Liquid ring vacuum pump question 1

[silebi66]

I would like to bother you guys a vacuum pump question. A liquid ring vacuum pump in which the delivery of the methanol gas was sucked is achieved by a circulating methanol liquid.

This liquid ring vacuum pump with methanol liquid as operating liquid can reach the suction side pressure around 50 mmHg. At suction pressure of 50 mmHg, the pressure at the suction pipe which connected to the reactor and reactor's top
Condenser is also 50mmHg. Now our boss asks us to maintain the reactant at 130C for 1hr at full vacuum condition, but the vacuum pump suction side is 50 mmHg.

How this liquid ring vacuum pump (50 torr) to be achieved to this full vacuum condition? I wonder is anyone to make this 50 torr vacuum pump to work in full vacuum condition by adjusting the compression pressure? Or this full vacuum condition is a mission impossible step.

Thank you very much if you can kindly provide any suggestion or a hint. Happy Merry Christmas!!

 

[quark]

Theoretically, vapour pressure of sealing liquid at liquid temperature is the minimum pressure possible. Full vacuum is an impossible condition but there are technologies to give you closer values if you define what the final vacuum is. Dry pumps can easily get you close to 10 mm Hg absolute.

 

[MortenA]

Quark has is right - and the vaoupr pressure of MeOH at 130 deg C is >>1 bar

ref

http://en.wikipedia.org/wiki/Methanol_(data_page)

I think that wrt. to the performance of your pump you are referring to a datasht. that considrs a pump with water as the liquid.

Best regards, Morten

 

[cwinter]

If you can cool your liquid ring pump then perhaps you can keep the pressure at 50mmHg or lower. The reactor can be hot and far away.
(as long as you do not have any liquid Methanol in the reactor - you should be OK).

 

[MJCronin]

Quark is correct, Liquid ring vacuum pumps have limitations.

To achieve a higher vacuum, you must consider a different type of vacuum pump.......

http://en.wikipedia.org/wiki/Vacuum_pump

MJCronin
Sr. Process Engineer