Hi,

I have a mixture of hydrocarbons with a wide range of boiling points (200-620 centigrade). I want to distill this mixture in vacuum. I have no problem for distillation of light fractions with boiling points less than 450oC. But for the fraction with boiling point in the range of 450-620 centigrade, I need to do the distillation in high vacuum (0.01-0.001 mbar)! How cant I get this amount of vacuum by combination of different vacuum pumps (Roots Vacuum Pump; SIDE CHANNEL Vacuum Pumps; Liquid Ring Vacuum Pumps and Rotary vane Vacuum pump!)?

The size of the distillation chamber (Made of black iron sheets) which we use is about 50000 lit, so the speed of vacuum should be more than 1500 m3/h. Is there any suggestion for me? Which vacuum pumps should I use? How should I connect them together (parallel or serial?)?

 

For smaller systems I've used a turbomolecular pump (which may be what you're calling a rotary vane pump) in series with a mechanical roughing pump (in our application a scroll pump for oil-free operation).

For the record, a turbomolecular pump is not the same as a rotary vane pump.

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

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

 

However I suggest that the OP talks to the people who design and sell pumps.

They have lots of experience with that sort of question.