Treatment after fire in ion membrane electrolyzer
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This post was last edited by sunjl1981 on 2013-1-6 22:08. Due to the penetration of the cathode outlet of the ion membrane electrolyzer, the overflow of hydrogen and catholyte causes hydrogen to catch fire during ignition. How to deal with it? Let's discuss whether it is possible to gradually increase nitrogen from the cathode outlet to maintain the positive pressure of the cathode system, and then gradually reduce the current? Or is there a better way to solve it? # , , &
Let me first talk about my personal opinion (the Asahi Kasei electrolyzer used in this unit): Is this the way to deal with hydrogen fires in the unit cell cathode system?: That is to gradually increase the nitrogen in DP-234, and slowly reduce the current while maintaining the positive pressure of hydrogen. After the current drops to a certain level, increase the amount of nitrogen through valves 55# and 56# (maintain 4.4mH2O for the cathode system and 4 for the anode system). .0mH2O, maintain the single tank pressure after the current drops to zero, slowly close 10#, 12#, 9#, 11#, then close 55#, 56#, open the 13#, 14# valves, and finally operate according to the parking operation ticket. Let's discuss whether this is feasible?
Additional explanation: Add nitrogen from valves 55# and 56# to maintain the pressure of the cathode and anode systems. This is mainly to prevent chlorine and hydrogen from the main pipe from pouring into the unit tank. Opening 13# and 14# is to relieve pressure in the unit tank.
Everyone is here to communicate, especially if you have experienced it before, you can talk more about how to deal with it, so that everyone can take a look at it, so that everyone can deal with it calmly once such a situation occurs. If the fire in the ion membrane electrolyzer is relatively small, I think you should cover the fire area with a wet quilt and use a fire extinguisher to suffocate the fire. If the fire is relatively large, I think the above method should be used. Do you agree?
I personally think that when the electrolytic cell is running and the cell catches fire due to catholyte outlet leakage, it is a good idea to fill the cathode outlet main pipe with nitrogen. But the key is how to control these operational issues when such a situation occurs, such as how much nitrogen can you fill to stop the current from falling. If you don't manage the time well, accidents may occur. Maybe when encountering this situation, instead of rushing to cut off the power, try to use a dry powder fire extinguisher to put out the fire first before parking the car.
The person above is right. Once there is a fire at the cathode outlet, if it can be discovered in time, you can use a dry powder fire extinguisher to put out the fire first before parking the car. But when the fire gets bigger, nearby unit slots also catch on fire. It is ineffective to use a fire extinguisher. Then, the current can only be slowly reduced while ensuring the positive pressure of hydrogen. However, how to maintain positive hydrogen pressure during the current reduction process and how to control it are the key.
First of all, I would like to thank the teacher for the encouragement. If the fire is as you said, it is so big that it also catches nearby unit slots, and it will be impossible to control it with a fire extinguisher. So who can calmly control and ensure that the current is slowly reduced while the hydrogen is at positive pressure? Find a practical way to increase the frequency of inspections by the operators on the job. The electrolysis staff in my unit patrol their posts once every half hour.
Whether this situation can be controlled in a timely and effective manner mainly depends on the importance the company attaches to the emergency plan and its proficiency in daily drills of the emergency plan.
Spraying directly with a dry powder fire extinguisher is the most timely and effective method.
This is just my personal thought. Everyone has a better way to talk about.
How can we ensure timely discovery? Everyone talks about their own opinions. This post was last edited by wanhonghui1111 on 2008-2-25 14:56 ]
Try to use a dry powder fire extinguisher to put out the fire first, but at the same time you can fill it with some nitrogen. Only by ensuring the positive pressure of hydrogen can you slowly reduce the current. Having said that, another good way is for the staff to have a clear mind.
Strengthen patrol inspections, and inspections must be carried out carefully and not in a superficial manner. I think: in the fire * * Under control, use a fire extinguisher to extinguish it first (isolate from the system when running multiple tanks), then fill it with nitrogen, and then reduce the current. A few days ago, this kind of accident occurred in our company, and six outlet hoses were burned out. The operator pressed the emergency stop button and stopped everything at once. Or it slowly goes out like this. Fortunately no further problems occurred.
Our company has had such fire incidents before. The flames were relatively small. We used a dry powder fire extinguisher to put out the fire first and then stopped the company for maintenance. This is consistent with the previous handling opinions.
Everything you said is good, but you can't make an emergency stop. If there is positive pressure, there is no problem. But if there is negative pressure, you can imagine the consequences. No problem, it is really fatal. I have encountered this problem, the operator made an emergency stop, and there was an explosion. Fortunately, no one was hurt, and the equipment was damaged a lot.
I think that if the emergency stop button is pressed and the chain is successful (the chlorine pump and the hydrogen pump trip at the same time), there should be no negative pressure in the electrolyzer and system. If the chain fails, it may cause negative pressure ； Or, only one (chlorine pump, hydrogen pump) trips. Then it is even more dangerous, the membrane may be damaged, and chlorine and hydrogen may be mixed together, causing more serious consequences. Personal opinion, please correct me if I am wrong. :P
I think pressing the emergency stop button will cause an emergency stop, cut off the gas phase, purge with nitrogen, relieve pressure with chlorine, and put out the fire with a fire extinguisher at the same time. Because after parking, the gas phase is under positive pressure, and the fire will not burn into the inside of the tank. The most important thing is to conduct plan drills on a daily basis.
When this kind of accident occurs, if you press the emergency stop button, if everything is normal, the chlorine and hydrogen pumps will trip in series, and there will be no negative pressure, which is safe. If the chain is not successful, the chlorine and hydrogen pumps will not trip in chain, negative pressure will occur, and an explosion accident will occur. If the chlorine (hydrogen) pump chain trips, but the hydrogen (chlorine) pump chain does not trip, and if not handled in time, the membrane may be damaged, causing the chlorine and hydrogen gases to mix, causing an explosion. Personal opinion, please give advice. :handshake
I think it is not possible to press the emergency stop button. Although negative pressure in the hydrogen system will not be generated when the vehicle is stopped, a backfire accident may occur as the pressure decreases rapidly. Where is the fire in the hydrogen system? If it occurs on the battery tank, you can simply use dry powder or carbon dioxide fire extinguisher to extinguish the fire. However, when extinguishing the fire, you must maintain positive pressure and reduce the pressure appropriately, but it must not be too fast or too low. If there is a hydrogen exhaust fire, you can add steam to blow it out or seal the hydrogen liquid with water to cut off the gas source.
I think the emergency stop button cannot be pressed. It is more dangerous when the hydrogen pump is not interlocked. I think the gas phase system of this tank should be separated from other tanks, and then the single tank should be stopped with reduced current. The question is who can take the risk to close the valve in this situation. I think prevention should be given priority. When a large leak in the cathode system is found, it should be stopped in time to eliminate the leak.
The teacher upstairs is right. I also think that you cannot press the emergency stop button. As the gas phase pressure decreases during parking, a backfire accident may occur once negative pressure occurs. It is recommended to increase the frequency of inspections by post operators to detect and deal with the first fire in the battery tank in a timely manner.