[Gasification] Fwd: RE: Whole log pyrolysis for char production was Re: W...

[Jason]

To Ken and all (Ken because you are actively designing),

as a novice, but somewhat successful, combustion system designer (does that
sound right?) I find it helpful to break down what you are trying to
achieve along with and the material or design considerations around this.
Having trained Architecturally there are three types of insulation to
consider: Reflective, Resistive and Capacitive. Thermal mass (ceramics) are
simply capacitive. In a batch burning system then the capacitance really
just smooths out the temperature variation over the cycle and is most
useful to elevate the low end. My way of thinking is that if you are
designing a two stage combustion system then resistive insulation in the
primary chamber may be the better approach to keep temperatures up. Kaowool
is cheap.

I am open to, or would even welcome, critique on that position.

My own system gets so hot that I risk too much pyrolysis too early and that
is why I have no need for any insulation. Early on I installed a
thermocouple and while it was still rising at around 100°C every 5 minutes
I measured 1050°C before the wires melted out of the thermocouple. I peak
at 850°C about one metre up the stack from the hottest point.

Regards

Jason


On Sat, Jan 4, 2014 at 7:48 AM, Doug <Doug.Williams at orcon.net.nz> wrote:

>
> Hi GF,
>
> Once the gases have formed and exists in a free space above the bed, it is
> unlikely to change due to the influence of refractory radiation. My
> understanding of this situation, is that you add more air to oxidise and
> combustion any hydrocarbons turning smoke gas into CO2 (cleaner emission),
> or like in a gasifier situation, pass it through an incandescent carbon bed
> at temperatures over say 1,000C> to enable the thermal disassociation to
> take place in a reducing environment. You end up then with the smoke gas
> being (theoretically) all producer gas hopefully hydrocarbon free (:-).
>
> I was informed that some steam locomotives in South Africa were converted
> to the type of gasifying principle and was used as an example of
> gasification during a conference there about 1985 from memory. I have a
> photo somewhere in the files.
>
> Hope this helps.
> Doug Williams,
> Fluidyne.
>
>
>
> > > On Jan 3, 2014, at 1:05 AM, GFWHELL at aol.com wrote:
> > >
> > >
> > > Regarding the reflected heat from the refractory: If you were to
> travel on the footplate of a steam locomotive at full regulator, you might
> observe a temperature of 2,500 f in the fire box. in which there is
> generally  a refractory (brick) arch above the grate which extends the
> flame pattern and generally helps the secondary air entering above the
> grate to insure compete combustion. I have observed these arches to glow
> bight Yellow, the surface of the brickwork actually  melting with the heat.
> I am certain the radiation has a  lot to do with complete combustion. Would
> this form of radiation help refine "smoke" (gas) breaking it down into
> short chain Molecules?
> > >
> > > GF
>
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