Hydrogen gas separation w/TCD

[jhobbs]

Hi, I am tring to separate hydrogen from different gases. I am using a TCD to determine this but I am having problems with coeluention of other gases (CO, CO2, N). Has anyone run into this problem and has suggestions.
Thanx
JEH

[chromatographer1]

Molecular Sieve 5A or 13X packed or micropacked columns

Carboxen 1004 or 1000 packed or micropacked columns.

Send me your email address and I can send you chromatograms.

Rodney George
Senior Research and Development Scientist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823

814-359-5737 voice
814-359-5459 fax
rgeorge@sial.com

[Answer Man]

A ShinCarbon column from Restek Corp should work well. Unlike a MSieve column, a ShinCarbon will not absorb CO2. If you chose this column, however, consider the 1/8 inch column as the TCD is not a sensitive detector.

http://www.restek.com/Fantasia/pdfCache/59519a.pdf

[puff]

I have similar problem, but I have also water vapour (2-4% vol) in analyzed gas. I have TCD and hydrogen as a carrier gas. Can I use mol sieve 13X to separate CO N2 and CO2 from a wet gas? It there a risk of deactivation of mol sieves and how often it need to be regenerated? Thanks for answers.

[BG]

hi,

effectivly if you have a lot of water ,it should be necessary to regenerate regulary.In general the symptom is shortless retention time....and bad separation.
But i have a question: you want to separate H2, CO, CO2 and N2.....with H2 as carrier gaz ?
Other point if you don't want to absorb CO2 on the molecularsieve heat the column at 350°C and this compound will elute.........and maybe water won't be a pb....

(sorry for my english!)

[puff]

Yes, I have H2, CO, CO2, N2 (sometimes Ar) and water vapour in analysed gas. I want to separate CO2, CO and N2 mostly. H2 is carrier gas, concentration in sample of H2 isn't interesting for me. I wonder if mol sieve will be applied for analysis it will be easy to use? And how many samples (50ul sample loop, 2-4% vol water vapour, 0-1% vol CO2) can be dosed between regenerations od sieves (2m 1/8")? I want to avoid time-consuming regenerations.
Thanks for sugestions

[chromatographer1]

I can send you chromatogram of using a Carboxen 1004 column which separates the analytes you desire and does not require regeneration of the packing due to water.

Email me if interested.

Rodney George
Senior Research and Development Scientist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823

814-359-5737 voice
814-359-5459 fax
rgeorge@sial.com

[BG]

OK; now , to know how much time is necessary to regenerate your column it's necessary to define yourself the frequency compared to your system in its globality.

You can't say for all systems doing the same analysis: "every 2 days i regenerate..."
So make analysis and when you see degradation in time or in resolution after X injections, say OK, now i will regenerate my column systematically after (X-10) injections for example..........sometime people regenerate every day. So you will understood .....there is no rules!!
I hope i've been clear with my bad english !

[chromatographer1]

The amount of time it takes is dependent upon how much water is in your carrier gas and in your samples.

This can vary. Analysts usually review the separation of the O2 from the N2 or from the methane peak. When the separation is marginal, the column is pulled and regenerated.

It is much nicer NOT to have to regenerate the column, that is why Carboxen 1004 is preferred if it can do the separation in the time required by your application.

It does require more column and more time but DOES NOT REQUIRE to be regenerated to remove water. Water DOES NOT AFFECT the separation characteristics. I have chromatograms I can share that demonstrate this.

best wishes,

Rodney George
Senior Research and Development Scientist
Gas Separations Research
Supelco
595 North Harrison Road
Bellefonte, PA 16823

814-359-5737 voice
814-359-5459 fax
rgeorge@sial.com

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