Method and system for protecting gas monitor in alkaline electrolyzed water gas production process

Abstract

The invention discloses a method for protecting a gas monitor in a gas production process by alkaline electrolyzed water, which comprises the following steps: a gas-liquid mixture containing alkaline liquid prepared by alkaline electrolyzed water sequentially passes through a first gas-water separator, a second gas-water separator, a third gas-water separator, a drying agent and the gas monitor; the gas-water separator is additionally arranged in front of the drying agent and the gas monitor, so that the replacement frequency of the drying agent and the gas monitor is reduced, the equipment maintenance cost is reduced, and the safety production stability is improved.

Description

Technical Field

[0001] This application relates to the field of alkaline water electrolysis for gas production, and specifically to a protection method and system for a gas monitor during the alkaline water electrolysis process. Background Technology

[0002] Alkaline electrolysis of water is a green and environmentally friendly method for producing hydrogen and oxygen. This process uses electricity to decompose water into hydrogen and oxygen, with the specific reaction equation as follows: [2H₂O + electricity = 2H₂ + O₂]. An alkaline electrolyte, such as potassium hydroxide solution, is typically used as the electrolyte, which helps improve electrolysis efficiency and stability. The generated hydrogen and oxygen are collected from the cathode and anode of the electrolytic cell, respectively. However, the oxygen content in the produced hydrogen and oxygen (<1.5%) and the hydrogen content in the oxygen (1.5%) require accurate monitoring by two gas detectors with an explosion-proof rating greater than Exia CT4. Exceeding these control limits can lead to decreased electrolysis efficiency, electrolyte contamination, equipment corrosion, and potential fire or explosion hazards.

[0003] Currently, the industry cannot solve the problem of gases containing small amounts of potassium hydroxide liquid in alkaline water electrolysis. Gas monitoring instruments are expensive and are electronic devices. The monitoring probes inside the instruments are easily damaged and inaccurate when exposed to highly corrosive potassium hydroxide solutions. Corroded probes cannot be repaired, which greatly increases equipment maintenance costs and production operation risks. Summary of the Invention

[0004] The purpose of this application is to provide a protection method for a gas monitor during alkaline water electrolysis gasification process to overcome the shortcomings of the prior art. By adding a gas-water separator before the desiccant and the gas monitor, the replacement frequency of the desiccant and the gas monitor can be reduced, equipment maintenance costs can be lowered, and the stability of safe production can be increased.

[0005] To address the aforementioned technical problems, this application discloses a method for protecting a gas monitor during alkaline water electrolysis gasification. The gas-liquid mixture containing alkaline liquid obtained from alkaline water electrolysis sequentially passes through a first gas-liquid separator, a second gas-liquid separator, a third gas-liquid separator, a desiccant, and a gas monitor to reduce the frequency of replacing the desiccant and the gas monitor. The gas-liquid mixture entering the third gas-liquid separator is cooled.

[0006] Preferably, the alkaline liquid content in the gas-liquid mixture entering the first gas-liquid separator is 30%-70%, the alkaline liquid content in the gas-liquid mixture entering the second gas-liquid separator is 0.1%-3%, and the alkaline liquid content in the gas-liquid mixture entering the third gas-liquid separator is 0.05%~1%.

[0007] Preferably, the gas-liquid mixture entering the third gas-liquid separator is cooled by cooling water, and the temperature is reduced to 25-30°C.

[0008] Preferably, the gas monitored by the gas monitor is discharged into the atmosphere or subjected to process treatment.

[0009] On the other hand, a protection system for a gas monitor during alkaline water electrolysis gasification process is also disclosed. The protection system includes an electrolytic cell, a first gas-water separator, a second gas-water separator, a third gas-water separator, a desiccant, and a gas monitor. The third gas-water separator is disposed between the desiccant and the second gas-water separator, and the desiccant is disposed between the gas monitor and the third gas-water separator.

[0010] Preferably, the third gas-water separator includes an upper part, a middle part, and a lower part, all of which are cylindrical. The middle part includes a cooling water chamber interlayer, and the radius of the middle cylinder is larger than the radius of the cylinders in the upper and lower parts.

[0011] Preferably, a cooling water inlet is provided at the lower part of the middle section of the third gas-water separator, and a cooling water outlet is provided at the upper part of the middle section.

[0012] Preferably, the upper part of the third gas-water separator is provided with an exhaust port, which is connected to a gas monitor through a pipe.

[0013] Preferably, the lower part of the third gas-water separator is provided with a liquid inlet pipe, and a pressure control valve is provided on the liquid inlet pipe.

[0014] Preferably, the bottom of the third gas-water separator is provided with a drain pipe, and a drain valve is provided on the drain pipe.

[0015] Compared with the prior art, this application has the following advantages: 1. By setting up a third gas-liquid separator, which is placed between the desiccant and the second gas-liquid separator, the gas-liquid mixture containing 0.05%~1% alkaline liquid obtained by alkaline electrolysis of water passes through the third gas-liquid separator, the desiccant and the gas monitor in sequence, thereby reducing the replacement frequency of the desiccant and the gas monitor, reducing equipment maintenance costs and increasing the stability of safe production.

[0016] 2. The gas-liquid mixture entering the third gas-liquid separator is cooled down to 25-30℃, thereby promoting gas-liquid separation. Attached Figure Description

[0017] The advantages of this application, as described above and / or in other aspects, will become clearer from the following detailed description in conjunction with the accompanying drawings and specific embodiments.

[0018] Figure 1 This is a schematic diagram of an alkaline water electrolysis gasification process system according to an embodiment of this application.

[0019] Figure 2 This is a schematic diagram of the protection system of the gas monitor during the alkaline water electrolysis gasification process according to an embodiment of this application.

[0020] Figure 3 This is a schematic diagram of the structure of a third gas-water separator according to an embodiment of this application.

[0021] The diagram shows: 1. Electrolytic cell; 2. First gas-water separator; 3. Second gas-water separator; 4. Third gas-water separator; 41. Upper part; 42. Middle part; 43. Lower part; 44. Exhaust port; 45. Liquid inlet pipe; 46. Pressure control valve; 47. Liquid outlet pipe; 48. Liquid outlet valve; 5. Desiccant; 6. Gas monitor; 7. Oxygen / water purification device. Detailed Implementation

[0022] The features and exemplary embodiments of various aspects of this application will now be described in detail. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain this application and are not configured to limit this application. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples of this application.

[0023] Reference Figure 1-2 , Figure 1 A schematic diagram of an alkaline water electrolysis gasification process system according to an embodiment of this application is shown. Figure 2 A schematic diagram of a protection system for a gas monitor during alkaline water electrolysis gasification according to an embodiment of this application is shown. The protection system for a gas monitor during alkaline water electrolysis gasification according to an embodiment of this application includes an electrolytic cell 1, a first gas-water separator 2, a second gas-water separator 3, a third gas-water separator 4, a desiccant 5, and a gas monitor 6. The third gas-water separator 4 is disposed between the desiccant 5 and the second gas-water separator 3, and the desiccant 5 is disposed between the gas monitor 6 and the third gas-water separator 4. See also... Figure 3 The third gas-water separator 4 includes an upper part 41, a middle part 42, and a lower part 43, all of which are cylindrical. The middle part 42 includes a cooling water chamber, and the radius of the middle cylinder is larger than the radii of the upper and lower cylinders. The radius of the middle cylinder is 15±1 cm, and the radii of the upper and lower cylinders are 10±1 cm. The gas monitor 6 includes a hydrogen-oxygen monitor and an oxygen-hydrogen monitor, such as... Figure 1As shown, the gas monitor connected to the hydrogen-alkali mixture is a hydrogen-oxygen monitor, and the gas monitor connected to the oxygen-alkali mixture is an oxygen-hydrogen monitor.

[0024] In one embodiment, a cooling water inlet is located at the lower part of the middle section of the third gas-liquid separator, and a cooling water outlet is located at the upper part of the middle section. The gas-liquid mixture entering the third gas-liquid separator 4 is cooled by the cooling water, reducing its temperature to 25-30°C, thereby promoting gas-liquid separation. Specifically, 7°C cooling water at a flow rate of 2±0.5 t / h is introduced into the jacket of the third gas-liquid separator.

[0025] In one embodiment, the upper part of the third gas-liquid separator 4 is provided with an exhaust port 44, which is connected to the gas monitor 6 via a pipe. The lower part of the third gas-liquid separator 4 is provided with a liquid inlet pipe 45, and a pressure control valve 46 is installed on the liquid inlet pipe 45. The pressure at the front end of the system is typically 1.5±0.2MPa, which is reduced to 0.2-0.3MPa by the pressure control valve 46. Flow monitoring points and pressure monitoring points are also installed on the liquid inlet pipe 45, located between the pressure control valve 46 and the liquid inlet, to control the flow rate and pressure of the gas-liquid mixture.

[0026] In one embodiment, the bottom of the third gas-liquid separator 4 is provided with a drain pipe 47, and a drain valve 48 is provided on the drain pipe 47. The drain valve 48 is a DN15 ball valve, and the drain pipe 47 is a pipe with a nominal diameter of DN15.

[0027] One embodiment of this application also includes a protection method for a gas monitor during the alkaline water electrolysis gasification process. The gas-liquid mixture containing alkaline liquid obtained from alkaline water electrolysis sequentially passes through a first gas-liquid separator 2, a second gas-liquid separator 3, a third gas-liquid separator 4, a desiccant 5, and a gas monitor 6 to reduce the replacement frequency of the desiccant 5 and the gas monitor 6. The gas-liquid mixture entering the third gas-liquid separator 4 is cooled. The gas separated by the second gas-liquid separator 3 (containing very little alkaline liquid) is supplied to the user after passing through an oxygen removal / water purification device 7. At the same time, the gas is also monitored by the gas monitor to ensure it meets production requirements.

[0028] In one embodiment, the alkaline liquid content in the gas-liquid mixture entering the first gas-liquid separator 2 is 30%-70%, the alkaline liquid content in the gas-liquid mixture entering the second gas-liquid separator 3 is 0.1%-3%, and the alkaline liquid content in the gas-liquid mixture entering the third gas-liquid separator 4 is 0.05%~1%.

[0029] In one embodiment, the gas-liquid mixture entering the third gas-liquid separator 4 is cooled by cooling water, reducing its temperature to 25-30°C. Compared to a third gas-liquid separator without cooling function, the gas-liquid mixture entering the gas monitor has a temperature of 80-90°C. After adding the third gas-liquid separator with cooling function, the temperature of the gas-liquid mixture decreases, and the lower the temperature, the better the gas-liquid separation effect.

[0030] A gas-liquid mixture with an alkaline liquid content of 0.05% to 1% enters from the lower part of the third gas-liquid separator 4. The gas density increases slightly and is discharged from the upper part of the third gas-liquid separator, while the alkaline liquid density decreases significantly and is collected at the bottom of the third gas-liquid separator.

[0031] In one embodiment, the gas monitored by the gas monitor 6 is either discharged into the atmosphere or subjected to process treatment. The gas flow rate of the gas monitor 6 is 200-800 ml / min.

[0032] In one embodiment, the third gas-water separator 4 is made of 316L austenitic stainless steel.

[0033] The working method of this application will be further described below with specific embodiments. Example 1

[0034] Taking the hydrogen side as an example (the same applies to the oxygen side), the electrolyzer produces 1000 Nm³ / h of hydrogen and 500 Nm³ / h of oxygen. The hydrogen-alkali mixture produced by the alkaline electrolyzer first passes through the first gas-liquid separator 2. The alkaline solution separated by the first gas-liquid separator 2 flows through pipelines to the alkaline electrolyzer. The hydrogen after separation by the first gas-liquid separator contains 0.1-3% alkaline liquid. The hydrogen containing 0.1-3% alkaline liquid continues to flow into the second gas-water separator 3 for secondary separation. The bottom of the second gas-water separator 3 is equipped with a drain port. A large portion of the hydrogen separated by the second gas-water separator (containing a very small amount of alkaline liquid, with an alkaline liquid content of 0.05%~1%) passes through the oxygen removal / water purification device 7 to supply gas to the user. At the same time, a small amount of gas also passes through the third gas-water separator 4 and the desiccant 5. Finally, it is monitored by a hydrogen-oxygen gas monitor to determine whether it meets the production requirements. The third gas-liquid separator 4 is equipped with a cooling water jacket. Cooling water is introduced into the jacket of the third gas-liquid separator 4 to cool the gas-liquid mixture. The gas-liquid mixture enters from the bottom of the third gas-liquid separator, where the gas density is lower and rises, exiting from the top of the separator. The alkaline liquid density decreases significantly and is collected at the bottom of the third gas-liquid separator. The gas without alkaline solution is then introduced from the top of the third gas-liquid separator to the hydrogen-oxygen gas monitor. This reduces the frequency of replacing the gas desiccant and gas monitor, lowers equipment maintenance costs, and increases the stability of safe production.

[0035] This application provides a protection method and system for a gas monitor during alkaline water electrolysis gasification process. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for protecting a gas monitor during alkaline water electrolysis gasification process, characterized in that, The gas-liquid mixture containing alkaline liquid obtained by alkaline electrolysis of water passes sequentially through a first gas-liquid separator, a second gas-liquid separator, a third gas-liquid separator, a desiccant, and a gas monitor to reduce the replacement frequency of the desiccant and the gas monitor. The gas-liquid mixture entering the third gas-liquid separator is cooled.

2. The protection method according to claim 1, characterized in that, The alkaline liquid content in the gas-liquid mixture entering the first gas-liquid separator is 30%-70%, the alkaline liquid content in the gas-liquid mixture entering the second gas-liquid separator is 0.1%-3%, and the alkaline liquid content in the gas-liquid mixture entering the third gas-liquid separator is 0.05%~1%.

3. The protection method according to claim 1, characterized in that, The gas-liquid mixture entering the third gas-liquid separator is cooled by cooling water, and its temperature drops to 25-30℃.

4. The protection method according to claim 1, characterized in that, The gas monitored by the gas monitor is either released into the atmosphere or subjected to process treatment.

5. A protection system for a gas monitor during alkaline water electrolysis gasification process, characterized in that, The protection system includes an electrolytic cell, a first gas-water separator, a second gas-water separator, a third gas-water separator, a desiccant, and a gas monitor. The third gas-water separator is disposed between the desiccant and the second gas-water separator, and the desiccant is disposed between the gas monitor and the third gas-water separator.

6. The protection system according to claim 5, characterized in that, The third gas-water separator includes an upper part, a middle part, and a lower part, all of which are cylindrical. The middle part includes a cooling water chamber interlayer, and the radius of the middle cylinder is larger than the radius of the cylinders in the upper and lower parts.

7. The protection system according to claim 5, characterized in that, The third gas-water separator has a cooling water inlet located at the lower part of its middle section and a cooling water outlet located at the upper part of its middle section.

8. The protection system according to claim 5, characterized in that, The upper part of the third gas-water separator is provided with an exhaust port, which is connected to a gas monitor through a pipe.

9. The protection system according to claim 5, characterized in that, The lower part of the third gas-liquid separator is provided with a liquid inlet pipe, and a pressure control valve is installed on the liquid inlet pipe.

10. The protection system according to claim 5, characterized in that, The bottom of the third gas-water separator is provided with a drain pipe, and a drain valve is installed on the drain pipe.

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