Centrifugal Naphtha pump install design question
Centrifugal Naphtha pump install design question
(OP)
Installing a small close coupled centrifugal pump (Goulds NPE 1ST) with single mech seal (John Crane Type 21) in a 5 - 10 GPM Naphtha injection service.
(injecting into suction side of crude charge system , system is at 20 - 30 PSI, to provide additional light ends to cut gravity and help atm tower operation).
Control valve (fail close) downstream of small naphtha pump...if control valve fails closed for an extended period of time before operations catches it...how likely is it that pump would overheat, seal leak, and start a fire?
(injecting into suction side of crude charge system , system is at 20 - 30 PSI, to provide additional light ends to cut gravity and help atm tower operation).
Control valve (fail close) downstream of small naphtha pump...if control valve fails closed for an extended period of time before operations catches it...how likely is it that pump would overheat, seal leak, and start a fire?
RE: Centrifugal Naphtha pump install design question
We use a simple bi-metallic heat sensor screwed right into the volute. Extremely reliable and cheap.
PUMPDESIGNER
RE: Centrifugal Naphtha pump install design question
Shouldn't your actions and this system evaluation become part of an overall PSM review of the system ? Is OSHA 1910 being implemented in this plant ?
I am aware that many process chemical plants asssign an "engineer du-jour" to modify and rework critical plant systems. Sadly, I am also aware of the "MBA effect" that many plants suffer from...
This effect commonly places "any engineer with any background, to be assigned any problem, to be completed according to the schedule he just developed"
Is that happening here ?
"There comes a time in the affairs of man when he must take the bull by the tail and face the situation." W.C. Fields
RE: Centrifugal Naphtha pump install design question
Yes, this subject is being discussed because of the findings in a MOC (management of change) review meeting.
My question wasn't worded the best...does one typically find, when pump is dead headed, that the temperature increase from energy input by 1 HP motor pump on naphtha at ambient temperature to be worthy of any further thought or ist the temperature rise negligable?
RE: Centrifugal Naphtha pump install design question
RE: Centrifugal Naphtha pump install design question
Trust it helps you.
RE: Centrifugal Naphtha pump install design question
With such a small flow rate, you will probably find that the pump casing will "radiate" the heat stored by deadheading. This depends on temperatures and pressures, but the sums are fairly simple.
The thing that is disturbing to me is relying on a single mechanical seal for fire prevention. The single seal is there to stop leakage, not fires. If you need fire protection as well, you need additional measures.
Cheers
Steve McKenzie