Dear Rolf, I live in a region having vertisol soils, having pH >8.5. I must have tested biochar at least 10 times, and never got any positive results. Yours A.D.Karve
On Thu, Dec 13, 2012 at 1:48 PM, Energies Naturals C.B. < [email protected]> wrote: > Hallo all, > > this is a question I have asked quite often, but perhaps never on the list > . > > Whenever I read about the benefits of biochar, it is almost always in > relation with distinctively acid soils. > > Does anyone know the effect of biochar, itself beeing mostly basic, on > already basic soils ? > > Rolf > > > > > > > > Am 13.12.2012 05:10, schrieb Kevin: > > Dear Tom > > ----- Original Message ----- > *From:* Tom Miles <[email protected]> > *To:* [email protected] ; [email protected] ; 'Discussion > of biomass cooking stoves' <[email protected]> > *Sent:* Wednesday, December 12, 2012 2:18 AM > *Subject:* Re: [Stoves] [biochar-policy] Re: Equipment required for > testingstoves > > Charcoal burns in direct contact with air well above 600 C so any fire > at the charcoal stage would be above 500-600C. > > > > # There are two issues here: > > 1: The temperature at which charcoal burns > > 2: The average temperature experienced by the charcoal remaining after it > was produced. > > Certainly, charcoal can burn at temperatures well above 600C in air. > Surface temperatures of burning char can be very different than the core > temperature. Consider a flash fire, with high surface temperatures for a > short time. Core temperatures of the wood or char remaining can be very > much lower. This is a very complex heat transfer problem... unsteady state > three dimensional heat transfer to bodies of irregular shape, with change > in phase. What is important is the properties of the "unburned charcoal" > remaining for potential use as biochar. > > > > Higher temperature oxidized chars have great adsorption properties. They > compost readily. Great way to make terra preta. > > > > # Certainly, such "designer chars" could have very superior properties, > but at greater cost. The "bottom line" for the Farmer or Grower is the > "Benefit/Cost Ratio." Additionally, there may be special soil conditions > that such "designer chars" can handle better than "regular biochar" that > works adequately well for most common soil conditions. > > > > Best wishes, > > > > Kevin > > > > Tom > > *From:* [email protected] [ > mailto:[email protected] <[email protected]>] *On > Behalf Of *Kevin > *Sent:* Tuesday, December 11, 2012 8:18 PM > *To:* [email protected]; Discussion of biomass cooking stoves; > biochar-policy > *Cc:* Alex English; Tom Miles > *Subject:* [biochar-policy] Re: [Stoves] Equipment required for testing > stoves > > > > > > > > Dear Ron > > ----- Original Message ----- > > *From:* [email protected] > > *To:* Discussion of biomass cooking stoves<[email protected]>; > biochar-policy <[email protected]> > > *Cc:* Alex English <[email protected]> ; Kevin > Chisholm<[email protected]>; Tom > Miles <[email protected]> > > *Sent:* Tuesday, December 11, 2012 2:09 AM > > *Subject:* Re: [Stoves] Equipment required for testing stoves > > > > Lists (adding biochar-policy also), Kevin, Alex, Tom (who I add, because > he speaks Portuguese and might have caught an answer when we were in Manaus > a few years ago) > > See below > > *From: *"Kevin" <[email protected]> > *To: *"Discussion of biomass cooking stoves" < > [email protected]>, "Alex English" <[email protected]> > *Cc: *"Discussion of biomass cooking stoves" < > [email protected]> > *Sent: *Monday, December 10, 2012 8:24:34 PM > *Subject: *Re: [Stoves] Equipment required for testing stoves > > > > Dear Ron > > > > Would you agree that the Amazonians made Terra Preta with low temperature > char? > *[RWL1: I think others may have an answer - maybe based on > spectroscopy. I will start looking but don't know that field well enough > to know what others may have concluded about these ancient soils. I fear > that 500 years (minimum) in soil may hide the initial character that we can > readily see in a University setting. I know from being in several > Amazonian biochar "pits" that it is pretty hard to find a piece big enough > to test. I think it entirely possible that char left over from simple > three-stone fires could have been made at 500-600 C (or higher). Would you > call those temperatures high or low?] * > > > > *# KC1: Obviously, I am speculating, but I would speculate that Terra > Preta was made with charcoal from a number of sources:* > > *1: Char residue remaining after charring or burning of "wood waste from > initial jungle clearing.* > > *2: Char residue remaining from charring or burning of agricultural waste > and weeds* > > *3: Char and ash residue from cooking fires and possibly smudge pots* > > *4: Organic fertilizer supplements, from humanure, composted food scraps, > and probably dredgings from oxbow lakes.* > > *I would consider 500-600 C to be a "low temperature char." I haven't > seen any references to the existence of bellows technology in ancient > Amazonia, that would be necessary to produce significantly higher > temperatures.* > > *It is likely that the Amazonian Terrapretians would have quickly noticed > if such low temperature char additions to their agricultural practises were > causing poor results. If that was the case, they likely would have taken > steps to avoid application of char to fields. They would be looking for > short term benefits or harm. Given that they used char on a widespread > basis, and that it was basically low temperature char, it would thus seem > that Terra Preta worked with low temperature char, and it worked relatively > quickly, not requiring an aging period of several years.* > > > > > If so, are there any test results to show that an "intermediate > temperature char" would give better results than the "low temperature char?" > *[RWL2: I think that people like Dr. Johannes Lehmann and Evelyn > Krull may be getting to an answer for some specific soil and species. I > keep looking for it. > My note below to Alex was to make it easier for users to know what is > being used Some of my favorite biochar scientists like Drs. Julie Major > and Christoph Steiner were forced to use char bought off the side of a > remote Amazonian road. > I haven't seen any data emphasizing tests with a range of > temperatures. Drs. Stephen Joseph (low) and Hugh McLaughlin (high) > recommend different temperature regimes.] * > > > > *#KC2: Is it perhaps likely that "basic low temperature biochar" is good > for general agricultural applications, but that intermediate and high > temperature chars may be better for addressing special agricultural > problems. * > > > > I seem to recall that "high temperature char" and/or "activated char" > gives inferior results in a biochar application. > *[RWL3: How about giving a cite for that?] * > > > > *#KC3: Unfortunately, I cannot point to a specific cite.* > > Does this impression make sense to you? > *[RWL4: No - certainly not as a universal truth/] * > > > > *#KC4: Universal truths are scarce and hard to find. :-) If you put > yourself in the circumstances of an Amazonian Terrapretian of 3,000 years > ago, what would you do differently?* > > If so, is there a "preferred char making temperature range"? > *[RWL5: I am sure that it depends a lot on the intended recipient > soil - and probably on the plant species. #KC5:1 Certainly! Jungle woods > can vary in density from balsa at about 10 lb/cubic foot, to Lignum Vitae, > at about 68 pounds per cubic foot.* > > > > *My focus in this exchange below with Alex is to give soil researchers > and stove users a better idea of even getting close to knowing what char-T > they are using. * > > *#KC5:2 Char making temperature is easy to determine. It should thus be > very easy to determine the importance, or lack thereof, of char making > temperature. It would be very good to know this, to reduce variables in a > test analysis.* > > > > * There is a good bit of information out there relating pH to production > temperature - but pH also depends on fuel size and ash content and pH > changes over time. Who knows what else leads to a "preference"? > And we also hear from Dr. Spokas that what happens after char > production is maybe as much or more important. I think it is absolutely > amazing that we hear so many good reports (and few bad reports) when we > know so little even about the char-production temperature - and even the > wood species, etc, etc, etc. Ron] * > > > > *#KC: With that many "good reports" and so few "bad reports", and with so > many char variables, this would tend to downplay the importance of char > variables. The "bad reports", presuming that they were competently done, > could provide very important insights into what works, and what doesn't.* > > Best wishes, > > > > Kevin > > > > Best wishes, > > > > Kevin > > ----- Original Message ----- > > *From:* [email protected] > > *To:* Alex English <[email protected]> > > *Cc:* Discussion of biomass cooking stoves<[email protected]> > > *Sent:* Monday, December 10, 2012 9:46 PM > > *Subject:* Re: [Stoves] Equipment required for testing stoves > > > > Alex: > > Thanks: > > I see only a few remaining questions related to the thermocouples. My > interest is only in being able to report to the soil scientists the > temperature at which the char was produced. > > Q1. I think we should be able to say that a time average of a central > thermocouple measurement showing a slight drop over time of the highest > numbers is a pretty good estimate - that could be reproduced for "any" > similar "flaming pyrolysis" approacd. The properties (pH, surface areas, > labile component, etc) of such char should be compared (a Master's > thesis?) with char produced via other means. I think Nat Mulcahy's > non-flaming pyrolysis approach can produce varying temperature char. An > all-electric heating approach in any oxygen-free environment , operated at > different temperature should also be used to compare the char properties > with those from stoves. Maybe that data is already out there?? > > Q2. I think there could be some influence of the initial fuel moisture > content. Do you (anyone) have an opinion on that? I am trying to avoid > having to always measure temperatures, but still be able to give an > indication of the "likely" char temperature, by knowing how long a specific > volume or weight of fuel lasted. > > Q3. I wonder if the char temperature as measured by a thermocouple > system like yours would also be a function of the fuel itself (species, > characteristic size, shape, etc.) > > Q4. I am pretty sure that the top and bottom char will be > significantly different in a typical cooking cycle, where a very high flame > temperature is desired at first (affecting only the top part of the fuel > load), and then a much lower temperature desired later (affecting only the > lowest portion of the fuel load). My question, for anyone, is whether an > average temperature is at all valuable, if the average (obtained from the > total duration of the pyrolysis) covered a wide range of production > temperatures. Actually I have heard so many different opinions on the best > production temperature - maybe a mixture of char temperatures might be an > advantage. Thoughts? > > > Ron > > *From: *"Alex English" <[email protected]> > *To: *[email protected], "Discussion of biomass cooking stoves" < > [email protected]> > *Sent: *Monday, December 10, 2012 4:38:56 AM > *Subject: *Re: [Stoves] Equipment required for testing stoves > > Ron, > > On 09/12/2012 8:33 PM, [email protected] wrote: > > Alex etal > > Thanks for the cite. I think I understand most of the plot - which was > of amazing duration!. I am especially amazed at how uniform (and high) > the flame temperature was in the late time plot, even as the other plots > were dropping. > > It is a very steady gas producer. Conditions are constant except for the > distance and path composition between the pyrolysis front and the burner. > If it can be done over 100cm then why not 200 or 300. > > a. Since you have this one from 2000, you probably have quite a > few more - from which I/we might extract a good bit more information/ Any > other similar plots around that you can post? > > No I don't. > > > b. I am surprised that the "pyrolysis gas temperature" was so much > lower than the temperature of the char. Where was the probe for this > measurement - and had there been some mixing of secondary air at this > point? > > No mixing of secondary air at that point. That occurs in and above in a > 5cm burner mixing pipe. The tmperature difference is largely due to the > nature of unshielded thermocouples in gas.For the most part thermocouples > radiate away heat according to the temperatures of the surfaces that make > up the sphere around them. A thermocouple buried in the pellets that are > all carbonizing at 700C will give a fairly accurate measurement. A > thermocouple in the gas above the top of the pellet bed will radiate to the > pellet bed and, in this case the uninsulated container walls. The more that > pellet bed shrinks the larger the portion of the radiant sphere that is the > cool container walls. The larger the thermocouple, the greater the radiant > cooling , the lower the measurement. The higher the temperature the greater > the radiant loss, to the forth power. All the gas is also radiating and > convecting heat to the container walls. So there are two reasons for a slow > drop in gas temperature, and one reason for not trusting either. The same > holds true for the absolute value of post combustion measurement. > > There are gas-*aspirated pyrometers which shield a thermocouple with > ceramic layers that approach gas temperatures and give better numbers. We > will soon be using an 10 footer to probe the chain grate stoker gasses in > carbonizer- pyrolysis-gasifier mode.* > > *Grate fun.* > > > c. What is the present disposition of this equipment? > > Its in the recoverable bone yard. I should have shown it to Crispin when > he was here.....or perhaps not:) > > Alex > > > Nice work > > Ron > > > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > 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://www.bioenergylists.org/ > > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > 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://www.bioenergylists.org/ > > __._,_.___ > > *Reply via web > post<http://groups.yahoo.com/group/biochar-policy/post;_ylc=X3oDMTJxOWgwNGtiBF9TAzk3MzU5NzE0BGdycElkAzIyNDM4MDkwBGdycHNwSWQDMTcwNzQxODYxMgRtc2dJZAM0MTI2BHNlYwNmdHIEc2xrA3JwbHkEc3RpbWUDMTM1NTI4NTg3OA--?act=reply&messageNum=4126> > * > > Reply to sender > <[email protected]?subject=Re%3A%20%5BStoves%5D%20Equipment%20required%20for%20testing%20stoves> > > Reply to group > <[email protected]?subject=Re%3A%20%5BStoves%5D%20Equipment%20required%20for%20testing%20stoves> > > Start a New > Topic<http://groups.yahoo.com/group/biochar-policy/post;_ylc=X3oDMTJmbXJ2aW9tBF9TAzk3MzU5NzE0BGdycElkAzIyNDM4MDkwBGdycHNwSWQDMTcwNzQxODYxMgRzZWMDZnRyBHNsawNudHBjBHN0aW1lAzEzNTUyODU4Nzg-> > > Messages in this > topic<http://groups.yahoo.com/group/biochar-policy/message/4123;_ylc=X3oDMTM1OHFhdTVuBF9TAzk3MzU5NzE0BGdycElkAzIyNDM4MDkwBGdycHNwSWQDMTcwNzQxODYxMgRtc2dJZAM0MTI2BHNlYwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTM1NTI4NTg3OAR0cGNJZAM0MTIz>(2) > > *Recent Activity:* > > · *New > Members<http://groups.yahoo.com/group/biochar-policy/members;_ylc=X3oDMTJnOHRpNTRvBF9TAzk3MzU5NzE0BGdycElkAzIyNDM4MDkwBGdycHNwSWQDMTcwNzQxODYxMgRzZWMDdnRsBHNsawN2bWJycwRzdGltZQMxMzU1Mjg1ODc4?o=6> > ** 1 * > > Visit Your > Group<http://groups.yahoo.com/group/biochar-policy;_ylc=X3oDMTJmMms5c2o4BF9TAzk3MzU5NzE0BGdycElkAzIyNDM4MDkwBGdycHNwSWQDMTcwNzQxODYxMgRzZWMDdnRsBHNsawN2Z2hwBHN0aW1lAzEzNTUyODU4Nzg-> > > [image: Yahoo! > Groups]<http://groups.yahoo.com/;_ylc=X3oDMTJlZzg5c3BkBF9TAzk3NDc2NTkwBGdycElkAzIyNDM4MDkwBGdycHNwSWQDMTcwNzQxODYxMgRzZWMDZnRyBHNsawNnZnAEc3RpbWUDMTM1NTI4NTg3OA--> > > Switch to: > Text-Only<[email protected]?subject=Change%20Delivery%20Format:%20Traditional>, > Daily > Digest<[email protected]?subject=Email%20Delivery:%20Digest>• > Unsubscribe<[email protected]?subject=Unsubscribe>• > Terms > of Use <http://docs.yahoo.com/info/terms/> • Send us Feedback > <[email protected]?subject=Feedback%20on%20the%20redesigned%20individual%20mail%20v1> > > . > > __,_._,___ > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > 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://www.bioenergylists.org/ > > > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web > pagehttp://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > for more Biomass Cooking Stoves, News and Information see our web > site:http://www.bioenergylists.org/ > > > > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > 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://www.bioenergylists.org/ > > > -- *** Dr. A.D. Karve Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)
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