Crispin, Glad you find the iCan post of interest. I hope you will have some fun with it and expose the ideas to students in your area.
I have tried holes for the primary air supply in different positions, but not for the reasons you suggest. I will have to give it a try. Anything to help make the pyrolysis more nearly a linear process would be very nice indeed. I have tried the process with NO holes on the outer can. This really forces the primary air to be sucked down the sides of the iCan. This suggests some work to compare and contrast! I will not be able to do this for a week or more. Perhaps you can. If you do, please let me know your results. Please consider posting your suggestion as a comment on Greater Democracy so others can read it too. Thanks for the contribution. Cheers, Jock Jock Gill P.O. Box 3 Peacham, VT 05862 Carbon Negative Solutions (G) (802) 503-1258 On Dec 5, 2010, at 10:03 AM, Crispin Pemberton-Pigott wrote: > Dear Jock > > Very nice web pages and a well presented instructions provided by the link. > > I have a question relating to the iCan. > > Have you tried elevating the primary air holes in the outer can above the > bottom? I understand from the photos that the elevated holes are only on the > inner cans. > > The reason I ask is that I have found benefit from making the primary air > travel downwards at least part of the vertical height. The preheats the air > slightly and provides negative buoyancy reducing draft. As the inner can > starts to heat up, it increases the negative buoyancy because the inner can > is hotter and this interaction tend to self-regulate the power. > > If you get a significant preheat (I would make the gap between the cans no > more than 10mm) you can burn harder, denser fuels that will not pyrolyse with > a normal preheat. > > Give it a try! IT is really easy. > > Best regards > Crispin > > From: Jock Gill [mailto:[email protected]] > > > Ron, > > I have been able to make very good char, as tested by Hugh McLaughlin, from > grass tablets. These have a diameter of about 1.5 inches and I break them > into wafers about 1/2 CM thick. My first batch of grass tablet biochar was > actually made by Paul Anderson in one of his TLUDs. > > Please see this post from Nov. 2009: > http://www.greaterdemocracy.org/archives/931 > > I also find that quenching the biochar at the end of the pyrolysis is not > critical at all. If I leave one of my iCans overnight, I lose less than half > the charcoal. My guess is that this is the result of tuning the iCan for the > least amount of primary air. I have noted that when the pyrolysis is over, > the bed of charcoal emits "smoke". My goal is for zero smoke, but find that > I can still get god biochar if the smoke is essentially gone in less than two > minutes. My practice is to only quench after the smoke has essentially > finished f within in about 3 minutes after the pyrolysis flames extinguish > themselves. > > Cheers, > > Jock > > > Jock Gill > P.O. Box 3 > Peacham, VT 05862 > Carbon Negative Solutions > (G) (802) 503-1258 > > > > On Dec 5, 2010, at 1:42 AM, [email protected] wrote: > > > > > Richard and 2 lists: > > Thanks for the complete response. I conclude that pellets and briquettes are > possibly able to act similarly in char-making stoves, but briquettes look > better in traditional stoves. Apparently not much comparative work done yet > for advantages of production of one vs the other. >
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