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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Paul,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The structure and composition of rice husk ash make rice husks a unique fuel and so they should not be compared to straws. We did a fair amount of work with rice husk combustion after our work with alkali deposits. That work is proprietary to our client. We included phase diagrams in our alkali study that show the effect of K:Si composition and temperature on liquidus states. http://www.trmiles.com/alkali/Alkali_Report.pdf In practice unground rice husks are a very stable fuel for gasification. You need to burn out the carbon and get to some pretty high temperatures to have problems. Even if you have an excess of K relative to Si, which would be the case in adding coffee husks, you dot; have the slagging problems you would have with rice straw. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>While at the Asian Pacific Biochar Conference last month in Japan we visited the <a href="http://www.kippo.or.jp/e/nature/environment/Picture/252012_e.pdf"><i><span style='color:#1F497D;text-decoration:none'>Aito Eco</span></i><span style='color:#1F497D;text-decoration:none'>-plaza “Nanohana Kan”</span></a>. They use an updraft, stirred bed, gasifier supplied by Kansai Corporation to convert rice husks to biochar (Kuntan) and heat.</span> <span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>They feed 150 kg/hr husk at 2000 kcal/kg and get 50 kg/hr char. It is a stirred bed gasifier. They say that husks gasify in the bed at about 600C. Air is added above the bed to burn the gases. Stack gas is 15% O2 so they use lots of excess air. About 30% of the heat input is recovered as hot water which is used in the bio oil process and in winter for heating. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>They pack the product in clear 10 kg bags. I was interested in the labeling of the bags. They indicate 40% carbon and 50% silica. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Their label indicates that in 1 kg biochar they have<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'> K 11000mg</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'> Ca 5700</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'> Na 1700</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'> Mn 790</span><o:p></o:p></p><p class=MsoNormal style='text-indent:5.0pt'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'> Fe 190</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'> Zn 110</span><o:p></o:p></p><p class=MsoNormal style='text-indent:10.0pt'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Cu a very small quantity</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>They provide separate instructions for use in gardens, horticultural crops, row cropland tees. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The numbers of units and actual use are still not clear. I heard that Kansai Corp had installed 200 of these and made char from about 10% of their husk production of 100,000 tpy. <o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I would expect the traditional farm scale kuntan pyrolysis to be at a similar low temperature. We were told that Kuntan is used in growing rice plant seedlings because it is good for root development. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Steve M Haefele et. al. (IRRI) have published research on rice husk char. Carbon and potassium contents of the char are similar to the Aito label above. K concentrations in the char is 2 x the untreated char. C and N are in similar concentrations in the char as in the untreated husk. One furnace was developed at IRRI in conjunction with Nong Lam University in Vietnam. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>All of this research is relevant to the use of char from carbonizing stoves. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Tom <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Haefele, S. M., Y. Konboon, et al. (2011). "Effects and fate of biochar from rice residues in rice-based systems." Field Crops Research 121(3): 430-440. http://www.sciencedirect.com/science/article/pii/S0378429011000402<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> Although crop residues constitute an enormous resource, actual residue management practices in rice-based systems have various negative side effects and contribute to global warming. The concept of a combined bioenergy/biochar system could tackle these problems in a new way. Rice residues would be used for energy production, thereby reducing field burning and the use of fossil fuels, and the biochar by-product could help to improve soils, avoid methane emissions, and sequester carbon in soils. To examine some of these promises, we conducted field experiments from 2005 to 2008 in three different rice production systems. Objectives were to study the effect of biochar from rice husks on soil characteristics, assess the stability of carbonized rice residues in these different systems, and evaluate the agronomic effect of biochar applications. The results showed that application of untreated and carbonized rice husks (RH and CRH) increased total organic carbon, total soil N, the C/N ratio, and available P and K. Not significant or small effects were observed for soil reaction, exchangeable Ca, Mg, Na, and the CEC. On a fertile soil, the high C/N ratio of CRH seemed to have limited N availability, thereby slightly reducing grain yields in the first three seasons after application. On a poor soil, where the crop also suffered from water stress, soil chemical and physical improvements increased yields by 16–35%. Together with a parallel study including methane and CO2 emission measurements at one site, the results strongly suggest that CRH is very stable in various rice soils and systems, possibly for thousands of years. However, the study also showed that CRH was very mobile in some soils. Especially in poor sandy soil, about half of the applied carbon seemed to have moved below 0.30 m in the soil profile within 4 years after application. We concluded that biochar from rice residues can be beneficial in rice-based systems but that actual effects on soil fertility, grain yield, and soil organic carbon will depend on site-specific conditions. Long-term studies on biochar in field trials seem essential to better understand biochar effects and to investigate its behavior in soils.<o:p></o:p></span></p><p class=MsoNormal style='text-autospace:none'><span style='font-family:"Arial","sans-serif"'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></body></html>