Re: [Stoves] Alternative to charcoal adam-retort 39% efficiency
Paal W: To produce 2,7 kg charcoal you need about 10-12 kg firewood, depending on the kiln. ... Crispin: There is still a lot of work to do.--Oh, yes, i think there is,i am just here in Palestina for WORLDViSiON and we built a heavy duty adam-retort made with a casted cement outer case. 4m² volume for the wood chamber. ~1700kg (fresh cut (there were not able to get dry wood!)) orange wood, left overs from farms was loaded.about 400kg of good charcoal we received.If we assume a humidity of 50%, we deduct 850kg of water - means 850kg of oven dry wood transformed to charcoal,Means a perfect effciciency of ~47% ! (ok, if we assume 40% humidity, we still have 39%)Or the other way, 120cm of wood height shrinked 40cm, means 80cm of charcoal height, means charcoal becomes 2/3 of wood volume, good, good too.I am doing a one-man-job I wish a part of the huge research which is given to stoves, could be diverted to such kind of retorts...Chris ADAM, Industrial designer + appropriate technologistewww.biocoal.org-Original Message- Date: Wed, 10 Apr 2013 04:54:28 +0200 Subject: Re: [Stoves] Alternative to charcoal From: Kevin kchish...@ca.inter.net To: Discussion of biomass cooking stoves stoves@lists.bioenergylists.org Dear Dale You raise excellent points about the desirability of finding an Alternative to Charcoal. I feel that the problem is both very complex, AND very simple at the same time. The problem is very complex, when dealt with, as a whole, but very simple when broken down into the various facets of the issue that complicate it. If we look at the continuum between wood as a fuel, and charcoal as a fuel, we see that at the Wood End and the Charcoal End, there is a clear preference, need, or requirement for the respective fuels. In the center, there is a gray area, where either fuel can be utilized, to greater or lesser advantage and disadvantage. The problem is somewhat further complicated by those who see charcoal as a climate change tool and superimpose climate change considerations on stoves, perhaps even to the degree of relegating the fundamental heating and cooking aspects of a stove to a secondary level of importance. Everything starts with the biomass fuel... wood, grasses, agricultural products or waste, etc. In the logic I am about to lay out, I state that there are fundamentally three kinds of stove: 1: A Full Combustion Biomass stove, where all fuel is intended to be burned to completion 2: A Partial Combustion Biomass Stove, where char or charcoal is a desired end product. (This charcoal can be subsequently used as fuel, or as biochar.) 3: A Charcoal Combustion Stove. In the interests of simplicity, I ignore Charcoal Retorts, because of their basic thermal inefficiency much of the pyrolysis gas energy is simply vented. However, a retort that made use of the pyrolysis gas heat could be termed a Partial Combustion Biomass Stove.' A major advantage of this approach would be that it would clearly categorize stoves, and as a consequence, would allow for three different testing protocols.Each Testing protocol could be set up to best capture the performance parameters that were of most importance to each stove system. Crispin's Proposed Stove testing Protocols are perhaps best for Full Combustion Biomass Stoves. Equivalently relevant protocols could be developed for Partial Combustion and Charcoal stoves. I feel that the process should be Customer Driven. If a Customer wants to burn charcoal as fuel, then that is his decision. Or, if he wants to produce charcoal, for resale, or for use as biochar, or for subsequent use as a fuel, then that also should be his decision. This is where a good set of Testing Protocols would be really helpful... they would allow the Customer to select the stove system (or systems) that best met his needs. Note also that when fundamental performance information was available from the above three protocols, it would be very easy to develop a spread sheet that factored in all the relevant information, so that the Customer could make a rational decision on what would be the best stove system for his particular circumstances. Best wishes, Kevin . - Original Message - From: Andreatta, Dale A. To: Discussion of biomass cooking stoves Sent: Monday, April 08, 2013 6:09 PM Subject: [Stoves] Alternative to charcoal At the recent ETHOS conference Paul Means and Chris Lanning gave a very thought-provoking talk about an alternative to charcoal. The basic idea was to use a gasifying stove with prepared wood fuel. The prepared wood fuel would be bought by the user instead of charcoal, and the supply chain would be similar to charcoal. The big advantage is that the very inefficient step of charcoal production is eliminated. The stove would hopefully be easy to use and would smoke very little, so as to retain the benefits of a charcoal
Re: [Stoves] Alternative to charcoal adam-retort 39% efficiency
Dear Chris Well done! Please get a sample of the fresh wood and weigh it. Maybe 1/2 kg. Get the mass when supplied to the kiln. Then dry it later to get a real moisture content. It is a very important number. It think there is month way it is as high as 50%. The yield is a critical number for your process amd claims made. Regards Crispin -Original Message- From: sc...@t-online.de sc...@t-online.de Sender: Stoves stoves-boun...@lists.bioenergylists.org Date: Wed, 10 Apr 2013 11:47:38 To: Discussion of biomass cooking stovesstoves@lists.bioenergylists.org Reply-To: sc...@t-online.de sc...@t-online.de, Discussion of biomass cooking stoves stoves@lists.bioenergylists.org Subject: Re: [Stoves] Alternative to charcoal adam-retort 39% efficiency ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/ ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
Re: [Stoves] Alternative to charcoal
Dear stovers Wood or charcoal, the eternal discussion at the List; I don’t know if it possible to bring something new to the discussion but I will try. My experience is from forest in Norway and Africa, not in Canada. About 200 years ago we changed from open fire to cast iron stoves for cooking and heating and 80 years ago, when I was a child some still used open fire connected to chimney for cooking and heating in the rural arias; today there is about 50% more forest in Norway than for 100 years ago caused partly by less use of wood for cooking/ heating and partly from change of grazing animals. When I was in Africa 1984 to 2000 the forest was shrinking due to charcoal production, need of building materials and need of arable land. In Zambia with a population of 13m recently they had about 2m charcoal stoves each using 2.7 kg charcoal average every day. About 15% of adult people were in one or another way involved into the charcoal business. To produce 2,7 kg charcoal you need about 10-12 kg firewood, depending on the kiln. 10 kg of wood like pellets or woodchips into a TLUD will give 10 to 15 hours of cooking on the energy generally by charcoal cooking, left in the air around the kiln and in addition giving 2.5 kg biochar. If you change the wood from the forest with pelletized agriculture, forestry and milling waste and combustible waste from household, marked places, and industry, you save quite a lot of forest, and if the charcoal business with their decentralized infrastructure; change from charcoal to pellets and chopped waste wood, they will not lose their jobs. They will also create new jobs, which are extremely needed. With regards Paal W From: Crispin Pemberton-Pigott Sent: Tuesday, April 09, 2013 7:18 AM To: 'Discussion of biomass cooking stoves' Subject: Re: [Stoves] Alternative to charcoal Dear Jock The numbers I have for wood pellets suggest around 8,000 BTUs per pound. There is a pretty comprehensive list of heat values at the back of a WBT spreadsheet. 12,000 would be a a bit about right for charcoal. The heat value of char produced in a TLUD or a fire has not been very well studied. Jim Jetter’s Aug 2012 paper has some values. The heat value of wood is only what people are going to get from it, not what it would be if it were dried (which also applies to charcoal). I am in Central Java at the moment and the charcoal in the lab has been sitting around for a while. The average moisture content is 8.8% according the lab lady Julianna. The heat content is 26.7 MJ/kg which is slightly below the 12,000 BTU mark. The local wood even after months of drying is about 15-16% moisture. With a heat content of about 19.2 MJ/kg dry at 16% it is 15.7 MJ/kg. Lots of woods have a lower heat value than that and many people use damp wood – no doubt about it. It bubbles and dribbles continuously. So the reality is that what people put into their stoves is often below ½ the heat value of charcoal per kg. Further, the char produced by a TLUD is expected to be 0% moisture if it is used within a day or so it will pay to keep an eye on what exactly is being claimed. Fresh charcoal has a very low moisture level. Most fuelwood does not. That is the comparison I am thinking of. A direct comparison between the average fuelwood as used and locally made charcoal as used is ≈15.5 v.s. 29.5 MJ/kg. If I put 1 kg of 15% moisture wattle (15.9 MJ/kg) into a TLUD stove and create 20% char (20% of the moist mass) the net heat provided by the fire is 10 MJ/kg. The heat available from the char is still 29.5 so the total is the difference the bit between: 15.9-10 = 5.9 MJ. If someone wants to switch from wood fuel to a ‘cleaner’ TLUD and that TLUD is not 1.5 times as efficient in transferring heat, their raw fuel consumption will increase. Regards Crispin ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/ No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.2904 / Virus Database: 2641/6232 - Release Date: 04/08/13 ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http
Re: [Stoves] Alternative to charcoal
Dear Dale, the size and shape of the wood is important in a TLUD stove because the fuel is lighted at the top and the primary air has to pass through the biomass. Pieces of bamboo, stacked vertically in the fire chamber, work quite well in such a situation. This solution is however not available to stovers living in areas where bamboo is not naturally available. Yours A.D.Karve On Tue, Apr 9, 2013 at 2:39 AM, Andreatta, Dale A. dandrea...@sealimited.com wrote: At the recent ETHOS conference Paul Means and Chris Lanning gave a very thought-provoking talk about an alternative to charcoal. The basic idea was to use a gasifying stove with prepared wood fuel. The prepared wood fuel would be bought by the user instead of charcoal, and the supply chain would be similar to charcoal. The big advantage is that the very inefficient step of charcoal production is eliminated. The stove would hopefully be easy to use and would smoke very little, so as to retain the benefits of a charcoal stove. Their proposed fuel was crumbled wood, which would work well, but seemed to me to require a lot of big machinery and capital. How could one go from a tree to a fuel that would burn well in a gasifier with as little work as possible, and without too much costly equipment? The fuel should be as low or lower in cost than charcoal per unit of food cooked, and give a better ratio of food cooked per unit of tree. I did some preliminary experiments. With 779 g of natural wood from the trees in my yard, I used a Paul Anderson Champion gasifier and boiled 5 liters in 21.4 minutes (corrected). After an easy light the stove burned steadily with no attention, other than turning down the primary air when boiling started. About 10 minutes after boiling the pyrolysis ended and I transferred 123 grams of char sticks, glowing only weakly, into a charcoal stove, and continued simmering until nearly 2 hours after the start of boiling. I had good turndown on the charcoal stove and a lid on the pot. There was a little smoke during the pyrolysis phase, but not too much. This seems like excellent stove performance. Had I used a very good charcoal stove to perform a similar task, it might have taken 240 g of charcoal. This would take about 1800 g of wood if the charcoal were made efficiently, or 3000 g if it were made normally. (Reference Means and Lanning on the efficiency of charcoal production.) The wood I started with was about 1 inch diameter (2.5 cm) by 6 inches (15 cm) long, cut from my trees and dried outdoors but under cover for some months. I didn’t measure the moisture content, but a previous oven-drying test with similar wood showed about 12-14% moisture. A previous test with larger diameter wood didn’t go well, so I think this is about the maximum possible diameter. I don’t know how long it took to get to this moisture content, not months I’m sure, but at least some number of days. The production method for this alternative to charcoal would be to use a chain saw to cut wood into convenient lengths while in the forest, then take it to a central place. Here, use electric saws and/or hydraulic splitters to cut the wood to the appropriate size. Give the wood a modest amount of drying in the sun, or in some simple oven. The wood might have to finish drying at the place of use. I expect that split wood would dry faster than cut sticks, since the moisture doesn’t have to pass through the bark. Alternatively, use a chain saw and engine powered splitter to cut the wood to size in the forest, then transport to a central place for drying. When fairly dry, transport the wood to the users as with charcoal. During transport, the energy per unit weight would be lower than charcoal, but the energy per unit volume would be similar. The user might be given the option of buying shorter sticks for cooking smaller meals, or longer sticks for larger meals. In comparing the economics of this method to charcoal, I would think of the cost of the fuel as coming from 5 elements; the cost of the trees, the cost of the processing equipment, the cost of the labor, the cost of the transportation and distribution, and the cost of the stove. If the trees are free, then the fact that you don’t cut as many trees doesn’t help much. If the trees must be paid for, then this method looks more attractive. The processing equipment for charcoal is virtually free, but hopefully this method doesn’t take too much equipment. The labor for this method might be similar to charcoal, but it might be less because you are cutting and processing a lot fewer trees to serve the same number of customers. Transportation would be more expensive, since you are shipping more mass, though not a lot more volume. This method would require a gasifier or T-Char stove, which would be an expense, though hopefully not a lot compared to the annual cost of fuel. Thus, if the trees must be paid
Re: [Stoves] Alternative to charcoal
Dear Dale You raise excellent points about the desirability of finding an Alternative to Charcoal. I feel that the problem is both very complex, AND very simple at the same time. The problem is very complex, when dealt with, as a whole, but very simple when broken down into the various facets of the issue that complicate it. If we look at the continuum between wood as a fuel, and charcoal as a fuel, we see that at the Wood End and the Charcoal End, there is a clear preference, need, or requirement for the respective fuels. In the center, there is a gray area, where either fuel can be utilized, to greater or lesser advantage and disadvantage. The problem is somewhat further complicated by those who see charcoal as a climate change tool and superimpose climate change considerations on stoves, perhaps even to the degree of relegating the fundamental heating and cooking aspects of a stove to a secondary level of importance. Everything starts with the biomass fuel... wood, grasses, agricultural products or waste, etc. In the logic I am about to lay out, I state that there are fundamentally three kinds of stove: 1: A Full Combustion Biomass stove, where all fuel is intended to be burned to completion 2: A Partial Combustion Biomass Stove, where char or charcoal is a desired end product. (This charcoal can be subsequently used as fuel, or as biochar.) 3: A Charcoal Combustion Stove. In the interests of simplicity, I ignore Charcoal Retorts, because of their basic thermal inefficiency much of the pyrolysis gas energy is simply vented. However, a retort that made use of the pyrolysis gas heat could be termed a Partial Combustion Biomass Stove.' A major advantage of this approach would be that it would clearly categorize stoves, and as a consequence, would allow for three different testing protocols.Each Testing protocol could be set up to best capture the performance parameters that were of most importance to each stove system. Crispin's Proposed Stove testing Protocols are perhaps best for Full Combustion Biomass Stoves. Equivalently relevant protocols could be developed for Partial Combustion and Charcoal stoves. I feel that the process should be Customer Driven. If a Customer wants to burn charcoal as fuel, then that is his decision. Or, if he wants to produce charcoal, for resale, or for use as biochar, or for subsequent use as a fuel, then that also should be his decision. This is where a good set of Testing Protocols would be really helpful... they would allow the Customer to select the stove system (or systems) that best met his needs. Note also that when fundamental performance information was available from the above three protocols, it would be very easy to develop a spread sheet that factored in all the relevant information, so that the Customer could make a rational decision on what would be the best stove system for his particular circumstances. Best wishes, Kevin . - Original Message - From: Andreatta, Dale A. To: Discussion of biomass cooking stoves Sent: Monday, April 08, 2013 6:09 PM Subject: [Stoves] Alternative to charcoal At the recent ETHOS conference Paul Means and Chris Lanning gave a very thought-provoking talk about an alternative to charcoal. The basic idea was to use a gasifying stove with prepared wood fuel. The prepared wood fuel would be bought by the user instead of charcoal, and the supply chain would be similar to charcoal. The big advantage is that the very inefficient step of charcoal production is eliminated. The stove would hopefully be easy to use and would smoke very little, so as to retain the benefits of a charcoal stove. Their proposed fuel was crumbled wood, which would work well, but seemed to me to require a lot of big machinery and capital. How could one go from a tree to a fuel that would burn well in a gasifier with as little work as possible, and without too much costly equipment? The fuel should be as low or lower in cost than charcoal per unit of food cooked, and give a better ratio of food cooked per unit of tree. I did some preliminary experiments. With 779 g of natural wood from the trees in my yard, I used a Paul Anderson Champion gasifier and boiled 5 liters in 21.4 minutes (corrected). After an easy light the stove burned steadily with no attention, other than turning down the primary air when boiling started. About 10 minutes after boiling the pyrolysis ended and I transferred 123 grams of char sticks, glowing only weakly, into a charcoal stove, and continued simmering until nearly 2 hours after the start of boiling. I had good turndown on the charcoal stove and a lid on the pot. There was a little smoke during the pyrolysis phase, but not too much. This seems like excellent stove performance. Had I used a very good charcoal stove to perform a similar task, it might have taken 240 g of charcoal. This would take about
Re: [Stoves] Alternative to charcoal
Dear Dale and Friends The analysis of alternatives to charcoal should include the reasons why people prefer it, strongly, over wood when given a choice of either, with charcoal costing much more than wood per kg. Working out theoretically how to burn all the wood (which is what burning gases+burning char is doing) doesn't really address the reason why people don't want to burn wood if they have enough money - in other words if they have a choice. Once it is admitted that burning wood gas then char is the same as burning whole wood as far as the forest is concerned, we can also admit that transport and convenience have a lot to do with it. In other words, this is a question strongly influenced by social questions. The transport of charcoal (MJ per ton-mile) is much cheaper than transporting wood and this difference dominates the charcoal economy. It is impractical to ship wood 600 km in Mozambique because of cost of doing so. In order to get the comparisons right I feel we need to agree on some definitions. The wood can be dried in the field. The energy content can be taken to be about 15 to 16 MJ/kg. Charcoal can be taken to be 29 MJ/kg or about double the energy. Mental arithmetic becomes easy. Decent charcoal production (improvement of the source technology, not only the stove technology) should be considered because it is a heck of a lot cheaper to improve the production than to improve every single stove in all sizes everywhere). What I mean by this is that if we seek systems type improvements we should consider all the systems involved. In a way it is like the 'open fire' as the baseline. It does not help the analysis to seek really bad examples of open fires then compare the 'improvement' to it. Just a caution. One way to analyse this is to look at how the biofuel energy supply is already emerging. The shipping of wood pellets and torrefied wood shows there are ways to attract 'custom' selling packaged energy. A stick of wood is a package of energy. I want to add one comment about the cost of the products. I tested recently a TLUD pellet burner that by opening a small door, burns the charcoal afterwards. The gas flame was not as controllable as the charcoal one but that is a quibble. There was no need to transfer anything, it was just a sequential burner. The market price is $5.50 and the production cost is $2.20 or so. That is with a metal shell. With a clay shell it would be about $1.40 to make. I think that is cheap. I will process the test results to see what the performance in numbers was like. Pellets are a processed fuel and can include non-woody biomass. China is making millions of tons of them from agricultural waste with an aggressive expansion plan that include developing better and more efficient equipment. That may be the charcoal replacement of the future, provided people are willing to use them and the stoves deliver the cooking and heating experience they seek. Regards Crispin On 4/8/2013 4:09 PM, Andreatta, Dale A. wrote: At the recent ETHOS conference Paul Means and Chris Lanning gave a very thought-provoking talk about an alternative to charcoal. The basic idea was to use a gasifying stove with prepared wood fuel. The prepared wood fuel would be bought by the user instead of charcoal, and the supply chain would be similar to charcoal. The big advantage is that the very inefficient step of charcoal production is eliminated. The stove would hopefully be easy to use and would smoke very little, so as to retain the benefits of a charcoal stove. ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
Re: [Stoves] Alternative to charcoal
Crispin, Do you think it is useful to place a value on the reduced life span of a $5 TLUD when burning char compared to the same TLUD not burning the char? Alex On 08/04/2013 9:30 PM, Crispin Pemberton-Pigott wrote: Dear Dale and Friends The analysis of alternatives to charcoal should include the reasons why people prefer it, strongly, over wood when given a choice of either, with charcoal costing much more than wood per kg. Working out theoretically how to burn all the wood (which is what burning gases+burning char is doing) doesn't really address the reason why people don't want to burn wood if they have enough money -- in other words if they have a choice. Once it is admitted that burning wood gas then char is the same as burning whole wood as far as the forest is concerned, we can also admit that transport and convenience have a lot to do with it. In other words, this is a question strongly influenced by social questions. The transport of charcoal (MJ per ton-mile) is much cheaper than transporting wood and this difference dominates the charcoal economy. It is impractical to ship wood 600 km in Mozambique because of cost of doing so. In order to get the comparisons right I feel we need to agree on some definitions. The wood can be dried in the field. The energy content can be taken to be about 15 to 16 MJ/kg. Charcoal can be taken to be 29 MJ/kg or about double the energy. Mental arithmetic becomes easy. Decent charcoal production (improvement of the source technology, not only the stove technology) should be considered because it is a heck of a lot cheaper to improve the production than to improve every single stove in all sizes everywhere). What I mean by this is that if we seek systems type improvements we should consider all the systems involved. In a way it is like the 'open fire' as the baseline. It does not help the analysis to seek really bad examples of open fires then compare the 'improvement' to it. Just a caution. One way to analyse this is to look at how the biofuel energy supply is already emerging. The shipping of wood pellets and torrefied wood shows there are ways to attract 'custom' selling packaged energy. A stick of wood is a package of energy. I want to add one comment about the cost of the products. I tested recently a TLUD pellet burner that by opening a small door, burns the charcoal afterwards. The gas flame was not as controllable as the charcoal one but that is a quibble. There was no need to transfer anything, it was just a sequential burner. The market price is $5.50 and the production cost is $2.20 or so. That is with a metal shell. With a clay shell it would be about $1.40 to make. I think that is cheap. I will process the test results to see what the performance in numbers was like. Pellets are a processed fuel and can include non-woody biomass. China is making millions of tons of them from agricultural waste with an aggressive expansion plan that include developing better and more efficient equipment. That may be the charcoal replacement of the future, provided people are willing to use them and the stoves deliver the cooking and heating experience they seek. Regards Crispin On 4/8/2013 4:09 PM, Andreatta, Dale A. wrote: At the recent ETHOS conference Paul Means and Chris Lanning gave a very thought-provoking talk about an alternative to charcoal. The basic idea was to use a gasifying stove with prepared wood fuel. The prepared wood fuel would be bought by the user instead of charcoal, and the supply chain would be similar to charcoal. The big advantage is that the very inefficient step of charcoal production is eliminated. The stove would hopefully be easy to use and would smoke very little, so as to retain the benefits of a charcoal stove. ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/ ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
Re: [Stoves] Alternative to charcoal
Crispin, The numbers I have for wood pellets suggest around 8,000 BTUs per pound. Charcoal is about 12,000 BTUs per pound. From this, I get that charcoal has only about 50% more energy per pound than wood pellets. Would not this also apply to stick wood as well? An advantage of using local, non stick wood, biomass is that the transportation problem/cost can be substantially mitigated. What, for example, becomes of Jatropha seed cake that is the residue after pressing out the oil? If run through the press a second time does it become plastic like? I have seen this with other oil seed cakes. They can burn very well in TLUD. Regards, Jock On Apr 8, 2013, at 9:30 PM, Crispin Pemberton-Pigott crispinpig...@gmail.com wrote: Dear Dale and Friends The analysis of alternatives to charcoal should include the reasons why people prefer it, strongly, over wood when given a choice of either, with charcoal costing much more than wood per kg. Working out theoretically how to burn all the wood (which is what burning gases+burning char is doing) doesn’t really address the reason why people don’t want to burn wood if they have enough money – in other words if they have a choice. Once it is admitted that burning wood gas then char is the same as burning whole wood as far as the forest is concerned, we can also admit that transport and convenience have a lot to do with it. In other words, this is a question strongly influenced by social questions. The transport of charcoal (MJ per ton-mile) is much cheaper than transporting wood and this difference dominates the charcoal economy. It is impractical to ship wood 600 km in Mozambique because of cost of doing so. ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
Re: [Stoves] Alternative to charcoal
Dear Ron We are back to repeating old arguments. …directly contradicted this sentence just in from Crispin The transport of charcoal (MJ per ton-mile) is much cheaper than transporting wood and this difference dominates the charcoal economy A ton of damp wood and a ton of dry charcoal do not have the same energy content. That is why people transport charcoal 600 km to Maputo and to Dakar, not wood. Regards Crispin ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
Re: [Stoves] Alternative to charcoal
Dear Jock The numbers I have for wood pellets suggest around 8,000 BTUs per pound. There is a pretty comprehensive list of heat values at the back of a WBT spreadsheet. 12,000 would be a a bit about right for charcoal. The heat value of char produced in a TLUD or a fire has not been very well studied. Jim Jetter’s Aug 2012 paper has some values. The heat value of wood is only what people are going to get from it, not what it would be if it were dried (which also applies to charcoal). I am in Central Java at the moment and the charcoal in the lab has been sitting around for a while. The average moisture content is 8.8% according the lab lady Julianna. The heat content is 26.7 MJ/kg which is slightly below the 12,000 BTU mark. The local wood even after months of drying is about 15-16% moisture. With a heat content of about 19.2 MJ/kg dry at 16% it is 15.7 MJ/kg. Lots of woods have a lower heat value than that and many people use damp wood – no doubt about it. It bubbles and dribbles continuously. So the reality is that what people put into their stoves is often below ½ the heat value of charcoal per kg. Further, the char produced by a TLUD is expected to be 0% moisture if it is used within a day or so it will pay to keep an eye on what exactly is being claimed. Fresh charcoal has a very low moisture level. Most fuelwood does not. That is the comparison I am thinking of. A direct comparison between the average fuelwood as used and locally made charcoal as used is ≈15.5 v.s. 29.5 MJ/kg. If I put 1 kg of 15% moisture wattle (15.9 MJ/kg) into a TLUD stove and create 20% char (20% of the moist mass) the net heat provided by the fire is 10 MJ/kg. The heat available from the char is still 29.5 so the total is the difference the bit between: 15.9-10 = 5.9 MJ. If someone wants to switch from wood fuel to a ‘cleaner’ TLUD and that TLUD is not 1.5 times as efficient in transferring heat, their raw fuel consumption will increase. Regards Crispin ___ Stoves mailing list to Send a Message to the list, use the email address stoves@lists.bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
