[Stoves] Traditonal Charcola Making Process / retort

[AJH]

On Fri, 29 Jun 2007 13:04:19 +0800, Crispin Pemberton-Pigott wrote:

>But stick with wood for the moment: How many Kg of 15% MC wood is needed to
>gas-fire a stove needing 3.5 KWHe, using what is basically a charcoal making
>operation to generate the gas.

I'll reword that:

How many kg of 15% mc (wet basis) is needed to generate sufficient
offgas, when pyrolysed to 500C (typical charcoal kiln temperature or
TLUD yielding 80+% fixed carbon), which when burned to fire the kiln
will provide sufficient heat and temperature to be equivalent to an
electrci furnace using 3kWhr of electrcial energy to fire a clay stove
body? Looks easy enough to calculate...

The variables you haven't given are the  temprature and times of
firing. Although you gave a figure of 50% efficiency for the gas kiln
(presumably compared with 100% delivery of heat into the kiln by the
electrci elements). As far as I can see pottery firing only requires
sufficient heat and energy to raise the pottery to the correct
temprature to start the vitrification plus supply the minute amounts
of energy to cause the fusion, all other heat is lost. Also bear in
mind the natural gas flame has a higher adiabatic flame temprature
than the pyrolysis offgas flame.


AJH