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Does someone have experience of all feed pump cavitation and subsequently unit trip while changing over the feed pump from one to another. Or what are the probable reasons of feed pump cavitation while doing pump change over?
 
Answers
16/08/2011 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
The suction piping after the split to each pump should not be heat traced or jacketed. Avoid absorbing heat from the running but blocked in pump by running that way for only a short time, seconds, not minutes. Suction valves should be wide open. Except for the heat pickup issue, if the feed rate is held constant, the available NPSH should remain constant during the switching operation and not cause the problem.