Water replenishing and mass transfer system for direct hydrogen production and use method of water replenishing and mass transfer system

Abstract

The invention relates to the technical field of direct hydrogen production, in particular to a water supplementing and mass transferring system for direct hydrogen production and a using method thereof.The water supplementing and mass transferring system comprises a water supplementing system and an electrolysis system and is characterized in that the water supplementing system is arranged outside the electrolysis system and comprises a water supplementing source system and a mass transferring and water supplementing system; the water supplementing source system is communicated with the mass transfer water supplementing system, the mass transfer water supplementing system is communicated with the electrolysis system, the water supplementing source system comprises a storage tank and an intermediate tank, and the output end of the storage tank is communicated with the mass transfer water supplementing system and an inner cavity of the storage tank through a three-way pipe; the input end of the intermediate tank is communicated with the mass transfer water supplementing system, the output end of the intermediate tank is communicated with the input end of the storage tank, the water supplementing system which is separated from the electrolysis system but communicated with the electrolysis system is used, an electrolyzed high-concentration solution and a supplemented low-concentration solution are mixed for regeneration, the energy loss is low, and the hydrogen production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of direct hydrogen production, and in particular to a water replenishment mass transfer system for direct hydrogen production and a use method thereof. Background Art

[0002] The process of hydrogen production by water electrolysis is heavily dependent on freshwater resources. Non-fresh water has abundant hydrogen resources. Rational development of non-fresh water hydrogen production is an important choice to solve the current dilemma of green hydrogen development. There are two paths for non-fresh water hydrogen production, one is indirect hydrogen production and the other is direct hydrogen production. Indirect hydrogen production from non-fresh water is to separate and purify non-fresh water through water treatment technology to obtain high-purity fresh water for hydrogen production. This method increases the cost of hydrogen production and the difficulty of engineering operation and maintenance. Direct hydrogen production from non-fresh water uses the membrane separation principle driven by pressure difference, innovates from multiple paths such as materials and structural design, and realizes the direct coupling of water purification and alkaline electrolyzer electrolyte for automatic water replenishment.

[0003] The Chinese invention patent with announcement number CN117684216A, published on March 21, 2024, discloses an energy-free water replenishment device for in-situ direct hydrogen production from seawater without desalination. A layer of highly thermally conductive graphene non-woven fabric is arranged on the PTFE microporous membrane, which can not only provide support on the left and right sides, but also quickly transfer heat, reduce the temperature difference on both sides, and improve the mass transfer efficiency of the components; it can meet the demand for automatic water replenishment to the electrolyte of the alkaline electrolyzer without additional energy consumption, and widen the operating temperature. However, it uses external power to treat water purification and then replenishes water to the electrolyte in the alkaline electrolyzer, which results in high energy loss and increases the cost of hydrogen production. Summary of the invention

[0004] In response to the above technical problems, the present invention provides a water replenishment and mass transfer system for direct hydrogen production and a method of using the same. The water replenishment system is separate from but connected to the electrolysis system, and the high-concentration solution after electrolysis is mixed with the replenished low-concentration solution for regeneration, which has low energy loss and reduces the cost of hydrogen production.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A water replenishment and mass transfer system for direct hydrogen production, comprising a water replenishment system and an electrolysis system, characterized in that the water replenishment system is arranged outside the electrolysis system, the water replenishment system comprises a water replenishment source system and a mass transfer water replenishment system, the water replenishment source system is connected to the mass transfer water replenishment system, and the mass transfer water replenishment system is connected to the electrolysis system.

[0007] Furthermore, the water replenishment source system includes a storage tank and an intermediate tank, the storage tank output end is connected to the mass transfer water replenishment system and the storage tank inner cavity through a three-way pipe, the intermediate tank input end is connected to the mass transfer water replenishment system, and the intermediate tank output end is connected to the storage tank input end.

[0008] Furthermore, the mass transfer and water replenishment system includes an alkali solution supply system, a mass transfer component, a water tank, an alkali solution recovery system and an alkali solution interaction system, the alkali solution supply system includes an alkali solution pipeline and a filtering device inside the alkali solution pipeline; the alkali solution recovery system includes an alkali solution buffer storage tank; one end of the alkali solution pipeline is connected to the alkali solution interaction system, and the other end of the alkali solution pipeline is connected to the input end of the mass transfer component, and the output ends of multiple mass transfer components are all connected to the input end of the alkali solution buffer storage tank; the alkali solution buffer storage tank is connected to the alkali solution interaction system; multiple mass transfer components are arranged inside the water tank, the water tank input end is connected to the storage tank, and the water tank output end is connected to the intermediate tank.

[0009] Furthermore, the alkali solution interaction system includes a metering tank, a primary alkali solution storage tank, a secondary alkali solution storage tank and a tertiary alkali solution storage tank, and the electrolysis system is sequentially provided with the metering tank, the primary alkali solution storage tank and the secondary alkali solution storage tank along the water flow direction, the output end of the secondary alkali solution storage tank is connected with the input end of the tertiary alkali solution storage tank and the inner cavity of the secondary alkali solution storage tank, and the output end of the tertiary alkali solution is connected with the input end of the electrolysis system; the input end of the secondary alkali solution storage tank is also connected with the alkali solution pipeline and the output end of the alkali solution buffer storage tank.

[0010] Furthermore, the electrolysis system is a hydrogen production electrolysis cell device.

[0011] A method for using a water replenishment mass transfer system for direct hydrogen production comprises the following steps:

[0012] The electrolysis system discharges liquid to the secondary alkali liquid storage tank;

[0013] The mass transfer water replenishment system replenishes liquid into the secondary alkali solution storage tank;

[0014] The secondary alkali solution storage tank adds the replenished water to the electrolysis system.

[0015] Furthermore, the electrolysis system discharges liquid to a secondary alkali liquid storage tank, comprising the following steps:

[0016] The hydrogen production electrolyzer device transports the high-concentration alkali solution inside to the metering tank;

[0017] When the volume of alkali solution inside the metering tank reaches the set value, the solution is discharged into the primary alkali solution storage tank;

[0018] When the volume of alkali solution in the primary alkali solution storage tank reaches the set value, the alkali solution is discharged into the secondary alkali solution storage tank.

[0019] Furthermore, the mass transfer and water replenishment system replenishes liquid into the secondary alkali solution storage tank, comprising the following steps:

[0020] The storage tank inputs raw water into the water tank;

[0021] The mass transfer components in the water tank process the raw water into low-concentration alkali solution;

[0022] The mass transfer component inputs the low-concentration alkali solution into the alkali solution buffer storage tank through overflow;

[0023] When the liquid volume in the alkali solution buffer storage tank reaches the set value, the liquid is discharged into the secondary alkali solution storage tank.

[0024] Further, the secondary alkali solution storage tank adds the replenished water to the electrolysis system, comprising the following steps:

[0025] The high-concentration alkali solution input from the primary alkali solution storage tank and the low-concentration alkali solution in the alkali solution buffer storage tank are mixed in the secondary alkali solution storage tank to form alkali solution that meets the demand;

[0026] When the volume of alkali solution in the secondary alkali solution storage tank reaches the set value, the alkali solution is discharged into the tertiary alkali solution storage tank;

[0027] After the volume of alkali liquid in the tertiary alkali liquid storage tank reaches the set value, the liquid is discharged into the hydrogen production electrolyzer device.

[0028] Furthermore, the high-concentration alkali solution input from the primary alkali solution storage tank and the low-concentration alkali solution in the alkali solution buffer storage tank are mixed in the secondary alkali solution storage tank to form alkali solution that meets the demand, and the concentration of the alkali solution in the secondary alkali solution storage tank can be expressed by the following formula:

[0029] M=a(1-b)-c(1-d)

[0030] In the formula: M is the water replenishment amount of the secondary alkali liquid storage tank, a is the total amount of solution from the alkali liquid buffer tank entering the secondary alkali liquid storage tank, b is the concentration of the electrolyte from the alkali liquid buffer tank entering the secondary alkali liquid storage tank, c is the total amount of solution from the primary alkali liquid storage tank entering the secondary alkali liquid storage tank, d is the electrolyte concentration from the primary alkali liquid storage tank entering the secondary alkali liquid storage tank.

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

[0032] 1. The present invention uses a water replenishment system that is separate from but connected to the electrolysis system to mix and regenerate the high-concentration solution after electrolysis with the replenished low-concentration solution, which has low energy loss and reduces the cost of hydrogen production.

[0033] 2. The present invention separates the mass transfer and water replenishment system from the electrolysis system, eliminating conventional pure water preparation equipment and pipelines, liberating the overall working environment restrictions of the hydrogen production system, improving the processing efficiency of the mass transfer and water replenishment system, and increasing the benefits of resource utilization.

[0034] 3. The alkali solution interaction system provided by the present invention solves the problem of mismatch between the mass transfer and water replenishment system and the electrolyte concentration in the electrolysis system, which not only ensures the electrolyte reserves but also realizes electrolyte interaction, thereby improving the stability, efficiency and safety of the system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0036] This embodiment takes seawater as an external water replenishment source as an example. In addition to seawater, this system can also use industrial wastewater, domestic sewage, salt lake water and other domestic water as external water replenishment sources. In actual use, it is only necessary to consider the impact of large particles in different water sources on the mass transfer component (large particles may damage the membrane component in the mass transfer component). There is no need to perform special treatment on the water source. The membrane component of the mass transfer component only obtains water molecules from different water sources. Although the mass transfer component contains alkaline solution, it will not react with acidic substances in the water source.

[0037] See also Figure 1 , a water replenishment and mass transfer system for direct hydrogen production, comprising a water replenishment system and an electrolysis system, characterized in that the water replenishment system is arranged outside the electrolysis system, the water replenishment system comprises a water replenishment source system and a mass transfer water replenishment system, the water replenishment source system is connected to the mass transfer water replenishment system, and the mass transfer water replenishment system is connected to the electrolysis system.

[0038] The present invention uses a water replenishment system that is separate from the electrolysis system but connected to the electrolysis system, and mixes the high-concentration solution after electrolysis with the replenished low-concentration solution for regeneration, which has low energy loss and reduces the cost of hydrogen production. The mass transfer water replenishment system is designed separately from the electrolysis system, eliminating the conventional pure water preparation device and pipeline, freeing the overall working environment restrictions of the hydrogen production system, improving the treatment efficiency of the mass transfer water replenishment system, and increasing the benefits of resource utilization.

[0039] Furthermore, the water replenishment source system includes a storage tank and an intermediate tank, the storage tank output end is connected to the mass transfer water replenishment system and the storage tank inner cavity through a three-way pipe, the intermediate tank input end is connected to the mass transfer water replenishment system, and the intermediate tank output end is connected to the storage tank input end.

[0040] Furthermore, the mass transfer and water replenishment system includes an alkali solution supply system, a mass transfer component, a water tank, an alkali solution recovery system and an alkali solution interaction system, the alkali solution supply system includes an alkali solution pipeline and a filtering device inside the alkali solution pipeline; the alkali solution recovery system includes an alkali solution buffer storage tank; one end of the alkali solution pipeline is connected to the alkali solution interaction system, and the other end of the alkali solution pipeline is connected to the input end of the mass transfer component, and the output ends of multiple mass transfer components are all connected to the input end of the alkali solution buffer storage tank; the alkali solution buffer storage tank is connected to the alkali solution interaction system; multiple mass transfer components are arranged inside the water tank, the water tank input end is connected to the storage tank, and the water tank output end is connected to the intermediate tank.

[0041] Furthermore, the alkali solution interaction system includes a metering tank, a primary alkali solution storage tank, a secondary alkali solution storage tank and a tertiary alkali solution storage tank, and the electrolysis system is sequentially provided with the metering tank, the primary alkali solution storage tank and the secondary alkali solution storage tank along the water flow direction, the output end of the secondary alkali solution storage tank is connected with the input end of the tertiary alkali solution storage tank and the inner cavity of the secondary alkali solution storage tank, and the output end of the tertiary alkali solution is connected with the input end of the electrolysis system; the input end of the secondary alkali solution storage tank is also connected with the alkali solution pipeline and the output end of the alkali solution buffer storage tank.

[0042] Furthermore, the electrolysis system is a hydrogen production electrolysis cell device.

[0043] A method for using a water replenishment mass transfer system for direct hydrogen production comprises the following steps:

[0044] The electrolysis system discharges liquid to the secondary alkali liquid storage tank;

[0045] The mass transfer water replenishment system replenishes liquid into the secondary alkali solution storage tank;

[0046] The secondary alkali solution storage tank adds the replenished water to the electrolysis system.

[0047] Furthermore, the electrolysis system discharges liquid to a secondary alkali liquid storage tank, comprising the following steps:

[0048] The hydrogen production electrolyzer device transports the high-concentration alkali solution inside to the metering tank;

[0049] When the volume of alkali solution inside the metering tank reaches the set value, the solution is discharged into the primary alkali solution storage tank;

[0050] When the volume of alkali solution in the primary alkali solution storage tank reaches the set value, the alkali solution is discharged into the secondary alkali solution storage tank.

[0051] Furthermore, the mass transfer and water replenishment system replenishes liquid into the secondary alkali solution storage tank, comprising the following steps:

[0052] The storage tank inputs raw water into the water tank;

[0053] The mass transfer components in the water tank process the raw water into low-concentration alkali solution;

[0054] The mass transfer component inputs the low-concentration alkali solution into the alkali solution buffer storage tank through overflow;

[0055] When the liquid volume in the alkali solution buffer storage tank reaches the set value, the liquid is discharged into the secondary alkali solution storage tank.

[0056] Further, the secondary alkali solution storage tank adds the replenished water to the electrolysis system, comprising the following steps:

[0057] The high-concentration alkali solution input from the primary alkali solution storage tank and the low-concentration alkali solution in the alkali solution buffer storage tank are mixed in the secondary alkali solution storage tank to form alkali solution that meets the demand;

[0058] When the volume of alkali solution in the secondary alkali solution storage tank reaches the set value, the alkali solution is discharged into the tertiary alkali solution storage tank;

[0059] After the volume of alkali liquid in the tertiary alkali liquid storage tank reaches the set value, the liquid is discharged into the hydrogen production electrolyzer device.

[0060] Furthermore, the high-concentration alkali solution input from the primary alkali solution storage tank and the low-concentration alkali solution in the alkali solution buffer storage tank are mixed in the secondary alkali solution storage tank to form alkali solution that meets the demand, and the concentration of the alkali solution in the secondary alkali solution storage tank can be expressed by the following formula:

[0061] M=a(1-b)-c(1-d)

[0062] Where: M is the water replenishment of the secondary alkali liquid storage tank, a is the total amount of solution from the alkali liquid buffer tank entering the secondary alkali liquid storage tank, b is the concentration of the electrolyte from the alkali liquid buffer tank entering the secondary alkali liquid storage tank, c is the total amount of solution from the primary alkali liquid storage tank entering the secondary alkali liquid storage tank, and d is the concentration of the electrolyte from the primary alkali liquid storage tank entering the secondary alkali liquid storage tank. When in use, the concentration online detector in the secondary alkali liquid storage tank monitors the concentration of the internal solution in real time.

[0063] In order to achieve a balance in the water consumed by the electrolysis of the system, the solutes in the electrolyte interaction in the system are controlled to remain constant, and the electrolyte concentration is changed by the amount of water replenishment, thereby realizing the water replenishment function of the electrolysis system.

[0064] In this embodiment, the mass transfer water replenishment system needs to replenish pure water to the hydrogen production electrolyzer device at a rate of 100kg / h. After a period of electrolysis reaction, the alkalinity of the solution in the electrolyzer increases, and the concentration of the potassium hydroxide solution (KOH solution) in the electrolyzer increases to 30%. The concentration of the KOH solution output by the mass transfer water replenishment system is 25%; therefore, the mass transfer water replenishment system needs to transport 600kg of 25% KOH solution to the electrolyzer per hour, and the electrolyzer outputs 500kg of 30% KOH solution to achieve a water replenishment efficiency of 100kg per hour.

[0065] The specific steps are as follows: the high-concentration alkali solution (30%wtKOH solution) after electrolysis of the hydrogen production electrolyzer device is pumped to the alkali solution interactive system metering tank by the flow pump of the electrolyzer itself. The alkali solution metering tank is in units of 60L. After 60L is met, the electric regulating valve is opened to discharge the liquid to the primary alkali solution storage tank. After the primary alkali solution storage tank is filled with 500L, the liquid is discharged to the secondary alkali solution storage tank; in the secondary alkali solution storage tank, the 30%wtKOH solution from the electrolyzer is mixed with the less than 25%wtKOH solution from the alkali solution buffer storage tank. After the KOH solution concentration in the secondary alkali solution storage tank meets the requirements, the No. 1 alkali solution delivery pump is started to deliver the liquid to the tertiary alkali solution storage tank, and then the solution in the tertiary alkali solution storage tank is input into the hydrogen production electrolyzer device.

[0066] The solution input from the alkali solution buffer tank to the secondary alkali solution storage tank is transported by the No. 2 power pump of the alkali solution supply system and evenly distributed to 16 groups of mass transfer components, each of which includes 10 groups of pocket membrane components, which are 30 cm long, 5 cm wide and 25 cm high; the high-concentration alkali solution in the mass transfer component is driven by the concentration difference to absorb water molecules from seawater to form a low-concentration KOH solution; the low-concentration alkali solution after water replenishment treatment by the mass transfer component is collected by overflow of the alkali solution recovery system, and flows into the alkali solution buffer tank by the gravity of the liquid itself to complete the collection of the low-concentration alkali solution after water replenishment; the alkali solution buffer tank is equipped with a liquid level measurement sensor, and when the alkali solution is collected to a certain liquid level height, the No. 3 alkali solution delivery pump is started to deliver the liquid to the secondary alkali solution storage tank to further mix the alkali solution.

[0067] The water replenishment source system includes a storage tank, an intermediate tank, a water tank and two driving pumps; the No. 4 driving pump is used to transport the water replenishment source in the storage tank to the water tank to supply water to the mass transfer component in the water tank; wherein, a reflux pipe is arranged on the outlet side of the No. 4 driving pump to the storage tank, and the excess flow of the No. 4 driving pump is adjusted by a valve to return the excess flow of the No. 4 driving pump to the storage tank, thereby realizing the flow control entering the water tank; an overflow port is arranged on the other side of the water tank, and the overflow port sends the excess water source in the water tank to the intermediate tank for collection. After the collection is completed, the No. 5 driving pump is used to send the liquid to the storage tank to complete the supply and collection of the water replenishment source.

[0068] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A water replenishment mass transfer system for direct hydrogen production, comprising a water replenishment system and an electrolysis system, characterized in that: The water replenishment system is arranged outside the electrolysis system, and the water replenishment system includes a water replenishment source system and a mass transfer water replenishment system. The water replenishment source system is connected with the mass transfer water replenishment system, and the mass transfer water replenishment system is connected with the electrolysis system.

2. A water replenishment mass transfer system for direct hydrogen production according to claim 1, characterized in that: The water replenishment source system includes a storage tank and an intermediate tank. The output end of the storage tank is connected to the mass transfer water replenishment system and the inner cavity of the storage tank through a three-way pipe. The input end of the intermediate tank is connected to the mass transfer water replenishment system. The output end of the intermediate tank is connected to the input end of the storage tank.

3. A water replenishment mass transfer system for direct hydrogen production according to claim 2, characterized in that: The mass transfer and water replenishment system includes an alkali solution supply system, a mass transfer component, a water tank, an alkali solution recovery system and an alkali solution interaction system. The alkali solution supply system includes an alkali solution pipeline and a filtering device inside the alkali solution pipeline; the alkali solution recovery system includes an alkali solution buffer storage tank; one end of the alkali solution pipeline is connected to the alkali solution interaction system, and the other end of the alkali solution pipeline is connected to the input end of the mass transfer component, and the output ends of multiple mass transfer components are all connected to the input end of the alkali solution buffer storage tank; the alkali solution buffer storage tank is connected to the alkali solution interaction system; multiple mass transfer components are arranged inside the water tank, the water tank input end is connected to the storage tank, and the water tank output end is connected to the intermediate tank.

4. A water replenishment mass transfer system for direct hydrogen production according to claim 3, characterized in that: The alkali solution interaction system includes a metering tank, a primary alkali solution storage tank, a secondary alkali solution storage tank and a tertiary alkali solution storage tank. The electrolysis system is sequentially provided with the metering tank, the primary alkali solution storage tank and the secondary alkali solution storage tank along the water flow direction. The output end of the secondary alkali solution storage tank is connected with the input end of the tertiary alkali solution storage tank and the inner cavity of the secondary alkali solution storage tank. The output end of the tertiary alkali solution is connected with the input end of the electrolysis system; the input end of the secondary alkali solution storage tank is also connected with the alkali solution pipeline and the output end of the alkali solution buffer storage tank.

5. A water replenishment mass transfer system for direct hydrogen production according to claim 1, characterized in that: The electrolysis system is a hydrogen production electrolysis cell device.

6. A method for using a water replenishment mass transfer system for direct hydrogen production, characterized in that: A water replenishment mass transfer system for direct hydrogen production as claimed in any one of claims 1 to 5, comprising the following steps: The electrolysis system discharges liquid to the secondary alkali liquid storage tank; The mass transfer water replenishment system replenishes liquid into the secondary alkali solution storage tank; The secondary alkali solution storage tank adds the replenished water to the electrolysis system.

7. The method for using the water replenishment mass transfer system for direct hydrogen production according to claim 6, characterized in that: The electrolysis system discharges liquid to the secondary alkali liquid storage tank, comprising the following steps: The hydrogen production electrolyzer device transports the high-concentration alkali solution inside to the metering tank; When the volume of alkali solution inside the metering tank reaches the set value, the solution is discharged into the primary alkali solution storage tank; When the volume of alkali solution in the primary alkali solution storage tank reaches the set value, the alkali solution is discharged into the secondary alkali solution storage tank.

8. The method for using the water replenishment mass transfer system for direct hydrogen production according to claim 6, characterized in that: The mass transfer and water replenishment system replenishes liquid into the secondary alkali solution storage tank, comprising the following steps: The storage tank inputs raw water into the water tank; The mass transfer components in the water tank process the raw water into low-concentration alkali solution; The mass transfer component inputs the low-concentration alkali solution into the alkali solution buffer storage tank through overflow; When the liquid volume in the alkali solution buffer storage tank reaches the set value, the liquid is discharged into the secondary alkali solution storage tank.

9. The method for using the water replenishment mass transfer system for direct hydrogen production according to claim 6, characterized in that: The secondary alkali solution storage tank adds the replenished water to the electrolysis system, comprising the following steps: The high-concentration alkali solution input from the primary alkali solution storage tank and the low-concentration alkali solution in the alkali solution buffer storage tank are mixed in the secondary alkali solution storage tank to form alkali solution that meets the demand; When the volume of alkali solution in the secondary alkali solution storage tank reaches the set value, the alkali solution is discharged into the tertiary alkali solution storage tank; After the volume of alkali liquid in the tertiary alkali liquid storage tank reaches the set value, the liquid is discharged into the hydrogen production electrolyzer device.

10. The method for using the water replenishment mass transfer system for direct hydrogen production according to claim 9, characterized in that: The high-concentration alkali solution input from the primary alkali solution storage tank is mixed with the low-concentration alkali solution in the alkali solution buffer storage tank in the secondary alkali solution storage tank to form alkali solution that meets the demand. The concentration of the alkali solution in the secondary alkali solution storage tank can be expressed by the following formula: M=a(1-b)-c(1-d) In the formula: M is the water replenishment amount of the secondary alkali liquid storage tank, a is the total amount of solution from the alkali liquid buffer tank entering the secondary alkali liquid storage tank, b is the concentration of the electrolyte from the alkali liquid buffer tank entering the secondary alkali liquid storage tank, c is the total amount of solution from the primary alkali liquid storage tank entering the secondary alkali liquid storage tank, d is the electrolyte concentration from the primary alkali liquid storage tank entering the secondary alkali liquid storage tank.

Images