<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=utf-8" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 8.00.6001.23501">
<STYLE></STYLE>
</HEAD>
<BODY dir=ltr bgColor=#ffffff>
<DIV><FONT face=Arial>Dear Rebecca</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Firstly, I am concerned about the "Cristobalite Link"
below, in that it seems to overlap "silica", "cristobalite", and other forms of
quartz. See: <A
href="http://www.quartzpage.de/gen_mod.html">http://www.quartzpage.de/gen_mod.html</A> showing
how various forms of quartz exist at various temperatures.</FONT></DIV>
<DIV><FONT face=Arial>Note that "cristobalite" is one specific crystalline phase
of quartz.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Secondly, what is important is the "respirable" dust that
is actually respired. </FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>It is well known that respiring "silica dust" can cause
"Silicosis". It is well known that "Small Particulate Matter emissions" from
virtually any poor stove can cause serious health problems. Hence, the effort to
design "stove systems" that minimize "Small Particulate Matter Emissions" into
the living space, where they can potentially be respired.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Rice Hull Ash, even at 90% silica in the ash pit, is not a
problem, in that it is in the ash pit, where it is not respired. On the other
hand, an "apparently superior fuel" that only had say 25% silica content in the
ash pit would be vastly more hazardous, if it vented 10 or 100 times as much ash
into the living space, in respirable form.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>This is where competent and meaningful stove design and
testing comes into play. </FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>As has been said many times, "It is not so much the fuel,
but the stove system design, that is good or bad."</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Best wishes,</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Kevin</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=ravermeer@telus.net href="mailto:ravermeer@telus.net">Rebecca A.
Vermeer</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=paul.olivier@esrla.com
href="mailto:paul.olivier@esrla.com">Paul Olivier</A> ; <A
title=stoves@lists.bioenergylists.org
href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Cc:</B> <A title=jonnygms@gmail.com
href="mailto:jonnygms@gmail.com">Jon Anderson</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, June 14, 2013 3:44 AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Stoves] Fw: : Re: Insulation
and stove life</DIV>
<DIV><BR></DIV>
<DIV dir=ltr>
<DIV style="FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: 12pt">
<DIV>Hello Paul,</DIV>
<DIV>Larry just told me that the silica content of rice hull ash is over
90%. At the ETHOS 2013 Conference, I saw a TURBO stove developed in the
Philippines which used rice hull for fuel. Given your comment below
regarding cristobalite “which is a nasty carcinogen” and severely hazardous to
human health (see link below), would you recommend the use of rice hull
as a household fuel for cookstoves? </DIV>
<DIV> </DIV>
<DIV>Rebecca Vermeer</DIV>
<DIV> </DIV>
<DIV>CRISTOBALITE LINK:</DIV>
<DIV><A title=http://nj.gov/health/eoh/rtkweb/documents/fs/1657.pdf
href="http://nj.gov/health/eoh/rtkweb/documents/fs/1657.pdf">http://nj.gov/health/eoh/rtkweb/documents/fs/1657.pdf</A></DIV>
<DIV>
<DIV
style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none"><B></B></DIV></DIV>
<DIV>
<DIV
style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none"><B></B> </DIV></DIV>
<DIV>
<DIV
style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none"><B>From:</B>
<A title=paul.olivier@esrla.com href="mailto:paul.olivier@esrla.com">Paul
Olivier</A> </DIV>
<DIV style="FONT: 10pt tahoma">
<DIV style="BACKGROUND: #f5f5f5">
<DIV><B>Sent:</B> Wednesday, June 12, 2013 12:01 AM</DIV>
<DIV><B>To:</B> <A title=stoves@lists.bioenergylists.org
href="mailto:stoves@lists.bioenergylists.org">Discussion of biomass cooking
stoves</A> </DIV>
<DIV><B>Subject:</B> Re: [Stoves] : Re: Insulation and stove
life</DIV></DIV></DIV>
<DIV> </DIV></DIV>
<DIV
style="FONT-STYLE: normal; DISPLAY: inline; FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: small; FONT-WEIGHT: normal; TEXT-DECORATION: none">
<DIV dir=ltr>
<DIV>
<DIV>
<DIV>
<DIV>Paal,<BR><BR></DIV>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.<BR><BR></DIV>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.<BR><BR></DIV>
<DIV>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. <FONT color=#ff0000>Also rice hull ash can easily contain
cristobalite, which is a nasty carcinogen. Under ordinary conditions, no
farmer should be handling this stuff.<BR></FONT></DIV>
<DIV><FONT color=#00ff00></FONT> </DIV>Thanks.<BR></DIV>Paul<BR>
<DIV class=gmail_extra><BR><BR>
<DIV class=gmail_quote>On Wed, Jun 12, 2013 at 1:06 PM, Paal Wendelbo <SPAN
dir=ltr><<A href="mailto:paaw@online.no"
target=_blank>paaw@online.no</A>></SPAN> wrote:<BR>
<BLOCKQUOTE
style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote>
<DIV dir=ltr>
<DIV dir=ltr>
<DIV style="FONT-FAMILY: 'Calibri'; FONT-SIZE: 12pt">
<P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><SPAN
lang=EN-US><FONT style="FONT-SIZE: 11pt">Ron</FONT></SPAN></P>
<P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><SPAN
lang=EN-US><FONT style="FONT-SIZE: 11pt">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?</FONT></SPAN></P>
<P style="LINE-HEIGHT: 13pt; MARGIN: 0cm 0cm 10pt" class=MsoNormal><SPAN
lang=EN-US><FONT style="FONT-SIZE: 11pt">Regards Paal
W</FONT></SPAN></P></DIV></DIV></DIV><BR>_______________________________________________<BR>Stoves
mailing list<BR><BR>to Send a Message to the list, use the email
address<BR><A
href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</A><BR><BR>to
UNSUBSCRIBE or Change your List Settings use the web page<BR><A
href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org"
target=_blank>http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</A><BR><BR>for
more Biomass Cooking Stoves, News and Information see our web
site:<BR><A href="http://stoves.bioenergylists.org/"
target=_blank>http://stoves.bioenergylists.org/</A><BR><BR><BR></BLOCKQUOTE></DIV><BR><BR
clear=all><BR>-- <BR>Paul A. Olivier PhD<BR>26/5 Phu Dong Thien
Vuong<BR>Dalat<BR>Vietnam<BR><BR>Louisiana telephone: 1-337-447-4124 (rings
Vietnam)<BR>Mobile: 090-694-1573 (in Vietnam)<BR>Skype address:
Xpolivier<BR><A href="http://www.esrla.com/"
target=_blank>http://www.esrla.com/</A> </DIV></DIV>
<P>
<HR>
_______________________________________________<BR>Stoves mailing
list<BR><BR>to Send a Message to the list, use the email
address<BR>stoves@lists.bioenergylists.org<BR><BR>to UNSUBSCRIBE or Change
your List Settings use the web
page<BR>http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org<BR><BR>for
more Biomass Cooking Stoves, News and Information see our web
site:<BR>http://stoves.bioenergylists.org/<BR><BR></DIV></DIV></DIV>
<P>
<HR>
<P></P>_______________________________________________<BR>Stoves mailing
list<BR><BR>to Send a Message to the list, use the email
address<BR>stoves@lists.bioenergylists.org<BR><BR>to UNSUBSCRIBE or Change
your List Settings use the web
page<BR>http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org<BR><BR>for
more Biomass Cooking Stoves, News and Information see our web
site:<BR>http://stoves.bioenergylists.org/<BR><BR></BLOCKQUOTE></BODY></HTML>