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<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>At
least one fully-commercial gasifier/IC engine system makes deliberate use of
the exhaust->intake recycle loop with excellent results! Honor-bound not to
mention their name…<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Mark<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>
gasification-bounces@lists.bioenergylists.org
[mailto:gasification-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>Tom
Miles<br>
<b>Sent:</b> Monday, October 18, 2010 9:28 AM<br>
<b>To:</b> 'Discussion of biomass pyrolysis and gasification';
gasification@bioenergylists.org<br>
<b>Subject:</b> Re: [Gasification] the most important thing (quite possibly)
i've learned to date<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>Jim,<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>From my observation last
month the exhaust preheating/pyrolysis with your "pyrocoil" is the
one improvement that seems to account for your good quality gas (clean, low
CH4, High CO, H2). It would be interesting to test the boundaries of the
pre-pyrolysis in terms of maximum fuel MC and minimum particle size.<o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>Good concept that seems to
work. Similar systems are employed by Danish Technological University in
their Viking gasifier that is being commercialized (some day) by
COWI/Biosynergi. (http://www.biosynergi.dk/en/) You have commented on the
Viking on your site. I first saw it operating on straw at Lyngby, Denmark
(DTU), in about 1992. And by Thomas Koch (http://www.tke.dk/) in his three stage
gasifier. TERI in India has used the exhaust preheating with help from DTU. The
DTU experience has been well documented. <o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>It seems the engine
integration has led to a very productive stage of development. <o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'>Tom <o:p></o:p></span></p>
<p class=MsoNormal style='margin-left:.5in'><span style='font-size:11.0pt;
font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> gasification-bounces@lists.bioenergylists.org
[mailto:gasification-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>jim
mason<br>
<b>Sent:</b> Sunday, October 17, 2010 10:08 PM<br>
<b>To:</b> gasification@bioenergylists.org<br>
<b>Subject:</b> [Gasification] the most important thing (quite possibly) i've
learned to date<o:p></o:p></span></p>
</div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
<p class=MsoNormal style='margin-left:.5in'><br>
<br>
there are many variables to move around in a gasifier, and all of them are<br>
important. but once the basics are in order, i'm coming to the conclusion that<br>
the most impactful thing one can do/add/fix to the basic imbert design is to
use <br>
the ic engine exhaust to heat the incoming fuel.<br>
<br>
no, i don't have any numbers on this yet (we hope to get these soon), but the<br>
anecdotal experiences keep piling up. the biggest flexibility gains i'm finding<br>
both in poor fuel shape/size and moisture tolerance, as well as gas turndown
ratio, <br>
are from the ic exhaust heat exchanger. on our rig, this is called the
pyrocoil. other<br>
rigs call this something else.<br>
<br>
this is not terribly surprising. the ic exhaust is the biggest waste heat<br>
source we have around a gasifier. in principle, the ic exhaust has about about<br>
3x or 4x the heat available as the outgoing syngas. the incoming fuel similarly<br>
has much more heating capacity than the incoming air (the multiple i forget at<br>
the moment, but i do know the incoming air can only take up about 1/2 of the<br>
heat available in the outgoing syngas).<br>
<br>
also, the ic exhaust is much hotter than the outgoing syngas after preheating<br>
the incoming air. thus you can use the ic exhaust to do much more than dry the<br>
fuel. you can it to drive the fuel through pyrolysis, and really, get it up to<br>
about 4-500c before it falls into the hearth proper. this is a big difference<br>
from the typical situation of still moist fuel falling into the hearth.<br>
<br>
not only can you use the ic exhaust to add a very significant amount of heat to<br>
the system, you can also use it to change the character of pyrolysis in the<br>
reactor. a typical downdraft has very high temp short residence time pyrolysis<br>
right on top of the nozzles. this high temp pyrolysis optimizes the creation of<br>
teritary tars, or refractory tars, which are difficult to crack again (given<br>
lots of double carbon bonds). if you externally drive pyrolysis at lower temp<br>
over longer time, you get more primary and secondary tars, which are easier to<br>
crack downstream (fewer double carbon bonds). this seems to allow hearth<br>
conditions to be less perfect and still get good gas out.<br>
<br>
using ic exhaust to heat incoming fuel is not a complete get out of jail free<br>
card. but to me it seems the most impactful new thing one can do on these rigs.<br>
it seems to have more of an impact than any other single thing we've done to<br>
date on the gek.<br>
<br>
yes, all of it is important, and all of it should be tended to, but the above
is<br>
my current vote for the biggest bang for the effort. hopefully we can get some<br>
proper numbers on this soon (and prove or disprove the above conjecture).<br>
<br>
jim<br>
<br>
<br>
<br>
<br>
<br>
<br>
------------------------------------------------------------------------------<br>
Jim Mason<br>
Website: <a href="http://www.whatiamupto.com">http://www.whatiamupto.com</a><br>
Current Projects: <br>
- Gasifier Experimenters Kit (the GEK): <a
href="http://www.gekgasifier.com">http://www.gekgasifier.com</a><br>
- Escape from Berkeley alt fuels vehicle race: <a
href="http://www.escapefromberkeley.com">www.escapefromberkeley.com</a><br>
- ALL Power Labs on Twitter: <a
href="http://twitter.com/allpowerlabs">http://twitter.com/allpowerlabs</a><br>
- Shipyard Announce list: <a
href="http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com">http://lists.spaceship.com/listinfo.cgi/icp-spaceship.com</a><o:p></o:p></p>
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