[Stoves] : Re: Insulation and stove life

[Paul Olivier]

Paal,

One thing I look for on my burner is that all burner holes support a flame
throughout the process. If channeling occurs during the process or if char
is being burned as the process comes to a close, then one can see burner
holes that do not support a flame. This means that CO2 is being discharged
from the burner holes, and of course CO2 does not burn. When CO2 is formed,
this represents a big inefficiency, since combustion takes place far below
the pot. When this happens the sides of the reactor can easily turn red hot
and melt. I do not know how it is possible to spot the presence of CO2 if
the top of the reactor stays open and does not have a lid with burner holes.

If one turns up the fan a bit too high resulting in channeling, it can
happen that only a few holes (among a total of 80 in my case) do not
support a flame. If I turn the fan down a bit and shake the reactor, this
problem is immediately corrected. Also the effect of the presence of CO2
can be spotted by the cook in another way. The distribution of heat to the
pan is not even.

Also many of the positive characteristics of biochar are lost when biochar
is combusted and is reduced to ash. The combustion of biomass and biochar
takes place when channeling occurs, and the combustion of biochar takes
place if the fan is not turned off at the end of the process. Rice hull ash
and rice hill biochar are not at all the same thing when it comes to
growing plants. Also rice hull ash can easily contain cristobalite, which
is a nasty carcinogen. Under ordinary conditions, no farmer should be
handling this stuff.

Thanks.
Paul


On Wed, Jun 12, 2013 at 1:06 PM, Paal Wendelbo <paaw at online.no> wrote:

>   Ron
>
> By end of flame the color of the char is red to yellow, that indicate a
> temperature of 700 to 800 ˚C and when there is no smoke, complete
> combustion has taken place. Is that not good for biochar?
>
> Regards Paal W
>
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-- 
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam

Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
http://www.esrla.com/
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