Re: GAS-L: NOx and gasifiers

[Tami Bond <tami.bond@noaa.gov>]

Oh, I should have read those more detailed messages before I responded
to Tom...

I think Harmon was talking about cleaning NOx out *before* the engine,
yes? So the relevant temp would be gasification temp, not engine temp
which would be a fair bit higher. The issue raised by Claus is
different-- cleaning up the woodgas to affect the final exhaust content.

Claus says: 

> Our measurements of emissions from an IC engine[1] fueled by superficial
> wood gas (mixed from flask without e.g. tars and NH3) showed NOx
> emissions for lambda<1.5. Indeed they were lower than for natural gas
> with this engine, but not negligible.

It is interesting that woodgas produces lower emissions than natural
gas. I guess the gasification/engine sequence might be similar to the
'rich-quench-lean' strategy for NOx reduction in turbines, just a little
more physically spread out. Never thought about that before!

> At the Biomass Conference in Amsterdam last week, a poster claimed that
> 80-100% of NH3 was converted to NOx during flame(!) combustion.
> At the same conference Markus Kleinhappl presented measurements of NH3...

Questions following this and Mike's info:

- What is adiabatic flame temp (range) of woodgas?
- Does most NOx in final exhaust come from thermal mechanism or NH3
conversion? 
- Where does the NH3 in woodgas come from? Mike says either air or fuel,
but Tom says there is low N in the feedstock. The source matters because
you might expect to have NOx problems with different feedstocks if the
fuel is the major source.

Tami

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