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<DIV><FONT face=Arial>Dear Jim</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Gasification is basically safe, as evidenced by the fact
that the vast number of gasifier start-ups go smoothly, without a backfire,
hiccup, poof, burp, explosion, etc. However, as you say, there are the
"outliers"that are the problem.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>It seems there are two general Operating Procedures where
there is a potential for an explosion:</FONT></DIV>
<DIV><FONT face=Arial>1: Start-up</FONT></DIV>
<DIV><FONT face=Arial>2: Re-fuelling.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>It is difficult, and perhaps impossible, to specify
Start-up and refuelling procedures that are absolutely 100% safe. Even with
reasonable care, it may still be possible for a poof to happen. One of the
difficulties in operating a gasifier is that with blow-backs and poofs happening
so infrequently, it may be difficult to see the particular pattern that must be
in place for the poof to happen. </FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Nobody on the Wood Gas List wants harm to come to their
Customers and Friends. I wonder if it would be possible for the Wood Gas List to
write a FAQ Document to answer the question </FONT></DIV>
<DIV><FONT face=Arial>"What is a reasonably safe procedure to follow for
start-up and refuelling of a gasifier?"</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Probably most of the experienced Wood Gassers have had
their incidents, with singed eyebrows, burned arm hairs, etc. Such a Proposed
Document would go a long way toward reducing these these embarrassing incidents
and would go a long way toward preventing possibly serious
injuries.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>I would like to suggest, as a starting point, a general
outline as shown below. Many people on the List have real and valuable first
hand experience in starting, re-fuelling, and operating gasifiers, and I would
encourage them improve on the "starting point outline."</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>1: General Introduction and Disclaimer</FONT></DIV>
<DIV><FONT face=Arial>2: How explosions and unsafe conditions
result</FONT></DIV>
<DIV><FONT face=Arial>3: Examples of Incidents resulting in poofs, flash-backs,
and explosions</FONT></DIV>
<DIV><FONT face=Arial>4: What likely went wrong, and how to prevent
them</FONT></DIV>
<DIV><FONT face=Arial>5: Suggested "Good Practise" for starting, refuelling, and
on-going operation.</FONT></DIV>
<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial>Once the outline is finalized, I would volunteer to do a
write-up which pulled together all the operating experiences and suggestions
into a document for review by the Wood Gas List.</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>
<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=jim@allpowerlabs.org href="mailto:jim@allpowerlabs.org">jim mason</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=gasification@lists.bioenergylists.org
href="mailto:gasification@lists.bioenergylists.org">Discussion of biomass
pyrolysis and gasification</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, December 10, 2012 3:44
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [Gasification] filtration
options and their varying discontents</DIV>
<DIV><BR></DIV><BR><BR>
<DIV class=gmail_quote>On Mon, Dec 10, 2012 at 12:41 PM, David G. LeVine <SPAN
dir=ltr><<A href="mailto:dlevine@speakeasy.net"
target=_blank>dlevine@speakeasy.net</A>></SPAN> wrote:<BR>
<BLOCKQUOTE
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class=gmail_quote>
<DIV bgcolor="#FFFFFF" text="#000000">
<DIV>On 12/09/2012 10:34 PM, jim mason wrote:<BR></DIV>
<BLOCKQUOTE type="cite">other than the explosive risk</BLOCKQUOTE><BR>There
is an interesting question here:<BR><BR>Is there an explosion risk if the
gasses have not been diluted by the atmosphere?<BR></DIV></BLOCKQUOTE>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV>well, in principle, the gas should not be diluted with air during typical
operation, and thus no explosion problem. you are correct. </DIV>
<DIV><BR></DIV>
<DIV>the problem is typical operation is variable. during start up you
always go through a stoich point as you move air out of the system and
progressively make gas. even if you leave the system full of gas on shut
down, start up in the reactor can pass lots of air until things get up to temp
again. this can easily result in a combustible mixture in the
system.</DIV>
<DIV><BR></DIV>
<DIV>we've found this to be a fairly significant operational reality that
needs to be addressed for regular users. similar for the impact of
backfires from the engine igniting the intake stream. while things are
"usually" ok, the marginal events can be quite, umm, compelling . . .
we've started adding more pressure relief points where typically not needed to
cover these outliers. we're also looking to add a flame arrestor right
at the manifold to prevent backfires propagating.</DIV>
<DIV><BR></DIV>
<DIV>again, you never use these during typical operation. somewhat like
an ESP shouldn't cause any problems during regular operation. it is the
outliers that are of concern. when you start running these systems
regularly, you tend to find all the outliers. and the ones you don't
find in house, those out in the fields certainly will.</DIV>
<DIV><BR></DIV>
<DIV>j</DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #ccc 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote>
<DIV bgcolor="#FFFFFF" text="#000000">Let's start with gasoline, if we
evacuate a bell jar and inject enough gasoline so there is a layer of liquid
gasoline on the floor or in a pan, and we generate a hot arc 1/2" above the
gasoline, will there be an explosion? The correct answer is "only if
there is an air leak." <BR><BR>Without an air leak, there will be no
oxidizer, fire (or explosions) require three things: Fuel, Oxidizer
and Ignition. Fuel is gasoline (in this case), Ignition is the spark,
but where is the oxidizer? <BR><BR>If woodgas has excess oxidizer as
it exits the reaction zone, it simply burns off the extra gas. So,
unless there is an air leak, the reaction can not occur. However, if
there is an air leak in _any_ fuel system, there will be severe
problems.<BR><BR>Dave 8{)<SPAN class=HOEnZb><FONT color=#888888><BR>
<DIV>-- <BR><BR><EM>"The first method for estimating the intelligence of a
ruler is to look at the men he has around him."</EM> <BR>Niccolo
Machiavelli<BR><BR><EM>
<CENTER>NOTE TO ALL:</CENTER><BR>When forwarding emails, please use only
"Blind Carbon Copy" or "Bcc" for all recipients. Please "delete" or
"highlight & cut" any forwarding history which includes my email
address! It is a courtesy to me and others who may not wish to have their
email addresses sent all over the world! Erasing the history helps prevent
Spammers from mining addresses and viruses from being propagated.
</EM><BR><BR>THANK YOU!
</DIV></FONT></SPAN></DIV><BR>_______________________________________________<BR>Gasification
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clear=all>
<DIV><BR></DIV>-- <BR>
<DIV><BR></DIV><BR><BR>Jim Mason<BR>Website: <A
href="http://www.whatiamupto.com"
target=_blank>http://www.whatiamupto.com</A><BR>Current Projects:<BR>
- Gasifier Experimenters Kit (the GEK): <A
href="http://www.gekgasifier.com"
target=_blank>http://www.gekgasifier.com</A><BR> - Escape from
Berkeley alt fuels vehicle race: <A href="http://www.escapefromberkeley.com"
target=_blank>www.escapefromberkeley.com</A><BR> - ALL Power Labs
on Twitter: <A href="http://twitter.com/allpowerlabs"
target=_blank>http://twitter.com/allpowerlabs</A><BR> - Shipyard
Announce list: <A
href="http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com"
target=_blank>http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com</A><BR>
<P>
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