[Gasification] Gas Sampling

Indika Gallage indika at efpl.org
Thu Jun 29 10:14:14 CDT 2017

Hello Doug,

The gasifier has not been tested yet, but the designers claim to have 50% CO
in the gas with previous gasifiers, which was unimaginable to me. When we
were speaking of sampling the gas, we have been warned that the CO of the
gas may convert while sampling. This is why  I am researching on the fact. 


Certainly, the most sensible thing is a directly coupled gas analyser. The
equipment is rather costly; we will have to use the inline measurements if
we get lower readings from sampling to confirm.


Thank you for your time and a very clear explanation.


Best Regards 





From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of Doug
Sent: June 28, 2017 8:30 PM
To: gasification at lists.bioenergylists.org
Subject: Re: [Gasification] Gas Sampling


Hi Indika,

The short answer to your question is no, water vapor as you describe will
not result in lowering the CO content of your gas sample. It is not clear if
you expect to get 50% CO from your gas, which when analyzed has a lower CO
content. I have never seen producer gas with 50% CO content, but if you had
a directly coupled gas analyzer measuring continuously, you could expect to
see fluctuations depending on the system design and variation of fuel being
gasified. Any gas sample is only valid for the moment in time that it was
taken, but the key is to minimize, or understand why the system fluctuates.

We have had gas analysis done over 35 years, and samples collected in metal,
glass, and gas  bags, in each case water was used to collect the sample by
drainage suction. None of the measuring laboratories had issues with residue
moisture affecting the results. The only exception to the containment
limitations, were the gas bags, where-by the analysis must be done within
three days due to the H2 content escaping through the bag walls.

Hope this might help.

Doug Williams,




On 28/06/17 07:57, Indika Gallage wrote:



I have been using gas chromatography to analyse the producer gas mixture. I
would like to know, if the gas sample extracted from the gasifier will
change it's CO composition significantly with the presence of water vapor?
We have to sample a gas with 50% CO. 


I have gone through a research paper where they suggest that the composition
will not significantly vary, but these samples did not have the high
concentration of CO. However, the content of CO had the most variation out
of all the gasses, the conclusion of this paper was that the gasses did not
change composition at -15 C, 15c , 45C at 2758 and Kpa 8274 Kpa pressure.
("Evaluation of syngas storage under different pressures and temperatures",
Yang P,2009, Applied Engineering in Agriculture) 


can some one shed some light on this?



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