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<DIV>Paul and listers, Hello,</DIV>
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<DIV>People have expressed safety concerns over the underground concrete designs used in China, India, Nepal and elsewhere in Asia. An explosion in an underground chamber would throw slurry out of the reservoir, or, at the worst, cause the dome to crack, throwing soil around. </DIV>
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<DIV>I know which I would prefer: with the choice of being covered in slurry (if I was standing in the wrong place) or being in range of shrapnel from a metal tank. </DIV>
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<DIV>Best wishes,</DIV>
<DIV>David</DIV>
<DIV><A href="mailto:davidf@kingdombio.com"><EM><FONT size=2>davidf@kingdombio.com</FONT></EM></A></DIV>
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<DIV style="FONT-SIZE: 12pt; FONT-FAMILY: Tahoma"><FONT size=2 face=Verdana><FONT color=#604c78>******************************************************<BR>Dr David Fulford CEnv MEI, 15, Brandon Ave, Woodley, Reading RG5 4PU<BR> Tel: +44(0)118 326 9779 Mob: +44(0)7746 806401<BR>Kingdom Bioenergy Ltd, </FONT><A href="www.kingdombio.com"><EM><FONT color=#604c78>www.kingdombio.com</FONT></EM></A><FONT color=#604c78>, </FONT><A href="mailto:davidf@kindombio.com"><EM><FONT color=#604c78>davidf@kindombio.com</FONT></EM></A><BR><FONT color=#604c78> Skype Identity: djfulford</FONT></FONT></DIV></DIV>
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<DIV>------ Original Message ------</DIV>
<DIV>From: "Paul Harris" <<A href="mailto:paul.harris@adelaide.edu.au">paul.harris@adelaide.edu.au</A>></DIV>
<DIV>To: <A href="mailto:digestion@lists.bioenergylists.org">digestion@lists.bioenergylists.org</A></DIV>
<DIV>Sent: 30/10/2013 00:43:33</DIV>
<DIV>Subject: Re: [Digestion] Photosythetically Conditioned Biogas Compression</DIV>
<BLOCKQUOTE class=cite cite=52705635.3010008@adelaide.edu.au type="cite">
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<DIV class=moz-cite-prefix>G'day All,<BR><BR>Variable Volume (VV) storage has a number of advantages over Compression (C), which at 20 psi will not give you much advantage anyway. VV can be plastic, avoiding the shrapnel problem, and saves the cost/complication/energy consumption of C. You also get a simple visual indication of gas production/use with VV. Several members of this list can probably verify that with a plastic storage you get a hole and a rapid flare of gas rather than a large explosion<BR><BR>When we were talking about storing biogas at our University research site the maintenance supervisor said we would have to use steel containers and I thought to myself that I would rather stand alongside a plastic VV storage during a fire than be anywhere near a steel cylinder.<BR><BR>Happy Digesting<BR><PRE class=moz-signature cols="72">HOOROO
Mr Paul Harris
Visitor to The University of Adelaide</PRE>On 30/10/2013 8:00 AM, David wrote:<BR></DIV>
<BLOCKQUOTE class=cite cite=mid:527028F2.6020900@h4c.org type="cite"><BR><BR>Jacob,<BR><BR>Take 2,<BR><BR><BR>
<DIV class=moz-cite-prefix>On 10/29/2013 11:08 AM, Jacob Douenias wrote:<BR></DIV>
<BLOCKQUOTE class=cite cite=mid:CAK9JyBA-5apcJGkgRPoehY40w2cxy6WEvq9WiAhzvNi_58YWCQ@mail.gmail.com type="cite">Hi all! <BR><BR>Excited to join this group. I am a researcher working at carnegie mellon university in pittsburgh.I am working on a startup where we are making biogas at home and biologically purifying this gas.<BR><BR>Our gas composition at the end of our system is comprised of about 80% methane and 20% oxygen. We are concerned about the storage and possible compression of this gas due to the presence of oxygen in the gas. I know that 80% methane is well above the upper explosive limit of methane (our working conditions are 15-20psi for final gas compression and 60-80 degrees farenheight). I know it is bad practice to have oxygen mixed with combustible gas but at our composition should we worry about safely compressing this mixture to a low pressure (15-20psi) and storing it in gas cylinder? I would really love to hear what you think as I am just an architect who happens to read a lot about biochem. </BLOCKQUOTE><BR><BR>The upper limit of flammability for methane in air is of course about 15%. I took a bit of time between tasks to look it up, and in pure oxygen, the upper limit is 61%. (The lower limit is about the same in either case: ~5%.) There is a formula proposed by Zabetakis <LINK rel=File-List href="file:///C:%5CUsers%5CDavid%5CAppData%5CLocal%5CTemp%5Cmsohtmlclip1%5C01%5Cclip_filelist.xml"><LINK rel=themeData href="file:///C:%5CUsers%5CDavid%5CAppData%5CLocal%5CTemp%5Cmsohtmlclip1%5C01%5Cclip_themedata.thmx"><LINK rel=colorSchemeMapping href="file:///C:%5CUsers%5CDavid%5CAppData%5CLocal%5CTemp%5Cmsohtmlclip1%5C01%5Cclip_colorschememapping.xml">
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which indicates-- if I've done my figgers correct-- that at 20 PSI it should increase to perhaps 63% methane in oxygen. But note: that is an extrapolation, not a test result. And I would not call 80% "well above" that extrapolated limit.<BR><BR>I have to say, that particularly if I had children in the house-- you did say "biogas at home", and you did say "we"-- I would not want to take any implied risks. In the case of the information I have just given you, for example, maybe it's true, maybe I made a mistake. Maybe you didn't measure the gas ratio correctly and maybe it will change, if the presumed algae get frisky. Maybe, maybe.<BR><BR>If it were me, I would have a tendency to look at the gas cylinder and wonder whether I was unintentionally planning on making a bomb with its own built-in shrapnel, and then I would begin to wonder how I might store the gas some other way, such that if the marginally unthinkable did happen, nobody would be likely to be nearby, and nothing sharp and glittering would be hurled hither and thither as a result.<BR><BR><BR><BR><BR><BR>d.<BR>
<DIV class=moz-signature>-- <BR>
<DIV><SPAN style="FONT-SIZE: 110%">David William House<BR></SPAN>
<DIV style="FONT-SIZE: 80%; PADDING-LEFT: 3em">"The Complete Biogas Handbook" <CODE><A href="www.completebiogas.com" moz-do-not-send="true">www.completebiogas.com</A></CODE><BR><EM>Vahid Biogas</EM>, an alternative energy consultancy <CODE><A href="www.vahidbiogas.com" moz-do-not-send="true">www.vahidbiogas.com</A><BR><BR></CODE></DIV><CODE>
<DIV style="PADDING-LEFT: 2em">"Make no search for water. But find thirst,<BR>And water from the very ground will burst."
<DIV style="FONT-SIZE: 80%; PADDING-LEFT: 2em">(Rumi, a Persian mystic poet, quoted in <EM>Delight of Hearts</EM>, p. 77) <BR><BR><A class=moz-txt-link-freetext href="http://bahai.us/" moz-do-not-send="true">http://bahai.us/</A></DIV></DIV></CODE></DIV></DIV><BR>
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