LPG Pump for Low NPSH duty 1

[m2609]

I'm trying to find a pump suitable for the below application but having no joy, pump will be offshore and unfortunately it’s on the lowest level of the platform so no chance to increase the NPSHa. Unfortunately we cannot increase the low low level in the vessel so the static head is fixed. Pump will be located very close to the vessel, valves have been minimised and no strainer has been included to ensure we don’t reduce the NPSHa further (fluid is thought to be relatively clean). PD pump is preferred due to the low flow rate, however this will reduce the NPSHa further due to acceleration head loses.

Pumped Fluid: LPG (Dry HC Condensate)
SG: 0.58 to 0.70
Viscosity: 0.2cP
Pumping Temp: Ambient
Flow Rate: 5m3/hr (batch process so flow rate can be changed +/- 25%)
Differential Pressure: 1bar
NPSHa: 0.5m

Any suggestions would be great.

 

[BigInch]

http://www.corken.com/

What would you be doing, if you knew that you could not fail? Ans. Bonds and derivative brokering.

 

[TD2K]

Check with Roth pumps also.

 

[m2609]

Thanks for the responses, i have emailed both suppliers and waiting on a response. I’m not holding out much hope, based on the info on the websites my duty flow rate is too low. Also the pump will be located in a Zone 1 hazardous area, again based on the websites neither of these supplier have units suitable for this.

 

[TD2K]

Any chance of using a can pump extending below the lowest level to gain the head needed? I know it's going to look odd.

 

[m2609]

hi TD2K,

Yeah, thought about that already, but typically canned pumps are for quite high flow rates (or high compared to this duty!). I think I’m going to have to go back to our process department and find out if the pressure in the vessel can be increased as there doesn’t seem to be anything available for this duty.

 

[nfinit]

it is likely this is a bubble point fluid. You would want to check to see if they can raise the level in the vessel instead of the pressure.

 

[ciise]

Sero Pump Systems has some Side Channel pumps that are good for low NPSH, Low S.G, Low flow and High head. These pumps cant handle solids but I understand that is not your concern here. They ar available as mag drives too.

Thought might be worth a try:

http://austindenholm.com/id151.htm

 

[stanier]

Could you consider using an LPG compressor and suck the vapour off the liquid?

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[BigInch]

Too much discharge pressure, but maybe this will take you in the right direction. A submersible LPG pump. Could be worth a phone call.

http://www.veeder.com/page/2HP_Submersible_Pumps

If it ain't broke, don't fix it. If it's not safe ... make it that way.

 

[diverdan8]

M2609,
based off the conditions you supplied, I believe we have a few selections of low flow can pumps that fit this application.
If you are interested in getting a curve...

http://www.ruhrpumpen.com

 

[CompressorExpert]

M2609
Not sure if you have already solved your problem, but I strongly recommend sliding vane pumps. I've personally used those several times for LPG pumping application when theoretical NPSH; I mean acc. to process data sheet ;-)); were zero. You may want to consider PD pumps but need to reduce operating speed to reduce acceleration head loss, but I'm sure those will work too.
Problem with side channel pumps would be that these pumps are slightly big for your application, otherwise those could be second choice.

 

[DubMac]

You may want to look at a PC pump; they can be flanged right up to the vessel if needed. Whatever you use, it needs to be run as slow as possible; that means a bigger, more expensive pump.

 

[GasGasMan]

HELLO ALL,

I AM NEW HERE IN THIS SITE, AND IT IS GREAT TO SEE EXPERT GUYS HELPING OTHERS.

I HAVE THE FOLLOWING QUISTION:-

IS THERE LPG TRANSFER PUMP WITH DEFFRENTIAL PRESSURE 22 BAR? I AM GOING TO PUMP IT TO LPG VAPORIZER ( THE VAPORIZER WILL BE CUSTOM MADE DUE TO THIS HIGH PRESSURE PUMP)
THANK YOU
GASMAN

 

[petrochemical87]

gasgasman,
Dont hijack threads in this forum, start a new one!

 

[ciise]

http://austindenholm.com/products-services/pumps/sero-pump-systems/index.html

Sero Pump might work