effect of solution gas oil ratio on Screw Pump efficiency

[kald]

i want to ask about the effect of increase solution gas oil ratio (amount of gas dissolved in the oil) on Screw Pump efficiency used to transfer crude oil , and if this can increase clearances between the rotor and pump housing
and what the other bad effect of increased gas dissolved in the oil on the Screw Pump

 

[LittleInch]

I'm not sure what your point or issue is here.

If there is more gas dissolved, but you are operating at the inlet side above the partial pressure of said gas ( i.e. above bubble point) then the only big issue would be that the density should decrease and possibly viscosity as well, but otherwise you're still pumping a liquid so there should not be any significant change.

If you're below bubble point a the inlet then you're looking at a two phase pump and all hell will break loose.

So which is it?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[kald]

we are working below bubble point a the inlet of the screw pump , and i ask what pad effect of this separated gas on screw pump

 

[LittleInch]

Well that will depend on how far below the bubble point you are.

As the pressure increases along the screw the amount of gas will reduce, but the overall liquid flow of your pump will decrease and possibly the pressure able to be output. How much is dependent on the amount of gas actually present in the fluid at the inlet.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

Vague recollection of 2phase screw pumps in crude gas transfer is that gas void fraction (GVF) on a volumetric basis should be less than 95%. I may be wide off the mark here, but there is a limit prescribed by the 2phase pump vendor. Petronas / Shell tried out these pumps on a facility in the South China Sea many years ago ( 1990's), but abandoned this after a few years of troublesome operation - high power consumption was also one OPEX disadvantage.