<div dir="ltr"><div>Thanks so much, Richard, but that size is too big for a TLUD.<br><br></div>Paul<br><div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Jun 14, 2013 at 4:17 AM, Legacy Mail <span dir="ltr"><<a href="mailto:rstanley@legacyfound.org" target="_blank">rstanley@legacyfound.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto"><div>Tom, Paul,</div><div>the problem with running a fiberbound residue through, especially, an augur driven meat mincer type die, is that the process itself tends to shear the very fibers that do the binding. 1" dia x 1 long sausages are about as small as you can go from our experience .</div>
<div>Richard</div><div><br>Sent from my iPhone</div><div><div class="h5"><div><br>On Jun 12, 2013, at 21:07, "Tom Miles" <<a href="mailto:tmiles@trmiles.com" target="_blank">tmiles@trmiles.com</a>> wrote:<br>
<br></div><blockquote type="cite"><div><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Paul,<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The hulls would have to be incorporated into a meal that when dried would form into a ball or pellet shape by using something like a meat grinder. It might be possible to “ret” them with the coffee skins a la Bryant/Legacy. Then you would have something to form. I have always experienced a large quantity of fines with rice husks and straw. You could tie those up by combining them in a meal but you need something fibrous to hold them together. <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Think of other uses for composted rice husks. I know someone who has made thousands of cubic yards of peat substitute by composting rice husks. So it is clearly possible to biologically “process” the husks to a beneficial form. Once you have composted the hulls why use them as fuel? They could be better as a soil amendment. The composting should generate biological binders that would give you a choice of densification methods. Pressing hulls through a metal die will just wear out the die. Probably not the first choice. I think there is a form of fuel or soil amendment that could be created. Meanwhile keep the day job and perfect your rice husk TLUD <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Tom <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><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""> Stoves [<a href="mailto:stoves-bounces@lists.bioenergylists.org" target="_blank">mailto:stoves-bounces@lists.bioenergylists.org</a>] <b>On Behalf Of </b>Paul Olivier<br>
<b>Sent:</b> Wednesday, June 12, 2013 7:38 PM<br><b>To:</b> Discussion of biomass cooking stoves<br><b>Subject:</b> Re: [Stoves] Meat grinder fuels for TLUDs was Re: wheat husk pellets<u></u><u></u></span></p><p class="MsoNormal">
<u></u> <u></u></p><div><div><div><div><div><p class="MsoNormal">Tom's explanation still leaves me with a few questions.<u></u><u></u></p></div><p class="MsoNormal">Would the rice hull have to be ground into a powder to go through a meat grinder?<u></u><u></u></p>
</div><p class="MsoNormal">It takes a lot of energy and maintenance to grind up rice hulls.<u></u><u></u></p></div><p class="MsoNormal">With a conventional pellet machine, rice hulls do not have to be ground up.<u></u><u></u></p>
</div><div><p class="MsoNormal">What binder would be used with rice hulls?<u></u><u></u></p></div><div><p class="MsoNormal"><u></u> <u></u></p></div><p class="MsoNormal">Paul<u></u><u></u></p></div><div><p class="MsoNormal" style="margin-bottom:12.0pt">
<u></u> <u></u></p><div><p class="MsoNormal">On Thu, Jun 13, 2013 at 9:08 AM, Paul Anderson <<a href="mailto:psanders@ilstu.edu" target="_blank">psanders@ilstu.edu</a>> wrote:<u></u><u></u></p><p class="MsoNormal">Stovers,<br>
<br>Tom gave a good explanation. His message is now in the Listserv Archives. But how can such content be made more available for future readers?<u></u><u></u></p><div><p class="MsoNormal" style="margin-bottom:12.0pt">
<br><br>Paul<br><br>Paul S. Anderson, PhD aka "Dr TLUD"<br>Email: <a href="mailto:psanders@ilstu.edu" target="_blank">psanders@ilstu.edu</a> Skype: paultlud Phone: +1-309-452-7072<br>Website: <a href="http://www.drtlud.com" target="_blank">www.drtlud.com</a><u></u><u></u></p>
</div><div><div><p class="MsoNormal">On 6/12/2013 4:24 AM, Tom Miles wrote:<u></u><u></u></p><p class="MsoNormal" style="margin-bottom:12.0pt">Andrew,<br><br>Good explanation.<br><br>Think of two methods of forming fuels. One requires high heat and pressure.<br>
The other requires water and biological or chemical degradation.<br><br>Heat, pressure and some moisture (10% MC) are required for densification to<br>pellets, briquettes or fire logs. A dry biomass is finely ground and pressed<br>
through a metal die. There are two principal binding mechanisms. In one,<br>cellulose fibers pressed together with heat removes excess water and the<br>fibers are bonded to each other through what is called paper bonding, or<br>
hydrogen bonding. It is like wetting two pieces of paper and letting them<br>dry out. They are difficult to pull apart. This is a chemical bond that is a<br>major bonding mechanism for most densification. When you break the pellet or<br>
briquette it falls apart rather than snaps.<br> A second mechanism is lignin plastic flow, as Andrew describes below. The<br>lignin and part of the celluloses actually plasticize and flow. Under high<br>power magnification with a scanning electron microscope a portion of the<br>
wood looks like solid plastic with no identifiable fibers. These pellets<br>snap when you break them.<br><br>Both mechanisms are at play in a densifier. Together these mechanisms make a<br>durable pellet or briquette. As Andrew points out they require power and an<br>
extrusion process like a pellet mill.<br><br>A third mechanism that is used with mechanical densifiers is adding chemical<br>binders, starches, or even expanding clays. These were employed in the<br>older, low power cubers and briquetters to make animal feed. Molasses based<br>
binders were added to help stick hay together in cubes and to add nitrogen<br>(protein) etc. They often added 30% to the cost of the feed. We used sodium<br>hydroxide to hydrolyze straw to make it pliable for making cubes. It had the<br>
advantage of making the straw more digestable for the animals. This was fine<br>for using low quality feeds like straw in times of feed shortage but too<br>expensive when feed prices fell.<br><br>Wet methods of forming fuels are like the method described by Richard<br>
Stanley. Using water, chemicals, or biological degradation the biomass is<br>softened and the surface become sticky. You make a pulp, meal, or dough. You<br>can then use a press, like a piston press (a la Bryant), a meat grinder, a<br>
roller mill, or a cement mixer (Davis) to form the fuel into balls or<br>bricks. Then you dry it out. The sticking mechanisms include the paper<br>bonding, as described above, and adhesion by any number of sugars, starches,<br>
etc. that are activated or released by the process. The dried fuel is not as<br>dense as a pellet or briquette but it is uniform, it stays together, and It<br>burns very well because for the form of the fuel.<br><br>When we worked with Ben Bryant in the 1970s and 1980s we tried a number of<br>
simple wet pulping processes to make building products for both developed<br>and developing countries and fibers for erosion control. Some of his<br>products from this period are still made commercially. In the 1990s Ben<br>
introduced me to Richard and how he was applying some of the same wet<br>forming principles to make bricks for fuel (and for growing seedlings). The<br>lesson is to learn and understand how natural fibers and fiber chemistry can<br>
be used to an advantage. Sometimes a small percentage of long wet fibers can<br>be used to bind together dry fine particles.<br><br>Torrefaction. Think of torrefaction as roasting biomass fuel in the absence<br>of air. Biomass is heated first to dry it, then in the absence of air to<br>
280C. At this temperature it is completely dry and some of the cellulose has<br>converted to gas. You lose about 30% of the weight and 10% of the heating<br>value. The fuel is in the same form that you started with but it is dry and<br>
brittle. If you have a densifier then it takes less energy to pelletize it.<br>The pellets store well because they resist moisture. Torrefaction is used<br>primarily for preparing wood fuel for burning with coal in very large<br>
utility boilers. There are several torrefaction projects in Europe and a few<br>in North America. A plant in Mississippi has shipped a couple of large barge<br>loads of torrefied wood to customers in Europe.<br><br>There was a project in Rwanda some years ago that used partial torrefaction<br>
to prepare fuel bricks for domestic use. A professor from the US designed a<br>small torrefier and installed it in a refuse fuel operation run by a women's<br>coop. The torrefied biomass was formed into a brick using a fire log maker<br>
like the Shimada machine. A USAID employee we contacted knew of the project<br>but did not know if it was still in operation. I haven't heard of any<br>similar projects at the small scale.<br><br>I hope that this long-winded explanation helps make these processes clear.<br>
<br>Tom<br><br> <br><br><br>-----Original Message-----<br>From: Stoves [mailto:<a href="mailto:stoves-bounces@lists.bioenergylists.org" target="_blank">stoves-bounces@lists.bioenergylists.org</a>] On Behalf Of<br><a href="mailto:ajheggie@gmail.com" target="_blank">ajheggie@gmail.com</a><br>
Sent: Wednesday, June 12, 2013 1:01 AM<br>To: Discussion of biomass cooking stoves<br>Subject: Re: [Stoves] Meat grinder fuels for TLUDs was Re: wheat husk<br>pellets<br><br>[Default] On Wed, 12 Jun 2013 12:53:02 +0700,Paul Olivier<br>
<<a href="mailto:paul.olivier@esrla.com" target="_blank">paul.olivier@esrla.com</a>> wrote:<u></u><u></u></p><p class="MsoNormal">How does lignin soften to become a binding agent using a meat grinder?<br>This would be truly wonderful, if it were true.<u></u><u></u></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">It won't with a meat grinder, you will need some sort of binder, like<br>boiled starch or clay.<br><br>Lignin plastisises under high pressure and heat, the heat is normally<br>
derived from the friction of the material passing through the die. At<br>these pressures the cell walls collapse and then the lignin re sets to<br>form a pellet that is denser than the wood it was made from. All these<br>
systems use a lot of power and the expensive dies wear.<br><br>The Shimada press is the one that produces a hexagonal log with a hole<br>down the middle, often blackened on the outside from the heat from the<br>press walls.<br>
<br>Similarly rotary die extruders use pinch rollers to punch small<br>amounts of feed through the holes.<br><br><br>Have a look at:<br><br><a href="http://www.fao.org/docrep/x5738e/x5738e0j.htm" target="_blank">http://www.fao.org/docrep/x5738e/x5738e0j.htm</a><br>
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