Pump Reliability Question
Pump Reliability Question
(OP)
We are considering a pump purchase for a condition that is 1400 gpm at 550 ft TDH. The liquid is water used for cooling nozzles that spray into hot gas going to an electrostatic precipitator for gas cleaning. The operation is critical and runs 24/7. Two pumps will be installed one being an installed spare. One vendor has submitted a multistage ANSI pump and the curve looks good. The other has submitted an API horizontal centrifugal pump, single stage and the pump looks equally good. Cost of the API pump is about 3X of the multistage pumps. Loss of the pumps would be a significant operational cost. I am not familiar with the reliability of a multistage pump vs the API. Could you provided some feed back. Thanks for the help.





RE: Pump Reliability Question
Offhand lets make a rough estimate with an API reliability at 0.95 vs 0.85.
The chance of two APIs down would be 0.05^2 = 0.5% downtime.
Two nonAPIs down 0.15^2 => 97.75% reliability => 2.5% downtime. That's about 5 times less process downtime using an API. Now the question is, how much does lost production cost you?
In order to attempt to make a more or less direct cost comparsion between the two specs, you would have to consider increasing the power rating of the nonAPI you are thinking about purchasing to say 150% or more of the API pump, and also increase the maintenance time alloted to the nonAPI as well.
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Pump Reliability Question
I would lean toward the API pump if it's that critical, but also remember all of the other things you can do to improve reliability.
RE: Pump Reliability Question
**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: Pump Reliability Question
Johnny Pellin