[Stoves] response to Dr. A.D. Karve

[Michael J Antal]

Dear friends: as most of you know, our research results concerning the efficient production of charcoal have been recorded in dozens of archival journal publications over the past 30 years.  These archival journals are available in most university libraries around the world.  On numerous occasions I have offered to send these publications to anyone who requests them.  It's a pity that Dr. A.D. Karve never took the trouble to request them from me.

The conditions employed by Dr. Karve's chemical technologist have nothing to do with the conditions that we employ.  Dr. Karve can discover this for himself by reading our papers.

In our more recent work (during the past 6 years) we have reported our yields as fixed-carbon yields that reflect only the yield of fixed-carbon in the charcoal.  These yields have reached the thermochemical equilibrium limit.  These charcoals always have low (typically less than 25%, often less than 10%) VM.  All of our engineering papers always report the proximate analyses of our charcoals, including its VM content.

I will be glad to send Dr. Karve copies of our archival journal publications.  He only needs to request them.

Best regards, Michael. 
  
----- Original Message -----
From: adkarve <adkarve at pn2.vsnl.net.in>
Date: Friday, June 8, 2007 11:08 pm
Subject: [Stoves] 40% yield of charcoal
To: Discussion of biomass cooking stoves <stoves at listserv.repp.org>
Cc: Priyadarshini Karve <priyadarshini.karve at gmail.com>

> Dear Stovers,
> For the last couple of years we have been reading in this forum 
> about a
> charcoal making process that yielded almost 40% char. This process was
> developed in Hawaii. All that was revealed about this process was 
> that it
> was conducted under pressure.
> A chemical technologist in Pune (India), with whom we are 
> collaborating in
> another project, demystified this particular charcoal making process.
> According to him, the Hawaiian process mimicked the formation of 
> mineralcoal in nature, where biomass got heated while buried under 
> tons of soil and
> rock. One can imitate this process in a laboratory by filling wet 
> biomass in
> a pressure vessel and heating it to 200 degrees celsius.  The 
> water in the
> biomass gets converted into steam, which exerts pressure on the 
> biomass. The
> volatiles that normally escape from the biomass in the process of 
> pyrolysis,are not allowed to escape because the biomass is under 
> pressure. As a
> result, the tar is retained in the charcoal, adding to the weight 
> of the
> charcoal. That is the secret of the 40% charcoal yield. This 
> charcoal is
> however of a poor quality, because when one ignites it in a stove, the
> volatiles escape from it, giving rise to smoke and soot. Autoclaving
> distillery effluents with high organic content at 200 degrees C, under
> pressure, is already being practised in some distilleries in 
> India, as a
> measure of pollution control.
> Yours
> A.D.Karve
> 
> 
> 
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