Question

The delivery value will starting at the centrifugal pump kept is what

Answer 1

is general practice to close the delivery valve of the centrifugal pump during start up and it is highly recommended for the critical services where the liquid is at boiling/bubble point (Eg. Reflux pump of distillation column). The procedure is to close the delivery valve and start the pump. After this open the delivery valve slowely till 100%. This will stabilize the complete system.

If this procedure is not followed and valve is kept 100% open and pump is started, NPSHa for this will be minimum because of lossed due to acceleration during start up. This will result in cavitation of the pump.

I always start the pump like this in the plant to avoid any process issues. I have achieved the best results because of this