Regarding the issue of pump reversal caused by a power outage in the boiler feed water pump of a sulfuric acid plant.
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In a sulfur-based acid production plant, a power outage occurred in the boiler feed pump, which resulted in the pump’s outlet not closing in time and thus the pump started to rotate in reverse. The liquid level in the steam drum dropped from 50% to 13% within 2 minutes. There is a check valve at the water supply isolation valve (located next to the steam drum), as well as another check valve at the outlet of the boiler feed pump. The deaerator water temperature remains unchanged, while the level rises. I would like to ask the experts and experienced professionals: 1. Why is the level of the drum liquid dropping so rapidly? 2. Can the medium-pressure steam inside the steam drum flow back to the deaerator? 3. Have other sister factories encountered this phenomenon? Thank you all for the discussion! ! !
Personally, I feel that there shouldn’t be any backflow with two check valves in place. However, since you mentioned that the pump reversed its rotation, there must indeed be some backflow. If only the boiler feed pump lost power, it seems that quite a bit of water would still have drained out within 2 minutes
The personnel on site confirmed that the pump had reversed direction; it was the first time such a thing had happened, and they had many questions!
One is installed horizontally with the pump outlet vertical – which possibility is more likely?
When the quality of the boiler outlet check valve is poor, its lifespan is short; it fails to close properly under normal conditions. But with such a large amount, the valve core must be stuck or fallen off.
First, check whether the deaerator is still being fed with water Second, it is possible for the flow to reverse (the check valve cannot seal completely), and the temperature of the water supply pipe, apart from that of the deaerator, will not rise much ； Third, is it because the electric fan is still running?