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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Julien, <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thank you for the great list of references. Abrasive is probably the major reason that crop residues are not densified in the US. Die maintenance is simply too expensive. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>One aspect of densification that is often overlooked is the role of cellulose and sugars. Materials like fresh grasses with an abundance of sugars are easily densified because they carry their own binder. Mature plants like straws and husks require binders or more heat and pressure for binding. Molasses is a common binder for feed briquettes, cubes or pellets. Cassava and similar materials are often used. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>As fibers are pressed together they are heated by the resistance in the die. The heat drives out moisture and the binding mechanism is hydrogen bonding – hydrogen molecules binding hydroxyl radicals in the fibers. This is sometimes called “paper bonding”. When you put two pieces of paper together, wet them and let them dry they stick together. Paper bonding is the initial methods of binding in densification. Making a paper mache and letting it dry is the basis of many fuel logs or briquettes. I don’t know of anyone ensiling rice husks before densifying them but that may be an approach. Paper bonding is the mechanism for most low pressure pelleting equipment. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>As fibers heat further you can get lignin flow as you pass the “lignin glass transition temperature”. If you look at pellets with a scanning electron microscope (SEM) you can see the different forms of binding. The hish silica in rice husks may make this difficult. We have seen blends of rice husks and eucalyptus bark. That combination desifies well but the potassium in the bark can react with the silica in the hull to cause clinkers when it is burned. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Electricity is often another deterrent to densification. It takes about 50 kWh of electricity to bind a ton of biomass. Electricity for densification can be quite expensive in some areas. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Tom<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><b>From:</b> Stoves <stoves-bounces@lists.bioenergylists.org> <b>On Behalf Of </b>Julien Winter<br><b>Sent:</b> Sunday, January 13, 2019 5:16 AM<br><b>To:</b> Discussion of biomass cooking stoves <stoves@lists.bioenergylists.org><br><b>Subject:</b> [Stoves] Blue flame of TLUD-FA with rice hull fuel<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal>Hi Paul;<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>It is clear that the mineral content of rice hulls is high, and mostly SiO. There will be variation in ash content according to genotypes, and growing conditions (soil, weather, fertilizer, etc.)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>The high SiO content in rice hulls and straw makes this biomass very tough and abrasive for making compressed fuel. I suspect that is why we don't see rice hull pellets.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>In SE Asia, screw presses are used to make briquettes. Because the rice hulls are abrasive, the screws have only 20 hours operating life, before they have to go to a welding shop and rebuilt.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>You can find a playlist of videos of screw press machines on the "Biochar Bangladesh" YouTube Channel.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>The briquettes are broken up when used in a TLUD. The best person to ask about how they burn is Mahbubul Islam.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Below are a few references on compressed fuels from rice residues.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I am not working in this area at the moment.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Cheers,<o:p></o:p></p></div><div><p class=MsoNormal>Julien.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><div><p class=MsoNormal>COMPRESSED FUEL<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ahiduzzaman, M. 2007 Rice husk energy technologies in Bangladesh. In: Agricultural Engineering International: the CIGR Ejournal. Invited Overview No. 1. Vol. IX. January, 2007. 10 p. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ahiduzzaman, M; Islam, AKMS. 2009 Environmental impact of rice husk briquette fuel use in Bangladesh: A case study of Mymensingh. In Developments in Renewable Energy Technology (ICDRET), 2009 1st International Conference on the (pp. 1-4). IEEE.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ahiduzzaman, M; Islam, AKMS. 2011 Greenhouse gas emission and renewable energy sources for sustainable development in Bangladesh. Renewable & Sustainable Energy Reviews 15: 4659-4666 DOI: 10.1016/j.rser.2011.07.086 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ahiduzzaman, M; Islam, AKMS. 2013 Development of biomass stove for heating up die barrel of rice husk briquette machine. Procedia Engineering 56:777-781 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Alam MM; Islam; H; Hasan M; Siddique TA. 2011 A Study of Biomass Briquette in Bangladesh. Proceedings of the International Conference on Mechanical Engineering 2011 (ICME2011) 18-20 December 2011, Dhaka, Bangladesh ICME11-RE-002 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Bhattacharya, S.C.; Leon, M. A.; Rahman, M. M. 2002 A study on improved biomass briquetting. Energy for Sustainable Development VI(2): 107-110 <a href="http://www.retsasia.ait.ac.th/Publications/ESD.pdf">http://www.retsasia.ait.ac.th/Publications/ESD.pdf</a> <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Bhattacharya, SC; Bhatia, R; Islam, MN; Shah, N. 1985 Densified biomass in Thailand: potential, status and problems. Biomass 8: 255-266 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Bhattacharya, SC; Sett, S; Shrestha, RM. 1989 State of the Art for Biomass Densification. Energy Sources 11: 161-182 DOI: 10.1080/00908318908908952 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Chin, OC; Siddiqui, KM. 2000 Characteristics of some biomass briquettes prepared under modest die pressures. Biomass & Bioenergy 18: 223-228 DOI: 10.1016/S0961-9534(99)00084-7 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Chou, CS; Lin, SH; Peng, CC; Lu, WC. 2009 The optimum conditions for preparing solid fuel briquette of rice straw by a piston-mold process using the Taguchi method. Fuel Processing Technology 90: 1041-1046 DOI: 10.1016/j.fuproc.2009.04.007 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Grover PD; Mishra SK. 1996 Biomass Briquetting: Technology and Practices. FAO Regional Wood Energy Development Programme in Asia, Bangkok, Thailand. Field Document No.46. 48 p. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Hassan, Md. Kamrul; Pelkonen, Paavo; Pappinen, Ari. 2014 Rural households' knowledge and perceptions of renewables with special attention on bioenergy resources development - Results from a field study in Bangladesh. Applied Energy 136: 454-464 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Hu, JJ; Lei, TZ; Shen, SQ; Zhang, QG. 2013 Specific energy consumption regression and process parameters optimization in wet-briquetting of rice straw at normal temperature. Bioresources 8: 663-675 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Matúš M; Križan P; Ondruška J; Šooš L. 2011 Analysis of tool geometry for screw extrusion machines. J. Applied Mathematics 4:401-413 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Moral, MNA. 2005 Biomass densification: development of briquetting packages in Bangladesh. Renewable Energy Technologies in Asia. <a href="http://www.retsasia.ait.ac.th/">http://www.retsasia.ait.ac.th/</a><o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Moral, MNA; Shakya, GR; and Toan, PK. 2005 Technology Packages: Screw-press Briquetting Machines and Briquette-fired Stoves. Bhattacharya, SC; Kumar S. (editors). Published by: Regional Energy Resources Information Center (RERIC), Energy Field of Study, Asian Institute of Technology, P.O. Box 4, Klong Luang, Pathumthani 12120, Thailand 76 p.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ndindeng, SA; Mbassi, JEG; Mbacham, WF; Manful, J; Graham-Acquaah, S; Moreira, J; Dossou, J; Futakuchi, K. 2015 Quality optimization in briquettes made from rice milling by-products. Energy for Sustainable Development 29: 24-31 DOI: 10.1016/j.esd.2015.09.003 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Rahaman, SA; Salam, PA. 2017 Characterization of cold densified rice straw briquettes and the potential use of sawdust as a binder. Fuel Processing Technology 158: 9-19 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Singh, D; Kashyap, MM. 1985 Mechanical and combustion characteristics of paddy husk briquettes. Agricultural Wastes 13: 189-196. DOI: 10.1016/0141-4607(85)90033-2 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Wang, XT; Zhao, XT. 2014 The application of ceramic wear resistant materials in biomass briquetting Equipment. Energy & Environment 25: 1003-1009 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Wang, Y; Sun, Y; Wu, K; Xia, XF. 2016 Optimal design for rice straw briquetting process based on experiments. Proceedings of the Asme International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2016, Vol 2A, Article Number: UNSP V02AT03A047 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Xia, XF; Sun, Y; Wu, K; Jiang, QH. 2014 Modeling of a straw ring-die briquetting process. Bioresources 9: 6316-6328 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Xia, XF; Sun, Y; Wu, K; Jiang, QH. 2016 Optimization of a straw ring-die briquetting process combined analytic hierarchy process and grey correlation analysis method. Fuel Processing Technology 152: 303-309 DOI: 10.1016/j.fuproc.2016.06.018 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Yank, A. 2014 Low Pressure Densification of Rice Husk and Direct Combustion of Biomass in Improved Cookstoves. M.Sc. Thesis, McGill. 138 p. <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Yank, A; Ngadi, M; Kok, R. 2016 Physical properties of rice husk and bran briquettes under low pressure densification for rural applications. Biomass & Bioenergy 84: 22-30 DOI: 10.1016/j.biombioe.2015.09.015 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>RICE STRAW<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Acda, MN. 2016 Physical and chemical properties of fuel pellets from agricultural residues. Philippine Agricultural Scientist 99: 283-287 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Chakma, S; Ranjan, A; Choudhury, HA; Dikshit, PK; Moholkar, VS. 2016 Bioenergy from rice crop residues: role in developing economies. Clean Technologies and Environmental Policy 18: 373-394 DOI: 10.1007/s10098-015-1051-5 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Chou, CS; Lin, SH; Lu, WC. 2009 Preparation and characterization of solid biomass fuel made from rice straw and rice bran. Fuel Processing Technology 90: 980-987 DOI: 10.1016/j.fuproc.2009.04.012 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ewida, KT; El-Salmawy, H; Atta, NN; Mahmoud, MM. 2006 A sustainable approach to the recycling of rice straw through pelletization and controlled burning. Clean Technologies and Environmental Policy 8: 188-197<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ishii, K; Furuichi, T. 2014 Influence of moisture content, particle size and forming temperature on productivity and quality of rice straw pellets. Waste Management 34: 2621-2626 DOI: 10.1016/j.wasman.2014.08.008 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Ishii, K; Furuichi, T; Fujiyama, A; Watanabe, S. 2016 Logistics cost analysis of rice straw pellets for feasible production capacity and spatial scale in heat utilization systems: A case study in Nanporo town, Hokkaido, Japan. Biomass & Bioenergy 94: 155-166 DOI: 10.1016/j.biombioe.2016.08.007 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Jenkins, BM; Bakker, RR; Wei, JB. 1996 On the properties of washed straw. Biomass & Bioenergy 10: 177-200 DOI: 10.1016/0961-9534(95)00058-5 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Kargbo, FR; Xing, JJ; Zhang, YL. 2009 Pretreatment for energy use of rice straw: A review. African Journal of Agricultural Research 4: 1560-1565<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Lim, JS; Manan, ZA; Alwi, SRW; Hashim, H. 2012 A review on utilisation of biomass from rice industry as a source of renewable energy. Renewable & Sustainable Energy Reviews 16: 3084-3094 DOI: 10.1016/j.rser.2012.02.051 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Liu, XM; Liu, ZJ; Fei, BH; Cai, ZY; Jiang, ZH; Liu, XE. 2013 Comparative properties of bamboo and rice straw pellets. Bioresources 8: 638-647 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Liu, ZJ; Liu, XE; Fei, BH; Jiang, ZH; Cai, ZY; Yu, Y. 2013 The properties of pellets from mixing bamboo and rice straw. Renewable Energy 55: 1-5 DOI: 10.1016/j.renene.2012.12.014 <o:p></o:p></p></div><div><p class=MsoNormal>Missagia, B; Guerrero, C; Narra, S; Sun, YL; Ay, P; Krautz, HJ. 2011 Physicomechanical properties of rice husk pellets for energy generation. Energy & Fuels 25: 5786-5790 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Said, N; Bishara, T; Garcia-Maraver, A; Zamorano, M. 2013 Effect of water washing on the thermal behavior of rice straw. Waste Management 33: 2250-2256 DOI: 10.1016/j.wasman.2013.07.019 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Said, N; Daiem, MMA; Garcia-Maraver, A; Zamorano, M. 2014 Reduction of ash sintering precursor components in rice straw by water washing. Bioresources 9: 6756-6764 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Said, N; Abdel daiem, MM; Garcia-Maraver, A; Zamorano, M. 2015 Influence of densification parameters on quality properties of rice straw Pellets. Fuel Processing Technology 138: 56-64 DOI: 10.1016/j.fuproc.2015.05.011<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>Shone, CM; Jothi, TJS. 2016 Preparation of gasification feedstock from leafy biomass. Environmental Science and Pollution Research 23: 9364-9372 DOI: 10.1007/s11356-015-5167-2<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Yang, I; Kim, SH; Sagong, M; Han, GS. 2016 Fuel characteristics of agropellets fabricated with rice straw and husk. Korean Journal of Chemical Engineering 33: 851-857 DOI: 10.1007/s11814-015-0210-z <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Yao, XW; Xu, KL; Liang, Y. 2016 Comparing the thermo-physical properties of rice husk and rice straw as feedstock for thermochemical conversion and characterization of their waste ashes from combustion. Bioresources 11: 10549-10564 DOI: 10.15376/biores.11.4.10549-10564 <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><br clear=all><o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><p class=MsoNormal>-- <o:p></o:p></p><div><div><div><div><div><div><p class=MsoNormal>Julien Winter<br>Cobourg, ON, CANADA<o:p></o:p></p></div></div></div></div></div></div></div></div></div></div></div></body></html>