Whoops, NOx and True Flame temperatures

["Tom Reed" <tombreed@attbi.com>]

Dear Doug, Graeme and all:

Whoops!  Sorry my last post was to Graeme when it should have been to Doug
Williams (father?).  I DO know the difference....

TOM REED
----- Original Message -----
From: "Tom Reed" <tombreed@attbi.com>
To: "Graeme Williams" <graeme@powerlink.co.nz>; <gasification@crest.org>;
"Stoves" <Stoves@crest.org>
Sent: Wednesday, June 26, 2002 5:34 AM
Subject: NOx and True Flame temperatures


> Dear Graeme and all:
>
> Glad to have confirmation of my NOx suspicions from Graeme.
>
> ~~~~~~~~~~
> However, I would warn all about flame temperatures measured with
> thermocouples.  The thermocouples radiate the heat transferred by the
flame
> VERY efficiently, and so can come to a temperature as low as half the true
> flame temperature.  This can be fixed using a suction thermocouple which
> increases the velocity and heat transfer over the thermocouple (and the
cost
> and complexity of the measurement).
>
> The adiabatic flame temperature of most fuels is about 2000 C +/- 200 C.
> (See North American Handbook, Vol 1).  Acetylene in air is 2632, CO is
2468,
> H2 is 2210, methane is 1920, methanol is 1910  and PRODUER GAS is 1654  C
> (because it is so dilute).
>
> If you hold a platinum wire (or nichrome) in a methane Bunsen burner
flame,
> it will reach a yellow to white heat, 1000 to 1100 C, even though the true
> flame temperature is 1920.
>
> So beware most quoted "flame temperatures".
>
> Yours truly,            TOM REED                BEF GASWORKS
> ----- Original Message -----
> From: "Graeme Williams" <graeme@powerlink.co.nz>
> To: <gasification@crest.org>
> Sent: Wednesday, June 26, 2002 2:43 AM
> Subject: GAS-L: NOx and Gasifiers
>
>
> > Dear Colleagues,
> >
> > During the years that we have been playing with producer gas, both in
> > engines for power generation and for process heat in timber kilns, at no
> > time has NOx been an emission problem.
> >
> > Although gasifier temperatures are high, it appears that it just doesn't
> > happen in this process although I suppose anything is possible given
> certain
> > conditions existing.
> >
> > The adiabatic flame temperature of clean producer gas ie tar free has
> never
> > exceeded 1100 degrees Celcius, in our experience, and in fact is one of
> the
> > measures we use to check to see if tar is present in the gas stream.
> >
> > Hope this helps.
> >
> > Doug Williams
> > FLUIDYNE GASIFICATION
> >
> >
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>



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