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Phenol propylene has the same process, and is the first bottom reboiler in the distillation. First, the reboiler steam fluctuates inexplicably. The normal steam is around 11,000, but when it fluctuates, it can fluctuate from more than 1,000 to more than 18,000. At this time, the regulating valve is manual and the valve position is not changed. Immediately afterwards, I found that the outlet pressure of the forced circulation pump (which simultaneously feeds materials) dropped from 0.38MPa to 0.1MPa. Based on experience, I immediately switched the pump and cleaned the filter. But after switching the pump, the new pump could only last for more than 10 minutes before the same situation occurred. Due to the large size of the pipes, cleaning the filter takes a relatively long time, and the tower is operated in a fluctuating condition during the filter cleaning period. In the early stage, the filter was cleaned out as black sand-like substance. It was cleaned no less than 20 times that day. During the subsequent cleaning process, the black substance turned into dark yellow substance. Take the sample and send it to the laboratory for analysis. The black substance is insoluble in water and cumene (or very little dissolved) in a water bath at 80 degrees Celsius. The dissolved water phase is titrated with barium chloride and there is obvious precipitation. It is normal for this to contain sulfate in the process flow, but the content may be too high. Most of the yellow substance dissolved in the 80-degree water bath, and the titration obviously precipitated. The process operating conditions are: The feed to the tower itself is the organic phase that has been mixed and stratified with salt, containing about 10% bound water, and the material itself contains trace amounts of salt. The bottom of the tower is 204 degrees, but the reboiler is forced circulation and the normal circulation volume is 23. 8 tons, but due to damage to the instrument, the flow meter has not been replaced. In the previous operation, the orifice plate on the circulation line had a bypass stop valve, which was always closed. According to the process requirements, this valve should be used to adjust the circulation flow. The opinion given by experts is that the circulation volume of the reboiler is too small, which causes the steam to heat the material in large quantities, causing the heavy components and sulfates to coke together and black matter blocks the filter. Treatment method: Stop the system partially, cut off the inlet and outlet of the tower, cut off the steam, withdraw the material to the outside of the boundary area, clean the entire tower and reboiler with cumene, and then re-feed the tower. After establishing the cycle, it has been running normally for 3 or 4 days now. During this restart process, we adjusted the stop valve on the circulation line to the maximum according to the pressure and current of the pump. Please help analyze why this situation occurs. I am an expert and my opinion is reasonable, but it is not all. There may also be problems with material skewing. But because I was short of time, I didn't check it myself. Now that it's normal, I didn't pursue it anymore.