[Gasification] eliminating carbon monoxide from coal gas

[Doug Williams]

Hi Greg and Tom T.

As you have turned this discussion around to engines away from the simple question of how one might separate CO+H2 as a research tool, I would like to add a couple of engine observations that may be of relevance. I only have a Table (9-20  from page 9-19) extracted from Perry and Chilton’s Chemical Engineers Hand Book, Basic Considerations in the Combustion of Hydrocarbon Fuels with Air, for reference, but don't doubt the authors credentials(:-)

It quotes: Hydrogen 51,571Btu/lb      Spontaneous Ignition temperature of 1.066F,      Flame speed of 8.7ft/sec.

Carbon Monoxide.   Btu not  stated     ""          ""       ""        ""   1,128F         ""    ""  "  1.3ft/sec.

Methane.           21,502Btu/lb         ""         ""        ""        ""  1,150F         ""    ""  "  1.1Ft/sec.

As a mixture, the slower burning CO and CH4 provide the high torque at lower RPM, and H2 provides the punch or kick when a fast response to higher RPM or load change is required. De-rating can only be improved by squeezing in more gas/air mixture, given that your gas falls within an average 15% H2,18-20% CO, and <3% CH4. The presence of CH4 is also a precursor for condensible tar and light pyrolytic oils if over 3%, so can cause more problems than it's energy value. When you are testing differing biomass in a gasifier with an engine generator, it is common to see the power output increase as the carbon beds change from the original fuel type to the new, as the need for differing bed parameters begins to allow CH4 and condensible tars to join the gas stream in an uncracked state.

The above table were used to compile the Fluidyne Engine Tables www.fluidynenz.250x.com  and the comments from spending a lot of time (40 years) next to gasified engine generators. Many new to gasification can take what we offer as comment completely out of context, so it helps if you can qualify how the exchange of information and ideas may be considered, as we see anecdotal information passed on as fact in an eye blink!

Hope this may be of assistance for this topic.

Doug Williams,
Fluidyne.


On Mon, 13 Apr 2015 14:03:01 -0600
Greg Manning <a31ford at gmail.com> wrote:

> Leland, I totally agree with you, that is why I thought the "CO" was
> Typo....
> Greg
> On Apr 13, 2015 1:09 PM, <linvent at aol.com> wrote:
> 
> >  My question is why does one want to get rid of CO in the fuel gas as it
> > has a higher heating value than that of hydrogen and without CO, an engine
> > derating is much more significant just using hydrogen. The one component
> > that significantly increases engine performance is methane in the produced
> > gas as small quantities make a significant improvement in engine rating on
> > produced gas.
> > Sincerely,
> > Leland T. "Tom" Taylor
> > Thermogenics Inc.