Issues regarding the shutdown and standby period of Beihua Ji or Asahi Kasei electrolyzers
Thread Content
This post was last edited by nanren2 on 2016-8-25 09:21. Hello, everyone! There are two scenarios regarding the shutdown and standby of the electrolyzer in the operating procedures. One, as specified in the old procedures, is: 1) Maintain the following conditions while the electrolyzer is in standby mode. Anode chamber: Draws air into the absorption tower. Cathode chamber: Pressurized with N2. Ensure that the valve below is open. (The other valves are closed) Anode: 13, 15, 17, 27 (Absorption line: 200 mmH2O vacuum) Cathode: 14, 16, 8, 28, 60, 62 (5 Nm3/hr of N2 is bubbled in the sealed tank). It was confirmed that valve 18 is closed, and the LG-230 indicated that the pressure difference between the anode chamber and the cathode chamber was approximately 500 mmH2O. 2) When the waiting time exceeds one week (this “when the waiting time exceeds one week” should probably refer to the case where the waiting time is expected to exceed one week, right? ), introduce water to half the height of the inlet pipeline through 31, 32, and carry out the following steps. Or, once the electrolyzer decomposition time is determined, carry out the following steps. Anode chamber and cathode chamber: air evacuation enabled. Confirm that the valve below is open. (Other valves closed) Anode: 17, 27; Cathode: 14, 16, 28. Yet the current operating procedures only retain the first one! I wonder what methods people use to handle the anode system during the shutdown and standby period of the electrolyzer? My opinion is that no matter how long the electrolyzer has been shut down, as long as it is in standby mode, the second rule should be applied! Although the anode of the electrolyzer is isolated from the accident chlorine system, the pressure at the anode of the electrolyzer is somewhat higher; although the pressure difference relative to atmospheric pressure is lower, it still remains within the range of 2–6 KPa. The main advantage of this approach is that it allows for a complete isolation of the electrolyzer from other systems, especially in the face of instability in the accident chlorine system, such as the backflow of chlorine gas!
It’s dizzying to watch. . Are the valve numbers for these electrolytic cells fixed? If we just state the number, everyone will understand, right? It’s a little white one; please help~
In my opinion, the exhaust evacuation valve should be opened, as internal leaks in the chlorine valve are difficult to detect; faults in the exhaust system or a low negative pressure during cell evacuation can be identified promptly through DCS monitoring and inspections. As for the pressure difference, it can be maintained at 3 KPa as long as nitrogen is used for filling.
This is actually a matter of perspective – different people have different opinions on it. Personally, I lean towards enabling it, for the same reasons as before.
Valve 15# should be closed if the negative pressure in the anode chamber is too high. The purpose of opening 13# is to prevent leakage from valve 9#; any chlorine that leaks out is captured by the light chlorine absorber.