I am about to buld my first bio system and would like to use a vacuum pump to lower the temperature of meth evaparation. Does anybody have a chart or table showing pressure and temps that might be useful?

Vapour pressure of Methanol at various temperatures:

Temperature (Centigrade) Pressure (mm Hg)

0 30.24
5 41.26
10 55.59
15 74.02
20 97.48
25 127.05
30 163.97
35 209.67
40 265.75
45 334.04
50 416.58
55 515.64
60 633.72
65 773.59
70 938.26


http://www.petesextension.com/biodiesel/CH3OHVP.gif

http://www.petesextension.com/biodiesel/CH3OHInHg.gif

Am I right to assume that 1000mm is 1bar or 1 atmosphere.

Here's a calculator if you want to find other temps / pressures...

http://www.s-ohe.com/Methanol_cal.html

quote:

Originally posted by jamesrl:
Am I right to assume that 1000mm is 1bar or 1 atmosphere.

A bar is defined as 100 kPa. Neither of these tie intrinsically to a column height of some reference fluid.

Conversion between mm Hg and Bar is:

1 mm Hg = 0.001 333 224 bar

Taken from this link

Horn

760mm Hg = 1 atmosphere = 14.7 Lb per square inch = 1 bar = 100kPa = 1014 mbar (approximately, as in they are all approximately equal and approximate 'normal' atmospheric pressure).

All the best

Pete