Select permanent gases

[angelcaravaca1985]

Good afternoon

in order to work in steam reforming, I need to measure the following components: H2, O2, N2, CO,CH4 and CO2

I have a GC Agilent 7820 A GC. I consulted to the company, and they suggested me to use the "Select Permanent Gases" capilary column package (http://www.chem.agilent.com/en-US/produ ... fault.aspx).
It consists in a combination of a kind of a Porapak Q, and a molecular sieve capilary columns, which are optimised to measure in paralell all the above mentioned compounds
Does anyone have experience with this system?
should I buy it?
thank you very much
Ángel

[GasMan]

Angel,

If this is a short term project, this column would probably work. If this is to be a permanent analysis, I would not recommend it. The reason is that the CO2 will be absorbed on the Molecular Sieve column, and you will slowly see degradation in the separation on this column. The columns can be re-conditioned, but you usually condition Mol Sieve at 350°C, and Porapak Q has an upper limit of about 250°C. I do not know how these columns are installed and if it is possible to separate the columns so that they can be conditioned separately. One would normally use this column combination for this analysis, but the columns would be in series and connected together via a column isolation valve. The sample is injected into the Porapak Q column, where all of the gases except the CO2 will pass quickly through the Porapak Q column into the Mol Sieve column. The Mol Sieve column is then isolated and allows the CO2 to go directly to the detector, bypassing the Mol Sieve column. Once the CO2 has eluted, the Mol Sieve column is switched back into the carrier gas stream, and your gases can elute to the detector.

Gasman

[jearles]

I've ran these using a Haysep DB column. Done on a SRI 8610C, TCD with Argon Carrier Gas.