Device and method for preparing hydrogen from salt-containing wastewater

Abstract

The invention relates to a device and a method for preparing hydrogen from salt-containing wastewater. The device comprises an electrolysis unit, a gas-liquid separation unit, a first solid hydrogen storage unit and a second solid hydrogen storage unit, wherein the first solid hydrogen storage unit and the second solid hydrogen storage unit alternately perform hydrogenation reaction and dehydrogenation reaction. The electrolysis unit is used for electrolyzing the salt-containing wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolytic waste liquid; the gas-liquid separation unit is used for separating the gas-liquid mixture to obtain mixed gas and electrolytic waste liquid; the first solid hydrogen storage unit and the second solid hydrogen storage unit alternately perform hydrogenation reaction and dehydrogenation reaction, in a first hydrogen production state, the first solid hydrogen storage unit absorbs hydrogen, releases heat, exhausts waste gas and preheats salt-containing wastewater, and the second solid hydrogen storage unit absorbs heat, removes hydrogen and exhausts electrolytic waste liquid; in the second hydrogen production state, the functions of the two units are exchanged. The hydrogen can be continuously and efficiently produced, and the energy consumption is remarkably reduced.

Description

Technical Field

[0001] The invention relates to the technical field of water decomposition hydrogen production and wastewater treatment, and more specifically to a device and method for producing hydrogen from saline wastewater. Background Art

[0002] As a zero-carbon energy source, hydrogen has the advantages of wide use, high combustion calorific value, and only water emissions. It is one of the energy sources that many countries and organizations are focusing on researching. Hydrogen energy has great economic potential, and the hydrogen energy industry will become a new economic growth point in my country. At present, the preparation methods of hydrogen energy can be roughly divided into four types: coal-to-hydrogen, natural gas reforming hydrogen, water-to-hydrogen, and bio-hydrogen. In contrast, water-to-hydrogen has the advantages of high thermal efficiency and environmental friendliness, and is currently one of the most popular hydrogen production methods.

[0003] The production of hydrogen by water electrolysis consumes a lot of electricity. In order to solve the problem of high energy consumption of water electrolysis, people have begun to study the use of other energy sources to drive hydrogen electrolysis. Using wind energy, solar energy, process waste heat, etc. to drive hydrogen electrolysis can reduce the cost of electrolysis.

[0004] my country's chemical, pharmaceutical and other industries discharge a large amount of high-salt organic wastewater every year. In addition to its own high salt content and high COD, it also has the characteristics of strong acidity and alkalinity, high toxicity, complex chemical composition, and poor biodegradability. The main methods for treating saline wastewater are physical, chemical, and biological methods.

[0005] Electrolysis of saline organic wastewater to produce hydrogen is an innovative research direction. Hydrogen can be produced at the cathode through electrochemical methods, while organic pollutants can be degraded or recycled at the anode. This process not only helps to treat wastewater as a resource, but also provides a new and sustainable path for the production of hydrogen energy. However, the chloride ions in the wastewater will be oxidized at the anode to produce chlorine byproducts, and the separation and treatment of chlorine from hydrogen requires additional energy consumption. At the same time, the heat generated in the flow electrolysis reaction will be lost with the electrolyte. The above two reasons have caused this technical route to consume a lot of energy and have poor economic performance.

[0006] In summary, the main problem with the existing technology of producing hydrogen using salt-containing wastewater is that it is impossible to effectively separate waste gases such as chlorine and efficiently produce hydrogen while saving energy. Summary of the invention

[0007] The purpose of the present disclosure is to provide a device and method for producing hydrogen from saline wastewater, so as to solve the problem that the prior art cannot effectively separate waste gases such as chlorine and efficiently produce hydrogen while saving energy.

[0008] In order to achieve the above-mentioned purpose, one aspect of the present application provides a device for producing hydrogen from saline wastewater, which has a first hydrogen production state and a second hydrogen production state. The device includes: an electrolysis unit, which is used to electrolyze saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid, and the electrolysis unit has an inlet and a gas-liquid mixture outlet; a gas-liquid separation unit, which is used to perform gas-liquid separation on the gas-liquid mixture to obtain a mixed gas containing hydrogen and waste gas and electrolysis waste liquid, and the gas-liquid separation unit has a gas-liquid mixture inlet, a gas outlet and a waste liquid outlet, and the gas-liquid mixture inlet is connected to the gas-liquid mixture outlet of the electrolysis unit; a first solid-state hydrogen storage unit, which has a first air inlet, a first air outlet, a first electrolysis waste liquid inlet, a first wastewater inlet, and a first liquid outlet; a second solid-state hydrogen storage unit, which has a second air inlet, a second air outlet, a second electrolysis waste liquid inlet, a second wastewater inlet, and a second liquid outlet. In the first hydrogen production state, the first solid-state hydrogen storage unit performs a hydrogenation reaction and releases heat, the first air inlet is connected to the gas outlet of the gas-liquid separation unit, the first air outlet is used to discharge waste gas, the first wastewater inlet is used to input saline wastewater into the first solid-state hydrogen storage unit, and the first liquid outlet is connected to the inlet of the electrolysis unit; the second solid-state hydrogen storage unit is used to perform a dehydrogenation reaction and absorb heat, the second electrolysis waste liquid inlet is connected to the waste liquid outlet of the gas-liquid separation unit, the second air outlet is used to discharge hydrogen, and the second liquid outlet is used to discharge electrolysis waste liquid. In the second hydrogen production state, the second solid-state hydrogen storage unit is used to carry out hydrogenation reaction and release heat, the second air inlet is connected to the gas outlet of the gas-liquid separation unit, the second air outlet is used to discharge waste gas, the second wastewater inlet is used to input saline wastewater into the second solid-state hydrogen storage unit, and the second liquid outlet is connected to the inlet of the electrolysis unit; the first solid-state hydrogen storage unit is used to carry out dehydrogenation reaction and absorb heat, the first electrolysis waste liquid inlet is connected to the waste liquid outlet of the gas-liquid separation unit, the first air outlet is used to discharge hydrogen, and the first liquid outlet is used to discharge electrolysis waste liquid.

[0009] Furthermore, the device also includes a gas buffer unit, the gas buffer unit has a third gas inlet and a third gas outlet, the third gas inlet is connected to the gas outlet of the gas-liquid separation unit. In the first hydrogen production state, the third gas outlet is connected to the first gas inlet of the first solid-state hydrogen storage unit; in the second hydrogen production state, the third gas outlet is connected to the second gas inlet of the second solid-state hydrogen storage unit.

[0010] Furthermore, the device also includes a heat exchange unit, which has a wastewater inlet and a wastewater outlet and an electrolytic waste liquid inlet and an electrolytic waste liquid outlet. The wastewater inlet is used to input saline wastewater into the heat exchange unit, and the electrolytic waste liquid outlet is used to discharge the electrolytic waste liquid. In the first hydrogen production state, the wastewater outlet is connected to the first wastewater inlet of the first solid-state hydrogen storage unit, and the electrolytic waste liquid inlet is connected to the second liquid outlet of the second solid-state hydrogen storage unit; in the second hydrogen production state, the wastewater outlet is connected to the second wastewater inlet of the second solid-state hydrogen storage unit, and the electrolytic waste liquid inlet is connected to the first liquid outlet of the first solid-state hydrogen storage unit.

[0011] Furthermore, the device also includes a circulation pump, which has a water inlet and a water outlet, and the water outlet is connected to the inlet of the electrolysis unit. In the first hydrogen production state, the water inlet of the circulation pump is connected to the first liquid outlet of the first solid-state hydrogen storage unit; in the second hydrogen production state, the water inlet of the circulation pump is connected to the second liquid outlet of the second solid-state hydrogen storage unit.

[0012] Furthermore, the device has a temperature detector at the gas-liquid mixture outlet of the electrolysis unit for detecting the temperature of the gas-liquid mixture, and the device has a first flow meter at the first air inlet of the first solid-state hydrogen storage unit and a second flow meter at the second air inlet of the second solid-state hydrogen storage unit, and interlocking control is implemented between the temperature detector and the first flow meter, and between the temperature detector and the second flow meter.

[0013] Furthermore, the first solid-state hydrogen storage unit and the second solid-state hydrogen storage unit are solid-state hydrogen storage devices comprising hydrogen storage materials and heat exchange coils, and the hydrogen storage materials are selected from one or more of LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, and Mg.

[0014] Furthermore, the electrolytic unit is an electrolytic cell without a diaphragm.

[0015] Another aspect of the present application provides a method for producing hydrogen from saline wastewater, which uses the above-mentioned device to produce hydrogen from saline wastewater, including: in a first hydrogen production state, inputting the saline wastewater into a first solid-state hydrogen storage unit to preheat the saline wastewater; inputting the preheated saline wastewater into an electrolysis unit to electrolyze the saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid; inputting the gas-liquid mixture into a gas-liquid separation unit to perform gas-liquid separation on the gas-liquid mixture to obtain a mixed gas containing hydrogen and waste gas and electrolysis waste liquid; inputting the mixed gas into the first solid-state hydrogen storage unit, the first solid-state hydrogen storage unit absorbs hydrogen, releases heat and discharges waste gas, and inputting the electrolysis waste liquid into a second solid-state hydrogen storage unit, the second solid-state hydrogen storage unit absorbs heat, removes hydrogen and discharges electrolysis waste liquid. In the second hydrogen production state, the saline wastewater is input into the second solid-state hydrogen storage unit to preheat the saline wastewater; the preheated saline wastewater is input into the electrolysis unit to electrolyze the saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid; the gas-liquid mixture is input into the gas-liquid separation unit to perform gas-liquid separation on the gas-liquid mixture to obtain a mixed gas containing hydrogen and waste gas and electrolysis waste liquid; the mixed gas is input into the second solid-state hydrogen storage unit, the second solid-state hydrogen storage unit absorbs hydrogen, releases heat and discharges waste gas, and the electrolysis waste liquid is input into the first solid-state hydrogen storage unit, the first solid-state hydrogen storage unit absorbs heat, removes hydrogen and discharges electrolysis waste liquid.

[0016] Furthermore, the saline wastewater is wastewater containing 0.001 to 1 mol / L of chloride ions, preferably 0.001 to 0.1 mol / L of chloride ions, more preferably 0.001 to 0.01 mol / L of chloride ions, and the waste gas contains chlorine.

[0017] Furthermore, the saline wastewater is saline organic wastewater, and the saline organic wastewater contains one or more organic substances selected from phenols, alcohols, aldehydes, ketones, fatty acids, amino acids, and proteins.

[0018] The device and method provided in the present application realize the effective separation of exhaust gas and hydrogen by alternately using two solid-state hydrogen storage units, and at the same time utilize the heat of electrolytic waste liquid to preheat saline wastewater, thereby improving energy utilization efficiency and reducing dependence on external heat sources.

[0019] By controlling the hydrogenation and dehydrogenation reactions of hydrogen storage materials, not only can hydrogen and waste gas be effectively separated, but the waste heat in the electrolysis process can also be recycled, reducing the cost of hydrogen production and realizing the resource utilization of salt-containing wastewater, which has significant economic benefits and environmental value.

[0020] Through the above design, the device and method of the present application can achieve energy self-sufficiency and recycling in the hydrogen production process, significantly improving the efficiency and economy of hydrogen production. At the same time, for the treatment of salt-containing organic wastewater, not only the wastewater discharge problem is solved, but also hydrogen, a clean energy source, is extracted from it, providing a new solution for industrial wastewater treatment and resource recovery.

[0021] In addition, the design of the electrolyzer without a diaphragm simplifies the electrolysis process, reduces equipment cost and maintenance difficulty, and makes the entire system more stable and reliable, and easy to apply on a large scale. In practical applications, the technical solution of this application can effectively increase the output and purity of hydrogen, reduce energy consumption, and is of great significance to promoting the development and utilization of hydrogen energy and promoting the environmentally friendly treatment of industrial wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 A schematic diagram of a device for producing hydrogen from saline wastewater according to one embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram showing a first solid-state hydrogen storage unit and a second solid-state hydrogen storage unit in a first hydrogen production state according to an embodiment of the present invention is shown;

[0025] Figure 3 A schematic diagram of a first solid-state hydrogen storage unit and a second solid-state hydrogen storage unit in a second hydrogen production state according to an embodiment of the present invention is shown.

[0026] Description of reference numerals:

[0027] 1. Electrolysis unit; 11. Inlet; 12. Gas-liquid mixture outlet;

[0028] 2. Gas-liquid separation unit; 21. Gas-liquid mixture inlet; 22. Gas outlet; 23. Waste liquid outlet;

[0029] 3. First solid-state hydrogen storage unit; 31. First air inlet; 32. First air outlet; 33. First electrolytic waste liquid inlet; 34. First waste water inlet; 35. First liquid outlet; 36. Heat exchange coil;

[0030] 4. Second solid-state hydrogen storage unit; 41. Second air inlet; 42. Second air outlet; 43. Second electrolytic waste liquid inlet; 44. Second waste water inlet; 45. Second liquid outlet; 46. Heat exchange coil;

[0031] 5. Gas buffer unit; 51. Third air inlet; 52. Third air outlet;

[0032] 6. Heat exchange unit; 61. Wastewater inlet; 62. Wastewater outlet; 63. Electrolytic waste liquid inlet; 64. Electrolytic waste liquid outlet;

[0033] 7. Circulation pump; 71. Water inlet; 72. Water outlet;

[0034] 8. Temperature detector;

[0035] 9. First flow meter; 10. Second flow meter;

[0036] 101, first valve; 102, second valve; 103, third valve; 104, fourth valve; 105, fifth valve; 106, sixth valve; 107, seventh valve; 108, eighth valve; 109, ninth valve; 110, tenth valve. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with specific implementation methods. The embodiments shown below do not limit the invention content recorded in the claims. It should be noted that the embodiments and features in the embodiments in this application can be combined with each other without conflict.

[0038] In view of the deficiencies in the prior art mentioned in the background technology, one aspect of the present application provides a device for producing hydrogen from saline wastewater, the device having a first hydrogen production state and a second hydrogen production state, comprising: an electrolysis unit 1, for electrolyzing saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid, the electrolysis unit 1 having an inlet 11 and a gas-liquid mixture outlet 12; a gas-liquid separation unit 2, for performing gas-liquid separation on the gas-liquid mixture to obtain a mixed gas containing hydrogen and waste gas and electrolysis waste liquid, the gas-liquid separation unit 2 having a first hydrogen production state and a second hydrogen production state ... a second hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a first hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a first hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a second hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a first hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a second hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a first hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a second hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a second hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a second hydrogen production state and a second hydrogen production state, the gas-liquid separation unit 2 having a second hydrogen The separation unit 2 has a gas-liquid mixture inlet 21, a gas outlet 22 and a waste liquid outlet 23, and the gas-liquid mixture inlet 21 is connected to the gas-liquid mixture outlet 12 of the electrolysis unit 1; the first solid-state hydrogen storage unit 3 has a first air inlet 31, a first air outlet 32, a first electrolysis waste liquid inlet 33, a first wastewater inlet 34, and a first liquid outlet 35, and the second solid-state hydrogen storage unit 4 has a second air inlet 41, a second air outlet 42, a second electrolysis waste liquid inlet 43, a second wastewater inlet 44, and a second liquid outlet 45.

[0039] In the first hydrogen production state, the first solid-state hydrogen storage unit 3 performs a hydrogenation reaction of a hydrogen storage material (preferably a hydrogen storage alloy) and releases heat, the first air inlet 31 is connected to the gas outlet 22 of the gas-liquid separation unit 2, the first air outlet 32 ​​discharges waste gas, the first wastewater inlet 34 inputs saline wastewater into the first solid-state hydrogen storage unit 3, and the first liquid outlet 35 is connected to the inlet 11 of the electrolysis unit 1; the second solid-state hydrogen storage unit 4 performs a dehydrogenation reaction of a hydrogen storage material hydride (preferably a hydrogen storage alloy hydride) and absorbs heat, the second electrolytic waste liquid inlet 43 is connected to the waste liquid outlet 23 of the gas-liquid separation unit 2, the second air outlet 42 discharges hydrogen, and the second liquid outlet 45 discharges electrolytic waste liquid.

[0040] In the second hydrogen production state, the second solid-state hydrogen storage unit 4 performs a hydrogenation reaction of a hydrogen storage material (preferably a hydrogen storage alloy) and releases heat, the second air inlet 41 is connected to the gas outlet 22 of the gas-liquid separation unit 2, the second air outlet 42 discharges waste gas, the second wastewater inlet 44 inputs saline wastewater into the second solid-state hydrogen storage unit 4, and the second liquid outlet 45 is connected to the inlet 11 of the electrolysis unit 1; the first solid-state hydrogen storage unit 3 performs a dehydrogenation reaction of a hydrogen storage material hydride (preferably a hydrogen storage alloy hydride) and absorbs heat, the first electrolysis waste liquid inlet 33 is connected to the waste liquid outlet 23 of the gas-liquid separation unit 2, the first air outlet 32 ​​discharges hydrogen, and the first liquid outlet 35 discharges electrolysis waste liquid.

[0041] Through this design, the device can effectively switch between two hydrogen production states, which not only improves the efficiency of hydrogen production, but also realizes heat recovery and utilization, reducing energy consumption. In terms of implementation effect, this device can significantly reduce energy waste in industrial production and improve the thermal efficiency of the hydrogen production process. At the same time, through the alternating use of solid-state hydrogen storage units, it ensures the continuous supply of hydrogen and effectively solves the problem of intermittent hydrogen production. It has a wide range of application scenarios, not only suitable for large-scale industrial saline wastewater treatment, such as chemical, electroplating, and pharmaceutical industry wastewater treatment, but also suitable for hydrogen energy production scenarios, such as hydrogen refueling stations for hydrogen energy vehicles and energy supply for hydrogen fuel cells.

[0042] This alternating working mode allows the two solid-state hydrogen storage units to complement each other. When one unit is undergoing a hydrogenation reaction, the other unit is undergoing a dehydrogenation reaction, ensuring a continuous supply of hydrogen. In terms of implementation effect, this alternating mode effectively avoids the problem of overloading a single hydrogen storage unit and improves the stability and safety of the system. This state switching can not only maintain the continuity of hydrogen production, but also effectively utilize the waste heat generated during the electrolysis process to improve overall energy efficiency. In terms of implementation effect, the recovery and reuse of waste heat significantly reduces the energy consumption of hydrogen production and reduces the impact on the environment.

[0043] In one embodiment of the present application, the device also includes a gas buffer unit 5, which has a third gas inlet 51 and a third gas outlet 52. The third gas inlet 51 is connected to the gas outlet 22 of the gas-liquid separation unit 2. In the first hydrogen production state, the third gas outlet 52 is connected to the first gas inlet 31 of the first solid-state hydrogen storage unit 3; in the second hydrogen production state, the third gas outlet 52 is connected to the second gas inlet 41 of the second solid-state hydrogen storage unit 4.

[0044] Specifically, in the first hydrogen production state, the gas mixture of hydrogen and waste gas (such as chlorine) is first transported from the gas-liquid separation unit 2 to the gas buffer unit 5 (preferably a gas buffer tank) for temporary storage, and then transported to the first solid-state hydrogen storage unit 3 for hydrogenation reaction; similarly, in the second hydrogen production state, the gas mixture of hydrogen and waste gas (such as chlorine) is first transported from the gas-liquid separation unit 2 to the gas buffer unit 5 (preferably a gas buffer tank) for temporary storage, and then transported to the second solid-state hydrogen storage unit 4 for hydrogenation reaction.

[0045] The setting of the gas buffer unit can stabilize the gas flow rate and avoid the decrease in hydrogen production efficiency caused by gas flow rate fluctuations. In terms of implementation effect, the addition of the gas buffer unit makes the hydrogen production process smoother and avoids equipment damage and hydrogen production fluctuations caused by unstable gas flow rate.

[0046] In one embodiment of the present application, the device also includes a heat exchange unit 6, which has a wastewater inlet 61 and a wastewater outlet 62, as well as an electrolytic waste liquid inlet 63 and an electrolytic waste liquid outlet 64. The wastewater inlet is used to input saline wastewater into the heat exchange unit 6, and the electrolytic waste liquid outlet 64 is used to discharge the electrolytic waste liquid. In the first hydrogen production state, the wastewater outlet 62 is connected to the first wastewater inlet 34 of the first solid-state hydrogen storage unit 3, and the electrolytic waste liquid inlet 63 is connected to the second liquid outlet 45 of the second solid-state hydrogen storage unit 4; in the second hydrogen production state, the wastewater outlet 62 is connected to the second wastewater inlet 44 of the second solid-state hydrogen storage unit 4, and the electrolytic waste liquid inlet 63 is connected to the first liquid outlet 35 of the first solid-state hydrogen storage unit 3.

[0047] Specifically, in the first hydrogen production state, the electrolytic waste liquid generated by the electrolytic reaction in the electrolytic unit 1 has a certain amount of heat, and enters the heat exchange unit 6 after passing through the gas-liquid separation unit 2 and the second solid-state hydrogen storage unit 4; at the same time, the saline waste water (fresh saline waste water) also enters the heat exchange unit 6. In the heat exchange unit 6, the newly input saline waste water is preheated by the heat brought by the electrolytic waste liquid. The preheated saline waste water is then transported from the heat exchange unit 6 to the first solid-state hydrogen storage unit 3 for further preheating.

[0048] Similarly, in the second hydrogen production state, the electrolytic waste liquid generated by the electrolysis reaction in the electrolysis unit 1 has a certain amount of heat, and enters the heat exchange unit 6 after passing through the gas-liquid separation unit 2 and the first solid-state hydrogen storage unit 3; at the same time, the saline waste water (fresh saline waste water) also enters the heat exchange unit 6. In the heat exchange unit 6, the newly input saline waste water is preheated by the heat brought by the electrolytic waste liquid. The preheated saline waste water is then transported from the heat exchange unit 6 to the second solid-state hydrogen storage unit 4 for further preheating.

[0049] The addition of the heat exchange unit realizes the heat exchange between the saline wastewater and the electrolytic waste liquid, further improving the energy utilization efficiency. In terms of implementation effect, the recycling of heat energy reduces the dependence on external energy, reduces the overall operating cost, and also reduces waste heat emissions, which has positive significance for environmental protection.

[0050] In one embodiment of the present application, the device also includes a circulation pump 7, which has a water inlet 71 and a water outlet 72, and the water outlet 72 is connected to the inlet 11 of the electrolysis unit 1. In the first hydrogen production state, the water inlet 71 of the circulation pump 7 is connected to the first liquid outlet 35 of the first solid-state hydrogen storage unit 3; in the second hydrogen production state, the water inlet 71 of the circulation pump 7 is connected to the second liquid outlet 45 of the second solid-state hydrogen storage unit 4.

[0051] The use of circulating pumps ensures the continuous delivery of saline wastewater and improves the efficiency of wastewater treatment. In terms of implementation effect, the continuous delivery of wastewater improves the efficiency of the electrolysis unit, reduces the time of wastewater treatment, and speeds up the process of hydrogen production. The application scenarios are mainly suitable for industrial scenarios that require continuous wastewater treatment and hydrogen production, such as sewage treatment plants and chemical parks. In these scenarios, wastewater treatment and hydrogen production are usually carried out continuously. The use of circulating pumps can effectively improve the treatment efficiency and meet the needs of continuous production.

[0052] In one embodiment of the present application, the device has a temperature detector 8 at the gas-liquid mixture outlet 12 of the electrolysis unit 1, which is used to detect the temperature of the gas-liquid mixture, and the device has a first flow meter 9 at the first air inlet 31 of the first solid-state hydrogen storage unit 3, and a second flow meter 10 at the second air inlet 41 of the second solid-state hydrogen storage unit 4, and the temperature detector 8 and the first flow meter 9 and the temperature detector 8 and the second flow meter 10 are interlocked and controlled.

[0053] Specifically, in the first hydrogen production state, the gas flow rate entering the first solid-state hydrogen storage unit 3 is interlocked with the temperature detector 8, and the heat release is controlled by controlling the hydrogenation reaction rate, thereby controlling the preheating of the saline wastewater. For example, when the temperature detector 8 detects that the temperature of the gas-liquid mixture produced by electrolysis is too high (exceeding the threshold), it means that the electrolysis reaction temperature is too high. At this time, it is necessary to appropriately reduce the temperature of the saline wastewater entering the electrolysis unit 1, that is, it is necessary to appropriately reduce the heat release in the first solid-state hydrogen storage unit 3. At this time, the first flowmeter 9 should be controlled to appropriately reduce the input gas flow in the first solid-state hydrogen storage unit 3.

[0054] Similarly, in the second hydrogen production state, the gas flow rate entering the second solid-state hydrogen storage unit 4 is interlocked with the temperature detector 8, and the heat release is controlled by controlling the hydrogenation reaction rate, thereby controlling the preheating of the saline wastewater. For example, when the temperature detector 8 detects that the temperature of the gas-liquid mixture produced by electrolysis is too high (exceeding the threshold), it means that the electrolysis reaction temperature is too high. At this time, it is necessary to appropriately reduce the temperature of the saline wastewater entering the electrolysis unit 1, that is, it is necessary to appropriately reduce the heat release in the second solid-state hydrogen storage unit 4. At this time, the second flowmeter 10 should be controlled to appropriately reduce the input gas flow in the second solid-state hydrogen storage unit 4.

[0055] The temperature detection is used to properly control the gas flow of the hydrogenation reaction, ensuring the safety and stability of the hydrogen production process and the entire system. The interlocking control of the temperature detector and the flow meter makes the entire hydrogen production process more intelligent and precise, and can adjust the parameters of the electrolysis and hydrogenation reactions in real time, ensuring the quality of hydrogen while also improving the safety of the system.

[0056] In one embodiment of the present application, the first solid-state hydrogen storage unit 3 and the second solid-state hydrogen storage unit 4 are solid-state hydrogen storage devices comprising hydrogen storage materials and heat exchange coils 36 and 46, and the hydrogen storage materials are selected from one or more of LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, and Mg.

[0057] These hydrogen storage materials have high hydrogen storage density and good thermal stability, which can effectively improve the storage and release efficiency of hydrogen. In terms of implementation effect, the selection of materials with high hydrogen storage density makes the solid-state hydrogen storage unit smaller in size, and the efficiency of storing and releasing hydrogen is higher, which reduces the difficulty and cost of hydrogen storage and transportation.

[0058] The main purpose and effect of including heat exchange coils in the first solid-state hydrogen storage unit and the second solid-state hydrogen storage unit is to achieve effective management and utilization of thermal energy. The heat exchange coil allows the saline wastewater to be preheated before entering the electrolysis unit. When the wastewater flows through the heat exchange coils of the first or second solid-state hydrogen storage unit, it absorbs the heat generated by the hydrogen storage material (such as hydrogen storage alloy) absorbing hydrogen and releasing heat. This preheating method increases the initial temperature of the wastewater when it enters the electrolysis unit, which is beneficial to the electrolysis reaction because the electrolysis efficiency generally increases with the increase in temperature. At the same time, preheating reduces the need for additional heat sources and improves the overall energy efficiency of the system.

[0059] In one embodiment of the present application, the electrolysis unit 1 is an electrolyzer without a diaphragm. An electrolyzer without a diaphragm, also known as a diaphragmless electrolyzer, has several advantages in the fields of water decomposition to produce hydrogen and salt-containing organic wastewater treatment.

[0060] In a diaphragmless electrolyzer, the electrolyte can flow freely without the obstruction of a diaphragm, which generally improves the current efficiency and hydrogen production rate. The presence of a diaphragm increases the mass transfer resistance and the voltage drop inside the electrolyzer, resulting in increased energy consumption. In a diaphragmless design, the electrolyte between the cathode and anode can circulate more freely, which helps to improve the mass transfer efficiency of the reactants, thereby improving the current efficiency and hydrogen production rate.

[0061] The diaphragm-free design simplifies the structure of the electrolyzer and can omit the diaphragm and related sealing and supporting structures, so the equipment manufacturing and maintenance costs are usually lower. The cost of using and replacing the diaphragm is high, and in long-term operation, the diaphragm may become clogged, damaged or degraded, requiring regular inspection and replacement. The diaphragm-free design avoids these additional maintenance tasks.

[0062] In the treatment of wastewater containing organic matter, the diaphragm-free design can promote the effective oxidation of organic matter at the anode. The diaphragm may hinder the migration of waste from the cathode side to the anode, while the diaphragm-free design can ensure the uniform distribution of wastewater and improve the efficiency of the oxidation reaction, thereby better achieving the degradation or resource utilization of organic matter. In addition, the diaphragm-free design helps to more evenly distribute the heat generated during the electrolysis process, which can simplify the thermal management of the system.

[0063] Another aspect of the present application provides a method for producing hydrogen from saline wastewater. The method uses the above-mentioned device to produce hydrogen from saline wastewater, including: in a first hydrogen production state, inputting the saline wastewater into a first solid-state hydrogen storage unit 3 to preheat the saline wastewater; inputting the preheated saline wastewater into an electrolysis unit 1 to electrolyze the saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid; inputting the gas-liquid mixture into a gas-liquid separation unit 2 to perform gas-liquid separation on the gas-liquid mixture to obtain a mixed gas containing hydrogen and waste gas and electrolysis waste liquid; inputting the mixed gas into the first solid-state hydrogen storage unit 3, the first solid-state hydrogen storage unit 3 absorbs hydrogen, releases heat and discharges waste gas, inputting the electrolysis waste liquid into a second solid-state hydrogen storage unit 4, and the second solid-state hydrogen storage unit 5 is used to separate the gas-liquid mixture into a gas-liquid separation unit 2 to obtain a mixed gas containing hydrogen and waste gas and electrolysis waste liquid. The solid-state hydrogen storage unit 4 absorbs heat, removes hydrogen and discharges electrolytic waste liquid; in the second hydrogen production state, the saline wastewater is input into the second solid-state hydrogen storage unit 4 to preheat the saline wastewater; the preheated saline wastewater is input into the electrolysis unit 1 to electrolyze the saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolytic waste liquid; the gas-liquid mixture is input into the gas-liquid separation unit 2 to perform gas-liquid separation on the gas-liquid mixture to obtain a mixed gas containing hydrogen and waste gas and electrolytic waste liquid; the mixed gas is input into the second solid-state hydrogen storage unit 4, the second solid-state hydrogen storage unit 4 absorbs hydrogen, releases heat and discharges waste gas, and the electrolytic waste liquid is input into the first solid-state hydrogen storage unit 3, the first solid-state hydrogen storage unit 3 absorbs heat, removes hydrogen and discharges electrolytic waste liquid.

[0064] This method can not only produce hydrogen efficiently, but also purify and recycle salty wastewater. It is suitable for industrial wastewater treatment and hydrogen energy production scenarios with high environmental protection requirements, such as the pharmaceutical, food processing and power industries. In terms of implementation effect, this method can significantly reduce wastewater and waste heat emissions, improve resource recycling rate, save energy consumption, and reduce environmental impact.

[0065] In one embodiment of the present application, the saline wastewater is wastewater containing 0.001 to 1 mol / L chloride ions, and the waste gas contains chlorine. Preferably, the waste gas is chlorine. This method is particularly suitable for the treatment of chlorine-containing wastewater, and can effectively remove chloride ions in the wastewater and recover chlorine at the same time. In terms of implementation effect, this method can achieve the separation of chlorine and hydrogen products, realize the recycling and reuse of chlorine, reduce the cost of wastewater treatment, and improve economic benefits. The application scenarios are mainly concentrated in the fields of chlor-alkali industry and chlorine-containing wastewater treatment, such as electroplating wastewater treatment, chemical wastewater treatment, etc. These fields often have high chlorine-containing wastewater discharge. The method of the present application can effectively reduce the pollution of chloride ions to the environment, and at the same time recover chlorine for use in the production process, achieving the dual goals of wastewater treatment and resource recovery.

[0066] In one embodiment of the present application, the saline wastewater is saline organic wastewater, and the saline organic wastewater contains one or more organic substances selected from phenols, alcohols, aldehydes, ketones, fatty acids, amino acids, and proteins. This method can not only treat saline organic wastewater, but also convert organic matter into usable energy in the hydrogen production process. In terms of implementation effect, this method can effectively remove organic matter in wastewater and produce hydrogen at the same time, thereby achieving wastewater purification and resource recycling, reducing the difficulty and cost of wastewater treatment, and improving the comprehensive utilization rate of energy and resources. The application scenario is mainly applicable to the fields of organic wastewater treatment and biomass energy production, such as petrochemical, papermaking and food processing industries. These industries will produce a large amount of saline organic wastewater during the production process. The method of the present application can effectively achieve the harmless treatment of wastewater and the recycling of energy, which is of great significance for promoting green low-carbon economy and sustainable development.

[0067] In order to solve the problems of high energy consumption for gas product separation and serious waste of sensible heat of wastewater after electrolysis in hydrogen production by electrolysis of salt-containing organic wastewater, the present invention proposes a method for waste heat recovery and coordinated hydrogen purification based on solid-state hydrogen storage. According to one embodiment, the specific scheme of the present invention is as follows Figure 1 , Figure 2 and Figure 3 shown.

[0068] Figure 1 The schematic diagram of the structure of the device for producing hydrogen from saline wastewater is shown. The device comprises:

[0069] - Electrolysis unit 1, whose function is to electrolyze saline wastewater to generate a gas-liquid mixture, which contains hydrogen, waste gas and electrolysis waste liquid. The electrolysis unit 1 has an inlet 11 for inputting preheated saline wastewater; and a gas-liquid mixture outlet 12 for discharging the gas-liquid mixture after electrolysis. In this embodiment, the electrolysis unit 1 is an electrolytic cell without a diaphragm, which simplifies the electrolysis process, reduces equipment cost and maintenance difficulty, and improves the stability of the system.

[0070] - Gas-liquid separation unit 2, whose function is to separate the gas-liquid mixture output by electrolysis unit 1 to obtain mixed gas and electrolysis waste liquid. Gas-liquid separation unit 2 has a gas-liquid mixture inlet 21 connected to the gas-liquid mixture outlet 12 of electrolysis unit 1; a gas outlet 22 for discharging the separated mixed gas (mixed gas of chlorine-containing waste gas and hydrogen); and a waste liquid outlet 23 for discharging the separated electrolysis waste liquid.

[0071] The gas-liquid separation unit 2 separates the gas-liquid mixture into a mixed gas containing hydrogen and waste gas and electrolysis waste liquid. In the first hydrogen production state, the mixed gas is sent to the first solid-state hydrogen storage unit 3, and the electrolysis waste liquid enters the second solid-state hydrogen storage unit 4; in the second hydrogen production state, the mixed gas is sent to the second solid-state hydrogen storage unit 4, and the electrolysis waste liquid enters the first solid-state hydrogen storage unit 3.

[0072] - The first solid-state hydrogen storage unit 3 has a first air inlet 31, a first air outlet 32, a first electrolytic waste liquid inlet 33, a first waste water inlet 34, and a first liquid outlet 35. The first solid-state hydrogen storage unit 3 contains a hydrogen storage material and a heat exchange coil 36, and the hydrogen storage material is selected from one or more of LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, and Mg.

[0073] In the first hydrogen production state, if Figure 1 and Figure 2 As shown in part b), the first solid-state hydrogen storage unit 3 absorbs hydrogen, releases heat, and discharges the waste gas containing chlorine from the first gas outlet 32; fresh saline wastewater is input from the first wastewater inlet 34, and the saline wastewater is preheated by the heat released by the hydrogenation reaction, and the preheated wastewater is supplied to the electrolysis unit 1 through the first liquid outlet 35. In the first hydrogen production state, the hydrogen storage material in the first solid-state hydrogen storage unit 3 undergoes a hydrogenation reaction to generate a hydrogen storage material hydride.

[0074] In the second hydrogen production state, if Figure 1 and Figure 3 As shown in part a), the first solid-state hydrogen storage unit 3 will undergo a dehydrogenation reaction, so that the hydrogen storage material hydride is converted into hydrogen storage material. The hydrogen storage material hydride in the first solid-state hydrogen storage unit 3 absorbs heat from the electrolytic waste liquid from the gas-liquid separation unit 2, releases hydrogen, and discharges the electrolytic waste liquid through the first liquid outlet 35.

[0075] - A second solid-state hydrogen storage unit 4, having a second air inlet 41, a second air outlet 42, a second electrolytic waste liquid inlet 43, a second waste water inlet 44, and a second liquid outlet 45. The second solid-state hydrogen storage unit 4 contains a hydrogen storage material and a heat exchange coil 46, and the hydrogen storage material is selected from one or more of LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, and Mg.

[0076] In the first hydrogen production state, if Figure 1 and Figure 2As shown in part a), the second solid-state hydrogen storage unit 4 contains the hydrogen storage material hydride obtained by the hydrogenation reaction in the second hydrogen production state in the previous cycle. In the first hydrogen production state, the second solid-state hydrogen storage unit 4 will undergo a dehydrogenation reaction, so that the hydrogen storage material hydride is converted into a hydrogen storage material. The second solid-state hydrogen storage unit 4 absorbs heat from the electrolytic waste liquid from the gas-liquid separation unit 2, releases hydrogen, and discharges the electrolytic waste liquid through the second liquid outlet 45.

[0077] In the second hydrogen production state, if Figure 1 and Figure 3 As shown in part b), the second solid-state hydrogen storage unit 4 absorbs hydrogen, releases heat, and discharges the waste gas containing chlorine from the second gas outlet 42; fresh saline wastewater is input from the second wastewater inlet 44, and the saline wastewater is preheated by the heat released by the hydrogenation reaction, and the preheated wastewater is supplied to the electrolysis unit 1 through the second liquid outlet 45. In the second hydrogen production state, the hydrogen storage material in the second solid-state hydrogen storage unit 4 undergoes a hydrogenation reaction to generate a hydrogen storage material hydride.

[0078] - The gas buffer unit 5 has a third gas inlet 51 and a third gas outlet 52. The third gas inlet 51 is connected to the gas outlet 22 of the gas-liquid separation unit 2, and is used to receive the mixed gas and maintain a stable gas pressure. In the first hydrogen production state, the third gas outlet 52 is connected to the first gas inlet 31 of the first solid-state hydrogen storage unit 3; in the second hydrogen production state, the third gas outlet 52 is connected to the second gas inlet 41 of the second solid-state hydrogen storage unit 4. The gas buffer unit is preferably in the form of a gas buffer tank.

[0079] - The heat exchange unit 6 has a wastewater inlet 61, a wastewater outlet 62, an electrolytic waste liquid inlet 63 and an electrolytic waste liquid outlet 64. The wastewater inlet 61 is used to input saline wastewater into the heat exchange unit 6, and the electrolytic waste liquid outlet 64 is used to discharge the electrolytic waste liquid. In the first hydrogen production state, the electrolytic waste liquid inlet 63 is connected to the second liquid outlet 45 of the second solid hydrogen storage unit 4, and the wastewater outlet 62 is connected to the first wastewater inlet 34 of the first solid hydrogen storage unit 3; in the second hydrogen production state, the wastewater outlet 62 is connected to the second wastewater inlet 44 of the second solid hydrogen storage unit 4, and the electrolytic waste liquid inlet 63 is connected to the first liquid outlet 35 of the first solid hydrogen storage unit 3. By using the heat exchange unit 6, the heat of the electrolytic waste liquid to be discharged can be recycled to achieve preheating of the saline wastewater.

[0080] - A circulation pump 7, having a water inlet 71 and a water outlet 72. The water outlet 72 is connected to the inlet 11 of the electrolysis unit 1, and is used to send the preheated wastewater into the electrolysis unit 1. In the first hydrogen production state, the water inlet 71 of the circulation pump 7 is connected to the first liquid outlet 35 of the first solid hydrogen storage unit 3; in the second hydrogen production state, the water inlet 71 of the circulation pump 7 is connected to the second liquid outlet 45 of the second solid hydrogen storage unit 4.

[0081] A temperature detector 8 is arranged at the gas-liquid mixture outlet 12 of the electrolysis unit 1 and is used to detect the temperature of the gas-liquid mixture.

[0082] - The first flow meter 9 and the second flow meter 10 are respectively arranged at the first air inlet 31 of the first solid-state hydrogen storage unit 3 and the second air inlet 41 of the second solid-state hydrogen storage unit 4. Interlocking control is implemented between the temperature detector 8 and the first flow meter 9 and the second flow meter 10 to maintain the thermal stability and hydrogen production efficiency of the entire system.

[0083] In the method of the present invention, the first hydrogen production state and the second hydrogen production state are continuously alternated. As the two states are continuously switched, the functions of the first solid-state hydrogen storage unit 3 and the second solid-state hydrogen storage unit 4 are also continuously exchanged, thereby realizing the continuous and efficient production of hydrogen, the separation and recovery of waste gas (such as chlorine) after wastewater treatment, and the recycling of heat generated by electrolysis, saving the additional energy required for preheating the electrolyte.

[0084] According to a specific embodiment, the electrolytic unit is preferably an electrolytic cell, the electrolytic cell does not contain a diaphragm, the liquid flow direction is perpendicular to the electrode, the electrode cathode material is composed of an alloy of two or more elements of Ni, Mo, Co, La, and Zn, the anode material is composed of an alloy of two or more elements of Ni, Mn, Co, Fe, and Cu, and the electrode substrate is a nickel wire mesh woven in plain, twill or double twill, and the mesh number is 10 to 100 meshes;

[0085] According to a specific embodiment, the power supply of the electrolyzer can be grid electricity or renewable energy electricity;

[0086] According to a specific embodiment, the lower limit of the operating load of the electrolytic cell is 0 to 20%;

[0087] According to a specific embodiment, the hydrogen storage material used in the first and second solid-state hydrogen storage units is one or more of LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, Mg, etc., preferably LaNi5-based alloy material;

[0088] According to a specific embodiment, the internal pressure of the first solid-state hydrogen storage unit and the second solid-state hydrogen storage unit is controlled at 1 to 10 MPa when absorbing hydrogen, and the hydrogen absorption temperature is 25 to 85° C.;

[0089] According to a specific embodiment, the outlet pressure of the first solid-state hydrogen storage unit and the second solid-state hydrogen storage unit during hydrogen release is 1 to 10 MPa, and the hydrogen release temperature is 25 to 85° C.;

[0090] According to a specific implementation, the ratio of the circulation pump flow rate to the system hydrogen production is 1:100 to 1:10, so as to ensure that the saline wastewater has an appropriate residence time in the electrolysis unit, thereby increasing the reaction temperature and the conversion efficiency of the anode organic pollutants.

[0091] According to a specific implementation manner, the gas buffer unit is preferably a gas buffer tank, the gas storage pressure of the gas buffer tank is 10-98 MPa, and the gas storage temperature is 0-55°C; according to a specific implementation manner, the hydrogen storage mass in the gas buffer tank is greater than the hydrogen storage capacity of the first solid-state hydrogen storage unit / the second solid-state hydrogen storage unit, and the ratio is preferably 10:1-100:1, so as to ensure that the system has a certain load regulation capability.

[0092] According to a specific embodiment, the filling speed (flow rate) in the first solid-state hydrogen storage unit and the second solid-state hydrogen storage unit is interlocked with the temperature of the gas-liquid mixture produced by the electrolysis unit so that the electrolyte temperature in the system is controlled at 85-95°C.

[0093] like Figure 1 As shown in FIG, the device also includes a plurality of valves for controlling the connection or disconnection of each flow path under different hydrogen production conditions.

[0094] The first valve 101 is used to control the connection or disconnection of the flow path between the wastewater outlet 62 of the heat exchange unit 6 and the first wastewater inlet 34 of the first solid hydrogen storage unit 3. In the first hydrogen production state, the first valve 101 is opened and the flow path is connected; in the second hydrogen production state, the first valve 101 is closed and the flow path is disconnected.

[0095] The second valve 102 is used to control the connection or disconnection of the flow path between the wastewater outlet 62 of the heat exchange unit 6 and the second wastewater inlet 44 of the second solid hydrogen storage unit 4. In the first hydrogen production state, the second valve 102 is closed and the flow path is disconnected; in the second hydrogen production state, the second valve 102 is opened and the flow path is connected.

[0096] The third valve 103 is used to control the connection or disconnection of the flow path between the third gas outlet 52 of the gas buffer unit 5 and the first gas inlet 31 of the first solid hydrogen storage unit 3. In the first hydrogen production state, the third valve 103 is opened and the flow path is connected; in the second hydrogen production state, the third valve 103 is closed and the flow path is disconnected.

[0097] The fourth valve 104 is used to control the connection or disconnection of the flow path between the third gas outlet 52 of the gas buffer unit 5 and the second gas inlet 41 of the second solid hydrogen storage unit 4. In the first hydrogen production state, the fourth valve 104 is closed and the flow path is disconnected; in the second hydrogen production state, the fourth valve 104 is opened and the flow path is connected.

[0098] The fifth valve 105 is used to control the connection or disconnection of the flow path between the waste liquid outlet 23 of the gas-liquid separation unit 2 and the first electrolysis waste liquid inlet 33 of the first solid hydrogen storage unit 3. In the first hydrogen production state, the fifth valve 105 is closed and the flow path is disconnected; in the second hydrogen production state, the fifth valve 105 is opened and the flow path is connected.

[0099] The sixth valve 106 is used to control the connection or disconnection of the flow path between the waste liquid outlet 23 of the gas-liquid separation unit 2 and the second electrolysis waste liquid inlet 43 of the second solid hydrogen storage unit 4. In the first hydrogen production state, the sixth valve 106 is opened and the flow path is connected; in the second hydrogen production state, the sixth valve 106 is closed and the flow path is disconnected.

[0100] The seventh valve 107 is used to control the connection or disconnection of the flow path between the water inlet 71 of the circulation pump 7 and the first liquid outlet 35 of the first solid hydrogen storage unit 3. In the first hydrogen production state, the seventh valve 107 is opened and the flow path is connected; in the second hydrogen production state, the seventh valve 107 is closed and the flow path is disconnected.

[0101] The eighth valve 108 is used to control the connection or disconnection of the flow path between the electrolytic waste liquid inlet 63 of the heat exchange unit 6 and the first liquid outlet 35 of the first solid hydrogen storage unit 3. In the first hydrogen production state, the eighth valve 108 is closed and the flow path is disconnected; in the second hydrogen production state, the eighth valve 108 is opened and the flow path is connected.

[0102] The ninth valve 109 is used to control the connection or disconnection of the flow path between the water inlet 71 of the circulation pump 7 and the second liquid outlet 45 of the second solid hydrogen storage unit 4. In the first hydrogen production state, the ninth valve 109 is closed and the flow path is disconnected; in the second hydrogen production state, the ninth valve 109 is opened and the flow path is connected.

[0103] The tenth valve 110 is used to control the connection or disconnection of the flow path between the electrolytic waste liquid inlet 63 of the heat exchange unit 6 and the second liquid outlet 45 of the second solid hydrogen storage unit 4. In the first hydrogen production state, the tenth valve 110 is opened and the flow path is connected; in the second hydrogen production state, the tenth valve 110 is closed and the flow path is disconnected.

[0104] The opening and closing of each valve can be controlled manually, electrically, pneumatically, hydraulically, electromagnetically, etc. For example, electric power can be used to drive the opening and closing of the valve, and a motor can be used to drive a gear, a screw or a sprocket. Electric valves are suitable for systems that require remote control or automated operation, and are usually equipped with a position feedback system to ensure that the valve is in the desired position. In addition, solenoid valves are preferably used to drive the valve through electromagnetic force to achieve precise control and rapid response. Electromagnetic control can realize the opening and closing of the valve by switching the current on and off.

[0105] exist Figure 1In the specific embodiment shown, the first solid-state hydrogen storage unit 3 is provided with two liquid inlets (i.e., the first electrolytic waste liquid inlet 33 and the first wastewater inlet 34), which are respectively used to input electrolytic waste liquid and saline wastewater. However, in other specific embodiments, only one liquid inlet may be provided, and under different hydrogen production conditions, the electrolytic waste liquid or the saline wastewater is respectively input by opening or closing the valve; similarly, in the specific embodiment shown, the second solid-state hydrogen storage unit 4 is provided with two liquid inlets (i.e., the second electrolytic waste liquid inlet 43 and the second wastewater inlet 44), which are respectively used to input electrolytic waste liquid and saline wastewater. However, in other specific embodiments, only one liquid inlet may be provided, and under different hydrogen production conditions, the electrolytic waste liquid or the saline wastewater is respectively input by opening or closing the valve.

[0106] exist Figure 1 In the specific embodiment shown, the first solid-state hydrogen storage unit 3 is provided with a liquid outlet (i.e., the first liquid outlet 35), which is used to output the electrolytic waste liquid or the saline waste water by opening or closing the valve under different hydrogen production states. However, in other specific embodiments, two liquid outlets (e.g., the first electrolytic waste liquid outlet and the first waste water outlet) may be provided, which are used to output the electrolytic waste liquid and the saline waste water respectively; similarly, in the specific embodiment shown, the second solid-state hydrogen storage unit 4 is provided with a liquid outlet (i.e., the second liquid outlet 45), which is used to output the electrolytic waste liquid or the saline waste water by opening or closing the valve under different hydrogen production states. However, in other specific embodiments, two liquid outlets (e.g., the second electrolytic waste liquid outlet and the second waste water outlet) may be provided, which are used to output the electrolytic waste liquid and the saline waste water respectively.

[0107] exist Figure 1 In the specific embodiment shown, the first solid-state hydrogen storage unit 3 is provided with a gas outlet (i.e., the first gas outlet 32) for outputting waste gas (such as chlorine) or hydrogen under different hydrogen production conditions. However, in other specific embodiments, two gas outlets (e.g., a first waste gas outlet and a first hydrogen outlet) may be provided, and a valve is set to control the two gas outlets to independently output waste gas or hydrogen by opening or closing the valve under different hydrogen production conditions. Similarly, in the specific embodiment shown, the second solid-state hydrogen storage unit 4 is provided with a gas outlet (i.e., the second gas outlet 42) for outputting waste gas (such as chlorine) or hydrogen under different hydrogen production conditions. However, in other specific embodiments, two gas outlets (e.g., a second waste gas outlet and a second hydrogen outlet) may be provided, and a valve is set to control the two gas outlets to independently output waste gas or hydrogen by opening or closing the valve under different hydrogen production conditions.

[0108] Figure 2The material reaction and heat change in the first solid-state hydrogen storage unit 3 and the second solid-state hydrogen storage unit 4 in the first hydrogen production state are shown. In part a), for the second solid-state hydrogen storage unit 4, the high-temperature electrolytic waste liquid flows through the heat exchange coil 46, the hydrogen storage material hydride absorbs the heat brought by the electrolytic waste liquid, a dehydrogenation reaction occurs, hydrogen (H2) is discharged from the left side, and the hydrogen storage material hydride is converted into hydrogen storage material; in part b), for the first solid-state hydrogen storage unit 3, hydrogen (H2) enters from the left side, the hydrogen storage material in the first solid-state hydrogen storage unit 3 undergoes a hydrogenation reaction and is converted into a hydrogen storage material hydride, releasing heat, and at the same time, the salt-containing wastewater flows through the heat exchange coil 36, absorbing the heat released by the hydrogenation reaction, achieving a preheating effect.

[0109] Figure 3 The material reaction and heat change in the first solid-state hydrogen storage unit 3 and the second solid-state hydrogen storage unit 4 in the second hydrogen production state are shown. In part a), for the first solid-state hydrogen storage unit 3, the high-temperature electrolytic waste liquid flows through the heat exchange coil 36, the hydrogen storage material hydride absorbs the heat brought by the electrolytic waste liquid, a dehydrogenation reaction occurs, hydrogen (H2) is discharged from the left side, and the hydrogen storage material hydride is converted into hydrogen storage material; in part b), for the second solid-state hydrogen storage unit 4, hydrogen (H2) enters from the left side, the hydrogen storage material in the second solid-state hydrogen storage unit 4 undergoes a hydrogenation reaction and is converted into a hydrogen storage material hydride, releasing heat, and at the same time, the salt-containing wastewater flows through the heat exchange coil 46, absorbing the heat released by the hydrogenation reaction, achieving a preheating effect.

[0110] The heat exchange coils in the first solid-state hydrogen storage unit and the second solid-state hydrogen storage unit ensure the stability of the overall temperature of the hydrogen production device and the effective use of thermal energy.

[0111] In a specific embodiment, the first solid-state hydrogen storage unit and the second solid-state hydrogen storage unit are devices having a shell and a porous partition. The main effect of the porous partition in the solid-state hydrogen storage unit is to evenly distribute hydrogen and promote gas-solid contact, thereby improving the adsorption and release efficiency of hydrogen. It can also prevent the hydrogen storage material from agglomerating during the process of absorbing and releasing hydrogen, ensuring the stability of the hydrogen storage process and the full utilization of the material.

[0112] The salt-containing wastewater applicable to the present invention has a wide range, and the chloride ion concentration can be 0.001-1 mol / L, preferably 0.001-0.1 mol / L, and more preferably 0.001-0.01 mol / L, including but not limited to salt-containing organic wastewater, which may contain organic substances such as phenols, alcohols, aldehydes, ketones, fatty acids, amino acids, proteins, etc. Using such wastewater as a raw material not only solves the problem of wastewater discharge, but also extracts hydrogen, a clean energy, from it, providing a new solution for industrial wastewater treatment and resource recovery.

[0113] Salt-containing wastewater may contain one or more of the following salt substances: NaCl, KCl, Na2SO4, K2SO4, MgCl2, CaCl2, NaNO3, KNO3, NaHCO3, Na2CO3, MgSO4, CaSO4, NH4Cl, Na2HPO4, Na3PO4, etc.

[0114] In the first and second solid-state hydrogen storage units, the hydrogen storage material is preferably one or more of LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, and Mg, and more preferably a hydrogen storage alloy. When the first and second solid-state hydrogen storage units absorb hydrogen, these hydrogen storage materials undergo a hydrogenation reaction and are converted into hydrogen storage material hydrides. For example, LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, and Mg undergo a hydrogenation reaction and can be converted into LaNi5H6, TiFeH6, and LaNi5H6, respectively. 1.95 、ZrV2H 4.8 、TiMn2H 2.47 , V-Ti-Cr-H, MgH2.

[0115] The device and method of the present invention realizes efficient production and storage of hydrogen by alternately utilizing the different functions of the first solid-state hydrogen storage unit 3 and the second solid-state hydrogen storage unit 4, and simultaneously utilizes the heat of the electrolytic waste liquid and the heat released by the hydrogenation reaction to preheat the saline wastewater, thereby improving energy utilization efficiency and reducing dependence on external heat sources. This design can not only effectively separate hydrogen and waste gas, but also recycle waste heat in the electrolysis process, reduce the cost of hydrogen production, and realize resource utilization of saline wastewater.

[0116] It should be noted that, in the description of the present application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0117] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0118] raw material

[0119] The saline organic wastewater used in the following Examples 1 and 2 and Comparative Example 1 comes from a dye manufacturing plant, and its main components include NaCl (about 10 g / L), KCl (about 5 g / L), organic matter (phenols, alcohols, with a concentration of about 200 mg / L), COD (about 1000 mg / L), and BOD (about 500 mg / L).

[0120] Measurement method

[0121] For organic wastewater and discharged electrolytic waste liquid, the pollutant detection methods include conductivity method (NaCl, KCl), high performance liquid chromatography (organic matter), potassium dichromate method (COD), and 5-day BOD test method (BOD).

[0122] In addition, other experimental results and data involved in this application, unless otherwise specified, are obtained using conventional measurement methods in the art.

[0123] Example 1

[0124] use Figure 1 The device shown carries out a process for producing hydrogen by electrolysis of saline organic wastewater.

[0125] The first hydrogen production state: the first valve 101, the third valve 103, the sixth valve 106, the seventh valve 107, and the tenth valve 110 are opened, and the second valve 102, the fourth valve 104, the fifth valve 105, the eighth valve 108, and the ninth valve 109 are closed. The salt-containing organic wastewater first flows through the heat exchange unit 6, and the salt-containing organic wastewater is preheated by the recovered waste heat of the electrolytic waste liquid. The preheated wastewater then passes through the first valve 101 and enters the heat exchange coil 36 of the first solid hydrogen storage unit 3, and is heated by the hydrogen absorption and exothermic reaction of the hydrogen storage material outside the heat exchange coil 36, and then passes through the seventh valve 107 to enter the electrolysis unit 1 for electrolysis reaction, and the generated gas-liquid mixture enters the gas-liquid separation unit 2 after temperature detection. Subsequently, the gaseous product, i.e., the gas mixture containing hydrogen and waste gas (chlorine), enters the gas buffer unit 5, and then enters the first solid-state hydrogen storage unit 3 after passing through the third valve 103, wherein the hydrogen storage material filling undergoes a hydrogen absorption reaction, thereby achieving separation from the impurity chlorine; the liquid product, i.e., the electrolytic waste liquid passes through the sixth valve 106 and enters the heat exchange coil 46 of the second solid-state hydrogen storage unit 4, and heats the hydrogen storage material filling (hydrogen storage material hydride) outside the heat exchange coil 46 to undergo a hydrogen release reaction, and the electrolytic waste liquid then passes through the tenth valve 110 and enters the heat exchange unit 6 to heat the salt-containing organic wastewater before entering the first valve 101 in the next cycle.

[0126] Second hydrogen production state: open the second valve 102, the fourth valve 104, the fifth valve 105, the eighth valve 108, and the ninth valve 109, and close the first valve 101, the third valve 103, the sixth valve 106, the seventh valve 107, and the tenth valve 110. The salt-containing organic wastewater first flows through the heat exchange unit 6, and the salt-containing organic wastewater is preheated by the recovered waste heat of the electrolytic waste liquid. The preheated wastewater then passes through the second valve 102 and enters the heat exchange coil 46 of the second solid hydrogen storage unit 4, and is heated by the hydrogen absorption and exothermic reaction of the hydrogen storage material outside the heat exchange coil 46, and then enters the electrolysis unit 1 through the ninth valve 109 to undergo an electrolysis reaction, and the generated gas-liquid mixture enters the gas-liquid separation unit 2 after temperature detection. Subsequently, the gaseous product, i.e., the gas mixture containing hydrogen and waste gas (chlorine), enters the gas buffer unit 5, and then enters the second solid-state hydrogen storage unit 4 after passing through the fourth valve 104, wherein the hydrogen storage material filling undergoes a hydrogen absorption reaction, thereby achieving separation from the impurity chlorine; the liquid product, i.e., the electrolytic waste liquid passes through the fifth valve 105 and enters the heat exchange coil 36 of the first solid-state hydrogen storage unit 3, and heats the hydrogen storage material filling (hydrogen storage material hydride) outside the heat exchange coil 36 to undergo a hydrogen release reaction, and the electrolytic waste liquid then passes through the eighth valve 108 and enters the heat exchange unit 6 to heat the salt-containing organic wastewater before entering the second valve 102 in the next cycle.

[0127] The first hydrogen production state and the second hydrogen production state are continuously alternated. After 24 hours of continuous operation, the ratio between the system hydrogen production and energy consumption is calculated to obtain the energy conversion rate, which is 65.4%.

[0128] After wastewater treatment, the NaCl concentration in the electrolyte is about 3g / L, the KCl concentration is about 1.5g / L, the organic matter concentration is about 80mg / L, the COD is about 200mg / L, and the BOD is about 100mg / L.

[0129] The recovered waste gas is chlorine. After testing, the recovered volume is 3.4L and the purity is 98.7%.

[0130] The hydrogen output was 243.5 L with a purity of 99.99%.

[0131] Example 2

[0132] In a similar manner to Example 1, electrolysis of saline organic wastewater from the same source is performed to produce hydrogen, the only difference being that the heat exchange unit 6 is omitted in the hydrogen production device. In the first hydrogen production state, the electrolysis waste liquid is directly discharged through the second solid hydrogen storage unit 4, and the saline waste water is directly input into the first solid hydrogen storage unit 3; in the second hydrogen production state, the electrolysis waste liquid is directly discharged through the first solid hydrogen storage unit 3, and the saline waste water is directly input into the second solid hydrogen storage unit 4.

[0133] The energy conversion rate was calculated to be 40.9%.

[0134] After wastewater treatment, the NaCl concentration in the electrolyte is about 4.8g / L, the KCl concentration is about 2.4g / L, the organic matter concentration is about 130mg / L, the COD is about 255mg / L, and the BOD is about 160mg / L.

[0135] The recovered waste gas is chlorine. After testing, the recovered volume is 2.1L and the purity is 98.5%.

[0136] The hydrogen output was 138.2 L with a purity of 99.99%.

[0137] Comparative Example 1

[0138] The device of the prior art is used to electrolyze the salty wastewater to produce hydrogen.

[0139] The above wastewater is treated by electrochemical method, and the electrochemical treatment system includes an electrolytic cell and a power supply system. The method uses electrolytic reaction to achieve the simultaneous removal of inorganic salts and organic pollutants in the wastewater treatment process. In the electrolytic process, inorganic salts such as NaCl and KCl can be decomposed into chlorine and hydrogen through electrolytic reaction, and removed by electrodialysis; for organic pollutants, they are degraded and converted into low-toxic substances through electro-Fenton reaction; electrochemical oxidation generates oxidants such as chlorine, hydrogen peroxide, etc., which further degrades organic pollutants in water and reduces the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in wastewater.

[0140] After running for the same time as in Example 1, the energy conversion rate was calculated to be 23.1%.

[0141] After electrochemical treatment, the NaCl concentration was about 8.4 g / L, the KCl concentration was about 4.2 g / L, the organic matter concentration was about 127.5 mg / L, the COD was about 260 mg / L, and the BOD was about 180 mg / L.

[0142] No chlorine recovery.

[0143] The hydrogen output was 79.1 L with a purity of 98.1%.

[0144] The following Table 1 intuitively shows the experimental measurement results of Examples 1, 2 and Comparative Example 1.

[0145] Table 1

[0146]

[0147]

[0148] By comparing the results of Examples 1 and 2 with Comparative Example 1, it can be seen that the energy conversion rates of Examples 1 and 2 are significantly higher than those of Comparative Example 1, indicating that the parallel arrangement and alternating operation of the first and second solid-state hydrogen storage units can significantly improve energy utilization and save energy consumption; and the result of Example 1 is further better than that of Example 2, indicating that the device that additionally adopts a heat exchange unit can further improve energy utilization by utilizing waste heat twice and obtain the optimal effect.

[0149] In addition, Examples 1 and 2 of the present invention are also superior to Comparative Example 1 in terms of chlorine recovery and purity, hydrogen production and purity.

[0150] The above description only relates to specific embodiments of the present disclosure and is not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A device for producing hydrogen from saline wastewater, characterized in that: The device has a first hydrogen production state and a second hydrogen production state, and the device includes: An electrolysis unit (1) is used for electrolyzing saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid, wherein the electrolysis unit (1) has an inlet (11) and a gas-liquid mixture outlet (12); A gas-liquid separation unit (2) is used to perform gas-liquid separation on the gas-liquid mixture to obtain a mixed gas containing hydrogen and waste gas and electrolytic waste liquid, wherein the gas-liquid separation unit (2) has a gas-liquid mixture inlet (21), a gas outlet (22) and a waste liquid outlet (23), and the gas-liquid mixture inlet (21) is connected to the gas-liquid mixture outlet (12) of the electrolysis unit (1); A first solid-state hydrogen storage unit (3), wherein the first solid-state hydrogen storage unit (3) has a first air inlet (31), a first air outlet (32), a first electrolytic waste liquid inlet (33), a first waste water inlet (34), and a first liquid outlet (35), A second solid-state hydrogen storage unit (4), the second solid-state hydrogen storage unit (4) having a second air inlet (41), a second air outlet (42), a second electrolytic waste liquid inlet (43), a second waste water inlet (44), and a second liquid outlet (45); In the first hydrogen production state, The first solid-state hydrogen storage unit (3) is used to carry out a hydrogenation reaction and release heat, the first gas inlet (31) is connected to the gas outlet (22) of the gas-liquid separation unit (2), the first gas outlet (32) is used to discharge waste gas, the first wastewater inlet (34) is used to input saline wastewater into the first solid-state hydrogen storage unit (3), and the first liquid outlet (35) is connected to the inlet (11) of the electrolysis unit (1); The second solid-state hydrogen storage unit (4) is used to carry out a dehydrogenation reaction and absorb heat, the second electrolytic waste liquid inlet (43) is connected to the waste liquid outlet (23) of the gas-liquid separation unit (2), the second gas outlet (42) is used to discharge hydrogen, and the second liquid outlet (45) is used to discharge electrolytic waste liquid; In the second hydrogen production state, The second solid-state hydrogen storage unit (4) is used to carry out a hydrogenation reaction and release heat, the second gas inlet (41) is connected to the gas outlet (22) of the gas-liquid separation unit (2), the second gas outlet (42) is used to discharge waste gas, the second wastewater inlet (44) is used to input saline wastewater into the second solid-state hydrogen storage unit (4), and the second liquid outlet (45) is connected to the inlet (11) of the electrolysis unit (1); The first solid-state hydrogen storage unit (3) is used to carry out a dehydrogenation reaction and absorb heat, the first electrolytic waste liquid inlet (33) is connected to the waste liquid outlet (23) of the gas-liquid separation unit (2), the first gas outlet (32) is used to discharge hydrogen, and the first liquid outlet (35) is used to discharge electrolytic waste liquid.

2. The device according to claim 1, characterized in that The device further comprises a gas buffer unit (5), the gas buffer unit having a third gas inlet (51) and a third gas outlet (52), the third gas inlet (51) being in communication with the gas outlet (22) of the gas-liquid separation unit (2), In the first hydrogen production state, the third gas outlet (52) is in communication with the first gas inlet (31) of the first solid-state hydrogen storage unit (3); In the second hydrogen production state, the third gas outlet (52) is in communication with the second gas inlet (41) of the second solid-state hydrogen storage unit (4).

3. The device according to claim 1, characterized in that The device further comprises a heat exchange unit (6), wherein the heat exchange unit comprises a wastewater inlet (61) and a wastewater outlet (62), and an electrolytic waste liquid inlet (63) and an electrolytic waste liquid outlet (64), wherein the wastewater inlet is used to input saline wastewater into the heat exchange unit (6), and the electrolytic waste liquid outlet (64) is used to discharge the electrolytic waste liquid. In the first hydrogen production state, the wastewater outlet (62) is connected to the first wastewater inlet (34) of the first solid-state hydrogen storage unit (3), and the electrolytic waste liquid inlet (63) is connected to the second liquid outlet (45) of the second solid-state hydrogen storage unit (4); In the second hydrogen production state, the wastewater outlet (62) is connected to the second wastewater inlet (44) of the second solid-state hydrogen storage unit (4), and the electrolytic waste liquid inlet (63) is connected to the first liquid outlet (35) of the first solid-state hydrogen storage unit (3).

4. The device according to claim 1, characterized in that The device further comprises a circulation pump (7), wherein the circulation pump has a water inlet (71) and a water outlet (72), wherein the water outlet (72) is connected to the inlet (11) of the electrolysis unit (1). In the first hydrogen production state, the water inlet (71) of the circulation pump (7) is connected to the first liquid outlet (35) of the first solid-state hydrogen storage unit (3); In the second hydrogen production state, the water inlet (71) of the circulation pump (7) is in communication with the second liquid outlet (45) of the second solid-state hydrogen storage unit (4).

5. The device according to claim 1, characterized in that The device has a temperature detector (8) at the gas-liquid mixture outlet (12) of the electrolysis unit (1) for detecting the temperature of the gas-liquid mixture, and the device has a first flow meter (9) at the first air inlet (31) of the first solid-state hydrogen storage unit (3), and a second flow meter (10) at the second air inlet (41) of the second solid-state hydrogen storage unit (4), and interlocking control is performed between the temperature detector (8) and the first flow meter (9), and between the temperature detector (8) and the second flow meter (10).

6. The device according to any one of claims 1 to 5, characterized in that The first solid-state hydrogen storage unit (3) and the second solid-state hydrogen storage unit (4) are solid-state hydrogen storage devices comprising hydrogen storage materials and heat exchange coils (36, 46), and the hydrogen storage materials are selected from one or more of LaNi5, TiFe, ZrV2, TiMn2, V-Ti-Cr, and Mg.

7. The device according to any one of claims 1 to 5, characterized in that The electrolysis unit (1) is an electrolysis cell without a diaphragm.

8. A method for producing hydrogen from saline wastewater, characterized in that: The method uses the device according to any one of claims 1 to 7 to produce hydrogen from saline wastewater, and the method comprises: In the first hydrogen production state, Inputting the saline wastewater into the first solid-state hydrogen storage unit (3) to preheat the saline wastewater; The preheated saline wastewater is input into the electrolysis unit (1) to electrolyze the saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid; The gas-liquid mixture is input into the gas-liquid separation unit (2), and the gas-liquid mixture is subjected to gas-liquid separation to obtain a mixed gas containing hydrogen and waste gas and electrolytic waste liquid; The mixed gas is input into the first solid-state hydrogen storage unit (3), the first solid-state hydrogen storage unit (3) absorbs hydrogen, releases heat and discharges the waste gas; the electrolysis waste liquid is input into the second solid-state hydrogen storage unit (4), the second solid-state hydrogen storage unit (4) absorbs heat, removes hydrogen and discharges the electrolysis waste liquid; In the second hydrogen production state, Inputting the saline wastewater into the second solid-state hydrogen storage unit (4) to preheat the saline wastewater; The preheated saline wastewater is input into the electrolysis unit (1) to electrolyze the saline wastewater to generate a gas-liquid mixture containing hydrogen, waste gas and electrolysis waste liquid; The gas-liquid mixture is input into the gas-liquid separation unit (2), and the gas-liquid mixture is subjected to gas-liquid separation to obtain a mixed gas containing hydrogen and waste gas and electrolytic waste liquid; The mixed gas is input into the second solid-state hydrogen storage unit (4), and the second solid-state hydrogen storage unit (4) absorbs hydrogen, releases heat, and discharges the waste gas; the electrolysis waste liquid is input into the first solid-state hydrogen storage unit (3), and the first solid-state hydrogen storage unit (3) absorbs heat, removes hydrogen, and discharges the electrolysis waste liquid.

9. The method according to claim 8, characterized in that The saline wastewater is wastewater containing 0.001 to 1 mol / L of chloride ions, and the waste gas contains chlorine.

10. The method according to claim 9, characterized in that The saline wastewater is saline organic wastewater, and the saline organic wastewater contains one or more organic substances selected from phenols, alcohols, aldehydes, ketones, fatty acids, amino acids, and proteins.

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