<div dir="ltr">See comments below.<br><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Jul 30, 2013 at 12:24 AM, <span dir="ltr"><<a href="mailto:rongretlarson@comcast.net" target="_blank">rongretlarson@comcast.net</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-size:12pt;font-family:Arial">Paul and cc list (but the questions below pertinent to any and all)<br>
<br> This is to hope that you can perform a few more experiments re fuels. I am sure all your comments are correct comparing loose husks to pellets, but wonder if you could try and report on several other fuel options as well - especially telling us about prices in Vietnam. </div>
</div></blockquote><div><br></div><div>In Vietnam we have four major sources of TLUD fuel: from rice (lowland), from coconut (lowland), from coffee (highland) and from pine trees (highland). <br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div><div style="font-size:12pt;font-family:Arial">Your comment about running stoves for free because char produced in your stove is worth more than the pellets going in is very important. Can you give more cost (per kilo) detail on that? </div>
</div></blockquote><div><br></div><div>Rice hull biochar is commonly used in Vietnam as part of a potting soil mix. I have not seen applications where it is applied to the soil. Rice hull biochar is made in crude retorts where all of the gas is wasted. It is totally lacking in uniformity: some of it is burned to ash, whole some is barely torrefied. In spite of its lack of uniformity, it still commands a significant price. <br>
<br>But this price is hard to pinpoint because it is sold by volume, not by weight. A relatively small sack of rice hull biochar retails for about $1.20. Sacks of biochar are often stored outdoors, and they contain a lot of water. So a measurement by weight is not possible. I estimate a sack of biochar to contain no more than 3 kgs of dry biochar. This equates to about $400 US per ton for rice hull biochar. Loose rice hulls in this area sell for about $17 US per ton (in tropical areas they are often free). It takes about 3 kgs of rice hulls to produce one kg of biochar. So it takes $51 of rice hulls ($17x3) to produce $400 of rice hull biochar.<br>
<br></div><div>One ton of rice hull pellets sells for $76 per ton. So $228 of pellets ($76x3) will produce about $400 in biochar. A sack of raw pellets of a given size will produce a sack of biochar pellets of the same size. The raw pellet and the biochar pellet are easy to transport due to their high bulk density and low volume. So the biochar merchant brings a sack of raw pellets to the household, and receives in exchange a sack of biochar pellets of roughly the same volume.<br>
</div><div><br><br> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-size:12pt;font-family:Arial">The next three (are there more?) items are extensions - both on technical results and on economics.<br>
<br> First is wood chips. The stove camp activity was all based on this product because of a request from a South American (?) company wanting to harvest a large older forest, I think specifically planted decades ago to save nearby old growth forests. I presume chips are being preferred over pellets for cost reasons (I have heard a 3:1 price difference). Hopefully you can find a chip supply and tell us on their performance and economics in any of your stoves as well.<br>
</div></div></blockquote><div><br></div><div>Wood chips can be dried thermophilically outdoors under a compost fleece down to a 23% moisture content. To be used as TLUD fuel, they would then have to be further dried to about 12%, preferably sun-dried. The chips would have to be graded into several sizes to assure uniformity. The fines would have to run through a pellet machine to achieve uniformity. I think that uniform wood chips should work fine in a TLUD.<br>
</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-size:12pt;font-family:Arial"><br> Second is any fuel made by hand from paper, leaves, grasses, rice husks (?), etc - as promoted by Richard Stanley, etal. Presumably you saw my recent report on making something specifically for TLUDs. The advantages here are making productive use of materials having no other possible use and supplying jobs for low-income people. I am about also to respond to recent message from Richard along these lines (re using only hand muscles).<br>
</div></div></blockquote><div><br></div><div>In Vietnam I do not know of fuels made by hand. If TLUD fuels are made by hand, ideally the fuel here should be as small and as dense as possible. If primary air does not flow uniformly up through the fuel, CO2 is generated. If CO2 is generated the biochar is not uniform, heat is generated far below the pot, and the combustion of syngas is compromised.<br>
</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-size:12pt;font-family:Arial"><br> Third is use of small twigs, ag residues, straws, reeds, grasses, etc (similar to rice husks, but denser and available where husks are not) that can be used without any processing.. </div>
</div></blockquote><div><br></div><div>There is a company near Hanoi that prepares tobacco leaves. This process leaves behind a tobacco stem residue that is quite uniform and performs well in a TLUD. But most other raw biomass such as twigs, grasses and pine needles have to be rendered uniform. Pelleting is the best way that I know of to render biomass uniform.<br>
</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-size:12pt;font-family:Arial">Again, maybe a job creator - with hope that the char value exceeds the fuel cost This presently is the fuel of choice for backpackers as it can be found everywhere. Can this approach be expanded, again as a way for fuel preparers and cooks to make money rather than only expend it?<br>
<br> Fourth (and last) is the supply of larger wood (maybe only branches?) cut into small pieces (I saw a lot from board lumber cut to about 6-12 inch length almost all less than 1 square inch cross-section (NOT the standard fuel in the field). This was the main fuel alternative to chips at the stove camp for those not using TLUDs. Presumably this is also possible in Vietnam for vertical stacking in your device with optimum heights and packing densities. </div>
</div></blockquote><div><br></div><div>I have tried vertical stacking. But immediately I see on my burner (with 80 holes along the periphery), burner holes that do not support a flame. The culprit here is CO2 formation, and once again, if CO2 is generated, the biochar is not uniform, excess heat is generated far
below the pot, and the combustion of syngas is compromised. If the combustion of syngas is compromised, I am sure that some CO will not get properly combusted.<br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div><div style="font-size:12pt;font-family:Arial">Again emphasis to be on economics - still hoping to find lower fuel costs than pellets, but less bulky than husks, if possible.<br></div></div></blockquote><div><br></div>
<div>In general, the safest route is to make a pellet of irregular biomass. Preferably this should be a pellet of a 6 mm diameter. This brings me back to a point that I have made so often: funding organizations are not focusing enough on fuel preparation and biochar research. Once farmers in a given area understand the value of biochar (as many of them do here in Dalat where I live), then biochar merchants can make a lot of money exchanging raw pellets for biochar pellets.<br>
<br></div><div>Thanks.<br></div><div>Paul Olivier<br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-size:12pt;font-family:Arial">
<br> I pick on you as probably having some local labor available to try these alternatives with a chance of selling more stoves where costs can be an important factor - and you knowing of the importance of either getting more char in the ground or of making char with use of the pyrolysis gases. I'll be glad to split the costs of trying these other quite-different fuel options in your stove.<br>
<br> Somewhat along these lines, this is also to alert all to an EPA-GACC webinar on 20 August on batch stoves (10:00 AM Eastern). This received a few days ago: <br><i>The online registration form (<span><a href="https://unfoundation.conferencinghub.com/attendee/RegisterLogin.aspx?hubconfID=1632144&qtID=1&act=reg&cp=2861" target="_blank">https://unfoundation.conferencinghub.com/attendee/RegisterLogin.aspx?hubconfID=1632144&qtID=1&act=reg&cp=2861</a></span>)
includes a place to enter comments or questions you would like addressed during the webinar. <br></i><br><br><br> So Paul, thanks in advance for anything new you can report on the economics of these six fuel options.<br>
<br>Ron<br><br><hr><b>From: </b>"Paul Olivier" <<a href="mailto:paul.olivier@esrla.com" target="_blank">paul.olivier@esrla.com</a>><br><b>To: </b>"Discussion of biomass cooking stoves" <<a href="mailto:stoves@lists.bioenergylists.org" target="_blank">stoves@lists.bioenergylists.org</a>><br>
<b>Sent: </b>Sunday, July 28, 2013 9:06:32 PM<br><b>Subject: </b>[Stoves] pellets in an urban setting<div><div class="h5"><br><br><div dir="ltr"><div><div>I am getting excited about the use of pellets. In an urban setting in a developing country such as Vietnam, a pellet gasifier should be a lot more socially acceptable than a loose biomass gasifier.<br>
<br>Since pellets can be as much as 8 to 10 times more dense than loose biomass, the reactor can be much smaller. A net reactor height of only 8 inches is all that is needed to give a burn time of up to 90 minutes. Since the unit is small, it is
lightweight. The reactor weight is but 1.2 kg. It is easy to handle. With such a small reactor, the manufacturing cost drops considerably. This means that the most heat-resistant and non-corrosive stainless steels become affordable. This adds years to the life of the unit. This also means that the unit looks good and takes on the appearance of a high-end kitchen utensil. If the unit does not look good, it will be hard to sell.<br>
<br><a href="https://dl.dropboxusercontent.com/u/22013094/150%20Gasifier/Short/Photos/IMG_1571.JPG" target="_blank">https://dl.dropboxusercontent.com/u/22013094/150%20Gasifier/Short/Photos/IMG_1571.JPG</a><br><br>Pellets can be more cheaply
transported into urban areas than loose biomass. Dealing with loose biomass can often be dusty and
messy. The storage of pellets in a kitchen takes up much less space than
the storage of loose biomass. With pellets there should be a lot less
emissions of particulates. <br><br>Biochar pellets are easier to quantify than
loose biochar. A measurement of biochar volume is all that is needed. There is only a small reduction in volume as when a pellet is transformed into biochar. <br><br>The flame put out by a pellet gasifier is rich and intense throughout the burn:<br>
<a href="http://www.youtube.com/watch?v=84qDsbBO9p8" target="_blank">http://www.youtube.com/watch?v=84qDsbBO9p8</a><br></div><div>The flame does not turn ethereal.<br></div><div><br></div><div>It is true that pellets cost more than loose biomass. But pellets are cheaper to transport into a city than loose biomass, and the biochar produced from pellets has a higher value in Vietnam than the original pellets. I foresee the possibility of an exchange program where pellets are supplied free-of-charge in exchange for the biochar produced from these pellets.<br>
</div><div><br></div>Thanks.<br></div>Paul Olivier<br><div><div><div><div><div><div><br>-- <br>Paul A. Olivier PhD<br>26/5 Phu Dong Thien Vuong<br>Dalat<br>Vietnam<br>
<br>Louisiana telephone: 1-337-447-4124 (rings Vietnam)<br>Mobile: 090-694-1573 (in Vietnam)<br>Skype address: Xpolivier<br><a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a>
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<br><br clear="all"><br>-- <br>Paul A. Olivier PhD<br>26/5 Phu Dong Thien Vuong<br>Dalat<br>Vietnam<br>
<br>Louisiana telephone: 1-337-447-4124 (rings Vietnam)<br>Mobile: 090-694-1573 (in Vietnam)<br>Skype address: Xpolivier<br><a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a>
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