<html><body bgcolor="#FFFFFF"><div>Dear Greg and all </div><div><br></div><div>Very interesting and useful information. </div><div><br></div><div>Is this an open top gasifier (TBR, 1980) <span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.296875); -webkit-composition-fill-color: rgba(175, 192, 227, 0.230469); -webkit-composition-frame-color: rgba(77, 128, 180, 0.230469); ">or is it the top closed with air nozzles and a bustle(Imbert). The open top gasifier has more resistance to airflow than the nozzles, but compensates by the large cross section area of the magazine.</span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.292969); -webkit-composition-fill-color: rgba(175, 192, 227, 0.226562); -webkit-composition-frame-color: rgba(77, 128, 180, 0.226562);"><br></span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.296875); -webkit-composition-fill-color: rgba(175, 192, 227, 0.230469); -webkit-composition-frame-color: rgba(77, 128, 180, 0.230469); ">I suppose that your observation that small chips contaminated with even smaller stuff gasifies well is due in part to the fact that most of the resistance to airflow is in the reaction and not the fuel bed </span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.292969); -webkit-composition-fill-color: rgba(175, 192, 227, 0.226562); -webkit-composition-frame-color: rgba(77, 128, 180, 0.226562);"><br></span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.289062); -webkit-composition-fill-color: rgba(175, 192, 227, 0.222656); -webkit-composition-frame-color: rgba(77, 128, 180, 0.222656);">I have always been surprised that the main pressure drop through the bed is in the reaction zone and not the denser and longer unburned fuel<span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.28125); -webkit-composition-fill-color: rgba(175, 192, 227, 0.214844); -webkit-composition-frame-color: rgba(77, 128, 180, 0.214844); "> zone. This is due in part to the fact that the viscosity of hot gas is higher than that of colder gas (explained by Knudsen). I've never seen a good measurement of the axial temperatures in a functioning gasifier, though it would be easy to measure with a draft meter and thermocouple. </span></span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.277344); -webkit-composition-fill-color: rgba(175, 192, 227, 0.210938); -webkit-composition-frame-color: rgba(77, 128, 180, 0.210938);"><br></span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.273438); -webkit-composition-fill-color: rgba(175, 192, 227, 0.207031); -webkit-composition-frame-color: rgba(77, 128, 180, 0.207031);">Keep up the good observations. </span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.269531); -webkit-composition-fill-color: rgba(175, 192, 227, 0.203125); -webkit-composition-frame-color: rgba(77, 128, 180, 0.203125);"><br></span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.265625); -webkit-composition-fill-color: rgba(175, 192, 227, 0.199219); -webkit-composition-frame-color: rgba(77, 128, 180, 0.199219);">Tom Reed THE BIOMASS ENERGY FOUNDATION</span></div><div><span class="Apple-style-span" style="-webkit-tap-highlight-color: rgba(26, 26, 26, 0.273438); -webkit-composition-fill-color: rgba(175, 192, 227, 0.207031); -webkit-composition-frame-color: rgba(77, 128, 180, 0.207031);"><br></span></div><div><br>Sent from Tom Reed's Ipad</div><div><br>On Nov 28, 2010, at 10:09 AM, "Greg Manning" <<a href="mailto:a31ford@gmail.com">a31ford@gmail.com</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div>
<div><span class="027373814-28112010"><font size="2" face="Arial">OK, First off,
Greetings List(s)!</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial">Second:</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial"> Since my
accidental discovery of smaller feedstock sizes about a week ago, I've been
doing some tests (ok, mad scientist stuff), to the acceptable "Minimum" size
level in my downdraft units.</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial"> For those that
do not know me, briefly, I build smaller downdraft gasifiers (under 250KwT) I do
NOT go bigger than that, I have my reasons.</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial">I've been using a
"standard" sized woodchip, typical of most small industrial units (NOT your home
"shredder/mulchers") generally 15-30 hp units.</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial">These chippers
produce, for the most part, chips about 3 x 3 x 0.25 cm chips (3/4 x 3/4 x
3/16") and down to the point of dirt, or mash.</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial">6 - 7 years ago, I
had settled on a rotary screen design using a "fines" screen of 0.63
x 0.63 cm (1/4 x 1/4") square openings. this has been my "smaller"
size since then. (Until this week, we have always discarded
anything that was considered "fines", used these as mulch or horse
bedding).</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial">Upon the somewhat
accidental use of a fines pile as feedstock, much to my surprise, the unit
accepted the fines for the most part, for about 8 hours of operation, (these
where raw fines, directly from under the rotary drum), Yes the gasifier did
eventually plug up and shut down BUT, not knowing what was going on at the time
(I did NOT know the unit was running on fines) I was perplexed as to what had
caused the problem, upon investigation, and finding that the worker had
inadvertently used this pile, instead of the correct one, and finding out the
length of the time the unit had ran on them, I undertook the new question of
"how small I can go" in feedstock sizes.</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial">As it turns out, the
unit will run consistently on a much smaller chip size than originally thought.
We have since changed the fines screen in the rotary screener to 3/16" round
holes (punched panel) on an offset pattern (68% opening) the ratio change is as
follows:</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial"> Original 1/4 x
14" square openings, ratio of fines to acceptable feedstock 30% fines, 70%
feedstock</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial"> New
3/16" round openings, 10 - 13% fines, 87 - 90% acceptable.</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial"></font></span> </div>
<div><span class="027373814-28112010"><font size="2" face="Arial">Hoping that this
information is useful to someone.</font></span></div>
<div><span class="027373814-28112010"><font size="2" face="Arial">Kindest
regards: </font></span></div>
<p><font color="#0000ff" size="2" face="Arial">Greg Manning,</font> <br><font face="Arial"><font color="#0000ff" size="2">Canadian Gasifier Ltd.
(<a href="http://www.cangas.ca">www.cangas.ca</a>)</font></font><br><font color="#0000ff" size="2" face="Arial">Building
Hi-Pe</font><font color="#0000ff" size="2" face="Arial">r</font><font color="#0000ff" size="2" face="Arial">formance Gasifiers, Since</font> <font color="#0000ff" size="2" face="Arial">2001</font> <br><font face="Arial"> </font> <br><font color="#0000ff" size="2" face="Arial">Brandon, Manitoba, Canada</font> <br><font color="#0000ff" size="2" face="Arial">1 (204) 726-1851</font> <br><font face="Arial"> </font> </p>
<div> </div>
</div></blockquote><blockquote type="cite"><div><span>_______________________________________________</span><br><span>Gasification mailing list</span><br><span></span><br><span>to Send a Message to the list, use the email address</span><br><span><a href="mailto:Gasification@bioenergylists.org">Gasification@bioenergylists.org</a></span><br><span></span><br><span>to UNSUBSCRIBE or Change your List Settings use the web page</span><br><span><a href="http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org">http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org</a></span><br><span></span><br><span>for more Gasifiers, News and Information see our web site:</span><br><span><a href="http://gasifiers.bioenergylists.org/">http://gasifiers.bioenergylists.org/</a></span><br></div></blockquote></body></html>