<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>Tom, Paul, Dan and others, <br></div><div><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">I have gone away a bit from the TLUD principle as I started from a very polluting open top burn approach and using feedstock that is not uniform in particle size. Very wasteful, and as in Dan's case I ended up with a lot of fines (http://vuthisa.files.wordpress.com/2012/09/img00177.jpg). The only cost effective way that I could improve emissions of the Transportable Metal Kiln was to convert it into a retort, by using the heat from the conventional burn to heat the inner retorts. The flow rate of the air through the outer burn will be high, probably around 1.5 m3/sec and the quantity of feedstock necessary to provide the
heat to the inner retorts before the reaction becomes exothermic will probably match the closely packed feedstock volumetrically inside the 3 x 55 gal drums, which will ultimately yield the biochar. The burn is seen as successful only if ash remains in the outer vessel and all the biomass inside the 55 gal drums is pyrolysed. I don't need a TLUD type flow rate to ensure complete carbonisation, but the consumed wood in the outer drum has to be included in the overall yield percentage calculation. The addition of a conical lid and chimney (much akin to the New Hampshire metal kiln design) has increased the draft needed to vent emissions. In the conventional open drum burn I would place ±550 kg feedstock and end up with 120 kg charcoal, but 50% will be fines. In the 3-drum retort I would probably also use 550 kg but end up with ???? I would not like to venture an answer at this early stage, but hopefully end up with more than just 60 kg
of biochar. The principal advantages of my three drum retort should be the 25%
yield of char from the retort contents, coupled with the ability
to use lower quality fuel as the starter fuel (outside the
drum) and the self-stopping of the
retort design (better safety, no need fro water), and the self-running
aspect (light it and step back). </div><div><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">http://vuthisa.files.wordpress.com/2012/09/slits_drum.jpg</div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">http://vuthisa.files.wordpress.com/2012/09/dscf335.jpg</div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">http://vuthisa.files.wordpress.com/2012/09/branches_lid-removed2.png</div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">http://vuthisa.files.wordpress.com/2012/09/bottom.jpg<br></div><div style="color:
rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">Regards</div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><br></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">Kobus<br></div><br><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;">********************************************************************************<br></div><div>AD, Paul, Kobus and others. Many thanks for the suggestions. <br><br>What
is the largest practical size (kg fuel/hr, kW) for a single TLUD with a<br>clean stack for heat recovery? There must be a limit to the air penetration<br>to get a clean gas burn form a natural draft stack or even a fan driven<br>TLUD. <br><br>Tom <br><br><span></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><br><span></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><br><span></span></div><pre wrap=""><a class="moz-txt-link-freetext" href="http://www.vuthisa.com/">http://www.vuthisa.com</a>
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