A method and system for alkaline seawater electrolysis to produce hydrogen and for the comprehensive utilization of potassium resources.

Abstract

This invention belongs to the field of seawater electrolysis hydrogen production and comprehensive utilization technology, specifically relating to a method and system for alkaline seawater electrolysis hydrogen production and comprehensive utilization of potassium resources. The raw seawater is sterilized, purified, filtered to remove impurities, and subjected to ion separation treatment to remove divalent ions. Alkaline seawater electrolysis is then performed to produce hydrogen. The hydrogen production process is monitored, and the electrolyte from the alkaline seawater electrolysis hydrogen production is sent to a potassium extraction and utilization system. This potassium extraction and utilization system uses clinoptilolite as an adsorbent and employs an adsorption-desorption process to extract potassium. This invention, by coupling the alkaline seawater electrolysis hydrogen production process with the potassium resource extraction process, achieves the effective recovery and extraction of potassium from seawater while simultaneously producing hydrogen through alkaline seawater electrolysis, thus possessing greater practical significance.

Description

Technical Field

[0001] This invention belongs to the field of seawater electrolysis hydrogen production and comprehensive utilization technology, specifically relating to a method and system for alkaline seawater electrolysis hydrogen production and comprehensive utilization of potassium resources. Background Technology

[0002] As a widely available, clean, low-carbon, and diverse secondary energy source with multiple applications, the large-scale development of water electrolysis hydrogen production technology has become an inevitable trend. Compared to land-based hydrogen production, marine hydrogen production, with its advantages of abundant seawater resources and zero land occupation, can effectively absorb intermittent clean energy sources such as offshore wind power and photovoltaics, and is gradually becoming the core direction of the current hydrogen energy industry's industrialization. From the perspective of global energy transition, breakthroughs in seawater hydrogen production technology can not only significantly reduce dependence on traditional fossil fuels, but also promote deep decarbonization in the industrial sector, contributing to the construction of a zero-carbon energy system.

[0003] Potassium is a crucial nutrient element essential for plant growth and development and an indispensable core mineral raw material in fertilizer systems. Currently, traditional seawater potassium extraction processes mostly focus on the separation and extraction of single potassium components, resulting in cumbersome processes, high energy consumption, and poor resource utilization, failing to achieve the coupled utilization of seawater resources and energy. Furthermore, conventional seawater treatment and potassium extraction technologies struggle to simultaneously address clean energy production and mineral resource recovery, leading to a short and low-integration chain for seawater resource utilization.

[0004] To address the aforementioned shortcomings of existing technologies, this invention proposes a method for the comprehensive utilization of potassium resources through alkaline seawater electrolysis for hydrogen production. By coupling processes and optimizing the system, it achieves the coordinated development of hydrogen production through electrolysis, seawater purification, and efficient enrichment and recovery of potassium resources, thus overcoming the deficiencies of existing technologies such as low resource utilization, limited functionality, and high energy consumption. Summary of the Invention

[0005] The purpose of this invention is to propose a method and system for the comprehensive utilization of potassium resources through alkaline electrolysis of seawater for hydrogen production. This method first involves electrolyzing seawater to produce hydrogen, monitoring the hydrogen production process, and then extracting potassium from the electrolyte after a period of hydrogen production through an adsorption-desorption process. By coupling the alkaline electrolysis of seawater for hydrogen production with the potassium resource extraction process, the method can effectively recover and extract potassium from seawater while simultaneously performing alkaline electrolysis of seawater for hydrogen production, which has greater practical significance.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: A method for producing hydrogen and comprehensively utilizing potassium resources through alkaline electrolysis of seawater involves sterilizing and purifying the raw seawater, filtering to remove impurities, and separating divalent ions to remove them. Hydrogen is then produced through alkaline electrolysis of the seawater. The hydrogen production process is monitored, and the electrolyte from the alkaline electrolysis is fed into a potassium extraction and utilization system. This system uses clinoptilolite as an adsorbent and employs an adsorption-desorption process to extract potassium.

[0007] According to the above scheme, the divalent ions include calcium ions, magnesium ions, and sulfate ions.

[0008] According to the above scheme, 20-30% potassium hydroxide solution is added in advance to the alkaline electrolysis of seawater to produce hydrogen, and then treated seawater that has been sterilized, purified, filtered to remove impurities, and has had divalent ions removed is passed through for alkaline electrolysis of seawater to produce hydrogen.

[0009] According to the above scheme, the alkaline electrolysis of seawater for hydrogen production uses a chlorine-repellent oxygen evolution electrode; the single-cell voltage of the alkaline electrolysis hydrogen production system is 1.5-2.0V, and the current density is 400-600 mA / cm². 2 .

[0010] According to the above scheme, a chloride ion activity meter is installed in the alkaline electrolyzer to monitor the chloride ion activity and the seawater hydrogen production process during alkaline electrolysis of seawater. When the chloride ion activity is high and affects the alkaline electrolysis of seawater hydrogen production, the electrolyte from the alkaline electrolysis of seawater hydrogen production is discharged from the system and enters the potassium extraction and utilization system to extract potassium.

[0011] According to the above scheme, when the chloride ion activity reaches 1 mol / L, the electrolyte is discharged and enters the potassium extraction and utilization system for potassium extraction. High concentrations of chloride ions may trigger side reactions, adversely affecting the equipment and reducing the efficiency and purity of hydrogen production from seawater.

[0012] According to the above scheme, the eluent is saturated with sodium chloride; the temperature of the eluent is 85℃-95℃.

[0013] According to the above scheme, the adsorption-desorption process for potassium extraction is as follows: using clinoptilolite as the adsorbent and saturated sodium chloride as the eluent, a two-stage adsorption-two-stage desorption process is used, based on the temperature response mechanism of room temperature adsorption and high temperature elution, to achieve efficient enrichment and separation of potassium ions.

[0014] According to the above scheme, after potassium extraction via adsorption-desorption, the system is then processed through evaporation, concentration, salt precipitation, and cooling crystallization to prepare potassium chloride. The potassium extraction and utilization system employs an adsorption-desorption process, using clinoptilolite as the adsorbent and sodium chloride as the eluent. Leveraging the temperature response mechanism of room-temperature adsorption and high-temperature elution, it achieves efficient enrichment and separation of potassium ions. Subsequently, potassium chloride is prepared through evaporation, concentration, salt precipitation, and cooling crystallization, ultimately achieving the goal of potassium resource recovery and utilization. The evaporation, concentration, salt precipitation, and cooling crystallization processes are as follows: potassium is eluted from a saturated sodium chloride solution to obtain a high-concentration potassium chloride and sodium chloride solution; the high-temperature, high-concentration potassium chloride and sodium chloride solution is evaporated to precipitate solid sodium chloride; the solution after sodium chloride precipitation is cooled to precipitate potassium chloride.

[0015] According to the above scheme, the electrolyte for alkaline seawater electrolysis to produce hydrogen is heat-exchanged with a saturated sodium chloride solution. The electrolyte, after being cooled by the heat exchange, enters the potassium extraction and utilization system, where clinoptilolite is used as an adsorbent to adsorb and enrich potassium. The saturated sodium chloride solution, after being heated by the high-temperature electrolyte, is then heated as needed to serve as a desorption solution for potassium elution of the clinoptilolite after adsorbing potassium ions.

[0016] According to the above scheme, the solution after potassium chloride precipitation and the solution prepared with sodium chloride to form a saturated sodium chloride solution are recycled as the desorption solution for potassium extraction.

[0017] This invention also provides an alkaline seawater electrolysis hydrogen production and potassium resource comprehensive utilization system for the above-mentioned method. The system includes a purification and impurity removal system, an ion separation system, an alkaline electrolyzer hydrogen production system, and a potassium extraction and utilization system. The purification and impurity removal system is connected to the ion separation system, the ion separation system is connected to the alkaline electrolyzer hydrogen production system, and the alkaline electrolyzer hydrogen production system is connected to the potassium extraction and utilization system. The purification and impurity removal system includes an ultraviolet sterilization unit, a multi-media filter, a fine filtration unit, and an ultrafiltration unit, which sterilize and purify the raw seawater, filtering out solid insoluble impurities and microorganisms. The ion separation system includes a scale inhibitor addition unit, a fine filtration unit, and a nanofiltration unit. It selectively separates monovalent and divalent ions in seawater. Monovalent ions such as sodium ions, potassium ions, and chloride ions pass through the ion separation system and are used as feed water for the alkaline electrolyzer hydrogen production system. Divalent ions such as calcium ions, magnesium ions, and sulfate ions are retained in the concentrated water and discharged from the system. The alkaline electrolyzer hydrogen production system includes an alkaline electrolyzer, which comprises a chlorine-repellent oxygen evolution electrode, a hydrogen evolution electrode, and a diaphragm. The potassium extraction and utilization system includes an adsorption-desorption potassium extraction device, an evaporation concentration and salt precipitation unit, and a cooling crystallization unit. The highly concentrated electrolyte obtained during the efficient hydrogen production from alkaline seawater electrolysis enters the adsorption-desorption potassium extraction device, where clinoptilolite is used as the adsorbent to adsorb and enrich potassium. The eluent desorbs potassium ions from the clinoptilolite. The high-concentration potassium chloride and sodium chloride solution enters the evaporation concentration and salt precipitation unit for evaporation, precipitating solid sodium chloride. The solution after sodium chloride precipitation enters the cooling crystallization unit for cooling and precipitating potassium chloride.

[0018] According to the above scheme, the alkaline electrolytic cell hydrogen production system also includes an anode gas-liquid separator, a cathode gas-liquid separator, a gas drying device, and an analysis and detection device.

[0019] According to the above scheme, the alkaline electrolyzer hydrogen production system is further equipped with an electrolyte tank and an electrolyte replenishment pump to replenish the alkaline electrolyzer when necessary.

[0020] Furthermore, the ultrafiltration unit components can be one or several groups. Furthermore, the nanofiltration unit components can be one or several groups.

[0021] According to the above scheme, the purification and impurity removal system includes an ultrafiltration membrane backwashing unit for cleaning the ultrafiltration membrane; the ion separation system also includes a nanofiltration cleaning unit and a nanofiltration rinsing unit for cleaning and rinsing the nanofiltration unit.

[0022] According to the above scheme, the adsorption and desorption devices in the potassium extraction and utilization system can be flexibly configured into one or more sets to adapt to different scales of processing needs.

[0023] The beneficial effects of this invention are as follows: (1) This invention is the first to combine new energy seawater electrolysis hydrogen production with the comprehensive utilization of seawater elements. It realizes the conversion of new energy into hydrogen energy through seawater hydrogen production, while also realizing the extraction and utilization of potassium, a strategic element of marine resources, and reducing the burden of hazardous waste treatment. It is conducive to the unity of environmental and economic benefits.

[0024] (2) This invention couples alkaline seawater hydrogen production process and potassium extraction process. The alkaline seawater hydrogen production process is also an electrolyte concentration process. The highly concentrated electrolyte obtained by alkaline seawater electrolysis for efficient hydrogen production is used for potassium extraction from clinoptilolite, which can achieve effective potassium extraction from seawater with high efficiency. Approximately 200 grams of potassium can be extracted per ton of seawater.

[0025] (3) The alkaline seawater hydrogen production electrolysis process generates a large amount of heat, which in turn generates a large amount of hot electrolyte. The hot electrolyte is heat-exchanged with the desorption liquid in the clinoptilolite potassium extraction process. The electrolyte after heat exchange and cooling is used for clinoptilolite adsorption and enrichment of potassium at room temperature, and the desorption liquid after heat exchange and heating is used for high-temperature desorption. This can effectively utilize the heat generated in the electrolysis process, which is conducive to efficient adsorption and enrichment of potassium at room temperature, and can also save the heating link used in the desorption process, greatly reducing the energy consumption of the overall potassium extraction process and further improving the economic efficiency of the process.

[0026] (4) This invention sterilizes and purifies the raw seawater, filters out impurities, performs ion separation to remove divalent ions, and screens out components harmful to electrolysis, resulting in stable water quality and quantity. As the fresh water in the electrolyte of the electrolyzer is continuously consumed, the produced water continuously enters the hydrogen production system of the electrolyzer, continuously replenishing the fresh water consumed in the electrolyzer, forming an automatic electrolyte replenishment hydrogen production process, realizing the effective utilization of seawater to produce hydrogen.

[0027] (5) The alkaline electrolysis of seawater for hydrogen production and potassium resource comprehensive utilization system provided by the present invention can be used for alkaline electrolysis of seawater for hydrogen production and potassium resource extraction, so as to effectively recover and extract potassium elements in seawater while performing alkaline electrolysis of seawater for hydrogen production. Attached Figure Description

[0028] Figure 1 This is a flowchart of the overall process flow of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. This invention utilizes an alkaline electrolyzer to produce hydrogen from seawater while simultaneously achieving efficient and comprehensive utilization of potassium. Figure 1 This is a general process flow diagram of the present invention.

[0030] Example 1 Seawater samples were taken from the waters near Lingang, Tianjin, for the experiment. The seawater feed rate was 20 L / h, and the seawater contained calcium ions of 405 mg / L, magnesium ions of 1325 mg / L, potassium ions of 390 mg / L, sodium ions of 10080 mg / L, chloride ions of 18500 mg / L, conductivity of 42.5 mS / cm, and turbidity of 35 NTU. The seawater was pretreated by passing through an ultraviolet sterilization unit, a multi-media filter, a fine filtration unit, and an ultrafiltration unit to remove impurities and reduce turbidity. The ultrafiltration unit used was a Suez GH1812. After pretreatment, the ionic composition of the seawater remained basically unchanged, and the turbidity was reduced to 0.7 NTU.

[0031] Pretreated seawater, with scale inhibitor added, enters the ion separation system at a rate of 20 L / h. It is then pumped by a high-pressure pump into the fine filtration and nanofiltration units for ion separation. The nanofiltration unit is a Suez DK1812. The ion separation system produces 10 L / h of water with the following composition: calcium ions 15 mg / L, magnesium ions 43 mg / L, potassium ions 370 mg / L, sodium ions 9203 mg / L, chloride ions 14008 g / L, and turbidity less than 0.1 NTU. The concentrate from the ion separation system is discharged from the system at a rate of 10 L / h.

[0032] A certain amount of 27% potassium hydroxide solution is pre-placed in the alkaline electrolyzer. 10 L / h of permeate from the ion separation system is used as feed water and enters the alkaline electrolyzer hydrogen production system for electrolytic hydrogen production. The single-cell voltage of the alkaline electrolyzer hydrogen production system is 1.75 V, and the current density is 500 mA / cm². 2 The hydrogen and oxygen generated at the anode and cathode pass through a gas-liquid separator and a gas drying unit to obtain hydrogen and oxygen respectively. Electrolysis produces 17.9 Nm of hydrogen. 3 / h, hydrogen recovery rate 90%, a chloride ion activity meter is installed in the alkaline electrolysis cell, when the chloride ion activity reaches the set value of 1mol / L, the electrolyte is discharged from the system and enters the potassium element extraction and utilization system.

[0033] The hot electrolyte discharged from the electrolysis system is at approximately 90°C. This hot electrolyte is first exchanged with a saturated chloride solution for heat. After cooling, the electrolyte enters the adsorption-desorption device of the potassium extraction system and is then discharged. The adsorption column contains clinoptilolite, which adsorbs potassium ions from the electrolyte. The saturated sodium chloride solution, heated by heat exchange with the high-temperature electrolyte, is then heated to 90°C as a desorption solution (significantly saving energy compared to directly heating the saturated sodium chloride solution). The potassium ions in the clinoptilolite are then desorbed using the 90°C saturated sodium chloride solution, resulting in a high-concentration potassium chloride and sodium chloride solution. This high-temperature potassium chloride and sodium chloride solution is then evaporated to precipitate solid sodium chloride. The solution after sodium chloride precipitation is cooled to 30°C to precipitate potassium chloride. The solution after potassium chloride precipitation is mixed with some solid sodium chloride to prepare a saturated sodium chloride solution, which is then recycled as the desorption solution for potassium extraction. Alkaline electrolysis of seawater to produce hydrogen simultaneously yields a highly concentrated electrolyte for potassium extraction using clinoptilolite zeolite, effectively improving potassium ion extraction efficiency. Furthermore, the reduced presence of interfering ions such as calcium and magnesium in the feed solution also facilitates potassium extraction, achieving a potassium ion extraction rate as high as 92%. Simultaneously, this process effectively utilizes the heat generated during electrolysis, which is beneficial for efficient adsorption and enrichment of potassium at room temperature, while also saving the heating step required for desorption, significantly reducing the overall energy consumption of the potassium extraction process and improving its economic efficiency.

[0034] Comparative Example 1: Seawater samples were taken from the waters near Lingang, Tianjin, for the experiment. The seawater feed rate was 20 L / h, and the concentrations of calcium ions were 405 mg / L, magnesium ions 1325 mg / L, potassium ions 390 mg / L, sodium ions 10080 mg / L, chloride ions 18500 mg / L, conductivity 42.5 mS / cm, and turbidity 35 NTU. The seawater was directly fed into the adsorption column of the potassium extraction and utilization system and then discharged. The adsorption column contained clinoptilolite, which adsorbed potassium ions from the seawater. A saturated sodium chloride solution was heated to 90°C as the desorption solution to desorb potassium ions from the clinoptilolite, resulting in a high-concentration potassium chloride and sodium chloride solution. The high-temperature potassium chloride and sodium chloride solution was evaporated to precipitate solid sodium chloride. The solution after sodium chloride precipitation was cooled to 30°C to precipitate potassium chloride. The potassium ion extraction rate was 80%, significantly lower than that of the alkaline electrolysis of seawater for hydrogen production.

[0035] Example 2 Seawater samples were taken from the waters near Lingang, Tianjin, for the experiment. The seawater feed rate was 24 L / h, and the seawater contained calcium ions of 398 mg / L, magnesium ions of 1316 mg / L, potassium ions of 371 mg / L, sodium ions of 10045 mg / L, chloride ions of 18475 mg / L, conductivity of 42.1 mS / cm, and turbidity of 34 NTU. The seawater was pretreated by passing through a feed pump sequentially into an ultraviolet sterilization unit, a multi-media filter, a fine filtration unit, an ultrafiltration unit, and an ultrafiltration membrane backwashing unit. The ultrafiltration unit used was a Suez GH1812. After pretreatment, the ionic composition of the seawater remained basically unchanged, and the turbidity decreased to 0.7 NTU.

[0036] The pretreated seawater, at a rate of 24 L / h, is treated with scale inhibitor and then enters the ion separation system. It is then pumped by a high-pressure pump into the fine filtration unit and nanofiltration unit. The nanofiltration unit uses a Suez DK1812 filter. The ion separation system produces 10 L / h of water with the following composition: calcium 14 mg / L, magnesium ions 40 mg / L, potassium ions 366 mg / L, sodium ions 9089 mg / L, and chloride ions 13991 g / L, with a turbidity less than 0.1 NTU. The concentrate from the ion separation system, at a rate of 10 L / h, is discharged from the system.

[0037] A certain amount of 20% potassium hydroxide solution is pre-placed in the electrolyzer. 10 L / h of permeate from the ion separation system is used as feed water and enters the alkaline electrolyzer hydrogen production system for electrolytic hydrogen production. The single-cell voltage of the alkaline electrolyzer hydrogen production system is 1.73 V, and the current density is 506 mA / cm². 2 The generated hydrogen and oxygen are separated by a gas-liquid separator and a gas drying unit. Electrolysis produces 21.5 Nm3 / h of hydrogen with a hydrogen recovery rate of 90%. A chloride ion activity meter is installed in the alkaline electrolytic cell. When the chloride ion activity reaches the set value of 1 mol / L, the electrolyte is discharged from the system and enters the potassium extraction and utilization system.

[0038] After the electrolyte at 90°C is discharged from the electrolysis system, it is first used to exchange heat with a saturated chlorination solution. The saturated sodium chloride solution, heated by the heat exchange, is then heated to 90°C to serve as the desorption solution. This method saves energy compared to directly heating the saturated sodium chloride solution to 90°C. The electrolyte, cooled by the heat exchange, enters the adsorption column of the potassium extraction system before being discharged. The adsorption column contains clinoptilolite, which adsorbs potassium ions from the electrolyte. The potassium ions in the clinoptilolite are then desorbed using the 90°C saturated sodium chloride solution, resulting in a high-concentration potassium chloride and sodium chloride solution. The high-temperature potassium chloride and sodium chloride solution is then evaporated to precipitate solid sodium chloride. The solution after sodium chloride precipitation is cooled to 30°C to precipitate potassium chloride. The potassium ion extraction rate is 91.5%. The solution after potassium chloride precipitation is mixed with some solid sodium chloride to prepare a saturated sodium chloride solution, which is then recycled as the desorption solution for potassium extraction.

[0039] Comparative Example 2: Seawater from the waters near Tianjin Lingang was used in the experiment. The seawater feed rate was 24 L / h, and the concentrations of calcium ions were 398 mg / L, magnesium ions 1316 mg / L, potassium ions 371 mg / L, sodium ions 10045 mg / L, chloride ions 18475 mg / L, conductivity 42.1 mS / cm, and turbidity 34 NTU. The seawater was directly fed into the adsorption column of the potassium extraction and utilization system and then discharged. The adsorption column contained clinoptilolite, which adsorbed potassium ions from the seawater. A saturated sodium chloride solution was heated to 90°C as the desorption solution to desorb potassium ions from the clinoptilolite, resulting in a high-concentration potassium chloride and sodium chloride solution. The high-temperature potassium chloride and sodium chloride solution was evaporated to precipitate solid sodium chloride. The solution after sodium chloride precipitation was cooled to 30°C to precipitate potassium chloride. The potassium ion extraction rate was 78%, significantly lower than that of the alkaline electrolysis of seawater for hydrogen production. The solution after potassium chloride precipitation is mixed with some solid sodium chloride to prepare a saturated sodium chloride solution, which is then recycled as the desorption solution for potassium extraction.

[0040] Example 3 Seawater samples were taken from the waters near Lingang, Tianjin, for the experiment. The seawater feed rate was 18 L / h, and the seawater contained calcium ions of 400 mg / L, magnesium ions of 1331 mg / L, potassium ions of 393 mg / L, sodium ions of 10085 mg / L, chloride ions of 18503 mg / L, conductivity of 42.4 mS / cm, and turbidity of 35 NTU. The seawater was pretreated by sequentially passing through an ultraviolet sterilization unit, a multi-media filter, a fine filtration unit, an ultrafiltration unit, and an ultrafiltration membrane backwashing unit. The ultrafiltration unit used was a SUEZ GH1812. After pretreatment, the ionic composition of the seawater remained basically unchanged, and the turbidity decreased to 0.7 NTU.

[0041] The pretreated seawater, at a rate of 18 L / h, is treated with scale inhibitor and then enters the ion separation system. It is then pumped by a high-pressure pump into the fine filtration unit and nanofiltration unit. The nanofiltration unit uses a Suez DK1812 filter. The ion separation system produces 10 L / h of water with the following composition: calcium ions 17 mg / L, magnesium ions 46 mg / L, potassium ions 382 mg / L, sodium ions 9235 mg / L, and chloride ions 14023 g / L, with a turbidity less than 0.1 NTU. The concentrate from the ion separation system, at a rate of 10 L / h, is discharged from the system.

[0042] A certain amount of 25% potassium hydroxide solution is pre-placed in the electrolyzer. 10 L / h of permeate from the ion separation system is used as feed water and enters the alkaline electrolyzer hydrogen production system for electrolytic hydrogen production. The single-cell voltage of the alkaline electrolyzer hydrogen production system is 1.73 V, and the current density is 493 mA / cm². 2The generated hydrogen and oxygen are separated into hydrogen and oxygen by a gas-liquid separator and a gas drying unit. Electrolysis produces 15.9 Nm3 / h of hydrogen with a hydrogen recovery rate of 89%. A chloride ion activity meter is installed in the alkaline electrolytic cell. When the chloride ion activity reaches the set value of 1 mol / L, the electrolyte is discharged from the system and enters the potassium extraction and utilization system.

[0043] After the electrolyte at 90℃ is discharged from the electrolysis system, it is first heat-exchanged with a saturated chlorination solution. The saturated sodium chloride solution, heated by this process, is then heated to 90℃ to serve as the desorption solution. This method saves energy compared to directly heating the saturated sodium chloride solution to 90℃. The cooled electrolyte then enters the adsorption column of the potassium extraction system before being discharged. The adsorption column contains clinoptilolite, which adsorbs potassium ions from the electrolyte. The potassium ions are then desorbed from the clinoptilolite using the 90℃ saturated sodium chloride solution, resulting in a high-concentration potassium chloride and sodium chloride solution. This high-temperature potassium chloride and sodium chloride solution is then evaporated to precipitate solid sodium chloride. The solution after sodium chloride precipitation is cooled to 30℃ to precipitate potassium chloride. The potassium ion extraction rate is 91%. The solution after potassium chloride precipitation is mixed with some solid sodium chloride to prepare a saturated sodium chloride solution, which is then recycled as the desorption solution for potassium extraction.

[0044] Comparative Example 3: Seawater from the waters near Tianjin Lingang was used in the experiment. The seawater feed rate was 18 L / h, and the concentrations of calcium ions were 400 mg / L, magnesium ions 1331 mg / L, potassium ions 393 mg / L, sodium ions 10085 mg / L, chloride ions 18503 mg / L, conductivity 42.4 mS / cm, and turbidity 35 NTU. The seawater was directly fed into the adsorption column of the potassium extraction and utilization system and then discharged. The adsorption column contained clinoptilolite, which adsorbed potassium ions from the seawater. A saturated sodium chloride solution was heated to 90°C as the desorption solution to desorb potassium ions from the clinoptilolite, resulting in a high-concentration potassium chloride and sodium chloride solution. The high-temperature potassium chloride and sodium chloride solution was evaporated to precipitate solid sodium chloride. The solution after sodium chloride precipitation was cooled to 30°C to precipitate potassium chloride. The potassium ion extraction rate was 80%, significantly lower than the potassium ion extraction rate of the alkaline electrolysis seawater hydrogen production electrolyte in Example 3. The solution after potassium chloride precipitation is mixed with some solid sodium chloride to prepare a saturated sodium chloride solution, which is then recycled as the desorption solution for potassium extraction.

[0045] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for the comprehensive utilization of potassium resources through alkaline electrolysis of seawater to produce hydrogen, characterized in that: The raw seawater is sterilized and purified, filtered to remove impurities, and subjected to ion separation treatment to remove divalent ions. Alkaline electrolysis of seawater is then used to produce hydrogen. The hydrogen production process is monitored, and the electrolyte from the alkaline electrolysis of seawater is sent to a potassium extraction and utilization system. The potassium extraction and utilization system uses clinoptilolite as an adsorbent and employs an adsorption-desorption process to extract potassium.

2. The method according to claim 1, characterized in that: The divalent ions mentioned include calcium ions, magnesium ions, and sulfate ions.

3. The method according to claim 1, characterized in that: In the alkaline electrolysis of seawater to produce hydrogen, a solution of potassium hydroxide with a concentration of 20-30% is added beforehand, and then treated seawater that has been sterilized, purified, filtered to remove impurities, and has had divalent ions removed is passed through for alkaline electrolysis of seawater to produce hydrogen.

4. The method according to claim 1, characterized in that: Alkaline seawater electrolysis for hydrogen production employs a chlorine-repellent oxygen evolution electrode; the single-cell voltage of the alkaline electrolyzer hydrogen production system is 1.5-2.0V, and the current density is 400-600 mA / cm². 2 .

5. The method according to claim 1, characterized in that: During the alkaline electrolysis of seawater to produce hydrogen, the chloride ion activity and the seawater hydrogen production process are monitored. When the chloride ion activity is high and affects the alkaline electrolysis of seawater to produce hydrogen, the electrolyte from the alkaline electrolysis of seawater to produce hydrogen is discharged from the system and enters the potassium extraction and utilization system to extract potassium.

6. The method according to claim 1, characterized in that: The eluent is saturated sodium chloride; the temperature of the eluent is 85℃-95℃.

7. The method according to claim 1, characterized in that: The adsorption-desorption process for potassium extraction involves using clinoptilolite as the adsorbent and saturated sodium chloride as the eluent. It utilizes a two-stage adsorption-two-stage desorption process, based on the temperature response mechanism of room temperature adsorption and high temperature elution, to achieve efficient enrichment and separation of potassium ions. After potassium extraction via the adsorption-desorption process, the system is further processed through evaporation, concentration, salt precipitation, and cooling crystallization to prepare potassium chloride products.

8. The method according to claim 1, characterized in that: The electrolyte for alkaline seawater electrolysis to produce hydrogen is heat-exchanged with a saturated sodium chloride solution. After the electrolyte is cooled down by the heat exchange, it enters a potassium extraction and utilization system, where clinoptilolite is used as an adsorbent to adsorb and enrich potassium. The saturated sodium chloride solution, after being heated by the high-temperature electrolyte, is then heated as needed to serve as a desorption solution for potassium elution of the clinoptilolite that has adsorbed potassium ions.

9. A system for alkaline seawater electrolysis to produce hydrogen and comprehensively utilize potassium resources in the method of claim 1, characterized in that: It includes a purification and impurity removal system, an ion separation system, an alkaline electrolytic cell hydrogen production system, and a potassium extraction and utilization system. The purification and impurity removal system is connected to the ion separation system, the ion separation system is connected to the alkaline electrolytic cell hydrogen production system, and the alkaline electrolytic cell hydrogen production system is connected to the potassium extraction and utilization system. The purification and impurity removal system includes an ultraviolet sterilization unit, a multi-media filter, a fine filtration unit, and an ultrafiltration unit, which sterilize and purify the raw seawater, filtering out solid insoluble impurities and microorganisms. The ion separation system includes a scale inhibitor addition unit, a fine filtration unit, and a nanofiltration unit. It selectively separates monovalent and divalent ions in seawater. Monovalent ions in seawater pass through the ion separation system as feed water for the alkaline electrolyzer hydrogen production system, while divalent ions are retained in the concentrate and discharged from the system. The alkaline electrolyzer hydrogen production system includes an alkaline electrolyzer, which comprises a chlorine-repellent oxygen evolution electrode, a hydrogen evolution electrode, and a diaphragm. The potassium extraction and utilization system includes an adsorption-desorption potassium extraction device, an evaporation concentration and salt precipitation unit, and a cooling crystallization unit. The highly concentrated electrolyte obtained during the efficient hydrogen production from alkaline seawater electrolysis enters the adsorption-desorption potassium extraction device, where clinoptilolite is used as an adsorbent to enrich potassium. The eluent desorbs potassium ions from the clinoptilolite. The high-concentration potassium chloride and sodium chloride solution enters the evaporation concentration and salt precipitation unit for evaporation, precipitating solid sodium chloride. The solution after sodium chloride precipitation enters the cooling crystallization unit for cooling and precipitating potassium chloride.

10. The alkaline seawater electrolysis hydrogen production and potassium resource comprehensive utilization system according to claim 9, characterized in that: The alkaline electrolytic cell hydrogen production system also includes an anode gas-liquid separator, a cathode gas-liquid separator, a gas drying device, and an analysis and detection device; The purification and impurity removal system also includes an ultrafiltration membrane backwashing unit for cleaning the ultrafiltration membrane; The ion separation system also includes a nanofiltration cleaning unit and a nanofiltration rinsing unit for cleaning and rinsing the nanofiltration unit.

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