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How to Vaporize 1,3 Butadiene before Injection
Posted: Wed Oct 17, 2007 1:08 pm
by atharwasim
on my online GC, I am trying to inject calibration gas with 89% of 1,3 Butadiene through a vaporizer at 80 Deg C and there is always liquid at Vaporizer outlet, even I increased to temperature to 90 Deg C, What shall do?
Calibration Cylinder detail is as follows,
Cis-2-Butene: 2%, 1,2 Butadiene: 3%, But-1-yne: 0.3%, 1,3 Butadiene 89%
It is 10 litter cylinder pressurized with 200 psig helium Gas, the mixture contents are in liquid form
Regards,
Posted: Wed Oct 17, 2007 2:16 pm
by Peter Apps
Use a slower flow
Peter
Posted: Wed Oct 17, 2007 3:41 pm
by chromatographer1
Peter made a good call.
But also make certain that you do not have backpressure on the outlet vent line. If you have polymerization products partially blocking the vent line you can be recondensing the butadiene to the liquid phase. Watch you do not raise your temperature too high or you will get rubber forming or your blend could be chemically reacting and giving you a false sample.
best wishes,
Rod
Posted: Sat Oct 20, 2007 6:49 am
by atharwasim
Peter made a good call.
But also make certain that you do not have backpressure on the outlet vent line. If you have polymerization products partially blocking the vent line you can be recondensing the butadiene to the liquid phase. Watch you do not raise your temperature too high or you will get rubber forming or your blend could be chemically reacting and giving you a false sample.
best wishes,
Rod
My flow is 100 cc/min at 0.5 bar pressure, and vent to connected atm header, obvoiusly no back pressure. can some one suggest me the temp and other parameters required to vaporize this cal mixture?
Waseem
Posted: Sat Oct 20, 2007 6:31 pm
by Bruce Hamilton
Maybe I'm missing something here, but I haven't checked the proeprties of buitadiene, but let's assume it's similar to LPG, and the 100 cc/min flow is for the vapour phase.
I would have thought the vaporiser would only be putting in sufficient heat to ensure the 0.5 Bar sample was held gaseous, maybe at a temperature of around 40C?. You should ensure your outlet etc. are all at temperature to prevent any recondensation at the 0.5 bar pressure, or reduce the pressure further.
You should not need to put a lot of heat in, as the pressure reduction will do most of the change of state work, and 100 cc/min of gas is only 0.4 cc/min of liquid.
Bruce Hamilton
Posted: Fri Nov 09, 2007 3:39 pm
by Ron
Are you sure the liquid is butadiene?