<div>Stephen's report suggests two explanations - <b>neither of them connected with AD</b>. </div><div><br></div><div>The biogas community must make sure that accurate reports are published ASAP, before false rumours spread and take root.</div>
<div><br></div><div>1. Gas is the obvious scapegoat for any explosion -<b> but</b> <b>was the cause gas at all?</b> Many fine powders can explode if suspended in air - which can easily happen in a poorly-run factory with a dust-laden atmosphere. Starch has been known as an explosion hazard for decades. I recall a major explosion many years ago at the Bird's Custard Powder plant in Banbury, England - and custard powder is 99% corn starch. Almost identical to tapioca starch!</div>
<div><br></div><div>2. However, if the cause was gas, a gas explosion at the point of use is just that - <b>a simple gas explosion.</b> It could as easily happen with natural gas, LPG, hydrogen or any gaseous fuel. The source of the gas would only be relevant if biogas was more explosive than other commonly used fuel gases - which it is not. It's safer than many in fact.</div>
<div><br></div><div><b>Could someone with good local connections offer to get the facts - then nail the rumours! </b></div><div><br></div><div>In the meantime,<b> I would suggest we avoid discussing the matter on this list - </b>or we'll just feed the rumours. We should also avoid discussing it anywhere as a "<i>biogas explosion</i>". It's just an "<i>explosion</i>" unless proven to be due to gas. And it's just a "<i>gas explosion"</i> unless evidence emerges that the nature of the gas is relevant. </div>
<div><br></div><div>Duncan Martin PhD</div><div>Cloughjordan Ecovillage</div><div>Ireland</div><div><a href="http://www.thevillage.ie">www.thevillage.ie</a></div><div><br></div><div> </div><div><br></div><div><br></div><div>
<br></div><div><br></div><br><br><div class="gmail_quote">On 1 March 2011 03:48, Dr Stephen P Etheridge <span dir="ltr"><<a href="mailto:spe@biotrix.asia">spe@biotrix.asia</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div lang="EN-US" link="blue" vlink="purple">
<div>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">Fellow AD Listmembers</span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">I wrote a note on 29<sup>th</sup>
Jan re: Biogas explosions, a subject that could potentially affect everyone in
this sector. I did not realise that I would have to revisit the subject so soon.</span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">Last Friday at 4.30pm a
major biogas explosion at a Tapioca Starch Factory in Thailand injured 31, 18
seriously. Since that time 7 have died of burns injuries and this number is
expected to increase. </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">See: </span></p>
<p class="MsoNormal"><a href="http://www.baanmaha.com/community/blogs/entry470.html" target="_blank">http://www.baanmaha.com/community/blogs/entry470.html</a><b><span lang="EN-GB" style="color:navy"></span></b></p>
<p class="MsoNormal"><a href="http://www.thaivisa.com/forum/topic/446507-40-workers-injured-in-gas-explosion-in-chaiyaphum/" target="_blank">http://www.thaivisa.com/forum/topic/446507-40-workers-injured-in-gas-explosion-in-chaiyaphum/</a></p>
<p class="MsoNormal"><a href="http://www.nationmultimedia.com/home/31-workers-injured-in-gas-explosion-in-Chaiyaphum-30149629.html" target="_blank">http://www.nationmultimedia.com/home/31-workers-injured-in-gas-explosion-in-Chaiyaphum-30149629.html</a></p>
<p class="MsoNormal"><a href="http://www.ethailand.com/news/five-more-workers-killed-raising-gas-explosion-toll-to-seven-91356.html" target="_blank">http://www.ethailand.com/news/five-more-workers-killed-raising-gas-explosion-toll-to-seven-91356.html</a></p>
<p class="MsoNormal"><a href="http://koratfart.com/isaan-news/chaiyaphum-31-workers-injured-in-gas-explosion/" target="_blank">http://koratfart.com/isaan-news/chaiyaphum-31-workers-injured-in-gas-explosion/</a></p>
<p class="MsoNormal"><a href="http://www.nationmultimedia.com/2011/03/01/national/Factory-death-toll-hits-seven-30149747.html" target="_blank">http://www.nationmultimedia.com/2011/03/01/national/Factory-death-toll-hits-seven-30149747.html</a><span lang="EN-GB" style="color:navy"></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">Clearly this has the
potential to affect everyone in this sector but certainly those of us woking in
Thailand and S E Asia. As far as I am aware this would be the worst biogas accident
globally.</span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">The biogas plant was
built by P&S Designs Co., Ltd. - </span><span lang="EN-GB"><a href="http://www.psbiogas.com/eng/intro.html" target="_blank">http://www.psbiogas.com/eng/intro.html</a>
, however the explosion was not at the digester, but at the starch bagging
plant where the biogas is used.</span><span lang="EN-GB" style="color:navy"></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">The english language
press indicates that burning wild grass entered a biogas pipe, which seems
strange since biogas pipes are sealed. The Thai language press indicates that “hot
work” (i.e. welding) was taking place over a biogas pipe. It is common in
Thailand to use HDPE pipe for biogas but usually only up to the building where
the “point of use” is. After that it should be, and usually is,
stainless steel. However, if welding was taking place near an HDPE biogas pipe
then this could have resulted in inital ignition.</span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">There have been two
prior small explosions here with faulty burner gas valves but this can happen
with any gas boiler coupled with poor maintenance (</span><span lang="EN-GB" style="color:navy">Previous explosions detailed in Appendix 2</span><span lang="EN-GB"> <a href="http://www.eeec.eng.ku.ac.th/files/Handbook-BiogasSafety-IndustryFactory.pdf" target="_blank">http://www.eeec.eng.ku.ac.th/files/Handbook-BiogasSafety-IndustryFactory.pdf</a>)</span><span lang="EN-GB" style="color:navy">. From personal experience in the Thai Tapioca
sector the bagging area rarely gets the respect it deserves as a potentially
explosive area (</span><a href="http://www.youtube.com/user/Jermani099#p/a/u/2/s02zYPE_AgM" target="_blank">http://www.youtube.com/user/Jermani099#p/a/u/2/s02zYPE_AgM</a>
). Having said that, there are more than 200 large scale Tapioca biogas plants
in Thailand and a biogas explosion has not happened before. </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I suspect that biogas may have ignited and that this may
have triggered a starch explosion in the enclosed bagging area, but without
substantial information this is pure speculation at this point.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I will let the group know if there are substantive
developments and I am sure we would all wish to express our sympathies to those
involved.<span lang="EN-GB" style="color:navy"></span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy"> </span></p>
<p class="MsoNormal"><span lang="EN-GB" style="color:navy">Stephen Etheridge </span></p>
<p class="MsoNormal"><a href="mailto:spe@biotrix.asia" target="_blank">spe@biotrix.asia</a></p>
</div>
</div>
<br>_______________________________________________<br>
Digestion mailing list<br>
<br>
to Send a Message to the list, use the email address<br>
<a href="mailto:Digestion@bioenergylists.org">Digestion@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/digestion_lists.bioenergylists.org" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/digestion_lists.bioenergylists.org</a><br>
<br>
for more information about digestion, see<br>
Beginner's Guide to Biogas<br>
<a href="http://www.adelaide.edu.au/biogas/" target="_blank">http://www.adelaide.edu.au/biogas/</a><br>
and the Biogas Wiki <a href="http://biogas.wikispaces.com/" target="_blank">http://biogas.wikispaces.com/</a><br>
<br>
<br></blockquote></div><br>