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Yes they can depends on pyrolysis process conditions.
On 22 Nov 2020, at 10:45 am, Tom Miles <tmiles@...
Do low temperature straw and shell based vinegars have high concentrations of soluble alkali like potassium? Ash is often low in nut shells – 1-2% - compared with straws -5-8% - so one might expect the quantities of volatile nutrients to be low in nut shells but there are a lot of nut residues available.
Experiences with nut shell biochars seems to vary. Eudicot nuts like macadamia, pecan, and Brazil nut appear to have high lignin. Pistachio shells make a very interesting biochar.
In fact If you look at the literature the very low temperature wood vinegar which has virtually no tar is more efficient at growth promotion where as the higher temperature wood vinegar is more effective as a biopesticide.
Straw, bamboo and shell based vinegars seem to more effective than most hardwoods.
On 22 Nov 2020, at 8:55 am, John Miedema <jmiedema@...
The point of my last email (which I accidentally sent before I was finished) is that it is my opinion that we need to know exactly what we are doing and what we are making prior to just spraying WV into the environment.
The wood vinegar I make for my own use and agricultural research purposes has been repeatedly tested for toxins and is made in the same manner with the same feedstock. The heavy tar is either essentially avoided ( via temperature control) or decanted out than gasified in my downdraft gasifier by pouring it over the fuel.
I have been looking into the use of the aqueous phase of the condensed smoke from slow pyrolysis (wood vinegar WV) for a number of years. While the there are clearly a number of potentially significant values to be found utilizing WV in agricultural systems, the condensed and decanted WV is a highly variable material comprised from upwards of 300 different constituents. These constituents of the primary vapors consist of a very complex mixture of oxygenated compounds that represent the partial decomposition products of the macropolymers found in biomass, i.e., cellulose, hemicellulose, lignin, and extractive oils. In the absence of air these primary pyrolysis products tend to lose their complexity as they crack to form permanent gases and more thermally stable, organic compounds. After exposure to a more severe environment of a higher temperature (~700°C )the primary vapors lose complexity becoming secondary vapors significantly phenolic with a further yield reduction. Continuing to higher thermal levels (~ 950°C) the vapors convert again to tertiary vapors with further yield reduction but now aromatic nature containing benzene and polycyclic aromatic hydrocarbons (PAHs).
These changes in chemical constituents are a gradual shift and often a sample of smoke will contain a mixture of primary, secondary, and tertiary tars, depending upon the temperature and time history of each molecule in the smoke. This shift in the composition of pyrolysis vapors has also been demonstrated by analysis of pyrolysis condensates from a variety of different pyrolysis systems operating at different temperatures with the progression of organic vapor composition being given as: mixed oxygenates at 400°C; phenolic ethers at 500°C; alkyl phenolics at 600°C; heterocyclic ethers at 700°C; and PAR above 800°C (Elliott 1986, 1988).
You need to do experiments as each biomass/ pyrolysis system gives you different fractions of different PAH molecules. There is only a very smal amount of literature on this. Hormesis is rate and chemical soil and plant dependent.
AD and list;
Might there be any library showing optimum dosages of these compounds?
On Nov 21, 2020, at 2:29 AM, Anand Karve <adkarve@...
Most of the substances which harm plants, promote plant growth when applied in small doses. The cause of this phenomenon is that the presence of the harmful substance activates the defense mechanism of plants. One of the defence reactions is enhanced production of the growth hormone IAA. One must however calibrate the dose of the harmful substance. Yours A.D.Karve
On Fri 20 Nov, 2020, 10:08 PM Edgar Ramirez <edgar@... wrote:
Hello dear biochar enthusiasts,
I would like to start a conversation to know from your different experience and knowledge if the TARS and condensates might be use as plant growth promoters?
I have read from people using them as pesticides, but what about as a plant growing enhancer? or the other possible added value applications?; I would be grateful if you can share any good document talking about it.
Finally, I am also curious about that while making biochar if the gas exhaust is not good enough on a close container this tars might be absorbed by the biochar itself therefore affect the plant growing potential, what do you think about this matter?
Best Regards 🍀
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