Evaluation device and evaluation method for electrolytic hydrogen production alkali solution

Abstract

The invention belongs to the technical field of electrolytic water hydrogen production, and discloses an evaluation device for electrolytic hydrogen production alkali solution, including a simulated electrolytic cell, a cathode alkali solution storage tank, a cathode alkali solution circulation pump, an anode alkali solution storage tank, an anode alkali solution circulation pump and a direct current power supply; the simulated electrolytic cell includes a cathode plate, a cathode net, a diaphragm, an anode net and an anode plate connected in sequence, the inlet of the cathode alkali solution storage tank is connected to the alkali solution outlet of the cathode plate, and the outlet of the cathode alkali solution storage tank is connected to the alkali solution inlet of the cathode plate via the cathode alkali solution circulation pump; the inlet of the anode alkali solution storage tank is connected to the alkali solution outlet of the anode plate, and the outlet of the anode alkali solution storage tank is connected to the alkali solution inlet of the anode plate via the anode alkali solution circulation pump; a negative electrode terminal is provided on the top of the cathode plate, and a positive electrode terminal is provided on the top of the anode plate; the positive electrode of the direct current power supply is connected to the positive electrode terminal, and the negative electrode is connected to the negative electrode terminal. The problem that the properties of the alkali solution cannot be quantitatively evaluated during the operation of the existing industrial electrolytic hydrogen production system is compensated.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen production by electrolysis of water, and particularly relates to an evaluation device and an evaluation method for an alkaline solution for hydrogen production by electrolysis. Background Art

[0002] Hydrogen is considered the most ideal energy carrier due to its advantages of being green, low-carbon, efficient, storable and transportable. Using renewable energy such as wind power and photovoltaics to produce hydrogen by electrolysis of water is one of the most important ways to produce hydrogen in the future. At present, the main technologies for producing hydrogen by electrolysis of water include alkaline water electrolysis, solid polymer water electrolysis and solid oxide water electrolysis. Since alkaline water electrolysis is relatively mature, the equipment manufacturing cost is low and the single equipment is large in scale, it is the main water electrolysis technology currently used for hydrogen production.

[0003] The electrolyte for hydrogen production by alkaline water electrolysis usually uses 30% potassium hydroxide. The temperature of the alkaline solution reaches 70-90°C during operation. Long-term operation will cause certain corrosion to the plates and pipelines. On the one hand, it will affect the equipment body. On the other hand, impurities are introduced into the alkaline solution, causing changes in properties, which will affect the electrolysis reaction process of the alkaline solution. At present, there is no detection and evaluation method for alkaline solution for hydrogen electrolysis. In industrial production processes, the density of the alkaline solution is usually monitored to appropriately replenish the lost alkali, but in fact, the impact of changes in the properties of the alkaline solution on the electrolysis process has not received attention. The detection and evaluation of the properties of the alkaline solution alone is of great help in analyzing the operating status of the electrolytic hydrogen production system, adjusting the system parameters in a targeted manner, and operating and maintaining it. Summary of the invention

[0004] The purpose of the present invention is to provide an evaluation device and an evaluation method for electrolytic hydrogen production alkali solution, which solves the problem that the properties of the alkali solution cannot be quantitatively evaluated during the operation of the existing industrial electrolytic hydrogen production system.

[0005] The present invention is achieved through the following technical solutions:

[0006] An evaluation device for electrolytic hydrogen production alkali solution, comprising a simulated electrolytic cell, a cathode alkali solution storage tank, a cathode alkali solution circulation pump, an anode alkali solution storage tank, an anode alkali solution circulation pump and a DC power supply;

[0007] The simulated electrolytic cell comprises a cathode plate, a cathode net, a diaphragm, an anode net and an anode plate which are connected in sequence, and an alkali solution outlet and an alkali solution inlet are provided on the cathode plate and the anode plate;

[0008] The inlet of the cathode alkali solution storage tank is connected to the alkali solution outlet of the cathode plate, and the outlet of the cathode alkali solution storage tank is connected to the alkali solution inlet of the cathode plate via a cathode alkali solution circulation pump;

[0009] The inlet of the anode alkali solution storage tank is connected to the alkali solution outlet of the anode plate, and the outlet of the anode alkali solution storage tank is connected to the alkali solution inlet of the anode plate via an anode alkali solution circulation pump;

[0010] A negative electrode terminal is provided on the top of the cathode plate, and a positive electrode terminal is provided on the top of the anode plate; the positive electrode of the DC power supply is connected to the positive electrode terminal, and the negative electrode is connected to the negative electrode terminal, and the DC power supply is used to monitor the working voltage between the cathode plate and the anode plate.

[0011] Furthermore, a groove is provided in the middle of the cathode plate, a plurality of protrusions are provided inside the groove, and the cathode mesh is installed in the groove.

[0012] Furthermore, a groove is provided in the middle of the anode plate, a plurality of protrusions are provided inside the groove, and the anode mesh is installed in the groove.

[0013] Furthermore, the height of the protrusion is lower than the edge of the groove.

[0014] Furthermore, the alkali solution inlet is arranged at the lower side of the anode plate and the cathode plate, and the alkali solution outlet is arranged at the upper side of the anode plate and the cathode plate.

[0015] Furthermore, bolt holes are opened around the cathode plate and the anode plate, and the cathode plate and the anode plate are fixedly connected by bolts.

[0016] Furthermore, the cathode mesh and the anode mesh are rectangular nickel meshes.

[0017] Furthermore, the middle part of the diaphragm is made of polyphenylene sulfide woven cloth, and the surrounding parts are made of polytetrafluoroethylene.

[0018] The present invention also discloses an evaluation method for the evaluation device for electrolytic hydrogen production alkali solution, comprising the following steps:

[0019] 1) preparing alkali solution and placing them in a cathode alkali solution storage tank and an anode alkali solution storage tank respectively;

[0020] 2) starting the cathode alkali solution circulation pump and the anode alkali solution circulation pump, the alkali solution in the cathode alkali solution storage tank flows in from the alkali solution inlet of the cathode plate, and after electrolysis in the simulated electrolytic cell, returns to the cathode alkali solution storage tank from the alkali solution outlet of the cathode plate; at the same time, the alkali solution in the anode alkali solution storage tank flows in from the alkali solution inlet of the anode plate, and after electrolysis in the simulated electrolytic cell, returns to the anode alkali solution storage tank from the alkali solution outlet of the anode plate;

[0021] 3) Start the DC power supply to start the hydrogen production process;

[0022] 4) The DC power supply monitors the voltage change over time in real time. After the voltage stabilizes, it continues to react for tmin and records the average voltage VF1 within tmin;

[0023] 5) turn off the DC power supply, cathode alkali solution circulation pump and anode alkali solution circulation pump, discharge the alkali solution in the cathode alkali solution storage tank and the anode alkali solution storage tank, and replace them with pure water;

[0024] 6) Turn on the cathode alkali solution circulation pump and the anode alkali solution circulation pump to flush the electrolytic cell and pipelines, and repeat the cleaning until the pH of the aqueous solution is 7-8;

[0025] 7) draining the pure water in the cathode alkali solution storage tank and the anode alkali solution storage tank and replacing it with the waste alkali solution obtained from the industrial alkaline electrolytic cell;

[0026] 8) Turn on the cathode alkali solution circulation pump and the anode alkali solution circulation pump, turn on the DC power supply, and start the hydrogen production process;

[0027] 9) Monitor the change of voltage over time. After the voltage stabilizes, continue to react for tmin and record the average voltage VF2 within tmin;

[0028] 10) When VF2 / VF1≥1.1, it is determined that the alkali solution of the hydrogen production system needs to be replaced; when VF2 / VF1<1.1, it is determined that the alkali solution of the hydrogen production system continues to be used.

[0029] Compared with the prior art, the present invention has the following beneficial technical effects:

[0030] The invention discloses an evaluation device for electrolytic hydrogen production alkali solution, comprising a simulated electrolytic cell, an alkali solution storage tank, an alkali solution circulation pump and a direct current power supply. Newly prepared alkali solution and waste alkali solution are placed in the alkali solution storage tank for circulation respectively, and the direct current power supply is connected to perform electrolytic hydrogen production. By comparing the voltage value after stabilization, etc., the influence of the electrolyte on the actual electrolysis process is quantitatively evaluated, and it is judged whether the alkali solution needs to be replaced, which makes up for the problem that the properties of the alkali solution cannot be quantitatively evaluated during the operation of the existing industrial electrolytic hydrogen production system, and has practical guiding significance for industrial application. The device has a simple structure and is easy to be popularized and applied.

[0031] The present invention also discloses an evaluation method for the alkaline solution for hydrogen production by electrolysis. The evaluation method can detect the electrochemical properties of the alkaline electrolyte offline. The evaluation method is simple, simulates the real process of hydrogen production by alkaline electrolysis, and can fully reflect the actual working properties of the electrolyte. At the same time, the detection process has a small sampling volume, a short cycle, and simple operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of an evaluation device for electrolytic hydrogen production alkaline solution of the present invention;

[0033] Figure 2 It is a schematic diagram of the structure of the simulated electrolytic cell of the present invention.

[0034] Among them, 1 is a simulated electrolytic cell, 2 is a cathode alkali solution storage tank, 3 is a cathode alkali solution circulation pump, 4 is an anode alkali solution storage tank, 5 is an anode alkali solution circulation pump, and 6 is a DC power supply;

[0035] 11 is a cathode plate, 12 is a cathode mesh, 13 is a separator, 14 is an anode mesh, 15 is an anode plate, 16 is a negative electrode terminal, and 17 is a positive electrode terminal. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0037] like Figure 1 As shown, the present invention discloses an evaluation device for electrolytic hydrogen production alkali solution, comprising a simulated electrolytic cell 1, a cathode alkali solution storage tank 2, a cathode alkali solution circulation pump 3, an anode alkali solution storage tank 4, an anode alkali solution circulation pump 5 and a DC power supply 6, wherein the cathode alkali solution storage tank 2 and the cathode alkali solution circulation pump 3 are arranged on the cathode side of the simulated electrolytic cell 1, and the anode alkali solution storage tank 4 and the anode alkali solution circulation pump 5 are arranged on the anode side of the simulated electrolytic cell 1.

[0038] like Figure 2 As shown, the simulated electrolytic cell 1 includes a cathode plate 11, a cathode mesh 12, a diaphragm 13, an anode mesh 14 and an anode plate 15 which are connected in sequence. The cathode plate 11 and the anode plate 15 have an alkali solution outlet on their upper sides and an alkali solution inlet on their lower sides.

[0039] like Figure 1 As shown, the inlet of the cathode alkali liquid storage tank 2 is connected to the alkali liquid outlet of the cathode plate 11, and the outlet of the cathode alkali liquid storage tank 2 is connected to the inlet of the cathode alkali liquid circulation pump 3; the outlet of the cathode alkali liquid circulation pump 3 is connected to the alkali liquid inlet of the cathode plate 11;

[0040] The inlet of the anode alkali solution storage tank 4 is connected to the alkali solution outlet of the anode plate 15 , the outlet of the anode alkali solution storage tank 4 is connected to the inlet of the anode alkali solution circulation pump 5 , and the outlet of the anode alkali solution circulation pump 5 is connected to the alkali solution inlet of the anode plate 15 .

[0041] A negative electrode terminal 16 is provided on the top of the cathode plate 11, and a positive electrode terminal 17 is provided on the top of the anode plate 15; the positive pole of the DC power supply 6 is connected to the positive electrode terminal 17, and the negative pole is connected to the negative electrode terminal 16, and the DC power supply 6 is used to monitor the working voltage between the cathode plate 11 and the anode plate 15.

[0042] Specifically, the middle of the cathode plate 11 and the anode plate 15 is a rectangular groove, and the inside of the groove is a cylindrical protrusion. The height of the cylindrical protrusion is lower than the edge of the groove, and the height difference is equal to the thickness of the cathode mesh 12 and the anode mesh 14.

[0043] The alkali solution outlet and the alkali solution inlet are arranged to bypass the groove.

[0044] Bolt holes are formed around the cathode plate 11 and the anode plate 15 , and the cathode plate 11 and the anode plate 15 are fixedly connected by bolts.

[0045] The cathode mesh 12 and the anode mesh 14 are rectangular nickel meshes, and the size of the nickel meshes is the same as the size of the rectangular grooves in the middle of the cathode plate 11 and the anode plate 15;

[0046] Preferably, the diaphragm 13 is composed of two parts, the middle part is made of polyphenylene sulfide woven cloth, and the surrounding parts are made of polytetrafluoroethylene plastic.

[0047] The present invention also discloses a method for evaluating an electrolytic hydrogen production alkali solution, which is implemented by using the system and comprises the following steps:

[0048] 1) preparing potassium hydroxide solution and placing it in the cathode alkali solution storage tank 2 and the anode alkali solution storage tank 4 respectively;

[0049] 2) starting the cathode alkali solution circulation pump 3 and the anode alkali solution circulation pump 5, the alkali solution in the cathode alkali solution storage tank 2 flows in from the alkali solution inlet of the cathode plate 11, and after electrolysis in the simulated electrolytic cell 1, flows back to the cathode alkali solution storage tank 2 from the alkali solution outlet of the cathode plate 11; at the same time, the alkali solution in the anode alkali solution storage tank 4 flows in from the alkali solution inlet of the anode plate 15, and after electrolysis in the simulated electrolytic cell 1, flows back to the anode alkali solution storage tank 4 from the alkali solution outlet of the anode plate 15;

[0050] 3) starting the DC power supply 6, adjusting the current density to a set value, and starting the hydrogen production process;

[0051] 4) Monitor the change of voltage over time. After the voltage stabilizes, continue the reaction for 10 minutes and record the average voltage VF1 within 10 minutes;

[0052] 5) Turn off the DC power supply 6 and the alkali solution circulation pump, discharge the alkali solution in the cathode alkali solution storage tank 2 and the anode alkali solution storage tank 4, and replace them with pure water;

[0053] 6) Turn on the cathode alkali solution circulation pump 3 and the anode alkali solution circulation pump 5 to rinse the electrolytic cell and the pipeline, and repeat the pure water cleaning process until the pH of the aqueous solution is 7-8;

[0054] 7) draining the pure water in the cathode alkali solution storage tank 2 and the anode alkali solution storage tank 4 and replacing them with waste alkali solution obtained from an industrial alkaline electrolytic cell;

[0055] 8) Turn on the cathode alkali solution circulation pump 3 and the anode alkali solution circulation pump 5, turn on the DC power supply 6, adjust the current density to the set value, and start the hydrogen production process;

[0056] 9) The DC power supply 6 monitors the voltage change over time in real time. After the voltage stabilizes, the reaction continues for 10 minutes, and the average value VF2 of the voltage within 10 minutes is recorded;

[0057] 10) Calculate VF2 / VF1. When VF2 / VF1≥1.1, it indicates that the energy consumption will increase significantly if the alkaline solution is continued to be used for hydrogen production, and the alkaline solution in the hydrogen production system needs to be replaced. When VF2 / VF1<1.1, it indicates that the alkaline solution in the hydrogen production system can still be used normally.

[0058] In step 1), the concentration of the alkali solution is the same as the concentration of the initial alkali solution in the industrial alkaline electrolytic cell in step 7), and the mass concentration of potassium hydroxide is 20%-30%.

[0059] The current density of step 3) and step 8) is the same, which is 50mA / cm 2 -200mA / cm 2 .

[0060] In step 4) and step 9), when the voltage is stable, the voltage change value is ≤5mV / min.

Claims

1. An evaluation method for an evaluation device for electrolytic hydrogen production alkali solution, characterized in that: The evaluation device for electrolytic hydrogen production alkali solution comprises a simulated electrolytic cell (1), a cathode alkali solution storage tank (2), a cathode alkali solution circulation pump (3), an anode alkali solution storage tank (4), an anode alkali solution circulation pump (5) and a DC power supply (6); The simulated electrolytic cell (1) comprises a cathode plate (11), a cathode mesh (12), a diaphragm (13), an anode mesh (14) and an anode plate (15) which are connected in sequence, and an alkali solution outlet and an alkali solution inlet are provided on the cathode plate (11) and the anode plate (15); The inlet of the cathode alkali solution storage tank (2) is connected to the alkali solution outlet of the cathode plate (11), and the outlet of the cathode alkali solution storage tank (2) is connected to the alkali solution inlet of the cathode plate (11) via the cathode alkali solution circulation pump (3); The inlet of the anode alkali solution storage tank (4) is connected to the alkali solution outlet of the anode plate (15), and the outlet of the anode alkali solution storage tank (4) is connected to the alkali solution inlet of the anode plate (15) via the anode alkali solution circulation pump (5); A negative electrode terminal (16) is provided on the top of the cathode plate (11), and a positive electrode terminal (17) is provided on the top of the anode plate (15); the positive electrode of the DC power supply (6) is connected to the positive electrode terminal (17), and the negative electrode is connected to the negative electrode terminal (16), and the DC power supply (6) is used to monitor the operating voltage between the cathode plate (11) and the anode plate (15); The evaluation method of the evaluation device for electrolytic hydrogen production alkali solution comprises the following steps: 1) preparing alkali solution and placing it in a cathode alkali solution storage tank (2) and an anode alkali solution storage tank (4); 2) starting the cathode alkali solution circulation pump (3) and the anode alkali solution circulation pump (5), so that the alkali solution in the cathode alkali solution storage tank (2) flows in through the alkali solution inlet of the cathode plate (11), is electrolyzed in the simulated electrolytic cell (1), and then returns to the cathode alkali solution storage tank (2) through the alkali solution outlet of the cathode plate (11); at the same time, the alkali solution in the anode alkali solution storage tank (4) flows in through the alkali solution inlet of the anode plate (15), is electrolyzed in the simulated electrolytic cell (1), and then returns to the anode alkali solution storage tank (4) through the alkali solution outlet of the anode plate (15); 3) Starting the DC power supply (6) to start the hydrogen production process; 4) DC power supply (6) monitors the voltage change over time in real time. After the voltage stabilizes, continue to react for tmin and record the average voltage VF1 within tmin; 5) Turn off the DC power supply (6), the cathode alkali solution circulation pump (3) and the anode alkali solution circulation pump (5), drain the alkali solution in the cathode alkali solution storage tank (2) and the anode alkali solution storage tank (4), and replace them with pure water; 6) Start the cathode alkali solution circulation pump (3) and the anode alkali solution circulation pump (5) to flush the electrolytic cell and pipelines, and repeat the flushing until the pH of the aqueous solution is 7-8; 7) draining the pure water in the cathode alkali solution storage tank (2) and the anode alkali solution storage tank (4) and replacing it with waste alkali solution obtained from an industrial alkaline electrolytic cell; 8) Turn on the cathode alkali solution circulation pump (3) and the anode alkali solution circulation pump (5), turn on the DC power supply (6), and start the hydrogen production process; 9) Monitor the voltage change over time. After the voltage stabilizes, continue to react for tmin and record the average voltage VF2 within tmin; 10) When VF2 / VF1≥1.1, it is determined that the alkali solution of the hydrogen production system needs to be replaced; when VF2 / VF1<1.1, it is determined that the alkali solution of the hydrogen production system continues to be used.

2. The evaluation method of an evaluation device for electrolytic hydrogen production alkali solution according to claim 1, characterized in that: A groove is provided in the middle of the cathode plate (11), a plurality of protrusions are provided inside the groove, and the cathode mesh (12) is installed in the groove.

3. The evaluation method of an evaluation device for electrolytic hydrogen production alkali solution according to claim 1, characterized in that: A groove is formed in the middle of the anode plate (15), a plurality of protrusions are provided inside the groove, and the anode mesh (14) is installed in the groove.

4. The evaluation method of an evaluation device for electrolytic hydrogen production alkali solution according to claim 2 or 3, characterized in that: The height of the protrusion is lower than the edge of the groove.

5. The evaluation method of an evaluation device for electrolytic hydrogen production alkali solution according to claim 1, characterized in that: The alkali solution inlet is arranged on the lower side of the anode plate (15) and the cathode plate (11), and the alkali solution outlet is arranged on the upper side of the anode plate (15) and the cathode plate (11).

6. The evaluation method of an evaluation device for electrolytic hydrogen production alkali solution according to claim 1, characterized in that: Bolt holes are formed around the cathode plate (11) and the anode plate (15), and the cathode plate (11) and the anode plate (15) are fixedly connected by bolts.

7. The evaluation method of an evaluation device for electrolytic hydrogen production alkali solution according to claim 1, characterized in that: The cathode mesh (12) and the anode mesh (14) are rectangular nickel meshes.

8. The evaluation method of an evaluation device for electrolytic hydrogen production alkali solution according to claim 1, characterized in that: The middle part of the diaphragm (13) is made of polyphenylene sulfide woven cloth, and the surrounding part is made of polytetrafluoroethylene.

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