Ion-exchange membrane caustic soda single cell start-up and gas combining equipment

Abstract

The present invention discloses a device for merging gas during the single-tank start-up of ion-exchange membrane caustic soda production, which includes a cathode water seal cylinder body, an anode water seal cylinder body, a water seal connecting pipe, and a nitrogen gas inlet main pipe; the cathode water seal cylinder body includes a water seal water inlet pipe, a cathode water seal gas inlet pipe, and a cathode water seal exhaust pipe; the anode water seal cylinder body includes an anode water seal gas inlet pipe, an anode water seal exhaust pipe, a water seal overflow pipe, and a water seal drain pipe; one end of the nitrogen gas inlet main pipe is communicated with a nitrogen gas supply pipeline, and the other end is respectively communicated with the cathode water seal gas inlet pipe and the anode water seal gas inlet pipe through nitrogen gas inlet water seal pipes. Its advantages are as follows: (1) The device has a simple structure and low operation difficulty, and the gas merging can be completed without the cooperation of personnel; (2) The pressure is stable and steady during the operation process, solving the problem of operation pressure fluctuation caused by improper cooperation during the start-up and gas merging of the electrolytic cell, and prolonging the service life of the ion-exchange membrane; (3) It is convenient to realize the automatic control of gas merging.

Description

Technical Field

[0001] The present invention relates to an ion-exchange membrane caustic soda production device, in particular to an electrolytic cell start-up and gas merging device in ion-exchange membrane caustic soda production. Background Art

[0002] In current ion-exchange membrane caustic soda production, a production system usually consists of multiple electrolytic cells. Generally, it is not possible to start up and operate multiple electrolytic cells simultaneously. At this time, when the subsequent electrolytic cells need to be started up, or when a certain electrolytic cell is restarted after maintenance, it is necessary to merge the gas phases of the anode and cathode of a single electrolytic cell into the main system. Since the ion-exchange membrane electrolytic cell operates under positive pressure, the operating pressure of the main system is usually 10 - 30 kPa. During gas merging, the pressure of the single cell needs to be gradually increased from atmospheric pressure to the system pressure. Usually, this is completed by the cooperation of three people. Two people slowly open the outlet valves on the hydrogen and chlorine branches of the anode and cathode of a single electrolytic cell simultaneously, and one person monitors the hydrogen and chlorine pressures of the electrolytic cell and reports the hydrogen and chlorine pressure data so that the other two can cooperate to control the hydrogen pressure and chlorine pressure to ensure that the hydrogen-chlorine pressure difference is within a certain range until the pressure of the single electrolytic cell is the same as the main system header pressure. This operation has high control requirements and is prone to improper cooperation between two people, resulting in too large or too small anode-cathode pressure difference, damaging the ion-exchange membrane, reducing the service life of the ion-exchange membrane, or causing fluctuations in the header pressure, affecting the subsequent process sections. Summary of the Invention

[0003] To avoid damage to the ion-exchange membrane caused by electrolytic cell gas merging, fluctuations in the header pressure, and improve the convenience of gas merging operation, the present invention provides an ion-exchange membrane caustic soda single cell start-up and gas merging device.

[0004] The technical solution adopted by the present invention to solve its technical problems is: an ion-exchange membrane caustic soda single cell start-up and gas merging device, characterized by comprising:

[0005] A cathode water seal cylinder body, and the cathode water seal cylinder body comprises:

[0006] A water seal inlet pipe, one end of which is arranged at the upper part of the cathode water seal cylinder body, and the other end is connected to a water source;

[0007] A cathode water seal inlet gas pipe, one end of which vertically inserts into the inside of the cathode water seal cylinder body from the top of the cathode water seal cylinder body, the insertion depth is H, and the other end is connected to the hydrogen pipeline of a single electrolytic cell;

[0008] A cathode water seal exhaust pipe, one end of which is arranged at the top of the cathode water seal cylinder body;

[0009] An anode water seal cylinder body, and the anode water seal cylinder body comprises:

[0010] Anode water seal inlet pipe: One end is vertically inserted into the inside of the anode water seal cylinder from the top of the anode water seal cylinder, with an insertion depth of h, where h < H, and the other end is connected to the chlorine gas pipeline of a single electrolytic cell;

[0011] Anode water seal exhaust pipe, with one end arranged at the top of the anode water seal cylinder;

[0012] Water seal overflow pipe, with one end arranged at the upper part of the anode water seal cylinder;

[0013] Water seal drain pipe, with one end arranged at the lower part of the anode water seal cylinder for draining water;

[0014] Water seal connecting pipe, used to connect the lower parts of the cathode water seal cylinder and the anode water seal cylinder;

[0015] Nitrogen inlet main pipe, with one end connected to the nitrogen supply pipeline, and the other end connected to the cathode water seal inlet pipe and the anode water seal inlet pipe respectively through the nitrogen inlet water seal pipe;

[0016] Valves are provided on the water seal inlet pipe, cathode water seal inlet pipe, anode water seal inlet pipe, water seal drain pipe, nitrogen inlet main pipe, and nitrogen inlet water seal pipe.

[0017] As a further improvement of the present invention, the water seal overflow pipe has a water seal U-bend to prevent the gas in the anode water seal from flowing out to the wastewater treatment device through the water seal overflow pipe.

[0018] Preferably, the other end of the water seal drain pipe is connected to the upstream water seal overflow pipe of the water seal U-bend.

[0019] As a further improvement of the present invention, the other end of the water seal overflow pipe is connected to the wastewater treatment device.

[0020] As a further improvement of the present invention, the other end of the cathode water seal exhaust pipe is connected to the hydrogen gas vent pipe, and the other end of the anode water seal exhaust pipe is connected to the accident chlorine treatment system.

[0021] As a further improvement of the present invention, the materials of the cathode water seal cylinder and the anode water seal cylinder are PVC wrapped with fiberglass.

[0022] As a further improvement of the present invention, the valve is a program-controlled valve, and the signal of the program-controlled valve is connected to the DCS control system to realize automatic control of the valve opening / closing.

[0023] The beneficial effects of the present invention are as follows: (1) This device is used to incorporate the single-cell anode and cathode gas systems into the main system during the single-cell start-up in ion-exchange membrane caustic soda production. The device has a simple structure and low operation difficulty, and can complete gas incorporation without personnel cooperation; (2) The pressure is stable and steady during the operation process, solving the problem of operation pressure fluctuation caused by improper cooperation during the start-up and gas incorporation of the electrolytic cell, and prolonging the service life of the ion-exchange membrane; (3) It is convenient to realize automatic control of gas incorporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic structural diagram of the gas incorporation device for the single-cell start-up in ion-exchange membrane caustic soda production of the present invention.

[0025] The markings in the figure are:

[0026] 1 - Cathode water seal cylinder body, 101 - Water seal inlet pipe, 102 - Water seal inlet valve, 103 - Cathode water seal exhaust pipe, 104 - Cathode water seal inlet gas pipe, 105 - Cathode water seal inlet gas valve;

[0027] 2 - Anode water seal cylinder body, 201 - Water seal drain pipe, 202 - Water seal drain valve, 203 - Water seal overflow pipe, 204 - Water seal U-bend, 205 - Anode water seal exhaust pipe, 206 - Anode water seal inlet gas pipe, 207 - Anode water seal inlet gas valve;

[0028] 3 - Water seal communication pipe;

[0029] 4 - Nitrogen inlet main pipe, 401 - Nitrogen inlet main valve, 402 - Nitrogen inlet water seal pipe, 403 - Nitrogen inlet water seal valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be further described below with reference to the drawings and embodiments.

[0031] As Figure 1 shown, the gas incorporation device for the single-cell start-up in ion-exchange membrane caustic soda production of the present invention includes:

[0032] Cathode water seal cylinder body 1, and the cathode water seal cylinder body 1 includes:

[0033] Water seal inlet pipe 101, one end of which is arranged at the upper part of the cathode water seal cylinder body 1 and the other end is connected to a water source;

[0034] Cathode water seal inlet gas pipe 104, one end of which vertically inserts into the inside of the cathode water seal cylinder body 1 from the top of the cathode water seal cylinder body 1 with an insertion depth of H, and the other end is communicated with the hydrogen pipeline of a single electrolytic cell;

[0035] Cathode water seal exhaust pipe 103, one end of which is arranged at the top of the cathode water seal cylinder body 1 and the other end is connected to the hydrogen vent pipeline;

[0036] Anode water seal cylinder body 2, and the anode water seal cylinder body 2 includes:

[0037] The anode water seal inlet pipe 206 has one end vertically inserted into the interior of the anode water seal cylinder body 2 from the top of the anode water seal cylinder body 2, with an insertion depth of h, where h < H, and the other end is connected to the chlorine gas pipeline of a single electrolytic cell.

[0038] The anode water seal exhaust pipe 205 has one end arranged at the top of the anode water seal cylinder body 2, and the other end is connected to the accident chlorine treatment system.

[0039] The water seal overflow pipe 203 has one end arranged at the upper part of the anode water seal cylinder body 2, and the other end is connected to the wastewater treatment device. The water seal overflow pipe 203 has a water seal U-bend 204.

[0040] The water seal drain pipe 201 has one end arranged at the lower part of the anode water seal cylinder body 2, and the other end is communicated with the upstream water seal overflow pipe 203 of the water seal U-bend 204 for draining water.

[0041] The water seal connection pipe 3 is used to connect the lower parts of the cathode water seal cylinder body 1 and the anode water seal cylinder body 2.

[0042] One end of the nitrogen intake main pipe 4 is connected to the nitrogen supply pipeline, and the other end is respectively connected to the cathode water seal inlet pipe 104 and the anode water seal inlet pipe 206 through the nitrogen inlet water seal pipe 402.

[0043] Cathode water seal inlet valves 105, anode water seal inlet valves 207, water seal drain valves 202, nitrogen intake main valves 401, and nitrogen inlet water seal valves 403 are respectively arranged on the water seal inlet pipe 101, the cathode water seal inlet pipe 104, the anode water seal inlet pipe 206, the water seal drain pipe 201, the nitrogen intake main pipe 4, and the nitrogen inlet water seal pipe 402.

[0044] Before starting a single electrolyzer and the system, close the water seal drain valve 202, and open the cathode water seal inlet valve 105 and the anode water seal inlet valve 207 to connect the cathode water seal inlet pipe 104 with the electrolyzer hydrogen pipeline and the anode water seal inlet pipe 206 with the electrolyzer chlorine pipeline. At the same time, open the nitrogen inlet main valve 401 and the nitrogen inlet water seal valve 403 to fill nitrogen into the cathode water seal inlet pipe 104 and the anode water seal inlet pipe 206. Meanwhile, open the water seal water inlet valve 102 and slowly increase the water seal liquid level. As the liquid level continuously increases, the pressures of the cathode water seal inlet pipe 104 and the anode water seal inlet pipe 206 continuously increase, that is, the pressures of the hydrogen and chlorine pipelines at the anode and cathode of the electrolyzer also continuously increase. Since the insertion depth H of the cathode water seal inlet pipe 104 into the water seal is greater than the insertion depth h of the anode water seal inlet pipe 206 into the water seal, the pressures exerted by the liquid in the water seal on the cathode water seal inlet pipe 104 and the anode water seal inlet pipe 206 are different, and a constant pressure difference is generated. That is, as the pressures of the hydrogen and chlorine pipelines at the anode and cathode of the electrolyzer continuously increase, the pressure difference between the two remains constant until the pressures of the hydrogen and chlorine at the anode and cathode of a single cell are slightly greater than the main system manifold pressure. Then stop adding water, close the water seal water inlet valve 102, the nitrogen inlet water seal valve 403 and the nitrogen inlet main valve 401, close the anode water seal inlet valve 207, and close the cathode water seal inlet valve 105. Then slowly fully open the hydrogen and chlorine outlet valves at the anode and cathode of the electrolyzer respectively to complete the gas merging of a single cell. After the gas merging is completed, open the water seal drain valve 202 to drain the waste water in the water seal for later use. The gas merging process of a single electrolyzer can be completed without relying on personnel cooperation, and without any operation experience, it will not damage the electrolyzer and the ion membrane.

[0045] It is easy to understand that in the process, the pressure difference between the anode and cathode of this equipment has been determined and fixed according to the process requirements during the initial production, and the pressure difference cannot be adjusted after the equipment is manufactured. If there are new requirements for the hydrogen-chlorine pressure difference between the anode and cathode in the process, the pressure difference between the hydrogen and chlorine pipelines at the anode and cathode of a single electrolyzer during the gas merging process can be adjusted by adjusting the difference between the insertion depth H of the cathode water seal inlet pipe 104 into the water seal and the insertion depth h of the anode water seal inlet pipe 206 into the water seal. Usually, by adjusting, a pressure difference within 0 - 10 kPa can meet the process requirements.

Claims

1. Ion-exchange membrane caustic soda single-tank start-up and gas combination equipment, characterized in that, Comprising: The cathode water seal cylinder body, and the cathode water seal cylinder body includes: The water seal inlet pipe, one end of which is arranged at the upper part of the cathode water seal cylinder body, and the other end is connected to a water source; The cathode water seal inlet gas pipe, one end of which is vertically inserted into the inside of the cathode water seal cylinder body from the top of the cathode water seal cylinder body, with an insertion depth of H, and the other end is communicated with the hydrogen pipeline of a single electrolytic cell; The cathode water seal exhaust pipe, one end of which is arranged at the top of the cathode water seal cylinder body; The anode water seal cylinder body, and the anode water seal cylinder body includes: The anode water seal inlet gas pipe: one end of which is vertically inserted into the inside of the anode water seal cylinder body from the top of the anode water seal cylinder body, with an insertion depth of h, h < H, and the other end is communicated with the chlorine pipeline of a single electrolytic cell; The anode water seal exhaust pipe, one end of which is arranged at the top of the anode water seal cylinder body; The water seal overflow pipe, one end of which is arranged at the upper part of the anode water seal cylinder body; The water seal drain pipe, one end of which is arranged at the lower part of the anode water seal cylinder body for draining water; The water seal communication pipe for communicating the lower parts of the cathode water seal cylinder body and the anode water seal cylinder body; The nitrogen inlet main pipe, one end of which is communicated with a nitrogen supply pipeline, and the other end is respectively communicated with the cathode water seal inlet gas pipe and the anode water seal inlet gas pipe through a nitrogen inlet water seal pipe; Valves are arranged on the water seal inlet pipe, the cathode water seal inlet gas pipe, the anode water seal inlet gas pipe, the water seal drain pipe, the nitrogen inlet main pipe, and the nitrogen inlet water seal pipe.

2. The ion-exchange membrane caustic soda single-tank startup and parallel gas equipment according to claim 1, characterized in that: The water seal overflow pipe has a water seal U-shaped bend.

3. The ion-exchange membrane caustic soda single-tank start-up and parallel gas equipment according to claim 2, characterized in that: The other end of the water seal drain pipe is communicated with the upstream water seal overflow pipe of the water seal U-shaped bend.

4. The ion-exchange membrane caustic soda single-tank start-up and gas combination equipment according to any one of claims 1 to 3, characterized in that: The other end of the water seal overflow pipe is connected to a wastewater treatment device.

5. The ion-exchange membrane caustic soda single-tank start-up and gas combination equipment according to any one of claims 1 to 3, characterized in that: The other end of the cathode water seal exhaust pipe is connected to a hydrogen venting pipeline, and the other end of the anode water seal exhaust pipe is connected to an accident chlorine treatment system.

6. The ion-exchange membrane caustic soda single-tank start-up and gas-combining equipment according to any one of claims 1 to 3, characterized in that: The materials of the cathode water seal cylinder body and the anode water seal cylinder body are PVC wrapped with fiberglass.

7. The ion-exchange membrane caustic soda single-tank start-up and gas combination equipment according to any one of claims 1 to 3, characterized in that: The valve is a programmable control valve, and the signal of the programmable control valve is connected to a DCS control system to realize automatic control of the opening / closing of the valve.

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