Process for preparing light by hydrogen production waste heat through electrolysis of high-salinity wastewater and coupling salt separation
Through the electrolytic high-salt wastewater hydrogen production waste heat production and desalted salt separation process, combined with the electrolytic high-salt wastewater hydrogen production waste heat utilization module, the refrigerated sulfur removal module and the light salt preparation module, the problem of high-salt wastewater treatment in the chemical park is solved, and efficient fresh water production and salt separation is achieved, energy saving and sodium sulfate crystals are recovered.
Patent Information
- Application Number
- CN202510573229.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-06
- Publication Date
- 2025-08-19
AI Technical Summary
The prior art uses high energy consumption when treating high-salt wastewater in chemical parks, and traditional multi-stage flash evaporation and other methods are not cost-effective enough.
The hydrogen waste heat-making and desalted salt production process is adopted by electrolytic high-salt wastewater, and the hydrogen waste heat utilization module, the refrigeration and desalted salt production module is combined with the electrolytic high-salt wastewater to make fresh water and separate salt production. The absorption refrigeration cycle of ammonia water as the working fluid is used, and the evaporation crystallizer and solid-liquid separator are used to prepare fresh water and salt.
It realizes efficient preheating of electrolytic high-salt wastewater to make fresh water and separate salts, saves energy, and can recover valuable sodium sulfate crystals, improving heat utilization.
Smart Images
Figure CN120505644A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of utilization of waste heat from electrolysis of high-salt wastewater to produce hydrogen and the field of desalinated salt production technology, and in particular to a coupled salt separation production process using waste heat from electrolysis of high-salt wastewater to produce hydrogen. Background Art
[0002] my country's chemical parks currently produce large quantities of high-salinity wastewater year-round, and their treatment and disposal present challenges. Technologies like multi-stage flash evaporation consume high amounts of energy and are not optimal in the long term.
[0003] In order to solve the above problems, the present invention is proposed. Summary of the Invention
[0004] The present invention provides a coupled salt separation process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water. The process system mainly consists of a module for utilizing waste heat from electrolyzed high-salt wastewater to produce hydrogen, a freezing and desulfurization module, and a desalinated salt production module.
[0005] The present application discloses a coupled salt separation process for producing hydrogen from high-salt wastewater using waste heat to produce desalination and electrolysis, which may refer to a coupled salt separation system for producing hydrogen from high-salt wastewater using waste heat to produce desalination and electrolysis, or a coupled salt separation method for producing hydrogen from high-salt wastewater using waste heat to produce desalination and electrolysis.
[0006] Among them, the waste heat utilization module for electrolysis of high-salt wastewater to produce hydrogen includes: electrolytic cell and alkali solution circulation pump; the freezing desulfurization module includes: generator, concentrated solution pump, absorber, cooling crystallizer, throttle valve, intermediate condenser and sodium sulfate crystal collection tank.
[0007] The waste heat utilization module for hydrogen production from electrolysis of high-salt wastewater is coupled with the refrigeration desulfurization module through a generator.
[0008] The desalinated salt separation module includes: evaporation crystallizer, desalinated water condenser, cooling water pump, desalinated water collection tank, solid-liquid separator, brine reflux pump, sodium chloride crystal collection box, and heat dissipation circulation pump.
[0009] The refrigeration desulfurization module is coupled with the desalinated salt separation module through an intermediate condenser.
[0010] The connection relationship between the above modules is as follows:
[0011] The alkali liquid outlet of the electrolyzer is connected to the inlet of the alkali liquid circulation pump, which is then connected to the heat source inlet of the generator. The alkali liquid then passes through a section of heat exchange coils and into the generator. The heat source outlet of the generator is connected to the alkali liquid inlet of the electrolyzer, thus forming the alkali liquid circulation module for the hydrogen production waste heat utilization module from electrolysis of high-salinity wastewater.
[0012] The refrigeration desulfurization module is based on an absorption refrigeration cycle using ammonia solution as the working fluid. The ammonia vapor outlet of the generator is connected to the ammonia inlet of the intermediate condenser, which is in turn connected to the throttle valve inlet. The throttle valve outlet is connected to the ammonia inlet of the cooling crystallizer, and then passes through a section of heat exchange coil inside the cooling crystallizer. The ammonia outlet of the cooling crystallizer is connected to the ammonia inlet of the absorber. The top of the cooling crystallizer is connected to the chemical wastewater pipeline, and the bottom of the cooling crystallizer is connected to the sodium sulfate crystal collection tank. The ammonia solution outlet of the absorber is connected to the inlet of the concentrated solution pump, which is in turn connected to the ammonia solution inlet of the generator. The ammonia solution outlet of the generator is connected to the ammonia solution inlet of the absorber, thus forming the absorption refrigeration cycle using ammonia solution as the working fluid of the refrigeration desulfurization module.
[0013] The ammonia inlet of the intermediate condenser is equivalent to the heat source inlet, and the ammonia outlet of the intermediate condenser is equivalent to the heat source outlet.
[0014] The connection relationship between the freezing desulfurization module and the desalinated salt production module is as follows:
[0015] The original concentrated brine outlet of the cooling crystallizer is connected to the concentrated brine inlet of the evaporative crystallizer, the cold source side outlet of the intermediate condenser is connected to the inlet of the heat dissipation circulation pump, the heat dissipation circulation pump outlet is connected to the heat source side inlet of the evaporative crystallizer, and the heat source side outlet of the evaporative crystallizer is connected to the cold source side inlet of the intermediate condenser; the water vapor outlet at the top of the evaporative crystallizer is connected to the water vapor side inlet of the fresh water collecting condenser, the salt-concentrated brine mixture outlet at the bottom is connected to the salt-concentrated brine mixture inlet of the solid-liquid separator, the sodium chloride crystal outlet at the bottom of the solid-liquid separator is connected to the sodium chloride crystal collecting tank, the inlet of the concentrated brine reflux pump is connected to the concentrated brine outlet of the solid-liquid separator and the connected pipe extends below the liquid level, the concentrated brine reflux pump outlet is connected to the concentrated brine reflux port of the evaporative crystallizer; the fresh water side outlet of the fresh water collecting condenser is connected to the fresh water collecting tank, the inlet of the cooling pump is connected to the external cooling water, the outlet of the cooling pump is connected to the cooling water side inlet of the fresh water collecting condenser, and passes through the interior of the fresh water collecting cooler through a section of heat exchange coil, and the cooling water outlet of the fresh water collecting cooler leads to the outside.
[0016] The working principle of the present invention is as follows:
[0017] In the waste heat utilization module for electrolysis of high-salt wastewater to produce hydrogen, the alkali solution with a higher temperature produced by the electrolysis of high-salt wastewater in the electrolyzer to produce hydrogen enters the heat source side of the generator of the freezing and desulfurization module through the alkali solution circulation pump as the heat source of the absorption refrigeration cycle, and returns to the electrolyzer after releasing heat.
[0018] In the cryogenic desulfurization module, concentrated ammonia solution passes through the generator. Ammonia with a lower boiling point evaporates first, generating a large amount of ammonia vapor. The ammonia vapor enters the intermediate condenser, where it condenses and releases heat to form liquid pure ammonia. The liquid pure ammonia passes through a throttle valve, isenthalpic throttling, forming a low-temperature, low-pressure two-phase pure ammonia. The two-phase pure ammonia then enters the cooling crystallizer and undergoes evaporation and heat absorption refrigeration. Simultaneously, chemical wastewater containing sodium sulfate and sodium chloride is sprayed into the top of the cooling crystallizer through atomization. It flows through the surface of the heat exchange coil in the cooling crystallizer, achieving cryogenic desulfurization of the chemical wastewater, precipitating a large amount of sodium sulfate decahydrate crystals and collecting them in the sodium sulfate crystal collection tank. The ammonia vapor formed after absorbing heat and refrigeration in the cooling crystallizer enters the absorber and is absorbed by the dilute ammonia solution flowing back from the generator to the absorber, forming a concentrated ammonia solution. The concentrated ammonia solution is then returned to the generator through a concentrated solution pump for re-evaporation.
[0019] In the desalinated salt separation module, in the cooling crystallizer, the chemical wastewater containing sodium sulfate and sodium chloride is frozen and desulfurized to obtain the original concentrated brine, which first enters the evaporation crystallizer and uses the heat brought from the intermediate condenser by the heat dissipation circulation pump for low-temperature distillation to form water vapor and a salt-concentrated brine mixture. The water vapor enters the desalination condenser through the pipeline from the top of the evaporation crystallizer, is condensed by cooling water to form fresh water, and finally enters the fresh water collection tank to complete the desalination process; the salt-concentrated brine mixture enters the solid-liquid separator from the bottom of the evaporation crystallizer for solid-liquid separation to obtain sodium chloride crystals and concentrated brine. The sodium chloride crystals are collected by the sodium chloride crystal collection tank to complete the salt production process, and the concentrated brine is returned to the evaporation crystallizer through the concentrated brine reflux pump for further distillation.
[0020] The generator is provided with a heat source side inlet, a heat source side outlet, an ammonia vapor outlet, an ammonia solution side inlet, and an ammonia solution side outlet. A heat exchange coil is arranged inside the generator.
[0021] Preferably, the liquid level of the ammonia solution in the generator completely submerges the heat exchange coil therein, and the ammonia solution side outlet of the generator is located between the liquid level of the ammonia solution and the top of the heat exchange coil on the heat source side.
[0022] Preferably, the liquid level of the ammonia solution in the absorber is located between the ammonia solution inlet and the outlet of the absorber, and the ammonia solution inlet of the absorber is located higher than the outlet.
[0023] The side wall of the evaporation crystallizer has a heat source side inlet and a heat source side outlet. The top of the evaporation crystallizer has a water vapor outlet. The bottom of the evaporation crystallizer has a salt-concentrated brine mixture outlet.
[0024] Preferably, the raw brine liquid level of the evaporation crystallizer should completely submerge the heat exchange coil, and the raw brine side inlet and the brine reflux inlet of the evaporation crystallizer are both arranged higher than the raw brine liquid level.
[0025] Compared with the existing technology, the beneficial effects of the present invention are as follows:
[0026] 1. This application combines the waste heat utilization module for electrolysis of high-salt wastewater to produce hydrogen, the freezing and desulfurization module and the desalted salt production module, realizing the preheating of electrolysis of high-salt wastewater to produce desalted water and separation and salt production, achieving multiple goals at one stroke and greatly saving energy.
[0027] 2. The freezing desulfurization module realizes an absorption refrigeration cycle with ammonia water as the working fluid through the design of throttle valves, etc., with high heat utilization rate and can also obtain valuable sodium sulfate crystals. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 This is a schematic diagram of the device structure of this application;
[0029] The accompanying drawings are described as follows: 1-1, electrolytic cell, 1-2, alkali solution circulation pump, 2-1, generator, 2-2, concentrated solution pump, 2-3, absorber, 2-4, cooling crystallizer, 2-5, throttle valve, 2-6, intermediate condenser, 2-7, sodium sulfate crystal collection tank, 3-1, evaporation crystallizer, 3-2, fresh water collection condenser, 3-3, cooling water pump, 3-4, fresh water collection tank, 3-5, solid-liquid separator, 3-6, concentrated brine reflux pump, 3-7, sodium chloride crystal collection box, 3-8, heat dissipation circulation pump.
[0030] Figure 2 This is a schematic diagram of the process flow of this application. DETAILED DESCRIPTION
[0031] The present invention is described in further detail below with reference to the embodiments.
[0032] Those skilled in the art will understand that the following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the art or in the product specifications were used. Materials or equipment used without manufacturer identification are commercially available conventional products.
[0033] It will be understood by those skilled in the art that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we say that an element is "coupled" to another element, it can be directly coupled to the other element, or there may be intermediate elements. In addition, "coupled" as used herein may include wireless coupling.
[0034] In the description of the present invention, unless otherwise specified, "plurality" means two or more. Terms such as "inner," "upper," and "lower" indicating positions or states are based on those shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and are therefore not to be construed as limiting the present invention.
[0035] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "provided with" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.
[0036] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by those skilled in the art in the art to which the present invention pertains. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as such herein, will not be interpreted in an idealized or overly formal sense.
[0037] The following combination Figure 1 and Figure 2 A specific embodiment of the present invention is proposed:
[0038] The present invention provides a coupled salt separation process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water. The process system is mainly composed of three coupled modules: a module for utilizing waste heat from electrolyzed high-salt wastewater to produce hydrogen, a module for freezing and desulfurization, and a module for producing desalinated salt.
[0039] Among them, the waste heat utilization module for electrolysis of high-salt wastewater to produce hydrogen includes: electrolytic cell 1-1 and alkali solution circulation pump 1-2; the freezing desulfurization module includes: generator 2-1, concentrated solution pump 2-2, absorber 2-3, cooling crystallizer 2-4, throttle valve 2-5, intermediate condenser 2-6 and sodium sulfate crystal collection tank 2-7.
[0040] The waste heat utilization module for producing hydrogen from electrolysis of high-salt wastewater is coupled with the freezing and desulfurization module through generator 2-1.
[0041] The desalinated salt separation module includes: an evaporation crystallizer 3-1, a desalinated salt collecting condenser 3-2, a cooling water pump 3-3, a desalinated water collecting tank 3-4, a solid-liquid separator 3-5, a concentrated brine reflux pump 3-6, a sodium chloride crystal collecting box 3-7 and a heat dissipation circulation pump 3-8.
[0042] The refrigeration desulfurization module is coupled to the desalted salt separation module through the intermediate condenser 2-6.
[0043] The connection relationship between the above modules is as follows:
[0044] The alkali liquid outlet of the electrolytic cell 1-1 is connected to the inlet of the alkali liquid circulation pump 1-2, the outlet of the alkali liquid circulation pump 1-2 is connected to the heat source side inlet of the generator 2-1, and passes through a section of heat exchange coil through the inside of the generator, and the heat source side outlet of the generator 2-1 is connected to the alkali liquid inlet of the electrolytic cell 1-1, thereby forming an alkali liquid circulation of the waste heat utilization module for electrolysis of high-salt wastewater to produce hydrogen.
[0045] The refrigeration desulfurization module is based on an absorption refrigeration cycle using ammonia solution as the working fluid. The ammonia vapor outlet of generator 2-1 is connected to the ammonia inlet of intermediate condenser 2-6, which is in turn connected to the inlet of throttle valve 2-5. The outlet of throttle valve 2-5 is connected to the ammonia inlet of cooling crystallizer 2-4, and then passes through the interior of cooling crystallizer 2-4 via a heat exchange coil. The ammonia outlet of cooling crystallizer 2-4 is connected to the ammonia inlet of absorber 2-3. The top of cooling crystallizer 2-4 is connected to a chemical wastewater pipeline, and the bottom of cooling crystallizer 2-4 is connected to sodium sulfate crystal collection tank 2-7. The ammonia solution outlet of absorber 2-3 is connected to the inlet of concentrated solution pump 2-2, which is in turn connected to the ammonia solution inlet of generator 2-1. The ammonia solution outlet of generator 2-1 is connected to the ammonia solution inlet of absorber 2-3, thus forming the absorption refrigeration cycle using ammonia solution as the working fluid of the refrigeration desulfurization module.
[0046] The original concentrated brine outlet of the cooling crystallizer 2-4 is connected to the concentrated brine inlet of the evaporation crystallizer 3-1, the cold source side outlet of the intermediate condenser 2-6 is connected to the inlet of the heat dissipation circulation pump 3-8, the outlet of the heat dissipation circulation pump 3-8 is connected to the heat source side inlet of the evaporation crystallizer 3-1, the heat source side outlet of the evaporation crystallizer 3-1 is connected to the cold source side inlet of the intermediate condenser 2-6; the water vapor outlet at the top of the evaporation crystallizer 3-1 is connected to the water vapor side inlet of the desalination condenser 3-2, the salt-concentrated brine mixture outlet at the bottom of the evaporation crystallizer 3-1 is connected to the salt-concentrated brine mixture inlet of the solid-liquid separator 3-5, and the bottom chlorination of the solid-liquid separator 3-5 is connected. The sodium crystal outlet is connected to the sodium chloride crystal collecting tank 3-7, the inlet of the concentrated brine reflux pump 3-6 is connected to the concentrated brine outlet of the solid-liquid separator 3-5, the connecting pipe extends below the liquid level, and the outlet of the concentrated brine reflux pump 3-6 is connected to the concentrated brine reflux port of the evaporation crystallizer 3-1; the fresh water side outlet of the fresh water collecting condenser 3-2 is connected to the fresh water collecting tank 3-4, the inlet of the cooling pump 3-3 is connected to the external cooling water, the outlet of the cooling pump 3-3 is connected to the cooling water side inlet of the fresh water collecting condenser 3-2, and passes through the interior of the fresh water collecting cooler 3-2 through a section of heat exchange coil, and the cooling water outlet of the fresh water collecting cooler 3-2 leads to the outside.
[0047] It should also be noted that: the liquid level of the ammonia solution in the generator 2-1 should completely submerge the heat exchange coil on the heat source side, and the outlet of the ammonia solution side of the generator 2-1 should be located between the liquid level of the ammonia solution and the heat exchange coil on the heat source side; the liquid level of the ammonia solution in the absorber 2-3 should be located between the ammonia solution inlet and outlet of the absorber 2-3, and the inlet should be arranged higher than the outlet; the liquid level of the original brine in the evaporation crystallizer 3-1 should completely submerge the heat exchange coil on the heat source side, and the original brine side inlet and the brine reflux inlet of the evaporation crystallizer 3-1 should both be arranged higher than the original brine liquid level.
[0048] Furthermore, the chemical wastewater inlet of the cooling crystallizer 2-4 can use an atomizing nozzle to improve the efficiency of freezing and desulfurization.
[0049] Furthermore, the evaporation crystallizer 3-1 can adopt thermal methods suitable for low-grade heat sources such as low-temperature distillation and low-temperature flash evaporation to produce desalination.
[0050] Combine Figure 1 and Figure 2 The working process principle of the process of the present invention is described:
[0051] In the waste heat utilization module for electrolysis of high-salt wastewater to produce hydrogen, the alkaline solution with a relatively high temperature produced by electrolysis of high-salt wastewater to produce hydrogen in the electrolytic cell 1-1 enters the heat source side of the generator 2-1 of the freezing and desulfurization module through the alkaline solution circulation pump 1-2 as the heat source of the absorption refrigeration cycle, and returns to the electrolytic cell 1-1 after releasing the heat.
[0052] In the freezing and desulfurization module, the concentrated ammonia solution is first evaporated in the generator 2-1 by ammonia with a lower boiling point to generate a large amount of ammonia vapor. The ammonia vapor enters the intermediate condenser 2-6 and is condensed and releases heat to form liquid pure ammonia. The liquid pure ammonia passes through the throttle valve 2-5 and is throttled by isenthalpy to form low-temperature and low-pressure two-phase pure ammonia. The two-phase pure ammonia then enters the cooling crystallizer 2-4 and undergoes evaporation and heat absorption refrigeration. At the same time, chemical wastewater containing sodium sulfate and sodium chloride is sprayed into the top of the cooling crystallizer 2-4 in atomized form, flows through the surface of the heat exchange coil, and realizes freezing and desulfurization of the chemical wastewater, precipitating a large amount of sodium sulfate decahydrate crystals and collecting them in the sodium sulfate crystal collection tank 2-7. The ammonia vapor formed after heat absorption and refrigeration enters the absorber 2-3 and is absorbed by the dilute ammonia solution refluxed from the generator 2-1 to the absorber 2-3 to form concentrated ammonia solution. The concentrated ammonia solution is then returned to the generator 2-1 through the concentrated solution pump 2-2 for re-evaporation.
[0053] In the desalinated salt separation module, the original concentrated brine obtained by freezing and desulfurization first enters the evaporation crystallizer 3-1 and uses the heat brought by the heat dissipation circulation pump 3-8 from the intermediate condenser 2-6 for low-temperature distillation to form water vapor and salt and concentrated brine mixture. The water vapor enters the desalination condenser 3-2 through the pipeline from the top of the evaporation crystallizer 3-1, is condensed by cooling water to form fresh water, and finally enters the fresh water collection tank 3-4 to complete the desalination process; the salt and concentrated brine mixture enters the solid-liquid separator 3-5 from the bottom of the evaporation crystallizer 3-1 for solid-liquid separation to obtain sodium chloride crystals and concentrated brine. The sodium chloride crystals are collected by the sodium chloride crystal collection tank 3-7 to complete the salt production process, and the concentrated brine returns to the evaporation crystallizer 3-1 through the concentrated brine reflux pump 3-6 and is distilled again.
[0054] It should also be noted that the salt and brine mixture formed in the evaporation crystallizer 3-1 can obtain more than 92% sodium chloride crystals after separation in the solid-liquid separator 3-5. The remaining brine still has the potential to be distilled again, so it is pumped back to the evaporation crystallizer 3-1 through the brine reflux pump 3-6.
Claims
1. A process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water, characterized in that: The process is carried out using a coupled salt separation system using waste heat from electrolysis of high-salt wastewater to produce hydrogen and produce desalination, the system comprising: a waste heat utilization module for electrolysis of high-salt wastewater to produce hydrogen and a freezing and desulfurization module; The module for utilizing waste heat from electrolyzing high-salt wastewater to produce hydrogen comprises: an electrolytic cell (1-1) and an alkali solution circulation pump (1-2); The freezing desulfurization module includes: a generator (2-1), a concentrated solution pump (2-2), an absorber (2-3), a cooling crystallizer (2-4), a throttle valve (2-5), an intermediate condenser (2-6) and a sodium sulfate crystal collection tank (2-7); The connection relationship of the above modules is as follows: The alkali liquid outlet of the electrolytic cell (1-1) is connected to the inlet of the alkali liquid circulation pump (1-2), the outlet of the alkali liquid circulation pump (1-2) is connected to the heat source side inlet of the generator (2-1), and passes through the interior of the generator (2-1) through a section of heat exchange coil, and the heat source side outlet of the generator (2-1) is connected to the alkali liquid inlet of the electrolytic cell (1-1), thereby forming an alkali liquid circulation of the electrolysis high-salt wastewater hydrogen production waste heat utilization module; The ammonia vapor outlet of the generator (2-1) is connected to the ammonia side inlet of the intermediate condenser (2-6), and the ammonia side outlet of the intermediate condenser (2-6) is connected to the inlet of the throttle valve (2-5); the outlet of the throttle valve (2-5) is connected to the ammonia side inlet of the cooling crystallizer (2-4), and passes through the interior of the cooling crystallizer (2-4) through a section of heat exchange coil, and the ammonia outlet of the cooling crystallizer (2-4) is connected to the ammonia side inlet of the absorber (2-3), and the top of the cooling crystallizer (2-4) is connected to the ammonia side inlet of the absorber (2-3). The chemical wastewater pipeline is connected, and the bottom of the cooling crystallizer (2-4) is connected to the sodium sulfate crystal collection tank (2-7); the ammonia solution side outlet of the absorber (2-3) is connected to the inlet of the concentrated solution pump (2-2), and the outlet of the concentrated solution pump (2-2) is connected to the ammonia solution side inlet of the generator (2-1); the ammonia solution side outlet of the generator (2-1) is connected to the ammonia solution side inlet of the absorber (2-3), thereby forming an absorption refrigeration cycle with ammonia solution as the working medium of the freezing and desulfurization module; The process comprises the following steps: In the waste heat utilization module for electrolyzing high-salt wastewater to produce hydrogen, the high-temperature alkali solution generated by the electrolysis of high-salt wastewater to produce hydrogen in the electrolytic cell (1-1) enters the heat source side of the generator (2-1) of the freezing and desulfurization module through the alkali solution circulation pump (1-2) as the heat source of the absorption refrigeration cycle, and returns to the electrolytic cell (1-1) after releasing heat; In the freezing desulfurization module, in the generator (2-1), after the concentrated ammonia solution is heated, the ammonia first evaporates and generates ammonia vapor, and the ammonia vapor enters the intermediate condenser (2-6) and condenses to release heat to form liquid pure ammonia; the liquid pure ammonia passes through the throttle valve (2-5) to form low-temperature and low-pressure two-phase pure ammonia, and the two-phase pure ammonia then enters the cooling crystallizer (2-4) for evaporation and heat absorption refrigeration. At the same time, chemical wastewater containing sodium sulfate and sodium chloride enters from the top of the cooling crystallizer (2-4) and flows through the cooling crystallizer (2-4). The surface of the heat exchange coil in the cooling crystallizer (2-4) realizes the freezing and desulfurization of the chemical wastewater, and sodium sulfate decahydrate crystals are precipitated and collected in the sodium sulfate crystal collection tank (2-7); the ammonia vapor formed after absorbing heat and refrigerating in the cooling crystallizer (2-4) enters the absorber (2-3) and is absorbed by the dilute ammonia solution flowing back from the generator (2-1) to the absorber (2-3) to form a concentrated ammonia solution, and the concentrated ammonia solution is then returned to the generator (2-1) through the concentrated solution pump (2-2) to evaporate again.
2. The coupled salt separation process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water according to claim 1 is characterized in that: The system includes: a dilute salt production module; The dilute salt production module comprises: an evaporation crystallizer (3-1), a dilute salt collecting condenser (3-2), a cooling water pump (3-3), a fresh water collecting tank (3-4), a solid-liquid separator (3-5), a concentrated brine reflux pump (3-6), a sodium chloride crystal collection box (3-7) and a heat dissipation circulation pump (3-8); The connection relationship between the freezing and desulfurization module and the dilute salt production module is as follows: The original concentrated brine outlet of the cooling crystallizer (2-4) is connected to the concentrated brine inlet of the evaporation crystallizer (3-1), the cold source side outlet of the intermediate condenser (2-6) is connected to the inlet of the heat dissipation circulation pump (3-8), the outlet of the heat dissipation circulation pump (3-8) is connected to the heat source side inlet of the evaporation crystallizer (3-1), and the heat source side outlet of the evaporation crystallizer (3-1) is connected to the cold source side inlet of the intermediate condenser (2-6); the water vapor outlet at the top of the evaporation crystallizer (3-1) is connected to the water vapor side inlet of the desalination condenser (3-2), the salt-concentrated brine mixture outlet at the bottom of the evaporation crystallizer (3-1) is connected to the salt-concentrated brine mixture inlet of the solid-liquid separator (3-5), and the bottom of the solid-liquid separator (3-5) is connected to the salt-concentrated brine mixture outlet. The sodium chloride crystal outlet is connected to the sodium chloride crystal collection tank (3-7), the inlet of the concentrated brine reflux pump (3-6) is connected to the concentrated brine outlet of the solid-liquid separator (3-5), and the connected pipe extends below the liquid level. The outlet of the concentrated brine reflux pump (3-6) is connected to the concentrated brine reflux port of the evaporation crystallizer (3-1); the fresh water side outlet of the fresh water collecting condenser (3-2) is connected to the fresh water collecting tank (3-4), the inlet of the cooling pump (3-3) is connected to external cooling water, the outlet of the cooling pump (3-3) is connected to the cooling water side inlet of the fresh water collecting condenser (3-2), and passes through the interior of the fresh water collecting cooler (3-2) through a section of heat exchange coil, and the cooling water outlet of the fresh water collecting cooler (3-2) leads to the outside; The process further comprises the steps of: In the desalinated salt separation module, in the cooling crystallizer (2-4), the chemical wastewater containing sodium sulfate and sodium chloride is frozen and desulfurized to obtain the original concentrated brine, which first enters the evaporation crystallizer (3-1) and uses the heat brought from the intermediate condenser (2-6) by the heat dissipation circulation pump (3-8) to perform low-temperature distillation to form water vapor and a salt-concentrated brine mixture. The water vapor enters the desalination condenser (3-2) through a pipeline from the top of the evaporation crystallizer (3-1), is condensed by cooling water to form fresh water, and finally enters the fresh water collection tank (3-4) to complete the desalination process; the salt-concentrated brine mixture enters the solid-liquid separator (3-5) from the bottom of the evaporation crystallizer (3-1) for solid-liquid separation to obtain sodium chloride crystals and concentrated brine. The sodium chloride crystals are collected by the sodium chloride crystal collection tank (3-7) to complete the salt production process, and the concentrated brine is returned to the evaporation crystallizer through the concentrated brine reflux pump (3-6) for further distillation.
3. The coupled salt separation process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water according to claim 2 is characterized in that: The process for producing hydrogen from high-salt wastewater by electrolysis and producing desalination with waste heat coupled with salt separation is a system for producing hydrogen from high-salt wastewater by electrolysis and producing desalination with waste heat coupled with salt separation, or a method for producing hydrogen from high-salt wastewater by electrolysis and producing desalination with waste heat coupled with salt separation.
4. The process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water coupled with salt separation according to claim 2, characterized in that: The liquid level of the ammonia solution in the generator (2-1) completely submerges the heat exchange coil therein, and the ammonia solution side outlet of the generator (2-1) should be located between the liquid level of the ammonia solution and the top of the heat exchange coil on the heat source side.
5. The process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water coupled with salt separation according to claim 2, characterized in that: The liquid level of the ammonia solution of the absorber (2-3) is located between the ammonia solution inlet and outlet of the absorber (2-3), and the inlet is located higher than the outlet.
6. The coupled salt separation process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water according to claim 2, characterized in that: The original concentrated brine liquid level of the evaporation crystallizer (3-1) should completely cover the heat exchange coil, and the original concentrated brine side inlet and the concentrated brine reflux inlet of the evaporation crystallizer (3-1) are both arranged higher than the original concentrated brine liquid level.
7. The process for producing hydrogen from electrolyzed high-salt wastewater using waste heat to produce desalinated water coupled with salt separation according to claim 2, characterized in that: An atomizing nozzle is provided at the chemical wastewater inlet of the cooling crystallizer (2-4), and the chemical wastewater is atomized and sprayed into the cooling crystallizer (2-4) from the top.