The control valve is locked in the closed position

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I worked the day shift today. The first six hours were normal; the production volume of polypropylene increased, and the timing of material addition was adjusted as usual – everything was fine. But in the last two hours before quitting work, the control room staff informed me that the flow meter connected to the catalyst flushing valve was showing no flow. I immediately became worried, as anyone who has worked with polypropylene knows how serious this situation is； I was dealing with other issues nearby at that time; when I heard about it, I quickly checked the readings of the flow meters and found them to be zero. I promptly activated the bypass valve to supply fluid, but it didn’t help. The polymerization reaction was proceeding very rapidly. When I went down to check the pipes, I found that half of them were hot while the other half was cold – the pipes were partially blocked. There was also an emergency discharge mechanism in place. There were many problems with the control system, but I won’t go into details. In the end, the material was discharged. After releasing some gas, we began to slowly open the safety valve to release gas into our gas holder. During this process, we found that the main pipeline was blocked, while the other three drainage lines were functioning properly. Then fresh propylene was used for continuous flushing, preserving the three flushing pipelines ； We are now faced with another critical situation: the pressure in our vertical and horizontal reactors has balanced out, making it impossible to feed material into them. There is a constant risk of pressure buildup inside the pipes. Therefore, we quickly activated our vital solution – feeding material out to flush the propylene – and this finally prevented the risk of pressure buildup in the pipes.