The pressure-fed reflux pump often doesn’t operate
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Methanol distillation is a 4-column process. The pressure reflux pump has recently been experiencing a decrease in liquid pumping volume, requiring frequent pump evacuation. What could be the cause, and how can it be resolved? The temperature at the pump inlet is around 113 degrees.
The cavitation problem may be caused by the following factors: 1. Reduced pressure, 2. Increased temperature, 3. Leaks at the pump inlet (air ingress), 4. Low liquid level, resulting in insufficient net positive suction head
It’s clearly cavitation – the pump does not have sufficient net positive suction head. Lower the inlet temperature or increase the inlet pressure; try to reduce the pump’s flow rate as much as possible during operation, as a higher flow rate exacerbates the problem
Is this phenomenon a recent occurrence? If this phenomenon occurs despite the operating conditions remaining the same as before, it is necessary to check whether there is a leak somewhere. I’ve encountered this issue before, where nitrogen from the backup pump’s seal tank leaked in
This has happened to us as well; in most cases, cleaning the inlet filter is sufficient. . . We have mainly been using the catalyst for a few years now; there’s a bit of paraffin. . .