Tom,
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. The IBI has some good test methods that I am now using. Measure pH, salts, etc on diluted samples are a few I have changed to. Methods for metal are acid digest and is what I have been doing along with most others. The CEC I would like to change to an AOAC procedure for peat. And the butane activity is left out. Going to iodine. I have been doing 450 deg for calcining temp but now raised it to their 600 deg as that is where I have found the butane activity is highest (600 to 650 deg C) for most biochar when plotting curves. But the loss in weight seems to stabilize at ~450 deg C. I was thinking if activity was not that important the lower temperature is all that is required. They use a C/H ratio to determine if the biomass is sufficiently charred where I was measuring loss in weight after re-charring at 450 deg C. My procedure has some real problems and was looking for other ideas. I think theirs may be better but still we need to keep looking as I am not sure it will weed out tars that would be removed in my procedure and different feedstocks may end up with different C/H ratios even when fully charred. So on it goes. I was looking into a TGA to do the testing but after sending in samples to Leco I was not real happy with the results. This can determine moisture then switch over to nitrogen atm and char at predetermined temperature then add air and ash at predetermined temperature all in one unite and cycle. This should work well. I had them char in nitrogen a sample at different temperatures thinking I would get a value that leveled off at 450 deg C as what I have found in my pipe system. But my pipe system seems to work better. Not sure if air was in their system when they ran it after drying or if biomass does change in weight more than I found over temperature differences with my pipes. Thanks Frank Frank Shields Control Laboratories, Inc. 42 Hangar Way Watsonville, CA 95076 (831) 724-5422 tel (831) 724-3188 fax [email protected] www.compostlab.com _____ From: [email protected] [mailto:[email protected]] On Behalf Of Tom Miles Sent: Thursday, October 27, 2011 12:29 PM To: 'Discussion of biomass cooking stoves' Subject: Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14,Issue 17 Frank, Test methods. Many oof the ASTM methods for biomass are coal methods that have been adjusted for biomass. Usually the calcining temperature of a sample for biomass has been reduced by ASTM fro the 900C used for coal to 550C or 600 C for biomass. Tom From: [email protected] [mailto:[email protected]] On Behalf Of Frank Shields Sent: Thursday, October 27, 2011 12:06 PM To: 'Discussion of biomass cooking stoves' Subject: Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14, Issue 17 Dear Paul, The way I look at it; Biochar is not needed by the plant anymore than peat moss, perlite, sand, lime, gypsum etc. These are all materials used to change the texture of the soil. Better drainage, hold more water, make water more available, adjust pH that changes availability of nutrients, added porosity, add microbes that regulate the nutrients etc. If the biochar product adjusts one of these components to make the required constituents (water, nutrients, temperature etc) more optimum for the plant you will see a benefit. A lot of silica (as in rice hulls) may very well be the component that makes the change and the carbon fraction has nothing to do with it. Or it could all be from the carbon fraction or mixture of both. IMO it is important to determine the condition change that has created the increase in plant response. And the constituent of the biochar that has done it. Then we can determine the biochar quality that should be used on that specific site. But I think we can agree that it's the carbon component we regard as important when talking biochar. If it's the silica in rice hulls making the difference we could just add something like sand. Being carbon as the important fraction biochar quality should be rated based on the carbon component. Not only carbon concentration but also the carbon structure (or we could just as well add organic matter). Carbon comes in a range of biological activity. Very reactive like green grass, sugars, oils, vegetative materials. Semi-reactive materials like wood chips, stabilized compost, biosolids and organics from aeration ponds, finished septic systems etc and very stabilized like plastic, biochar. Available carbon increases microbes. That in turn uses a lot of oxygen making soils anaerobic creating lots of problems. The reason we compost and have septic systems before letting high reactive organics into the environment. Because biochar claim to have a very stabilized carbon (non-available to microbes and oxidation) we need to measure to the degree the carbon is stabilized in addition to the concentration to rate and compare biochar products. Rice biochar has low carbon (not good) but likely high stability (good). And a unique structure, that in the right locations and soil type, could make all the difference. It's the test methods that work best to determine the carbon concentration and properties that we need to sort out. Not an easy task thanks to people wanting to use coal testing methods for biochar. We need our own methods manual. Regards Frank Frank Shields Control Laboratories, Inc. 42 Hangar Way Watsonville, CA 95076 (831) 724-5422 tel (831) 724-3188 fax [email protected] www.compostlab.com _____ From: [email protected] [mailto:[email protected]] On Behalf Of Crispin Pemberton-Pigott Sent: Thursday, October 27, 2011 6:56 AM To: 'Discussion of biomass cooking stoves' Subject: Re: [Stoves] [biochar-production] Re: Stoves Digest, Vol 14,Issue 17 Dear Paul Do you know if the char has been characterised well, or is it from the smoky stacks you described earlier? Thanks Crispin ++++++ Frank, Rice hulls biochar makes as excellent soil amendment, as numerous test have shown. Yields on rice, water spinach and other plants have increased roughly 3-fold in the trials that were done in Vietnam and Cambodia. If it is not the best biochar, I would be truly exciting to find something better. Paul Olivier
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