Method for improving hydrogen production efficiency of alkaline electrolyzed water by using electrolyte concentration difference

Abstract

The invention discloses a method for improving alkaline water electrolysis hydrogen production efficiency by using electrolyte concentration difference, and belongs to the technical field of water electrolysis hydrogen production. The method comprises the following steps: adding KOH electrolyte with the concentration of 30wt% into the cathode region on one side of the diaphragm, and adding KOH electrolyte with the concentration of 35wt% into the anode region on the other side of the diaphragm; and electrifying the electrolytic bath, controlling the temperature to be 80-90 DEG C, and carrying out electrolytic reaction on the water under the action of the electric field. The hydrogen production efficiency of alkaline electrolyzed water is improved by utilizing the electrolyte concentration difference, the hydrogen production efficiency and the hydrogen purity can be improved, the energy consumption and the equipment cost can be reduced, the reliability and the durability of the system are improved, meanwhile, the environmental influence is reduced, and a positive role is played in promoting the production and the application of green hydrogen.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by water electrolysis, and more particularly to a method for improving the efficiency of hydrogen production by alkaline water electrolysis by utilizing electrolyte concentration difference. Background Art

[0002] At present, alkaline water electrolysis hydrogen production technology is widely used in industrial and laboratory-scale hydrogen production because of its simple operation and economic and environmental protection. The core of this technology is to use an alkaline environment to accelerate the electrolysis of water molecules to produce hydrogen and oxygen. Although alkaline water electrolysis hydrogen production technology has established its position in the field of hydrogen energy, it still faces challenges in improving energy efficiency and reducing energy consumption. In particular, the control of electrolyte concentration has a significant impact on hydrogen production efficiency. The ideal electrolyte concentration can not only speed up the transfer rate of electrons, but also effectively reduce energy loss, thereby increasing hydrogen production. However, past research has often focused more on the development of catalyst materials, while ignoring the important role of electrolyte concentration in electrolysis efficiency. This emphasis has led to the electrolysis system failing to fully realize its hydrogen production potential.

[0003] Therefore, how to develop a method for utilizing electrolyte concentration difference to improve the efficiency of hydrogen production by alkaline water electrolysis is an urgent problem that technicians in this field need to solve. Summary of the invention

[0004] In view of this, the present invention provides a method for improving the efficiency of hydrogen production by alkaline water electrolysis by utilizing electrolyte concentration difference.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for improving the efficiency of hydrogen production by alkaline water electrolysis by utilizing electrolyte concentration difference comprises the following steps:

[0007] (1) adding a KOH electrolyte with a concentration of 30 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 35 wt% to the anode region on the other side of the diaphragm;

[0008] (2) The electrolytic cell is powered on, and the temperature of the electrolytic cell and the electrolyte is controlled at 80-90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area;

[0009] The electrolytic cell comprises: a cathode end shell plate, a cathode electrode, a first sealing ring, a diaphragm, a second sealing ring, an anode electrode and an anode end shell plate, wherein the cathode end shell plate, the cathode electrode, the first sealing ring, the diaphragm, the second sealing ring, the anode electrode and the anode end shell plate are assembled in sequence and fastened together with a screw and a nut;

[0010] The cathode end shell plate and the anode end shell plate are provided with uniformly distributed mastoid structures;

[0011] The cathode end shell plate is provided with a first liquid inlet and a first gas-liquid outlet, and the anode end shell plate is provided with a second liquid inlet and a second gas-liquid outlet.

[0012] Further, in step (2), the current density of the electrolytic cell is 5000A / m 2 , working pressure is 0.8MPa,

[0013] Furthermore, the above-mentioned diaphragm is a PPS diaphragm.

[0014] Furthermore, the sealing ring is made of fluororubber.

[0015] Beneficial effects of the present invention: In order to improve the efficiency of the alkaline water electrolysis hydrogen production process, the present invention achieves this by cleverly utilizing the key factor of the electrolyte concentration difference. In the traditional alkaline water electrolysis hydrogen production process, a certain concentration of KOH is usually used as an electrolyte to promote the electrolysis reaction of water to produce hydrogen and oxygen. However, the efficiency of this process is often affected by multiple factors such as electrolyte concentration, temperature, and current density. The present invention optimizes the entire hydrogen production process by finely controlling these parameters, especially the electrolyte concentration difference.

[0016] The method of improving the efficiency of hydrogen production by alkaline water electrolysis by utilizing electrolyte concentration difference is mainly based on the principle of concentration cell. A concentration cell is a device that generates electric potential by utilizing the concentration difference of a substance. In the context of hydrogen production by alkaline water electrolysis, a potential difference can be generated by maintaining different electrolyte concentrations in the two half cells of the electrolytic cell, thereby promoting the electrolysis reaction of water and improving the efficiency of hydrogen production.

[0017] In the process of producing hydrogen by alkaline water electrolysis, oxygen evolution reaction (OER) occurs at the anode and hydrogen evolution reaction (HER) occurs at the cathode. The electrochemical performance of these two half reactions determines the efficiency of the entire electrolysis process. By maintaining different electrolyte concentrations at the anode and cathode, the kinetics of these two half reactions can be changed, reducing the overpotential during the reaction, thereby improving the overall electrolysis efficiency.

[0018] Through this systematic concentration adjustment, the present invention can not only reveal the specific effects of different concentrations on electrolysis efficiency, but also find the optimal anode and cathode concentration ratio, thereby maximizing the hydrogen production efficiency of the entire system. The innovation of this method is that the efficiency is improved by finely controlling the concentration difference of the electrolyte, rather than simply increasing the electrolysis voltage or the operating temperature. Such a technical solution can not only improve the efficiency of hydrogen production, but also reduce energy consumption and operating costs, which is of great significance for promoting the sustainable development of green energy.

[0019] Compared with the prior art, the method of the present invention for improving the efficiency of hydrogen production by alkaline water electrolysis by utilizing the electrolyte concentration difference has the following advantages and positive effects:

[0020] 1. Improve electrolysis efficiency: By optimizing the concentration of the electrolyte, the energy loss in the electrolysis process can be reduced and the electrolysis efficiency can be improved. This is because the optimization of the electrolyte concentration can reduce the polarization phenomenon in the electrolysis process, thereby reducing the overpotential and improving the energy conversion efficiency of the electrolytic cell.

[0021] 2. Reduce energy consumption: Increasing the electrolyte concentration can reduce energy consumption during the electrolysis process, because a lower overpotential means that at the same current density, the electrolytic cell requires a lower voltage, thereby reducing the consumption of electrical energy.

[0022] 3. Improve hydrogen purity: Optimizing the electrolyte concentration helps to improve the purity of hydrogen, because the hydrogen and oxygen produced during the electrolysis process can be separated from the electrolyte more effectively, reducing cross-contamination of the gas.

[0023] 4. Reduce equipment costs: By increasing the electrolyte concentration, the demand for expensive materials can be reduced. For example, in alkaline electrolyzers, the cost of electrodes and membranes accounts for a high proportion. By optimizing the electrolyte concentration, the loss of these components can be reduced, thereby reducing equipment costs.

[0024] 5. Improve system reliability and durability: Optimizing electrolyte concentration helps improve the reliability and durability of the electrolyzer, because lower overpotential can reduce thermal stress during the electrolysis process, thereby extending the service life of the equipment.

[0025] 6. Adapting to the volatility of renewable energy: The method of increasing the electrolyte concentration difference can make the electrolyzer better adapt to the volatility of renewable energy, because the electrolyzer can operate stably at different current densities, which is especially important for combination with intermittent energy sources such as wind and solar energy.

[0026] 7. Reduce environmental impact: By increasing the electrolyte concentration, the problem of alkali leakage and pollution during the electrolysis process can be reduced, because the optimized concentration can reduce the consumption of electrolyte, thereby reducing the potential impact on the environment.

[0027] 8. Promote green hydrogen production: Improving the efficiency of hydrogen production by alkaline water electrolysis will help increase the output of "green hydrogen" from renewable energy, which is of great significance for reducing carbon dioxide emissions and achieving sustainable development.

[0028] In summary, the method of the present invention for improving the efficiency of hydrogen production by alkaline water electrolysis by utilizing the electrolyte concentration difference can not only improve the hydrogen production efficiency and hydrogen purity, but also reduce energy consumption and equipment costs, improve the reliability and durability of the system, and reduce environmental impact, which plays a positive role in promoting the production and application of green hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is an exploded view of the electrolytic cell assembly of the present invention.

[0030] Figure 2 It is a schematic diagram of the overall structure of the electrolytic cell of the present invention.

[0031] Figure 3 It is the VA curve of the electrolytic cell with different electrolyte concentrations at the anode and cathode.

[0032] Among them, 1-nut, 2-first gas-liquid outlet, 3-first liquid inlet, 4-cathode end shell plate, 5-cathode electrode, 6-first sealing ring, 7-PPS diaphragm, 8-second sealing ring, 9-anode electrode, 10-second gas-liquid outlet, 11-second liquid inlet, 12-anode end shell plate, 13-screw, 14-nipple structure. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figure 1-2 As shown, the electrolytic cell of the present invention comprises: a cathode end shell plate 4, a cathode electrode 5, a first sealing ring 6, a PPS diaphragm 7, a second sealing ring 8, an anode electrode 9 and an anode end shell plate 12, wherein the cathode end shell plate 4, the cathode electrode 5, the first sealing ring 6, the PPS diaphragm 7, the second sealing ring 8, the anode electrode 9 and the anode end shell plate 12 are assembled in sequence and fastened together with a screw 13 and a nut 1; the sealing ring is made of fluororubber; uniformly distributed nipple structures 14 are provided on the cathode end shell plate 4 and the anode end shell plate 12; three first liquid inlets 3 and three first gas-liquid outlets 2 are provided on the cathode end shell plate 4, and three second liquid inlets 11 and three second gas-liquid outlets 10 are provided on the anode end shell plate 12.

[0035] Example 1

[0036] The method for improving the efficiency of hydrogen production by alkaline water electrolysis by using the electrolytic cell of the present invention and utilizing the electrolyte concentration difference comprises the following steps:

[0037] (1) adding a KOH electrolyte with a concentration of 30 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 35 wt% to the anode region on the other side of the diaphragm;

[0038] (2) The electrolytic cell is powered on, and the current density of the electrolytic cell is 5000A / m2 The working pressure is 0.8MPa, and the temperature of the electrolytic cell and the electrolyte is controlled at 90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area.

[0039] Comparative Example 1

[0040] The method for improving the efficiency of hydrogen production by alkaline water electrolysis by using the electrolytic cell of the present invention and utilizing the electrolyte concentration difference comprises the following steps:

[0041] (1) adding a KOH electrolyte with a concentration of 25 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 25 wt% to the anode region on the other side of the diaphragm;

[0042] (2) The electrolytic cell is powered on, and the current density of the electrolytic cell is 5000A / m 2 The working pressure is 0.8MPa, and the temperature of the electrolytic cell and the electrolyte is controlled at 90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area.

[0043] Comparative Example 2

[0044] The method for improving the efficiency of hydrogen production by alkaline water electrolysis by using the electrolytic cell of the present invention and utilizing the electrolyte concentration difference comprises the following steps:

[0045] (1) adding a KOH electrolyte with a concentration of 25 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 30 wt% to the anode region on the other side of the diaphragm;

[0046] (2) The electrolytic cell is powered on, and the current density of the electrolytic cell is 5000A / m 2 The working pressure is 0.8MPa, and the temperature of the electrolytic cell and the electrolyte is controlled at 90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area.

[0047] Comparative Example 3

[0048] The method for improving the efficiency of hydrogen production by alkaline water electrolysis by using the electrolytic cell of the present invention and utilizing the electrolyte concentration difference comprises the following steps:

[0049] (1) adding a KOH electrolyte with a concentration of 25 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 35 wt% to the anode region on the other side of the diaphragm;

[0050] (2) The electrolytic cell is powered on, and the current density of the electrolytic cell is 5000A / m 2The working pressure is 0.8MPa, and the temperature of the electrolytic cell and the electrolyte is controlled at 90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area.

[0051] Comparative Example 4

[0052] The method for improving the efficiency of hydrogen production by alkaline water electrolysis by using the electrolytic cell of the present invention and utilizing the electrolyte concentration difference comprises the following steps:

[0053] (1) adding a KOH electrolyte with a concentration of 30 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 30 wt% to the anode region on the other side of the diaphragm;

[0054] (2) The electrolytic cell is powered on, and the current density of the electrolytic cell is 5000A / m 2 The working pressure is 0.8MPa, and the temperature of the electrolytic cell and the electrolyte is controlled at 90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area.

[0055] Comparative Example 5

[0056] The method for improving the efficiency of hydrogen production by alkaline water electrolysis by using the electrolytic cell of the present invention and utilizing the electrolyte concentration difference comprises the following steps:

[0057] (1) adding a KOH electrolyte with a concentration of 35 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 35 wt% to the anode region on the other side of the diaphragm;

[0058] (2) The electrolytic cell is powered on, and the current density of the electrolytic cell is 5000A / m 2 The working pressure is 0.8MPa, and the temperature of the electrolytic cell and the electrolyte is controlled at 90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area.

[0059] like Figure 3 As shown, the figure shows the voltage-current data of different electrolyte concentrations of cathode-anode, including cathode 25wt%-anode 25wt%, cathode 25wt%-anode 30wt%, cathode 25wt%-anode 35wt%, cathode 30wt%-anode 30wt%, cathode 30wt%-anode 35wt% and cathode 35wt%-anode 35wt%. Under these different proportions, the voltage presents different values. Among them, when the cathode is 30wt% and the anode is 35wt%, the corresponding voltage always presents the minimum value under different currents, indicating that the electrolysis efficiency at this concentration is the highest.

[0060] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving the efficiency of hydrogen production by alkaline water electrolysis using electrolyte concentration difference, characterized in that: The steps include: (1) adding a KOH electrolyte with a concentration of 30 wt% to the cathode region on one side of the diaphragm, and adding a KOH electrolyte with a concentration of 35 wt% to the anode region on the other side of the diaphragm; (2) The electrolytic cell is powered on, and the temperature of the electrolytic cell and the electrolyte is controlled at 80-90°C. In the electrolytic cell, water undergoes an electrolysis reaction under the action of the electric field, and oxygen is obtained in the anode area and hydrogen is obtained in the cathode area; The electrolytic cell comprises: a cathode end shell plate, a cathode electrode, a first sealing ring, a diaphragm, a second sealing ring, an anode electrode and an anode end shell plate, wherein the cathode end shell plate, the cathode electrode, the first sealing ring, the diaphragm, the second sealing ring, the anode electrode and the anode end shell plate are assembled in sequence and fastened together with a screw and a nut; The cathode end shell plate and the anode end shell plate are provided with uniformly distributed nipple structures; The cathode end shell plate is provided with a first liquid inlet and a first gas-liquid outlet, and the anode end shell plate is provided with a second liquid inlet and a second gas-liquid outlet.

2. A method for improving the efficiency of hydrogen production by alkaline water electrolysis using electrolyte concentration difference according to claim 1, characterized in that: In step (2), the current density of the electrolytic cell is 5000A / m 2 , working pressure is 0.8MPa.

3. A method for improving the efficiency of hydrogen production by alkaline water electrolysis using electrolyte concentration difference according to claim 1, characterized in that: The diaphragm is a PPS diaphragm.

4. A method for improving the efficiency of hydrogen production by alkaline water electrolysis using electrolyte concentration difference according to claim 1, characterized in that: The sealing ring is made of fluororubber.

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