Chromatography Forum

Dear all,

I have a methanizer installed in my GC which is used to convert CO and CO2 to methane prior to analysing by FID. Does anyone know how to rejuvenate the nickel catalyst inside the methanizer without dismantling it? Thanks for your help.

If it has been poisoned by sulfur compounds then it is not readily possible to restore the device.

If it is only carbonized then use air and high temperature to burn the carbon off the catalyst.

Try to avoid putting hydrocarbons on your methanizer or any other components of your analysis except CO and CO2 by using a heartcut application.

best wishes,

Rod

HI
you can try to run samples with high H2 concentration at 370-400 deg C, we usually do thisand it works.
let me know

Yes, I agree with arie2044. He is correct, but sometimes it works and sometimes it doesn't. Given the cost of the catalyst column and the cost of wasted time usually it is more cost efficient to get a new catalyst column and get the work done.

best wishes,

Rod

Try to avoid putting hydrocarbons on your methanizer

Why? (Not disagreeing, just curious, since I've been arguing with an FID w/methanizer that refuses to stay in calibration, and isn't very linear.)

Because of the symptoms you describe. Many hydrocarbons will deposit carbon on the surface of the catalyst effectively blocking the catalytic conversion of CO and CO2 to methane. This is especially true of olefinic hydrocarbons.

Even if they don't block the active sites permanently, they may do so intermittently and cause inconsistent conversion of CO and CO2 to methane. I hope these reasons are true as they have been given to me as true.

Even so, the best reason I know not to allow hydrocarbons onto the methanizer column...................

because it works well, if you don't, and it works poorly if you do.

best wishes,

Rod

Hi
The best application for methanizer to keep it work stable, linear, etc., for years and i realy mean for years, is to use back flush valve between the column and the methanizer and to avoid any hydrocarbons heavier than C1 enter to methanizer. we use Porapack column, the ellution order is CO,CH4, CO2 and then backflush. we use 4 methanizers, and one of them we operate for more than 20 years, 10-12samples in 24 hours a day, every day year around. some samples contain hydrocarbons up to C7 and higher, some contain H2S & RSH, and other impurities. the system works.

Good luck

Thanks all for your suggestion.