Automatic pressure relief protection device for electrolytic cell shutdown
By designing an automatic pressure relief protection device for electrolytic cell shutdown, the problem of unsafe and unstable pressure relief during the electrolytic cell shutdown process was solved, achieving a safe and stable pressure relief process and improving production safety and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XINJIANG ZHONGTAI CHEM FUKANG ENERGY CO LTD
- Filing Date
- 2025-05-27
- Publication Date
- 2026-06-02
AI Technical Summary
Existing electrolytic cells have unsafe and unstable depressurization processes during shutdown, which can easily lead to explosions and damage to the ion exchange membrane, affecting production efficiency and product quality.
An automatic pressure relief protection device for electrolytic cell shutdown was designed, including components such as a hydrogen single-cell manifold, a chlorine single-cell manifold, a suspension separator, a flame arrester, a waste chlorine absorption device, a residual liquid storage tank, and a water seal tank. Through the reasonable connection of pipelines and valves and the control of the controller, a safe and stable pressure relief process is achieved.
It improves the safety and stability of electrolytic cell shutdown and pressure relief, reduces the risk of explosion, protects the ion exchange membrane, and improves production safety and efficiency.
Smart Images
Figure CN224313678U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electrolytic cell pressure relief protection technology, and is an automatic pressure relief protection device for electrolytic cell shutdown. Background Technology
[0002] Electrolytic cells play a crucial role in chlor-alkali chemical industry and other industries involving electrolysis processes. They are the core equipment of electrolysis units. Electrolytic cells (especially chlor-alkali electrolytic cells) simultaneously produce hydrogen (H2) and chlorine (Cl2) by electrolyzing brine (NaCl solution). The overall reaction equation is: 2NaCl + 2H2O → 2NaOH + H2↑ + Cl2↑. The anode (oxidation reaction) reaction equation is: 2Cl... − →Cl2↑+2e − Chloride ions are oxidized to produce chlorine gas (Cl2), which is an important chemical raw material (such as in the production of PVC and disinfectants). The cathode (reduction reaction) reaction formula is: 2H2O + 2e − →H₂↑+2OH − Water molecules are reduced to produce hydrogen gas (H2) and hydroxide ions (OH-). ⁻ ), hydroxide ions (OH-) ⁻ It then combines with sodium ions to form sodium hydroxide (NaOH).
[0003] The hydrogen gas produced on the cathode side of the electrolyzer requires strict pressure control, mainly for the following reasons:
[0004] (1) Explosion-proof safety
[0005] The volume concentration range of hydrogen explosion limits is 4% to 75%. If hydrogen is mixed with air or chlorine, it is very easy to cause an explosion.
[0006] (2) Protecting the ion exchange membrane
[0007] Excessive pressure difference between the cathode and anode of an electrolyzer can cause mechanical damage to the ion exchange membrane (such as perforation). If the gases on both sides of the ion exchange membrane are cross-contaminated, hydrogen mixed with chlorine will form an explosive mixture. It is usually required that the cathode pressure be slightly higher than that of the anode (about 0.1 bar to 0.3 bar) to prevent chlorine from back-permeating from the anode.
[0008] (3) System stability
[0009] Pressure fluctuations can affect electrolysis efficiency. For example, the hydrogen evolution rate is directly related to the current density, and a stable back pressure must be maintained.
[0010] In summary, the electrolysis process in electrolytic cells involves flammable, explosive, and toxic production environments. In particular, the start-up and shutdown procedures of electrolytic cells have a significant impact on the electrolytic cells and their ion-exchange membranes. Their operation involves the safety and stability of the electrolysis equipment and directly affects production efficiency, product quality, and economic benefits. Ensuring the safe and stable shutdown and depressurization of electrolytic cells has become an urgent technical challenge for chlor-alkali chemical enterprises. Summary of the Invention
[0011] This utility model provides an automatic pressure relief protection device for electrolytic cell shutdown, which overcomes the shortcomings of the prior art and can effectively solve the problem of low safety and stability in the existing electrolytic cell shutdown pressure relief process.
[0012] The technical solution of this utility model is achieved through the following measures: an automatic pressure relief protection device for electrolytic cell shutdown, comprising a hydrogen single-cell manifold, a chlorine single-cell manifold, a first suspension separator, a second suspension separator, a flame arrester, a waste chlorine absorption device, a residual liquid storage tank, and a water seal tank. A first hydrogen pipeline is fixedly connected between the front end of the hydrogen single-cell manifold and the middle inlet of the first suspension separator. A second hydrogen pipeline is fixedly connected to the top outlet of the first suspension separator. A first vent pipeline is fixedly connected to the second hydrogen pipeline. A flame arrester is fixedly installed on the venting pipeline. A first chlorine pipeline is fixedly connected between the front end of the chlorine single-tank manifold and the middle inlet of the second suspension separator. A second chlorine pipeline is fixedly connected to the top outlet of the second suspension separator. A waste chlorine pressure relief pipeline is fixedly connected between the second chlorine pipeline and the inlet of the waste chlorine absorption device. A hydrogen pressure relief pipeline is fixedly connected between the tail end of the hydrogen single-tank manifold and the top inlet of the water seal tank. A first residual liquid pipeline is connected to the tail end of the chlorine single-tank manifold. The outlet of the first residual liquid pipeline corresponds to the top inlet of the residual liquid storage tank.
[0013] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution:
[0014] The top outlet of the aforementioned waste chlorine absorption device is fixedly connected to a second venting pipeline, and the bottom outlet of the waste chlorine absorption device is fixedly connected to a second residual liquid pipeline.
[0015] A nitrogen pressurization pipeline is fixedly connected to the aforementioned hydrogen depressurization pipeline.
[0016] The upper outlet of the water seal tank, above the water level, is fixedly connected to a third venting pipeline.
[0017] The water seal tank has a fixed water supply pipeline connected to the upper inlet of the water seal tank above the water level.
[0018] A drainage pipeline is fixedly connected between the lower outlet of the water seal tank (where the water level is below the surface) and the top inlet of the residual liquid storage tank.
[0019] The bottom outlet of the first suspension separator is fixedly connected to a first drain line, and the bottom outlet of the second suspension separator is fixedly connected to a second drain line.
[0020] Pressure gauges are fixedly installed on the aforementioned hydrogen single-tank manifold, chlorine single-tank manifold, first hydrogen pipeline, and first chlorine pipeline.
[0021] A first regulating valve is fixedly installed on the aforementioned waste chlorine pressure relief pipeline; a second regulating valve is fixedly installed on the first vent pipeline between the second hydrogen pipeline and the flame arrester; a first shut-off valve is fixedly installed on the first residual liquid pipeline; a second shut-off valve is fixedly installed on the hydrogen pressure relief pipeline between the tail end of the hydrogen single tank manifold and the nitrogen pressurization pipeline; and a third shut-off valve is fixedly installed on the nitrogen pressurization pipeline.
[0022] The aforementioned device also includes a controller, and the pressure gauge, first regulating valve, second regulating valve, first shut-off valve, second shut-off valve, and third shut-off valve are all electrically connected to the controller.
[0023] This utility model has a reasonable and compact structure and is easy to use. It can effectively improve the stability and safety of the electrolytic cell pressure relief and improve the safety production rate of enterprises. Attached Figure Description
[0024] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.
[0025] Appendix Figure 1 The codes in the diagram are as follows: 1 for hydrogen single-tank manifold, 2 for chlorine single-tank manifold, 3 for first suspension separator, 4 for second suspension separator, 5 for flame arrester, 6 for waste chlorine absorption device, 7 for residual liquid storage tank, 8 for water seal tank, 9 for first hydrogen pipeline, 10 for second hydrogen pipeline, 11 for first vent pipeline, 12 for first chlorine pipeline, 13 for second chlorine pipeline, 14 for waste chlorine pressure relief pipeline, 15 for hydrogen pressure relief pipeline, 16 for first residual liquid pipeline, 17 for second vent pipeline, 18 for second residual liquid pipeline, 19 for nitrogen pressurization pipeline, 20 for... 21 is the third vent line, 22 is the water supply line, 23 is the first drain line, 24 is the second drain line, 25 is the pressure gauge, 26 is the first regulating valve, 27 is the second regulating valve, 28 is the first shut-off valve, 29 is the second shut-off valve, 30 is the third shut-off valve, 31 is the electrolytic cell, 32 is the hydrogen gas collecting branch pipe, 33 is the chlorine gas collecting branch pipe, 34 is the first liquid supply manifold, 35 is the second liquid supply manifold, 36 is the first liquid inlet branch pipe, 37 is the second liquid inlet branch pipe, 38 is the brine liquid supply line, and 39 is the sodium hydroxide liquid supply line. Detailed Implementation
[0026] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.
[0027] Unless otherwise specified, all equipment and devices used in this invention are existing, publicly known, and commonly used equipment and devices in the field.
[0028] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.
[0029] The present invention will be further described below with reference to the embodiments and accompanying drawings:
[0030] Example 1: As shown in the attached document Figure 1 As shown, the automatic pressure relief protection device for electrolytic cell shutdown includes a hydrogen single-tank manifold 1, a chlorine single-tank manifold 2, a first suspension separator 3, a second suspension separator 4, a flame arrester 5, a waste chlorine absorption device 6, a residual liquid storage tank 7, and a water seal tank 8. A first hydrogen pipeline 9 is fixedly connected between the front end of the hydrogen single-tank manifold 1 and the middle inlet of the first suspension separator 3. A second hydrogen pipeline 10 is fixedly connected to the top outlet of the first suspension separator 3. A first vent pipeline 11 is fixedly connected to the second hydrogen pipeline 10, and a flame arrester is fixedly installed on the first vent pipeline 11. The first chlorine pipeline 12 is fixedly connected between the front end of the chlorine single-tank manifold 2 and the middle inlet of the second suspension separator 4. The second chlorine pipeline 13 is fixedly connected to the top outlet of the second suspension separator 4. The waste chlorine pressure relief pipeline 14 is fixedly connected between the second chlorine pipeline 13 and the inlet of the waste chlorine absorption device 6. The hydrogen pressure relief pipeline 15 is fixedly connected between the tail end of the hydrogen single-tank manifold 1 and the top inlet of the water seal tank 8. The tail end of the chlorine single-tank manifold 2 is connected to the first residual liquid pipeline 16. The outlet of the first residual liquid pipeline 16 corresponds to the top inlet of the residual liquid storage tank 7.
[0031] As needed, such as Figure 1 As shown, a hydrogen single-cell manifold 1 and a chlorine single-cell manifold 2, parallel to the electrolytic cell 31, are arranged at intervals above the electrolytic cell 31. Several hydrogen gas collecting branch pipes 32 are fixedly connected to the cathode port of the electrolytic cell 31 at intervals on the left and right. Several chlorine gas collecting branch pipes 33 are fixedly connected to the anode port of the electrolytic cell 31 at intervals on the left and right. A first replenishment manifold 34 and a second replenishment manifold 35, parallel to the electrolytic cell 31, are arranged at intervals below the electrolytic cell 31. Several first inlet branch pipes 36 are fixedly connected to the bottom of the electrolytic cell 31 at intervals on the left and right. Several second inlet branch pipes 37 are fixedly connected to the bottom of the electrolytic cell 31 at intervals on the left and right. A brine replenishment pipeline 38 is fixedly connected to the left end inlet of the second replenishment manifold 35. A sodium hydroxide replenishment pipeline 39 is fixedly connected to the left end inlet of the first drain pipeline 23 and the left end inlet of the first replenishment manifold 34.
[0032] Hydrogen generated at the cathode of electrolytic cell 31 is collected into hydrogen single-cell manifold 1 via hydrogen gas collecting branch pipe 32. The hydrogen in hydrogen single-cell manifold 1 enters the first suspension separator 3 via the first hydrogen pipeline 9 for gas-liquid separation to obtain hydrogen and sodium hydroxide solution. The hydrogen is transported to each hydrogen-using device via the second hydrogen pipeline 10. The sodium hydroxide solution enters the first replenishment manifold 34 via the first drain pipeline 23 and the sodium hydroxide replenishment pipeline 39. The sodium hydroxide solution in the first replenishment manifold 34 replenishes the electrolytic cell 31 via the first inlet branch pipe 36.
[0033] The chlorine gas generated at the anode of the electrolytic cell 31 is collected by the chlorine gas collecting branch pipe 33 to the chlorine gas single tank manifold 2. The chlorine gas in the chlorine gas single tank manifold 2 enters the second suspension separator 4 through the first chlorine gas pipeline 12 for gas-liquid separation to obtain chlorine gas and brine. The chlorine gas is transported to each chlorine gas-using device through the second chlorine gas pipeline 13, and the brine enters the downstream process system through the second drain pipeline 24.
[0034] When the electrolytic cell 31 needs to be shut down (production operation is stopped), this utility model can be used for pressure relief protection, which can improve the safety and stability of the electrolytic cell 31 during shutdown pressure relief.
[0035] The above-mentioned automatic pressure relief protection device for electrolytic cell shutdown can be further optimized and / or improved according to actual needs:
[0036] Example 2: Its difference from Example 1 is as follows: (See attached) Figure 1 As shown, the top outlet of the waste chlorine absorption device 6 is fixedly connected to a second venting pipeline 17, and the bottom outlet of the waste chlorine absorption device 6 is fixedly connected to a second residual liquid pipeline 18.
[0037] As needed, the waste chlorine absorption device 6 includes a chlorine absorption tower and a circulating fan. The circulating fan is a vacuum pump and is fixedly installed on the exhaust pipe at the top of the chlorine absorption tower. The chlorine absorption tower contains alkaline solution. The circulating fan can adsorb the chlorine in this utility model into the chlorine absorption tower for alkaline absorption at a certain adsorption pressure, and then release the waste gas. The residual liquid after absorption enters the downstream process system through the second residual liquid pipeline 18.
[0038] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 As shown, a nitrogen pressurization line 19 is fixedly connected to the hydrogen depressurization line 15.
[0039] Example 4: Its difference from Examples 1 to 3 is as follows: (See attached) Figure 1 As shown, the upper outlet of the water seal tank 8, which is located above the water level, is fixedly connected to a third venting pipeline 20.
[0040] Example 5: It differs from Examples 1 to 4 in that, as shown in the appendix... Figure 1 As shown, the upper inlet of the water seal tank 8, above the water level, is fixedly connected to a water supply pipeline 21.
[0041] Example 6: Its difference from Examples 1 to 5 is as follows: (See attached) Figure 1 As shown, a drain pipe 22 is fixedly connected between the lower outlet of the water seal tank 8 (below the water level) and the top inlet of the residual liquid storage tank 7.
[0042] As needed, the hydrogen in the hydrogen single-tank manifold 1 can be slowly depressurized and vented through the water seal tank 8.
[0043] Example 7: Its difference from Examples 1 to 6 is as follows: (See attached) Figure 1 As shown, the bottom outlet of the first suspension separator 3 is fixedly connected to the first drain line 23, and the bottom outlet of the second suspension separator 4 is fixedly connected to the second drain line 24.
[0044] Example 8: It differs from Examples 1 to 7 in that: as shown in the appendix Figure 1 As shown, pressure gauges 25 are fixedly installed on the hydrogen single-tank manifold 1, the chlorine single-tank manifold 2, the first hydrogen pipeline 9, and the first chlorine pipeline 12.
[0045] Example 9: It differs from Examples 1 to 8 in that: as shown in the appendix Figure 1 As shown, a first regulating valve 26 is fixedly installed on the waste chlorine pressure relief pipeline 14; a second regulating valve 27 is fixedly installed on the first vent pipeline 11 between the second hydrogen pipeline 10 and the flame arrester 5; a first shut-off valve 28 is fixedly installed on the first residual liquid pipeline 16; a second shut-off valve 29 is fixedly installed on the hydrogen pressure relief pipeline 15 between the tail end of the hydrogen single tank manifold 1 and the nitrogen pressurization pipeline 19; and a third shut-off valve 30 is fixedly installed on the nitrogen pressurization pipeline 19.
[0046] Example 10: It differs from Examples 1 to 9 in that, as shown in the appendix... Figure 1 As shown, the device also includes a controller, and the pressure gauge 25, the first regulating valve 26, the second regulating valve 27, the first shut-off valve 28, the second shut-off valve 29, and the third shut-off valve 30 are all connected to the controller.
[0047] As required and in accordance with the explosion-proof requirements of chemical plants, especially given the wide range of hydrogen explosion limits (4% to 75%), the first regulating valve 26, the second regulating valve 27, the first shut-off valve 28, the second shut-off valve 29, and the third shut-off valve 30 are all pneumatic control valves.
[0048] Depending on the needs, the pipelines and equipment of the automatic pressure relief protection device for electrolytic cell shutdown can also be equipped with conventional valves, thermometers, and pressure gauges known and commonly used in the field, according to production requirements. The controller is a PLC controller, and the PLC controller model can be GL-FJ-XL01. The Xinhua XDPS6000 DCS control system is installed in the PLC controller.
[0049] This utility model uses a combination of controller and control system to regulate the timing of valve opening and closing, which saves manpower and improves the safety and stability of the depressurization process of electrolytic cell 31. At the same time, it meets the review standards of "Safety Production Standardization of Hazardous Chemical Enterprises" and responds to the safety principle of "minimizing on-site personnel when performing operations in high-risk areas".
[0050] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.
[0051] The usage process of the above embodiments includes:
[0052] The depressurization process of the chlorine single-tank manifold 2 is as follows: First, the first regulating valve 26 automatically opens to full opening at a rate of 2% per second. The waste chlorine absorption device 6 adsorbs the residual chlorine in each piece of equipment of this utility model. The chlorine (containing sodium chloride solution) in the chlorine single-tank manifold 2 enters the second suspension separator 4 through the first chlorine pipeline 12 for gas-liquid separation. Then, the chlorine after gas-liquid separation enters the waste chlorine absorption device 6 through the second chlorine pipeline 13 and the waste chlorine depressurization pipeline 14 for chlorine absorption treatment, resulting in absorption residue and waste gas. The waste gas is vented through the second vent pipeline 17, and the residue is transported to the downstream process system through the second residue pipeline 18. Finally, the waste chlorine absorption device 6 stops adsorbing the chlorine single-tank manifold 2 when it reaches a negative pressure state (negative 0.5 kPa). At this time, the first shut-off valve 28 is automatically opened, and the residual liquid (dilute sodium chloride solution) in the chlorine single-tank manifold 2 is discharged into the residue storage tank 7 through the first residue pipeline 16 for temporary storage.
[0053] The depressurization process of the hydrogen single-tank manifold 1 is as follows: First, the second regulating valve 27 is automatically opened, and the hydrogen gas (containing sodium hydroxide solution) in the chlorine single-tank manifold 2 enters the first suspension separator 3 through the first hydrogen pipeline 9 for gas-liquid separation; then, the hydrogen gas after gas-liquid separation passes through the second hydrogen pipeline 10 and the first vent pipeline 11 in sequence, and then passes through the flame arrester 5 for depressurization and venting; finally, when the hydrogen single-tank manifold 1 is depressurized to the process protection differential pressure value, the depressurization and venting stops, at which time the second shut-off valve 29 is automatically opened, and the hydrogen gas in the chlorine single-tank manifold 2 enters the water seal tank 8 through the hydrogen depressurization pipeline 15. The water pressure in the water seal tank 8 forces the hydrogen gas into the third vent pipeline 20 for slow depressurization and venting. Nitrogen gas enters the hydrogen single-tank manifold 1 in sequence through the nitrogen pressurization pipeline 19 and the hydrogen depressurization pipeline 15, maintaining the stability of the differential pressure of the hydrogen single-tank manifold 1.
Claims
1. An automatic pressure relief protection device for electrolytic cell shutdown, characterized in that... The system includes a hydrogen single-tank manifold, a chlorine single-tank manifold, a first suspension separator, a second suspension separator, a flame arrester, a waste chlorine absorption device, a residual liquid storage tank, and a water seal tank. A first hydrogen pipeline is fixedly connected between the front end of the hydrogen single-tank manifold and the middle inlet of the first suspension separator. A second hydrogen pipeline is fixedly connected to the top outlet of the first suspension separator, and a first vent pipeline is fixedly connected to the second hydrogen pipeline. A flame arrester is fixedly installed on the first vent pipeline. A first chlorine pipeline is fixedly connected between the front end of the chlorine single-tank manifold and the middle inlet of the second suspension separator. A second chlorine pipeline is fixedly connected to the top outlet of the second suspension separator. A waste chlorine pressure relief pipeline is fixedly connected between the second chlorine pipeline and the inlet of the waste chlorine absorption device. A hydrogen pressure relief pipeline is fixedly connected between the tail end of the hydrogen single-tank manifold and the top inlet of the water seal tank. A first residual liquid pipeline is connected to the tail end of the chlorine single-tank manifold, and the outlet of the first residual liquid pipeline corresponds to the top inlet of the residual liquid storage tank.
2. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 1, characterized in that... The top outlet of the waste chlorine absorption device is fixedly connected to a second venting pipeline, and the bottom outlet of the waste chlorine absorption device is fixedly connected to a second residual liquid pipeline.
3. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 1, characterized in that... A nitrogen pressurization pipeline is fixedly connected to the hydrogen depressurization pipeline.
4. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 1, 2, or 3, characterized in that... The upper outlet of the water seal tank, above the water level, is fixedly connected to a third venting pipeline.
5. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 4, characterized in that... The upper inlet of the water seal tank, above the water level, is fixedly connected to a water supply pipeline.
6. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 5, characterized in that... A drainage pipeline is fixedly connected between the lower outlet of the water seal tank (where the water level is below the tank) and the top inlet of the residual liquid storage tank.
7. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 5 or 6, characterized in that... The bottom outlet of the first suspension separator is fixedly connected to the first drain line, and the bottom outlet of the second suspension separator is fixedly connected to the second drain line.
8. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 7, characterized in that... Pressure gauges are fixedly installed on the hydrogen single-tank manifold, the chlorine single-tank manifold, the first hydrogen pipeline, and the first chlorine pipeline.
9. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 3, 5, 6, or 8, characterized in that... A first regulating valve is fixedly installed on the waste chlorine pressure relief pipeline; a second regulating valve is fixedly installed on the first vent pipeline between the second hydrogen pipeline and the flame arrester; a first shut-off valve is fixedly installed on the first residual liquid pipeline; a second shut-off valve is fixedly installed on the hydrogen pressure relief pipeline between the tail end of the hydrogen single tank manifold and the nitrogen pressurization pipeline; and a third shut-off valve is fixedly installed on the nitrogen pressurization pipeline.
10. The automatic pressure relief protection device for electrolytic cell shutdown according to claim 9, characterized in that... It also includes a controller, a pressure gauge, a first regulating valve, a second regulating valve, a first shut-off valve, a second shut-off valve, and a third shut-off valve, all of which are electrically connected to the controller.