Pump Vs Blowcase 2

[Renoyd]

Hello,

For a separator liquid outlet, what are the pros and cons by using a pump against a blowcase? Speciacally, will this choice affect the slug capacity required for the separator? Thanks.

 

[BigInch]

And a "blowcase" is what exactly? Using the separator pressure to move the liquid out?



**********************
"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/

 

[Artisi]

I know what a "hardcase" is, I know what a "nutcase" is, I know what a "blowjob" is , but a blowcase - beats me as well.

That unless the OP is talking about a hydro-cyclone.

 

[786392]

May be the OP is Talking about some sort of pneumatic lifting mechanism;Just a wild thought?

Best Regards
Qalander(Chem)

 

[BigInch]

Could be, but we'll let him tell us, rather than play the 1000 guesses game.

**********************
"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/

 

[zdas04]

OK. a blowcase is an auxiliary vessel that accumulates liquid separated within a vessel during the fill cycle, then is isolated from the primary vessel while high pressure gas is used to evacuate the blowcase into a tank or pipeline.

There are literally millions of these beasts in use in the world (it is becoming very common for wellhead compressors to have them on the suction scrubber) and they work very well providing you have a source of high pressure gas.

One mistake I see a lot of packagers make is that the equalizing line (to dump the power gas pressure back to the primary vessel) is often too small. Some packagers don't put valves on this line at all and allow the leakage through the 1/8 inch tubing to eventually return the blowcase to service. I evaluated one system that had 10 bbl/day capacity with the small line and 500 bbl/day with a 1-inch line and a control valve.

Back to the OP, Pumps have packing glands to leak, rotating (or oscillating) parts to break, and have a limited number of start/stop cycles before failure. Blowcases have none of these problems. Basically if I (1) have a source of gas at high enough pressure; and (2) have a reasonable place to exhaust the power gas at the end of the cycle (e.g., if you are trying to get liquids out of a flare stack knockout drum, the exhaust gas might have to go to the flare stack) then I will always prefer a blowcase at low pressures.


David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

"Everyone is entitled to their own opinion, but not their own facts" Patrick Moynihan

 

[BigInch]

I figured it might have been something like that. Of course if the pressure is available, its a pretty efficient way to keep liquids moving. That's the only issue I see, other than the atmospheric venting, burning off of methane or whatever else you have to/allowed to do with the power gas.

**********************
"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/

 

[zdas04]

Virtually always, the power gas goes back into the primary vessel so the only cost is the hp required to boost it back up.

David

 

[Renoyd]

Good explanation, David.

 

[786392]

Thanks David,(Although somewhat belated)
This has been definitely a Learning update indeed!

Best Regards
Qalander(Chem)