Hydrocarbon analysis

Chromatography Forum: GC Archives: Hydrocarbon analysis
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Wednesday, October 31, 2001 - 07:21 am:

Hello

I work on 3800 Varian GC natural gas analyser with 3 channel. One channel is for liquids fraction (condensate hydrocarbon) and this is limited on temperature (165 C) by the HayeSepT column which is a trap column for permanent gas channel.
C10 - C15 fraction has b.p. above 165 C.
Is my determination accurate in this case ?
Is there any phase with higher max. temp. to replace the HayeSepT ?

Thank You
Dana


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Monday, December 3, 2001 - 08:17 pm:

HayeSepT column is porus polymer suport, it is better for light hydrocarbon, for condensate ( C10 to C30), you can use CP-sil 5 CB megabore column, look varian aplications note for natural gas analysis...http://www.varianinc.com/cgi-bin/nav?varinc/docs/csb/gcnotes/index&cid=333758

good luck


Top of pagePrevious messageNext messageBottom of pageLink to this message  By James Templet on Tuesday, March 19, 2002 - 07:04 am:

I have a old model 002a Combustion Engineering gas chromatagraph with a FID detector. It is a 2 column, 2 valve , backflush arrangement to measure IPA and MEOH in a hydrocarbon stream.
The problem that I am having is that when I introduce the calibration stream to the analyzer, it takes around six cycles to reach the value of my standard gas. What might cause this problem?


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Rodney George on Monday, March 25, 2002 - 07:50 am:

I would guess that you have the calibration gas running at too low a flow rate for the active sites in the sampling system to saturate and allow a respresentative sample from reaching the sampling valve. Either that or your columns/sample loop have active sites which are doing the same thing. In any case until all the absorptive sites are saturated you will not get a respresentative amount of those alcohols to your detector.
Try turning up the calibration gas flow and see if that helps in reducing the number of cycles.
If that does not help then the problem is probably in the GC itself and not the sampling system.
I would then replace the sampling loop or columns, especially column #1 and see if that fixes the problem. If that does not do it, then replace the sampling valve.
But the most common cause is 'cost saving' by having the expensive calibration blend flow rate being set too low (or maybe it is almost empty!).
Good luck.
Rodney George
Senior Research Chemist
Gas Separations Research
Supelco
rgeorge@sial.com


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Fred on Tuesday, March 30, 2004 - 08:17 am:

What is the proper way to vent a Hewlett Packard 5890 Series 11 Gas Chromatagraph?


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Tuesday, March 30, 2004 - 11:43 am:

The detector you wish to vent, the hot air from the oven you wish to vent?????


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