Method for calculating overpotential of hydrogen production by industrial electrolysis of water

Abstract

The invention discloses an industrial electrolytic water hydrogen production overpotential calculation method, which comprises the following steps: step 1, confirming that an electrolytic bath works normally, the produced hydrogen is qualified and all operation indexes are within a specified range, and simultaneously eliminating the phenomenon that parasitic electrolysis exists in the electrolytic bath; 2, calculating the theoretical electrolysis voltage E0 of the electrolytic tank under the working condition; step 3, measuring the working voltage of the electrolysis chamber of the electrolytic tank, namely the operating voltage U of the electrolytic tank; 4, calculating the equivalent resistance Rd of the electrolytic tank; step 5, calculating the resistance partial voltage E1 of the electrolytic tank by using the equivalent resistance Rd of the electrolytic tank obtained in the step 4: step 6, calculating the overvoltage E2 of the electrolytic tank by using the theoretical electrolytic voltage E0 obtained in the step 2, the operating voltage U of the electrolytic tank obtained in the step 3 and the resistance partial voltage E1 obtained in the step 5. The overpotential calculated by the method is more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of overpotential calculation methods and relates to a method for calculating the overpotential of industrial water electrolysis to produce hydrogen. Background Art

[0002] The theoretical electrolysis voltage of water generally refers to the value of the reversible electrochemical process under equilibrium state. In fact, when the current passes through the water electrolysis cell, the electrode process is often irreversible. At this time, the electrode potential value will deviate from the equilibrium potential value (reversible potential or steady-state potential), and the electrode electromotive force must be greater than the reversible electromotive force or theoretical electrolysis voltage. This phenomenon that the electrode potential deviates from the equilibrium value when the current passes through the electrode is called the polarization phenomenon of the electrode, or polarization phenomenon for short. The degree of polarization is measured by the deviation of the electrode potential from the equilibrium potential. This deviation is called the super (over) potential, also known as the polarization amount. Many scholars have calculated the overvoltage through empirical equations, but the actual potential difference of a pair of electrodes in the electrolytic cell cannot be determined by the change of free energy during the reaction process, so it cannot be calculated using chemical thermodynamic equations. The polarization phenomenon needs to be explained by the electrode process kinetics. The percentage of hydrogen and oxygen overpotentials in the operating voltage of water electrolysis is relatively large. Therefore, it is very important to study the overpotential in actual production to reduce energy consumption. Summary of the invention

[0003] The purpose of the present invention is to provide a method for calculating the overpotential of industrial water electrolysis hydrogen production, and the overpotential calculated by the method is more accurate.

[0004] The technical solution adopted by the present invention is: The calculation method of the overpotential of industrial water electrolysis for hydrogen production is implemented in the following steps: Step 1: confirm that the electrolyzer is working normally, the hydrogen produced is qualified, and all operating indicators are within the specified range, and at the same time, exclude the phenomenon of parasitic electrolysis in the electrolyzer; Step 2, calculating the theoretical electrolysis voltage E0 of the electrolytic cell under working conditions; Step 3, measuring the working voltage of the electrolytic cell, i.e., the operating voltage U of the electrolytic cell; Step 4, calculating the equivalent resistance Rd of the electrolytic cell; Step 5, using the equivalent resistance Rd of the electrolytic cell obtained in step 4, calculate the resistance voltage E1 of the electrolytic cell: Step 6, using the theoretical electrolysis voltage E0 obtained in step 2, the operating voltage U of the electrolytic cell obtained in step 3 and the resistance partial voltage E1 obtained in step 5, calculate the overvoltage E2 of the electrolytic cell.

[0005] The present invention is also characterized in that: In step 2, the calculation formula of the theoretical electrolysis voltage E0 is: E0=1.23-0.0008×(T-25)+0.0435×logP Where: 1.23 is the theoretical electrolysis voltage of water at 1 atmosphere and 25°C, V; T is the operating temperature of water electrolysis, °C; P is the operating pressure of water electrolysis, Pa.

[0006] In step 4, the calculation formula of the equivalent resistance Rd of the electrolytic cell is: Rd=Rt+R1+R2+R3 Wherein, Rt is the resistance of the electrolyte during the electrolysis process, Ω; R1 is the plate resistance, Ω; R2 is the diaphragm resistance, Ω; R3 is the contact wire resistance, Ω.

[0007] The electrolyte resistance Rt is calculated from the gas content C, and the gas content C is obtained by simulating actual industrial production using a gas content measuring device.

[0008] The gas content measuring device comprises an electrolytic cell, which comprises an anode plate, a cathode plate and a diaphragm, wherein the diaphragm and the cathode plate can be translated in the electrolytic cell; the cathode and the anode of the electrolytic cell are respectively connected to a gas-liquid separator through pipelines, a pressure controller is arranged on the top of the gas-liquid separator, and the gas-liquid separator is connected to a first pipeline for hydrogen and oxygen to escape, and a pressure-controlled valve is arranged on the first pipeline; a variable power supply is arranged between the positive and negative poles of the electrolytic cell.

[0009] The electrolytic cell and the two gas-liquid separators are also connected through a second pipeline. Valves are arranged at the connection between the second pipeline and the two gas-liquid separators. The second pipeline is also provided with a temperature controller, a heat exchanger and a circulation pump.

[0010] The specific steps of using the gas content measuring device to measure the gas content and calculate the resistance Rt of the gas-containing electrolyte are as follows: Step a, according to the plate diameter D1 of the industrial electrolytic cell actually used and the distance L1 between the anode and cathode plates, the distance L0 between the anode and cathode plates in the gas content measuring device is adjusted by translating the cathode plate, and the diaphragm is adjusted to be located in the middle of the anode and cathode plates. The distance L0 between the anode and cathode plates is specifically adjusted according to the following formula: D1 / D0=L1 / L0 Wherein, D1 is the plate diameter of the industrial electrolytic cell, D0 is the plate diameter of the gas content measuring device, L1 is the distance between the positive and negative plates in the industrial electrolytic cell, and L0 is the distance between the positive and negative plates in the gas content measuring device; Step b, adding electrolyte to the gas content measuring device, until the electrolyte fills the entire electrolytic cell and overflows to the two gas-liquid separators, and forms a certain liquid level height H, and the composition of the added electrolyte must be consistent with the composition of the electrolyte used in actual production; Step c, turning on the variable power supply to start electrolysis, controlling the current density, electrolysis temperature, and operating pressure during the electrolysis process to be consistent with actual production, and when the electrolysis process is stable, recording the electrolyte levels H1 and H2 in the two gas-liquid separators, and calculating the gas content of the electrolyte according to the following formula: C = (H1 + H2 - 2H) × S f / [(H1+H2)×S f +S0×L0)] Among them, S f is the cross-sectional area of ​​the gas-liquid separator, S0 is the area of ​​the anode and cathode plates in the gas content measurement device; Step d, calculating the resistance Rt of the gas-containing electrolyte according to the following formula: Rt=9.5C×R0 Where R0 is the actual resistance of the electrolyte without bubbles in the industrial electrolytic cell, Ω.

[0011] In step 5, the resistance voltage E1 of the electrolytic cell is calculated according to the following formula: E1=I×Rd Where I is the electrolysis current, A.

[0012] In step 6, the overvoltage E2 of the electrolytic cell is calculated according to the following formula: E 2= U-E0-E1 Where U is the operating voltage of the electrolytic cell, V; E0 is the theoretical electrolysis voltage of the electrolytic cell under working conditions, V; E1 is the resistance divided voltage of the electrolytic cell, V.

[0013] The beneficial effects of the present invention are: (1) The method of the present invention uses a self-made device to measure the gas content of the electrolyte during the industrial electrolysis of water, and then calculates the resistance of the gas-containing electrolyte in industrial production. The position of the diaphragm and cathode plate in the device is adjustable, and the internal temperature of the device is controlled to be consistent with the industrial production temperature through a circulating pump, a temperature controller and a heat exchanger. Then, by controlling the current density and operating pressure during the electrolysis process to be consistent with the actual production process, the device can accurately simulate the actual electrolysis process, and then accurately measure the gas content of the electrolyte during the production process and calculate the resistance of the gas-containing electrolyte; (2) The method of the present invention measures and calculates the resistance of the gas-containing electrolyte through a gas content measuring device, and then indirectly calculates the magnitude of the overpotential of hydrogen production by electrolysis of water through the equivalent resistance method. The calculated overpotential value conforms to the actual production and can be used to calculate the overpotential value in the actual industrial production process, thereby better controlling the overpotential, guiding the production process to be carried out efficiently, reducing production costs, and improving market competitiveness; (3) The method of the present invention provides a new way to obtain superpotential. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the gas content measuring device in the method of the present invention.

[0015] In the figure, 1. electrolytic cell, 2. anode plate, 3. cathode plate, 4. diaphragm, 5. gas-liquid separator, 6. pressure controller, 7. first pipeline, 8. pressure-controlled valve, 9. variable power supply, 10. second pipeline, 11. valve, 12. temperature controller, 13. heat exchanger, 14. circulation pump. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] The method for calculating the overpotential of industrial water electrolysis hydrogen production of the present invention indirectly calculates the overpotential of water electrolysis by using an equivalent resistance method.

[0018] During water electrolysis, the voltage applied to a pair of electrodes in the electrolytic cell must be greater than the theoretical electrolysis voltage of water in order to overcome the various resistance voltage drops and electrode polarization electromotive force generated when the current flows through the electrolytic cell. The polarization electromotive force is the sum of the cathode hydrogen evolution overpotential and the anode oxygen evolution overpotential. Therefore, the operating voltage (actual decomposition voltage) of the water electrolytic cell can be expressed as follows: U=E0+E1+E2 Where: U is the operating voltage of the electrolytic cell, V; E0 is the theoretical electrolysis voltage of the electrolytic cell under working conditions; E1 is the resistance partial voltage of the electrolytic cell (voltage other than theoretical electrolysis voltage and overvoltage), V; E2 is the electrode overvoltage of the electrolytic cell, V.

[0019] The calculation method of E1 is: E1=I×Rd Where, I is the electrolysis current, A; Rd is the equivalent resistance of the electrolyte, Ω, which includes the resistance of all parts such as the diaphragm, plates, electrode contacts, and electrolyte.

[0020] Due to the existence of overpotential, it is difficult to directly calculate the resistance of the electrolyte using Ohm's law. The method of the present invention provides a more accurate overvoltage calculation method through experimental modeling and simulation measurement, combined with the practical operation experience of the electrolytic cell, to provide data support for the electrolysis industry to continue to explore overpotential.

[0021] The method for calculating the overpotential of industrial water electrolysis hydrogen production according to the present invention is specifically implemented according to the following steps: Step 1: confirm that the electrolyzer is working normally, the hydrogen produced is qualified, and all operating indicators are within the specified range, and at the same time, exclude the phenomenon of parasitic electrolysis in the electrolyzer; Step 2, calculate the theoretical electrolysis voltage E0 of the electrolytic cell under working conditions according to the following formula: E0=1.23-0.0008×(T-25)+0.0435×logP Where: 1.23 is the theoretical electrolysis voltage of water at 1 atmosphere and 25°C, V; T is the operating temperature of water electrolysis, °C; P is the operating pressure of water electrolysis, Pa.

[0022] Step 3, measuring the working voltage of the electrolytic chamber, that is, the operating voltage U of the electrolytic cell; Step 4, calculate the equivalent resistance Rd of the electrolytic cell: The equivalent resistance Rd of the electrolytic cell mainly includes the electrolyte resistance Rt (including bubbles), the plate resistance R1 (including catalyst), the diaphragm resistance R2 and the contact wire resistance R3, which can be expressed as: Rd=Rt+R1+R2+R3 Among them, the plate resistance R1 (including catalyst), the diaphragm resistance R2 and the contact wire resistance R3 can all be obtained from the manufacturer.

[0023] The specific calculation method of electrolyte resistance Rt is: The resistance of the electrolyte in the industrial water electrolysis process cannot be directly measured, so the method of the present invention is designed as follows Figure 1 The device shown is used to measure the gas content C of the electrolyte containing bubbles in the industrial electrolysis process, and then calculate the resistance Rt of the electrolyte. Figure 1 As shown, the gas content measuring device includes an electrolytic cell 1, which includes an anode plate 2, a cathode plate 3 and a diaphragm 4, wherein the diaphragm 4 and the cathode plate 3 can be translated in the electrolytic cell 1, that is, the positions of the diaphragm 4 and the cathode plate 3 are adjustable. The cathode and the anode of the electrolytic cell 1 are respectively connected to a gas-liquid separator 5 through pipelines, a pressure controller 6 is arranged on the top of the gas-liquid separator 5, and the gas-liquid separator 5 is connected to a first pipeline 7 for hydrogen and oxygen to escape, and a pressure control valve 8 is arranged on the first pipeline 7. A variable power supply 9 is arranged between the positive and negative poles of the electrolytic cell 1.

[0024] The electrolytic cell 1 and the two gas-liquid separators 5 are also connected through a second pipeline 10. Valves 11 are provided at the connection between the second pipeline 10 and the two gas-liquid separators 5. The second pipeline 10 is also provided with a temperature controller 12, a heat exchanger 13 and a circulation pump 14, which are used to circulate the electrolyte in the entire device to keep the temperature of each part of the device consistent and consistent with the temperature of the actual production electrolytic cell.

[0025] The specific operating steps of the gas content measuring device of the present invention are as follows: Step a, according to the plate diameter D1 of the industrial electrolytic cell actually used and the distance L1 between the anode and cathode plates, the distance L0 between the anode and cathode plates in the gas content measuring device is adjusted by translating the cathode plate 3, and the diaphragm 4 is adjusted to be located in the middle of the anode and cathode plates. The distance L0 between the anode and cathode plates is specifically adjusted according to the following formula: D1 / D0=L1 / L0 Wherein, D1 is the plate diameter of the industrial electrolytic cell, D0 is the plate diameter of the gas content measuring device, L1 is the distance between the positive and negative plates in the industrial electrolytic cell, and L0 is the distance between the positive and negative plates in the gas content measuring device.

[0026] Step b, add electrolyte to the gas content measuring device until the electrolyte fills the entire electrolytic cell 1 and overflows to the two gas-liquid separators 5, and forms a certain liquid level H in the gas-liquid separators 5. At this time, the reaction has not started, no gas is generated, the pressure in the two gas-liquid separators 5 is the same, and therefore the liquid level is equal. The composition of the added electrolyte must be consistent with the composition of the electrolyte used in actual production.

[0027] Step c, turning on the variable power supply 9 to start electrolysis, during the electrolysis process, the current density, electrolysis temperature, and operating pressure conditions are controlled to be consistent with the actual production. When the electrolysis process is stable, the liquid levels in the two gas-liquid separators 5 rise due to the gas dissolved in the electrolyte. The electrolyte liquid levels H1 and H2 in the two gas-liquid separators 5 are recorded, and the gas content of the electrolyte is calculated according to the following formula: C = (H1 + H2 - 2H) × S f / [(H1+H2)×S f +S0×L0)] Among them, S f is the cross-sectional area of ​​the gas-liquid separator, and S0 is the area of ​​the anode and cathode plates in the gas content measuring device.

[0028] Step d, calculating the resistance Rt of the gas-containing electrolyte according to the following formula: Rt=9.5C×R0 Where R0 is the actual resistance of the electrolyte without bubbles in the industrial electrolytic cell, Ω.

[0029] The above formula is derived by the following method: According to the above step c, different current densities are set (the set current densities are all within the current density range commonly used in industrial production), and the gas content C under different densities is obtained. Then, the resistance meter is used to measure the electrolyte resistance Rt corresponding to different gas contents, and the relationship diagram between C and Rt under different current densities is obtained. The above formula is derived based on the relationship diagram, and the above formula is applied to the calculation of the resistance of gas-containing electrolyte under industrial production conditions.

[0030] Step 5, calculate the resistance voltage E1 of the electrolytic cell from the equivalent resistance Rd of the electrolytic cell according to the following formula: E1=I×Rd Where I is the electrolysis current, A.

[0031] Step 6, calculate the overvoltage E2 of the electrolytic cell according to the following formula: E 2= U-E0-E1 Where U is the operating voltage of the electrolytic cell, V; E0 is the theoretical electrolysis voltage of the electrolytic cell under working conditions, V; E1 is the resistance divided voltage of the electrolytic cell, V.

[0032] Example 1 The parameters of the electrolytic cell and electrolysis process parameters used in the industrial electrolysis of water for which the overpotential needs to be calculated in this embodiment are: The length of the electrolytic cell is 5.5 m, the plate spacing L1 is 1.8 cm, the plate diameter D1 is 2.2 m, and the plate resistance R1 is 0.5×10 -5 Ω, diaphragm resistance R2 is 0.23×10 -5 Ω, the contact wire resistance R3 is 0.2×10 -5 Ω.

[0033] The electrolyte is 30% KOH solution, and the actual resistance R0 of the electrolyte is 2.29×10 -5 Ω, electrolysis temperature T is 90℃, operating voltage U of the electrolytic cell is 1.75V, current density is 1000A / m 2 , the pressure on the hydrogen side is 1.6MPa, and the pressure on the oxygen side is 1.6MPa.

[0034] The parameters of the gas content measuring device in this embodiment are: The diameter of the electrolytic cell is 10 cm; the anode plate and the cathode plate are both nickel electrodes, and the diameter D0 is 10 cm; the diaphragm is a PPS diaphragm with a thickness of 0.2 mm and a diameter of 10 cm; the cross-sectional area of ​​the gas-liquid separator is S f 1cm 2 ; According to the diameter and plate spacing of the industrial electrolytic cell, the plate spacing L0 in the gas content measuring device is set to 0.08cm.

[0035] The parameters of the electrolysis process simulated by the gas content measurement device are as follows: The electrolyte is 30% KOH solution, the electrolyte flow rate is 8 cm / s, and the current density is 1000 A / m 2 , the electrolysis temperature T is 90°C, the pressure on the hydrogen side is 1.6MPa, and the pressure on the oxygen side is 1.6MPa. When not electrolyzed, the liquid level height H in the two gas-liquid separators is 0.2cm.

[0036] When the electrolysis is stable, the liquid levels H1 and H2 in the two gas-liquid separators are measured to be 0.5 cm and 0.8 cm respectively.

[0037] According to the above parameters, the theoretical electrolysis voltage E0 of the electrolytic cell under working conditions is calculated to be 1.45 V, the gas content C of the electrolyte is 0.12, and the electrolyte resistance Rt is 2.61×10 -5 Ω, the equivalent resistance Rd of the electrolytic cell is 3.54×10 -5 Ω, the electrolysis current I is 3799A, the resistance partial voltage E1 of the electrolytic cell is 0.13V, and finally the overvoltage E2 of the electrolytic cell is 0.17V.

[0038] Example 2 The calculation method of the overpotential of industrial water electrolysis hydrogen production in this embodiment is specifically implemented according to the following steps: Step 1: confirm that the electrolyzer is working normally, the hydrogen produced is qualified, and all operating indicators are within the specified range, and at the same time, exclude the phenomenon of parasitic electrolysis in the electrolyzer; Step 2, calculating the theoretical electrolysis voltage E0 of the electrolytic cell under working conditions; Step 3, measuring the working voltage of the electrolytic cell, i.e., the operating voltage U of the electrolytic cell; Step 4, calculating the equivalent resistance Rd of the electrolytic cell; Step 5, using the equivalent resistance Rd of the electrolytic cell obtained in step 4, calculate the resistance voltage E1 of the electrolytic cell: Step 6, using the theoretical electrolysis voltage E0 obtained in step 2, the operating voltage U of the electrolytic cell obtained in step 3 and the resistance partial voltage E1 obtained in step 5, calculate the overvoltage E2 of the electrolytic cell.

[0039] Example 3 The calculation method of the overpotential of industrial water electrolysis hydrogen production in this embodiment is specifically implemented according to the following steps: Step 1: confirm that the electrolyzer is working normally, the hydrogen produced is qualified, and all operating indicators are within the specified range, and at the same time, exclude the phenomenon of parasitic electrolysis in the electrolyzer; Step 2, calculating the theoretical electrolysis voltage E0 of the electrolytic cell under working conditions; Step 3, measuring the working voltage of the electrolytic cell, i.e., the operating voltage U of the electrolytic cell; Step 4, calculating the equivalent resistance Rd of the electrolytic cell; Step 5, using the equivalent resistance Rd of the electrolytic cell obtained in step 4, calculate the resistance voltage E1 of the electrolytic cell: Step 6, using the theoretical electrolysis voltage E0 obtained in step 2, the operating voltage U of the electrolytic cell obtained in step 3 and the resistance partial voltage E1 obtained in step 5, calculate the overvoltage E2 of the electrolytic cell.

[0040] In step 2, the calculation formula of the theoretical electrolysis voltage E0 is: E0=1.23-0.0008×(T-25)+0.0435×logP Where: 1.23 is the theoretical electrolysis voltage of water at 1 atmosphere and 25°C, V; T is the operating temperature of water electrolysis, °C; P is the operating pressure of water electrolysis, Pa.

[0041] Example 4 The calculation method of the overpotential of industrial water electrolysis hydrogen production in this embodiment is specifically implemented according to the following steps: Step 1: confirm that the electrolyzer is working normally, the hydrogen produced is qualified, and all operating indicators are within the specified range, and at the same time, exclude the phenomenon of parasitic electrolysis in the electrolyzer; Step 2, calculating the theoretical electrolysis voltage E0 of the electrolytic cell under working conditions; Step 3, measuring the working voltage of the electrolytic cell, i.e., the operating voltage U of the electrolytic cell; Step 4, calculating the equivalent resistance Rd of the electrolytic cell; Step 5, using the equivalent resistance Rd of the electrolytic cell obtained in step 4, calculate the resistance voltage E1 of the electrolytic cell: Step 6, using the theoretical electrolysis voltage E0 obtained in step 2, the operating voltage U of the electrolytic cell obtained in step 3 and the resistance partial voltage E1 obtained in step 5, calculate the overvoltage E2 of the electrolytic cell.

[0042] In step 2, the calculation formula of the theoretical electrolysis voltage E0 is: E0=1.23-0.0008×(T-25)+0.0435×logP Where: 1.23 is the theoretical electrolysis voltage of water at 1 atmosphere and 25°C, V; T is the operating temperature of water electrolysis, °C; P is the operating pressure of water electrolysis, Pa.

[0043] In step 4, the calculation formula of the equivalent resistance Rd of the electrolytic cell is: Rd=Rt+R1+R2+R3 Wherein, Rt is the resistance of the electrolyte during the electrolysis process, Ω; R1 is the plate resistance, Ω; R2 is the diaphragm resistance, Ω; R3 is the contact wire resistance, Ω.

[0044] The electrolyte resistance Rt is calculated from the gas content C, and the gas content C is obtained by simulating actual industrial production using a gas content measuring device.

[0045] Example 5 On the basis of Example 4, the gas content measuring device includes an electrolytic cell 1, which includes an anode plate 2, a cathode plate 3 and a diaphragm 4, wherein the diaphragm 4 and the cathode plate 3 can be translated in the electrolytic cell 1; the cathode and the anode of the electrolytic cell 1 are respectively connected to a gas-liquid separator 5 through pipelines, a pressure controller 6 is arranged on the top of the gas-liquid separator 5, and the gas-liquid separator 5 is connected to a first pipeline 7 for hydrogen and oxygen to escape, and a pressure-controlled valve 8 is arranged on the first pipeline 7; a variable power supply 9 is arranged between the positive and negative poles of the electrolytic cell 1.

[0046] The electrolytic cell 1 and the two gas-liquid separators 5 are also connected via a second pipeline 10 . Valves 11 are provided at the connection between the second pipeline 10 and the two gas-liquid separators 5 . The second pipeline 10 is also provided with a temperature controller 12 , a heat exchanger 13 and a circulation pump 14 .

[0047] The specific steps of using the gas content measuring device to measure the gas content and calculate the resistance Rt of the gas-containing electrolyte are as follows: Step a, according to the plate diameter D1 of the industrial electrolytic cell actually used and the distance L1 between the anode and cathode plates, the distance L0 between the anode and cathode plates in the gas content measuring device is adjusted by translating the cathode plate 3, and at the same time adjusting the diaphragm 4 to be located in the middle of the anode and cathode plates. The distance L0 between the anode and cathode plates is specifically adjusted according to the following formula: D1 / D0=L1 / L0 Wherein, D1 is the plate diameter of the industrial electrolytic cell, D0 is the plate diameter of the gas content measuring device, L1 is the distance between the positive and negative plates in the industrial electrolytic cell, and L0 is the distance between the positive and negative plates in the gas content measuring device; Step b, adding electrolyte to the gas content measuring device, the electrolyte should be added until it fills the entire electrolytic cell 1 and overflows to the two gas-liquid separators 5, and forms a certain liquid level height H, and the composition of the added electrolyte should be consistent with the composition of the electrolyte used in actual production; Step c, turn on the variable power supply 9 to start electrolysis, control the current density, electrolysis temperature and operating pressure in the electrolysis process to be consistent with the actual production, and when the electrolysis process is stable, record the electrolyte levels H1 and H2 in the two gas-liquid separators 5, and calculate the gas content of the electrolyte according to the following formula: C = (H1 + H2 - 2H) × S f / [(H1+H2)×S f +S0×L0)] Among them, S f is the cross-sectional area of ​​the gas-liquid separator, S0 is the area of ​​the anode and cathode plates in the gas content measurement device; Step d, calculating the resistance Rt of the gas-containing electrolyte according to the following formula: Rt=9.5C×R0 Where R0 is the actual resistance of the electrolyte without bubbles in the industrial electrolytic cell, Ω.

[0048] Example 6 On the basis of Example 4, the gas content measuring device includes an electrolytic cell 1, which includes an anode plate 2, a cathode plate 3 and a diaphragm 4, wherein the diaphragm 4 and the cathode plate 3 can be translated in the electrolytic cell 1; the cathode and the anode of the electrolytic cell 1 are respectively connected to a gas-liquid separator 5 through pipelines, a pressure controller 6 is arranged on the top of the gas-liquid separator 5, and the gas-liquid separator 5 is connected to a first pipeline 7 for hydrogen and oxygen to escape, and a pressure-controlled valve 8 is arranged on the first pipeline 7; a variable power supply 9 is arranged between the positive and negative poles of the electrolytic cell 1.

[0049] The electrolytic cell 1 and the two gas-liquid separators 5 are also connected via a second pipeline 10 . Valves 11 are provided at the connection between the second pipeline 10 and the two gas-liquid separators 5 . The second pipeline 10 is also provided with a temperature controller 12 , a heat exchanger 13 and a circulation pump 14 .

[0050] The specific steps of using the gas content measuring device to measure the gas content and calculate the resistance Rt of the gas-containing electrolyte are as follows: Step a, according to the plate diameter D1 of the industrial electrolytic cell actually used and the distance L1 between the anode and cathode plates, the distance L0 between the anode and cathode plates in the gas content measuring device is adjusted by translating the cathode plate 3, and at the same time adjusting the diaphragm 4 to be located in the middle of the anode and cathode plates. The distance L0 between the anode and cathode plates is specifically adjusted according to the following formula: D1 / D0=L1 / L0 Wherein, D1 is the plate diameter of the industrial electrolytic cell, D0 is the plate diameter of the gas content measuring device, L1 is the distance between the positive and negative plates in the industrial electrolytic cell, and L0 is the distance between the positive and negative plates in the gas content measuring device; Step b, adding electrolyte to the gas content measuring device, the electrolyte should be added until it fills the entire electrolytic cell 1 and overflows to the two gas-liquid separators 5, and forms a certain liquid level height H, and the composition of the added electrolyte should be consistent with the composition of the electrolyte used in actual production; Step c, turn on the variable power supply 9 to start electrolysis, control the current density, electrolysis temperature and operating pressure in the electrolysis process to be consistent with the actual production, and when the electrolysis process is stable, record the electrolyte levels H1 and H2 in the two gas-liquid separators 5, and calculate the gas content of the electrolyte according to the following formula: C = (H1 + H2 - 2H) × S f / [(H1+H2)×S f +S0×L0)] Among them, S f is the cross-sectional area of ​​the gas-liquid separator, S0 is the area of ​​the anode and cathode plates in the gas content measurement device; Step d, calculating the resistance Rt of the gas-containing electrolyte according to the following formula: Rt=9.5C×R0 Where R0 is the actual resistance of the electrolyte without bubbles in the industrial electrolytic cell, Ω.

[0051] In step 5, the resistance voltage E1 of the electrolytic cell is calculated according to the following formula: E1=I×Rd Where I is the electrolysis current, A.

[0052] In step 6, the overvoltage E2 of the electrolytic cell is calculated according to the following formula: E 2= U-E0-E1 Where U is the operating voltage of the electrolytic cell, V; E0 is the theoretical electrolysis voltage of the electrolytic cell under working conditions, V; E1 is the resistance divided voltage of the electrolytic cell, V.

Claims

1. A method for calculating the overpotential of industrial water electrolysis for hydrogen production, characterized in that: Follow the steps below to implement it: Step 1: confirm that the electrolyzer is working normally, the hydrogen produced is qualified, and all operating indicators are within the specified range, and at the same time, exclude the phenomenon of parasitic electrolysis in the electrolyzer; Step 2, calculating the theoretical electrolysis voltage E0 of the electrolytic cell under working conditions; Step 3, measuring the working voltage of the electrolytic cell, i.e., the operating voltage U of the electrolytic cell; Step 4, calculating the equivalent resistance Rd of the electrolytic cell; Step 5, using the equivalent resistance Rd of the electrolytic cell obtained in step 4, calculate the resistance voltage E1 of the electrolytic cell: Step 6, using the theoretical electrolysis voltage E0 obtained in step 2, the operating voltage U of the electrolytic cell obtained in step 3 and the resistance partial voltage E1 obtained in step 5, calculate the overvoltage E2 of the electrolytic cell.

2. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 1, characterized in that: In step 2, the calculation formula of the theoretical electrolysis voltage E0 is: E0=1.23-0.0008×(T-25)+0.0435×logP Where: 1.23 is the theoretical electrolysis voltage of water at 1 atmosphere and 25°C, V; T is the operating temperature of water electrolysis, °C; P is the operating pressure of water electrolysis, Pa.

3. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 1, characterized in that: In step 4, the calculation formula of the equivalent resistance Rd of the electrolytic cell is: Rd=Rt+R1+R2+R3 Wherein, Rt is the resistance of the electrolyte during the electrolysis process, Ω; R1 is the plate resistance, Ω; R2 is the diaphragm resistance, Ω; R3 is the contact wire resistance, Ω.

4. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 3, characterized in that: The electrolyte resistance Rt is calculated from the gas content C, and the gas content C is obtained by simulating actual industrial production using a gas content measuring device.

5. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 4, characterized in that: The gas content measuring device comprises an electrolytic cell (1), the electrolytic cell (1) comprising an anode plate (2), a cathode plate (3) and a diaphragm (4), wherein the diaphragm (4) and the cathode plate (3) are capable of translational movement in the electrolytic cell (1); the cathode and the anode of the electrolytic cell (1) are respectively connected to a gas-liquid separator (5) via pipelines, a pressure controller (6) is arranged on the top of the gas-liquid separator (5), and the gas-liquid separator (5) is connected to a first pipeline (7) for hydrogen and oxygen to escape, and a pressure-controlled valve (8) is arranged on the first pipeline (7); and a variable power supply (9) is arranged between the positive and negative electrodes of the electrolytic cell (1).

6. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 5, characterized in that: The electrolytic cell (1) and the two gas-liquid separators (5) are also connected via a second pipeline (10). Valves (11) are provided at the connection points between the second pipeline (10) and the two gas-liquid separators (5). The second pipeline (10) is also provided with a temperature controller (12), a heat exchanger (13) and a circulation pump (14).

7. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 6, characterized in that: The specific steps of using the gas content measuring device to measure the gas content and calculate the resistance Rt of the gas-containing electrolyte are as follows: Step a, according to the plate diameter D1 of the industrial electrolytic cell actually used and the distance L1 between the anode and cathode plates, the distance L0 between the anode and cathode plates in the gas content measuring device is adjusted by translating the cathode plate (3), and at the same time adjusting the diaphragm (4) so ​​that it is located in the middle of the anode and cathode plates. The distance L0 between the anode and cathode plates is specifically adjusted according to the following formula: D1 / D0=L1 / L0 Wherein, D1 is the plate diameter of the industrial electrolytic cell, D0 is the plate diameter of the gas content measuring device, L1 is the distance between the positive and negative plates in the industrial electrolytic cell, and L0 is the distance between the positive and negative plates in the gas content measuring device; Step b, adding electrolyte to the gas content measuring device, until the electrolyte fills the entire electrolytic cell (1) and overflows into the two gas-liquid separators (5), and forms a certain liquid level height H, and the composition of the added electrolyte must be consistent with the composition of the electrolyte actually used in production; Step c, turning on the variable power supply (9) to start electrolysis, during which the current density, electrolysis temperature and operating pressure are controlled to be consistent with actual production. When the electrolysis process is stable, the electrolyte levels H1 and H2 in the two gas-liquid separators (5) are recorded, and the gas content of the electrolyte is calculated according to the following formula: <h2 style=";text-align:left;direction:ltr">C=(H1+H2-2H)×S<h2 style=";text-align:left;direction:ltr"> f <h2 style=";text-align:left;direction:ltr"> / [(H1+H2)×S<h2 style=";text-align:left;direction:ltr"> f <h2 style=";text-align:left;direction:ltr"> +S0×L0)] Among them, S f is the cross-sectional area of ​​the gas-liquid separator, S0 is the area of ​​the anode and cathode plates in the gas content measurement device; Step d, calculating the resistance Rt of the gas-containing electrolyte according to the following formula: Rt=9.5C×R0 Where R0 is the actual resistance of the electrolyte without bubbles in the industrial electrolytic cell, Ω.

8. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 1, characterized in that: In step 5, the resistance voltage E1 of the electrolytic cell is calculated according to the following formula: E1=I×Rd Where I is the electrolysis current, A.

9. The method for calculating the overpotential of industrial water electrolysis hydrogen production according to claim 1, characterized in that: In step 6, the overvoltage E2 of the electrolytic cell is calculated according to the following formula: BY 2= E0–E1 Wherein, U is the operating voltage of the electrolytic cell, V; E0 is the theoretical electrolysis voltage of the electrolytic cell under working conditions, V; E1 is the resistance divided voltage of the electrolytic cell, V.

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