away by the circulating cooling water pipeline 3, and the heat pump absorber 36 is used to transfer the heat of the circulating cooling water pipeline 3 to the cold and heat pump working medium pipeline 102, so as to realize the recovery of waste heat. The hydrogen cooler 22 is connected to the refrigerator 35 through the refrigerant pipeline 9, and the refrigerant pipeline 9 transports the refrigerant generated by the refrigerator 35 to the hydrogen cooler 22, so as to facilitate the cooling of hydrogen. 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 is heated by the steam generator 32 to become high-temperature water vapor, and the high-temperature water vapor is transported to the hydrogen dryer 23 through the steam pipeline 8 for drying hydrogen, and the high-temperature water vapor is cooled in the hydrogen dryer 23 and then re-input into the steam generator 32 through the hot water pipeline 7, so as to realize the recovery of waste heat.

[0047] The outlet of the heat pump compressor 31 is connected to the steam generator 32 and the inlet of the expander 34 in sequence through the hot heat pump working medium pipeline 101, and the outlet of the expander 34 is connected to the refrigerator 35, the heat pump heat absorber 36 and the inlet of the heat pump compressor 31 in sequence through the cold heat pump working medium pipeline 102, forming a heat pump cycle. During the cycle, the heat pump working medium absorbs the heat of the hydrogen cooler 22 and the hydrogen and oxygen liquid separation unit 12 in sequence, realizing the recycling and conversion of heat energy, which is conducive to reducing the compression ratio of the heat pump compressor 31 and improving the energy utilization rate of the system. The heat energy generated in the water electrolysis process and the hydrogen cooling process can be converted into useful heat energy through the heat pump cycle, thereby reducing the overall energy consumption.

[0048] The hot heat pump working fluid pipeline 101 and the cold heat pump working fluid pipeline 102 are both connected to the regenerator 33. On the hot heat pump working fluid pipeline 101, the regenerator 33 is located between the steam generator 32 and the expander 34; on the cold heat pump working fluid pipeline 102, the regenerator 33 is located between the heat pump heat absorber 36 and the heat pump compressor 31. Before the heat pump working fluid enters the heat pump compressor 31, the heat of the working fluid in the hot heat pump working fluid pipeline 101 is recovered by the regenerator 33, which increases the working fluid temperature entering the heat pump compressor 31, reduces the temperature difference of the heat pump compressor 31 heating the heat pump working fluid to the required temperature of the steam generator 32, and is conducive to reducing the compression ratio of the heat pump compressor 31. By adding the regenerator 33, the compression ratio of the heat pump compressor 31 of the present invention can be reduced to 3.7, which is conducive to enriching the selection range of the heat pump working fluid and improving the energy utilization rate of the system. At the same time, the reduction of the compression ratio is conducive to reducing the production and manufacturing costs of the heat pump compressor and the expander.

[0049] Embodiment 1:

[0050] See also Figure 1, this embodiment discloses a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, including a hydrogen-oxygen liquid separation unit 12, a hydrogen cooler 22 and a hydrogen dryer 23 connected in sequence;

[0051] It also includes a heat pump compressor 31, a steam generator 32, an expander 34, a refrigerator 35 and a heat pump absorber 36;

[0052] The hydrogen and oxygen liquid separation unit 12 is connected to the heat pump absorber 36 through the circulating cooling water pipeline 3; the hydrogen cooler 22 is connected to the refrigerator 35 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;

[0053] The outlet of the heat pump compressor 31 is connected to the steam generator 32 and the inlet of the expander 34 in sequence through the hot heat pump working medium pipeline 101, and the outlet of the expander 34 is connected to the refrigerator 35, the heat pump heat absorber 36 and the inlet of the heat pump compressor 31 in sequence through the cold heat pump working medium pipeline 102;

[0054] The hot heat pump working medium pipeline 101 and the cold heat pump working medium pipeline 102 are both connected to the regenerator 33;

[0055] On the heat pump working medium pipeline 101, the regenerator 33 is located between the steam generator 32 and the expander 34;

[0056] On the cold and hot pump working medium pipeline 102 , the regenerator 33 is located between the heat pump absorber 36 and the heat pump compressor 31 .

[0057] Preferably, on the heat pump working fluid pipeline 101, the regenerator 33 is located between the steam generator 32 and the expander 34, which is beneficial to recovering the heat of the heat pump working fluid in the heat pump working fluid pipeline 101, and is beneficial to reducing the difficulty of the expander 34 in reducing the pressure and temperature of the heat pump working fluid, which is beneficial to improving the efficiency of the expander 34 and reducing the overall energy consumption of the system.

[0058] On the cold heat pump working medium pipeline 102, the regenerator 33 is located between the heat pump absorber 36 and the heat pump compressor 31. The heat of the high-temperature heat pump working medium in the hot heat pump working medium pipeline 101 is transferred to the low-temperature heat pump working medium in the cold heat pump working medium pipeline 102, realizing heat recovery and reuse.

[0059] Preferably, the heat pump compressor 31 and the expander 34 are coaxial, which is beneficial to reducing the overall size and footprint of the system. At the same time, by recovering the shaft work generated by the expander 34, the heat pump compressor 31 is less dependent on external energy, thereby improving the energy efficiency of the entire system.

[0060] Preferably, it also includes a feed pipeline 1, an electrolyzer 11, a crude product pipeline 2 and a power distribution module 41, the inlet of the hydrogen and oxygen 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.

[0061] Preferably, a condensate pipeline 6 is provided on the hydrogen-oxygen-liquid separation unit 12, and the hydrogen-oxygen-liquid separation unit 12 is connected to the feed pipeline 1 via the condensate pipeline 6 to achieve recycling of materials.

[0062] Preferably, the hydrogen-oxygen-liquid separation unit 12 is provided with an oxygen pipeline 4 , and the oxygen pipeline 4 is used to discharge the oxygen separated by the hydrogen-oxygen-liquid separation unit 12 .

[0063] Preferably, a hydrogen deoxidizer 21 is further included. The hydrogen-oxygen liquid-liquid separation unit 12 is sequentially connected to the hydrogen deoxidizer 21 and the hydrogen cooler 22 via the hydrogen pipeline 5. The provision of the hydrogen deoxidizer 21 is beneficial to improving the purity of the hydrogen.

[0064] Preferably, a hydrogen downstream unit 24 is further included, and the outlet of the hydrogen dryer 23 is connected to the hydrogen downstream unit 24 .

[0065] Preferably, the heat pump compressor 31 is electrically connected to the power distribution module 41 .

[0066] Embodiment 2:

[0067] See also Figure 2 This embodiment provides a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system. Different from the first embodiment, the heat pump compressor 31 and the expander 34 in this embodiment are not coaxial, that is, the heat pump compressor 31 and the expander 34 are separately connected to the electrical connection distribution module 41, and the heat pump compressor 31 and the expander 34 work independently without interfering with each other. The system can flexibly adjust the power of the heat pump compressor 31 and the expander 34 according to demand, which helps to improve the adaptability and response speed of the system, so that the system can better meet the needs of different environments and working conditions.

[0068] Embodiment three:

[0069] See also Figure 1 and Figure 2 , this embodiment provides a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, specifically including a water electrolysis hydrogen production module, a hydrogen drying and purification module, a heat pump module and a power distribution module 41;

[0070] The water electrolysis hydrogen production module includes an electrolyzer 11, a hydrogen-oxygen-liquid separation unit 12, a feed pipeline 1, a crude product pipeline 2, an oxygen pipeline 4, a hydrogen pipeline 5 and a condensed water pipeline 6; 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 to separate and roughly process the hydrogen, oxygen and water produced by the electrolyzer 11;

[0071] 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 a hydrogen downstream unit 24, and the hydrogen deoxidizer 21, the hydrogen cooler 22, the hydrogen dryer 23 and the hydrogen downstream unit 24 are connected in sequence;

[0072] The heat pump module, the water electrolysis hydrogen production module and the hydrogen drying and purification module are connected respectively.

[0073] The heat pump module includes a heat pump compressor 31, a steam generator 32, a regenerator 33, an expander 34, a refrigerator 35 and a heat pump absorber 36, which are sequentially connected to form a heat pump working medium circuit 10, and the heat pump working medium circulates sequentially in the heat pump working medium circuit 10;

[0074] The heat pump compressor 31 is used to compress the heat pump working fluid and increase the temperature and energy quality of the heat pump working fluid;

[0075] The steam generator 32 is connected to the hydrogen dryer 23 via a hot water pipeline 7 and a steam pipeline 8;

[0076] In the steam generator 32, the hot water in the hot water pipeline 7 absorbs the heat of the heat pump working fluid at the outlet of the heat pump compressor 31 and generates steam, and the generated steam is used to provide heat for the hydrogen dryer 23;

[0077] The regenerator 33 is used for heat exchange between heat pump working fluids, increasing the temperature of the heat pump working fluid at the inlet of the heat pump compressor 31 and reducing the pressure ratio of the heat pump compressor 31, which is conducive to enriching the selection range of heat pump working fluids;

[0078] The heat pump working medium circuit 10 includes a hot heat pump working medium pipeline 101 and a cold heat pump working medium pipeline 102;

[0079] The regenerator 33 is connected to the upstream steam generator 32 and the downstream expander 34 respectively through the hot heat pump working medium pipeline 101, and the regenerator 33 is connected to the upstream heat pump heat absorber 36 and the downstream heat pump compressor 31 respectively through the cold heat pump working medium pipeline 102;

[0080] The heat pump working fluid is cooled in the regenerator 33 through the hot heat pump working fluid pipeline 101, and the heat pump working fluid is heated in the regenerator 33 through the cold heat pump working fluid pipeline 102, thereby realizing internal energy recovery;

[0081] The expander 34 is used to expand the heat pump working fluid to do work and generate cold energy;

[0082] The refrigerator 35 is connected to the hydrogen cooler 22 via a refrigerant pipeline 9;

[0083] In the refrigerator 35, the coolant in the refrigerant pipeline 9 absorbs the cold energy of the heat pump working fluid at the outlet of the expander 34, heats the heat pump working fluid, and provides cold energy for the hydrogen cooler 22;

[0084] The heat pump absorber 36 is connected to the hydrogen and oxygen liquid separation unit 12 through a circulating cooling water pipeline 3;

[0085] The heat pump heat absorber 36 further heats the heat pump working medium at the outlet of the refrigerator 35 through the circulating cooling water in the circulating cooling water pipeline 3, and at the same time reduces 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;

[0086] The power distribution module 41 is connected to the water electrolysis hydrogen production module, the hydrogen drying and purification module and the heat pump module respectively through cables, and provides power to each module.

[0087] See also Figure 1 , the expander 34 can be coaxial with the heat pump compressor 31 to recover shaft work and save energy consumption of the heat pump compressor 31;

[0088] See also Figure 2 The expander 34 and the heat pump compressor 31 may also be arranged non-coaxially.

[0089] The beneficial effects of the present invention are: through the regenerator 33, heat recovery between heat pump working fluids is achieved, the temperature of the heat pump working fluid entering the heat pump compressor 31 is increased, the pressure ratio of the heat pump compressor 31 to reach the target temperature is reduced, the equipment load is reduced, and it is beneficial to enrich the selection range of heat pump working fluids. At the same time, by recovering the waste heat generated in the water electrolysis process, hot water is recovered to produce steam for heating the hydrogen dryer 23, and the waste heat released by the hydrogen in the cooling process of the hydrogen cooler 22 is recovered. In addition, hot water is recovered to produce steam for heating the hydrogen dryer 23, thereby improving the energy utilization rate of the system. The present invention improves the energy utilization rate of hydrogen production by electrolysis of water, reduces operating costs, is beneficial to enrich the selection range of heat pump working fluids, and reduces the equipment cost of the heat pump compressor 31 and the expander 34.

[0090] In this embodiment, 1000 Nm 3 / h electrolyzer 11 as an example, after the product generated by electrolysis of electrolyzer 11 is transported to hydrogen oxygen liquid separation unit 12, the heat of hydrogen oxygen liquid separation unit 12 is taken away by circulating cooling water pipeline 3, the flow rate of circulating cooling water in circulating cooling water pipeline 3 is 150t / h, the pressure of circulating cooling water is 0.4MPa, the temperature of circulating cooling water entering hydrogen oxygen liquid separation unit 12 is 65℃, and the temperature of circulating cooling water discharged from hydrogen oxygen liquid separation unit 12 is 80℃, thus realizing energy recovery. In the prior art, circulating cooling water needs to be recooled to 65℃ by cooling tower for recycling, and the heat in the cooling process of circulating cooling water is dissipated to the environment, causing waste. The present invention uses air as the working medium of heat pump, and by consuming an additional 6.17MW of energy, it can provide cold energy as low as -14.1℃ for hydrogen cooler 22 and heat energy as high as 315.1℃ for hydrogen dryer 23, and the available energy is 1.94MW and 10.7MW respectively. It saves the energy consumption of the system and significantly improves the efficiency.

[0091] Based on the above structure, the present invention also discloses a method for using a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, see Figure 3 , including the following steps:

[0092] S1, separating hydrogen, oxygen and water through the hydrogen-oxygen-liquid separation unit 12;

[0093] S2, the separated hydrogen is cooled by the hydrogen cooler 22, and the cooled hydrogen enters the hydrogen dryer 23 for drying;

[0094] S3, during the hydrogen cooling process, the refrigerator 35 provides cold air to the hydrogen cooler 22 through the refrigerant pipeline 9 to cool the hydrogen. At the same time, the refrigerator 35 exchanges the heat from the hydrogen in the refrigerant pipeline 9 to the heat pump working fluid pipeline 102, thereby realizing energy recovery and utilization, and increasing the temperature of the heat pump working fluid before entering the heat pump compressor 31, which is beneficial to reducing the compression ratio of the heat pump compressor 31.

[0095] 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 avoiding the waste of heat by directly discharging the hot water;

[0096] S5, utilize the circulating cooling water pipeline 3 to take away the heat of the hydrogen and oxygen liquid separation unit 12, utilize the heat pump heat absorber 36 to transfer the heat of the circulating cooling water pipeline 3 to the cold and hot pump working medium pipeline 102, effectively utilize the heat generated in the process of hydrogen and oxygen liquid separation, and transfer this part of heat to the heat pump system through the cooperation of circulating cooling water and heat pump heat absorber 36, realize energy recovery and reuse, increase the temperature of the heat pump working medium before entering the heat pump compressor 31, and help to reduce the compression ratio of the heat pump compressor 31.

[0097] 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 pipeline 101, 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 34;

[0098] S7, the expander 34 expands the inflowing heat pump working fluid and generates cold energy. The expanded heat pump working fluid enters the refrigerator 35, the heat pump heat absorber 36 and the inlet of the heat pump compressor 31 in sequence through the cold heat pump working fluid pipeline 102, forming a heat pump cycle. The hot heat pump working fluid pipeline 101 heats the heat pump working fluid in the cold heat pump working fluid pipeline 102 through the regenerator 33, and the heat of the working fluid in the hot heat pump working fluid pipeline 101 is recovered through the regenerator 33, which further reduces the compression ratio of the heat pump compressor 31, which is beneficial to enrich the selection range of heat pump working fluids and improve the energy utilization rate of the system.

[0099] The method of the present invention realizes heat recovery between heat pump working fluids through the regenerator 33, increases the temperature of the heat pump working fluid entering the heat pump compressor 31, is conducive to reducing the pressure ratio of the heat pump compressor, is conducive to enriching the selection range of heat pump working fluids, and is conducive to improving the energy utilization rate of the system. At the same time, by recovering the waste heat generated in the water electrolysis process and the waste heat released by the hydrogen in the cooling process of the hydrogen cooler 22, the energy utilization rate of the system is improved, the temperature of the heat pump working fluid entering the heat pump compressor 31 is further increased, and the pressure ratio of the heat pump compressor is reduced. In addition, the hot water is recovered to produce steam to provide heat for the hydrogen dryer 23, which further improves the energy utilization rate of the system.

[0100] Embodiment 4:

[0101] See also Figure 3 This embodiment discloses a method for using a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, which is as follows:

[0102] The feed pipeline 1 delivers the reactants into the electrolytic cell 11, and the power of the electrolytic cell is provided by the power distribution module 41;

[0103] 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 in the circulating cooling water pipeline 3;

[0104] The oxygen at the outlet of the hydrogen-oxygen liquid separation unit 12 is discharged to the atmosphere through the oxygen pipeline 4 after post-treatment, and the condensed water can be reused. The condensed water is discharged into the feed pipeline 1 through the condensed water pipeline 6, and 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;

[0105] 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;

[0106] 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 steam in the steam pipeline 8. The steam after heating is condensed into hot water, which is discharged into the steam generator 32 through the hot water pipeline 7. The hot water pipeline 7 evaporates again in the steam generator 32 and enters the steam pipeline 8.

[0107] 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;

[0108] The pressurized and heated heat pump medium enters the steam generator 32 through the heat pump medium circuit 10, heats the hot water in the hot water pipe 7 to the boiling point and turns into steam, and the steam is discharged from the steam pipe 8;

[0109] Then the heat pump working fluid enters the regenerator 33 through the heat pump working fluid loop 10 for cooling, and the heat pump working fluid at the outlet of the heat pump heat absorber 36 is further heated to meet the conditions of the inlet of the heat pump compressor 31;

[0110] Then the heat pump working fluid enters the expander 34 through the heat pump working fluid circuit 10 to expand and do work. In this embodiment, the expander 34 is coaxial with the heat pump compressor 31 to reduce the power consumption of the power distribution module 41;

[0111] After the pressure and temperature of the heat pump working fluid in the expander 34 are reduced, the heat pump working fluid enters the refrigerator 35 through the heat pump working fluid circuit 10. The heat pump working fluid cools the refrigerant in the refrigerant pipeline 9 in the refrigerator 35 and increases the temperature of the heat pump working fluid itself.

[0112] After the heat pump working fluid passes through the refrigerator 35, the heat pump working fluid enters the heat pump heat absorber 36 through the heat pump working fluid loop 10, absorbs the heat of the circulating cooling water in the circulating cooling water pipeline 3, and realizes the cooling of the circulating cooling water;

[0113] After passing through the heat pump absorber 36 , the heat pump working fluid enters the regenerator 33 to absorb the heat of the heat pump working fluid at the outlet of the steam generator 32 , further increasing the temperature to meet the conditions for entering the heat pump compressor 31 .

[0114] 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 claims of the present invention.

Claims

1. A low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system, 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 (34), a refrigerator (35) and a heat pump absorber (36); The hydrogen and oxygen liquid separation unit (12) is connected to the heat pump absorber (36) via a circulating cooling water pipeline (3), the hydrogen cooler (22) is connected to the refrigerator (35) 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) and the inlet of the expander (34) via a hot heat pump working fluid pipeline (101); the outlet of the expander (34) is connected in sequence to the refrigerator (35), the heat pump absorber (36) and the inlet of the heat pump compressor (31) via a cold heat pump working fluid pipeline (102); The hot heat pump working fluid pipeline (101) and the cold heat pump working fluid pipeline (102) are both connected to a regenerator (33); On the heat pump working medium pipeline (101), the regenerator (33) is located between the steam generator (32) and the expander (34); On the cold and hot pump working medium pipeline (102), the regenerator (33) is located between the heat pump absorber (36) and the heat pump compressor (31).

2. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 1 is characterized in that: The heat pump compressor (31) and the expander (34) are coaxial.

3. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 1 is characterized in that: The heat pump compressor (31) and the expander (34) are not coaxial.

4. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 1 is characterized in that: It also comprises a feed pipeline (1), an electrolyzer (11), a crude product pipeline (2) 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 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).

5. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 4 is characterized in that: The hydrogen-oxygen-liquid separation unit (12) is provided with a condensed water pipeline (6), and the hydrogen-oxygen-liquid separation unit (12) is connected to the feed pipeline (1) via the condensed water pipeline (6).

6. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 1 is characterized in that: The hydrogen-oxygen-liquid separation unit (12) is provided with an oxygen pipeline (4).

7. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 1 is characterized in that: It also comprises a hydrogen deoxidizer (21), and the hydrogen-oxygen liquid-gas separation unit (12) is connected in sequence to the hydrogen deoxidizer (21) and the hydrogen cooler (22) via a hydrogen pipeline (5).

8. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 1 is 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).

9. The low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system according to claim 4, characterized in that: The heat pump compressor (31) is electrically connected to the power distribution module (41).

10. A method for using a low-pressure ratio water electrolysis hydrogen production energy optimization heat pump system based on any one of claims 1 to 9, characterized in that: The following steps are involved: S1, separating hydrogen, oxygen and 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 (35) provides cooling capacity to the hydrogen cooler (22) through the refrigerant pipeline (9) to cool the hydrogen, and at the same time, the refrigerator (35) transfers the heat released by the refrigerant pipeline (9) to the cold and heat pump working fluid pipeline (102); 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 the waste heat generated by water electrolysis to produce hydrogen from the hydrogen-oxygen-liquid separation unit (12), and using the heat pump heat absorber (36) to transfer the heat of the circulating cooling water pipeline (3) to the cold and heat pump working fluid pipeline (102); 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 pipeline (101), 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 (34); S7, the expander (34) expands the inflowing heat pump working fluid to perform work and generate cold energy, and the expanded heat pump working fluid enters the refrigerator (35), the heat pump heat absorber (36) and the inlet of the heat pump compressor (31) in sequence through the cold and hot pump working fluid pipeline (102), thereby forming a heat pump cycle, and the hot heat pump working fluid pipeline (101) heats the heat pump working fluid in the cold and hot pump working fluid pipeline (102) through the regenerator (33).

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