Reasons for fluctuations in the flow rate of the feed pump in the coking heater
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What is the reason why the flow rate of the feed pump in our coking heater keeps fluctuating? That is, during operation, with no other adjustments made, the outlet flow rate will drop suddenly and frequently; after manual intervention with the outlet control valve, it will fluctuate up and down several times before stabilizing. This is a major concern for us because the heating furnace has a low flow interlock.
First, calibrate the gauge to rule out the possibility of incorrect readings from the instrument; all other factors are related to the pump. Open the filter at the inlet of the backup pump, clean it, and then try starting the pump.
Observe whether there is any change in the back pressure at the pump outlet, and whether the process load fluctuates thereafter
I’ve also checked it; we have two pumps, and the other one, A, is imported. When pump A is used, the flow rate remains stable. We plan to replace Pump B with another pump; we just finished negotiating the technical agreement. However, the manufacturer of Pump B insists that there is nothing wrong with their pump; the cause remains unknown at present.
1. Quality issues with the pump itself. 2. Unstable or insufficient flow at the inlet. 3. Is there coking in the furnace tubes?
We are about to conduct a heavy-load test run of the pump to see if it is due to the pump’s design being optimized for minimum flow rates that it cannot meet the requirements.
It is possible that the pump’s performance shows a hump-shaped pattern, and if the device’s resistance curve intersects the pump’s performance curve at two points, then the situation described by the original poster could occur. (If this is indeed the case, controlling the control valve to make the pump operate at a higher flow rate may help; if the operation remains stable, this is likely to be the cause of the problem.)