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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'>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'>The C/N ratio is almost useless in when preparing compost formulations contrary to what most people think. The carbon is determined on a Total Carbon and so is nitrogen. What we really need is available C and N and the availability changes during the composting process. If you add wood chips to a compost they will be there in a large part when the compost is finished – so should not be counted. Oils and other lipids will biodegrade quickly lowering the pH. Then it’s the slow release of carbon to available form as the process continues. With nitrogen becoming available as ammonia the pH goes up. It can out-gas and be lost so availability of nitrogen should also be a continuous process. All this occurs with in vegetative material that has wood chips added only for porosity.<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'>So a measure of total N and total C at the beginning has little use and is only a guideline. Real way is to measure the Total N and C at the beginning and again at the end to determine the C removed as CO2 IMO. But to answer your question you might as well test for Total N and total C to get a C/N ratio with the char along with the wood chips. <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'>As for food scraps; They are the hardest to compost unless well mixed in with a lot of other materials. That because they are readily available C and N and react fast and that causes smells and fluctuation in pH, hugh oxygen demands making anaerobic conditions etc. New interest is AD dry systems then aerobic composting remaining material that have been partial stabilized. <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'>Frank<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><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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-bounces@lists.bioenergylists.org [mailto:stoves-bounces@lists.bioenergylists.org] <b>On Behalf Of </b>Tom Miles<br><b>Sent:</b> Monday, October 31, 2011 1:01 PM<br><b>To:</b> 'Discussion of biomass cooking stoves'<br><b>Subject:</b> Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14, Issue 17<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Frank<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'>If I am taking char from a TLUD and adding it to cooking scraps for compost do I ignore the carbon in the char when calculating the Carbon to Nitrogen ratio? <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'>Thanks<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>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><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> <a href="mailto:stoves-bounces@lists.bioenergylists.org">stoves-bounces@lists.bioenergylists.org</a> <a href="mailto:[mailto:stoves-bounces@lists.bioenergylists.org]">[mailto:stoves-bounces@lists.bioenergylists.org]</a> <b>On Behalf Of </b>Frank Shields<br><b>Sent:</b> Monday, October 31, 2011 12:05 PM<br><b>To:</b> 'Discussion of biomass cooking stoves'<br><b>Subject:</b> Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14, Issue 17<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear 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'>For compost the purpose is to ‘stabilize’ the carbon to a point the environment can replenish oxygen and nutrients at a rate plants and biota is not effected. When in an ag situation we have growers ready to supplement nutrients (nitrogen) at the ready when plants or lab tests indicate needed. Stabilized values I like to see is < 4 mg CO2-C / g organic matter / day. This dry weight. But many people use 8 mg CO2-C as a stabilized value. <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'>I think biochar is not even in the picture for nitrogen up-take or oxygen depletion in an ag soil because they will be so low. Perhaps over time in a non ag environment the carbon may deplete the nitrogen - put more likely just hold the nitrogen from being leached for later use. <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'>Frank <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'><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'><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><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> <a href="mailto:stoves-bounces@lists.bioenergylists.org">stoves-bounces@lists.bioenergylists.org</a> <a href="mailto:[mailto:stoves-bounces@lists.bioenergylists.org]">[mailto:stoves-bounces@lists.bioenergylists.org]</a> <b>On Behalf Of </b>Tom Miles<br><b>Sent:</b> Friday, October 28, 2011 11:50 AM<br><b>To:</b> 'Discussion of biomass cooking stoves'<br><b>Subject:</b> Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14, Issue 17<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Crispin, Frank,<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'>Apart from fraud, it is nice to have a general indication of how much of the fuel will convert to a gas before burning and how much would, in theory, remain as char. IN practice you oxidize part of he “fixed” carbon as well. <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'>In carbonization the volatile carbon is a useful indicator of the extent of carbonization. We look for volatile carbon to be less than 20% for most applications. That does not mean that all biochar needs to be less than 20% volatile carbon. Other measures of labile carbon would be helpful. <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'>For biochar applications it would be useful to know how much of the carbon is likely to be consumed by organisms and will thereby have a demand on nitrogen or other nutrients. I have assumes that is the volatile fraction. How much char C do you include in calculating a C:N ration for composting, for example? If you intend to deliver a char to a uses that will supply it’s own N how much to you have to add? How much char from stoves can you estimate will have a demand on plant nutrients if used as biochar? <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><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> <a href="mailto:stoves-bounces@lists.bioenergylists.org">stoves-bounces@lists.bioenergylists.org</a> <a href="mailto:[mailto:stoves-bounces@lists.bioenergylists.org]">[mailto:stoves-bounces@lists.bioenergylists.org]</a> <b>On Behalf Of </b>Crispin Pemberton-Pigott<br><b>Sent:</b> Friday, October 28, 2011 1:09 PM<br><b>To:</b> 'Discussion of biomass cooking stoves'<br><b>Subject:</b> Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14, Issue 17<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Dear Frank<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA 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:10.0pt;font-family:"Arial","sans-serif";color:navy'>My main disagreement is the term Fixed Carbon and that it means the total weigh DAF where it should be a measure of carbon in that fraction. I will need to get over that. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I assure you that Fixed Carbon does not have a clear and scientific meaning. I have given up hope with analyses that use the term. That means, it is ‘helpful’ but not an exact measure of anything.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>It really is taken to mean the carbon that happens not to disappear when the sample is treated in a certain way. Treat it in another way and the ‘fixed’ portion changes so it is an inherent property of the protocol times the fuel, not a property of the fuel alone.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The coal industry is so large that they feel they can get away with internal definitions and that makes huge problems for stovers because we never really know what we are being handed to burn. With biomass that has historically been the ‘chemistry’ of the fuel contents. But the principal users of ‘fixed carbon’ are the coal consumers like power stations. To give the DAF value of anything is misleading because we need to know what % it is of the fuel, not of part of the fuel.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>There are many tricks played by people promoting processed fuels that involve switching the fuel energy content numbers during the conversation. For example, people will report the ‘as received’ heat content as the fuel’s heating value (which is true) and then point out that their ‘Processing’ increases this to a much higher ‘DAF value’ showing a ‘60% increase in energy per kg’ even though it takes energy to remove the water and calculate out the ash. Plain fraud. Whenever someone reports the energy content you have to not only ask on what basis the figure was derived, but also investigate the protocol to see if it really is what it claims to be. Many people believe that there is free energy to be harvested in this manner.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Crispin<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></body></html>