Questions about Biochar

Discussion in 'The big picture' started by bazman, Jul 1, 2012.

  1. bazman

    bazman Junior Member

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    Hi All

    I would like to offer myself as a resource with regards to questions about Biochar, production systems, biomass sources, emissions, effects on climate change and anything else you may come up with. I work with many of the worlds leading engineers and soil scientists working with in the field of Biochar, so anything outside of my knowledge range can be sourced.
     
  2. cottager

    cottager Junior Member

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    Awesome! Thanks bazman :)

    I've made a little, just for myself, but wouldn't mind knowing how to make small-scale production, large surface area char.

    I'm nearly there (it's a bit like bread making ... all about the holes lol).
     
  3. bazman

    bazman Junior Member

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    I would suggest the best way to make your own Biochar is via a batch gasifier like my Fatboy system. Duel skin up draft top lit interrupted combustion gasifier.

    https://www.biochar.net/fatboy-gasifier/
    and my updated Fatboy2
    https://www.biochar.net/fatboy-v2-gasifier/

    Applying water (quenching) will help increase the porous structure of the biochar as the steam jets thought the carbonised biomass.

    V3 is on the drawing board. Charmaster Dolph from northern NSW has challenged me to develop a unit based on a larger recycled gas tank. I intend to again share/open source the plans once I start this project.
     
  4. eco4560

    eco4560 New Member

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    'Charmaster Dolph' sounds like a character in Dungeons and Dragons....
     
  5. bazman

    bazman Junior Member

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    Dolph is a good guy, but not to far from a D&D character. :rofl:
     
  6. NGcomm

    NGcomm Junior Member

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    Hi bazman. I was checking out the gasifier made by Peter Davies of Real Power Systems last Thursday and I have a question that I hope you can help with. A lot of people talk about pyrolysis kilns which only hit around 600-650c for biochar. My issue with this is that at this temperature a lot of lignite-tar creosote is produced which is a strong anti-septic. This, when mixed into the soil, kills off a lot of the bacteria and mycelium, the exact reason biochar is being produced so as to provide a habitat for these sentient beings. My question is, although the pore structure is changed at higher temperatures, is it changed so much that it isn't worthwhile running at a higher temperature, like 1,000c+ so you get rid of the creosote?

    The Real Power System is being run primarily as a bio-generator. It runs a gas generator and produces around 10-15% in biochar/charcoal as a residue of the process so it is not primarily made to produce the biochar. It has worked, in real world testing of multi thousand tonne throughput with sewage, wood waste and even old tires. I am simply trying to work out the balance between energy production (gas-gen) and biochar production. If the output is not defined as biochar (as I believe the IBI are trying to state it isn't) and to lower the temperature so it fits into their definition then it appears that we create a product that kills more biota than it helps plus produces less energy output than it could. Thoughts?
     
  7. bazman

    bazman Junior Member

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    The optimal temperature for Biochar production is around 550 deg C, Temperature ranges around the 350-400 mark are left with excess volatile matter. You can smell excess volatiles in Biochar produced in systems like my Fatboy so I always compost the Biochar which removes those types of issues. Processing at 1000deg C will greatly reduce the carbon content and is a lot harder to achieve. I will be talking to a gasification engineer today so I will ask the question and get his point of view.

    The IBI have 3 levels of what it classes as Biochar which is mainly based on the Biochar's organic carbon content, I feel this is not really the right way to head as it should be classed on Biochar's fixed recalcitrant carbon content. A recalcitrant carbon content above 60% is what you should be aiming for when producing a quality Biochar.
     
  8. NGcomm

    NGcomm Junior Member

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    Thanks bazman. Great information and I look forward to the engineers comments. FYI the bio-gen system I checked out produced 1200c before dropping to 600c, it could also be moderated quite easily to stew away at around 450c at 10% of normal throughput if energy generation wasn't needed. A brew had been sitting in the system for 12 hours at that level and took around 12 minutes to fire up to full heat and energy production.

    Tell me if I am wrong but you appear to agree with me on the creosote/volatile matter issue. I wonder how many people know that biochar needs to be treated before it is used in soils otherwise the house (biochar) will kill its inhabitants (biota). Sounds like IBI should be stating that biochar is dangerous to your living soils unless appropriate inoculate has been included?
     
  9. bazman

    bazman Junior Member

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    A lot of variables come into play, technology, feed stock, heat range and processing time. I have no real data on the system you are referring to, it sounds like it is developed around producing energy more so than producing high quality Biochar. The smell test is quite a good indicator of the level of volatiles in the Biochar, the Biochars I work with which are produced at 550 deg C have no volatile smell with no detectable Polycyclic aromatic hydrocarbons (PAHs). They are safe to apply directly to soils. What you produce at home is a different matter, that is why for my 'backyard' designs I always suggest mixing the produced Biochar into composts.

    You have to also think about the long term effects as Biochar will stabilise into a more soil like structure over a few years and any volatiles will get broken down as long as you have not used crazy amounts of Biochar without post processing.

    Using wood coals from home combustion stoves is even worse. I get asked a lot about using them, they are potentially full of volatiles and I always stress this fact and that if they want to use them they should compost them which will help buffer some of those negative effects.

    All the Biochar I sell comes with a small bag of humus compost inoculant with suggestions to add other components like liquid sea kelp and/or fish emulsion to help improve the blend. While my poultry litter biochar contains manure nutrients my new wood based Biochar won't contain that same value of nutrient making post blending even more important. I often say Biochar is like an empty sponge, you need to let it soak up nutrient and positive biota before application to your soils.
     
  10. S.O.P

    S.O.P Moderator

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    Did you ever add Biochar to your worm farm as it was processing? Would worm bacteria find a home in the char?
     
  11. bazman

    bazman Junior Member

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    My worm castings cast iron bath tub is still sitting where it fell over, so no not yet. I do have a high % Biochar compost going that is full of worms and soil life. That Biochar was made from my home unit. I will try and grab a photo to show the worms around the Biochar.
     
  12. S.O.P

    S.O.P Moderator

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    I added the rest of my dirty bag you gave me to the worm farm just to use it up. It was relatively thick in there.

    I should have run some control tests. Definitely didn't affect the worms.
     
  13. S.O.P

    S.O.P Moderator

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    Barry,

    I was linked a video to rocket stoves with higher efficiencies for developing countries and started to tinker around on the site. Clicking through lead me to a retailer of the stoves, with one of the by-products of cooking being biochar.

    Is there a way to make a efficient rocket stove with a primary, yet ancillary function, of biochar production? Is there a timing issue there, as in, the time to cook an egg isn't proportional to make char?

    Here is the video:

    [video=youtube;HWM3BELk8Uo]https://www.youtube.com/watch?v=HWM3BELk8Uo[/video]

    Here is the site: Aprovecho Research
     
  14. bazman

    bazman Junior Member

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    James and myself have talked about the idea of modifying a rocket stove by adding a grate and quench bath under where the fuel burns which will allow bit's of char to drop into water and collect. Apart from doing that you will only really get char from when you put the unit out. Rocket stoves are designed to be continuously fed.
     
  15. S.O.P

    S.O.P Moderator

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    Not sure if you watched the video, but they have an 'industrial' stove that heats a 60L pot. What if that system was modified, or something similar, that area was used for the production of char, and a heating plate put on top for cooking, so while you cook, you make char.
     
  16. bazman

    bazman Junior Member

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    You would need to find a use for the syngas produced as you apply heat to that biomass it would produce flammable/toxic smoke, to ignite it you would need to mix it with an air source.

    The idea is not far from a retort, but once the inner chamber started to produce syngas you cannot stop it. Retorts are like a hard fuel rocket, hard to control once going.

    You would be better adding a grate and quench bath to the rocket stoves fire area.
     
  17. hutchemo

    hutchemo New Member

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    biochar from pallets

    Hello,
    i live in new york city and have access to all the pallets I could ever want. I was imagining using them in my char stove. I'm concerned about potential chemicals that I can't be certain are or are not used on the pallets. My research has shown that shipping pallets are largely not pressure treated but sometimes they are sprayed with mildicides or fungicides during shipping. My understanding is that when burning char at higher heats you release more volatiles and thus my finished product might not have much of the chemical left but my question is what would happen to these chemicals? Are they simply released into the atmosphere? I'm not sure if it is worth risking, if I am not sure of the history of the pallet.

    thanks!
     
  18. Unmutual

    Unmutual Junior Member

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    The chemicals have to go somewhere. They are either released as is, or are changed during the burning process(maybe to something safe, maybe to something even worse). Which one occurs would probably be dependent on the chemical used. How dangerous(if at all) the released gasses are would like-wise be dependent on which chemical was used. From what I can find, a bleach solution is normally used for pallets and can last from 5 days up to 6 months(though other methods are available, bleach seems to be the most popular). As with most chemicals, it's not the toxicity alone that is dangerous, but how much you consume(by breathing in, skin contact, drinking, etc.). If I were to use pallets for burning, I'd probably wait the 6 months then burn them(though from what I understand, pallets burn mighty hot).
     
  19. hutchemo

    hutchemo New Member

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    thanks for the reply. that all makes perfect sense to me.
    if i wait the six months you suggest that means the chemicals are just slowly off gassing anyway right?
    Can you send me a link to where you found information about the chemicals used on pallets? If its just bleach I am not too worried but who knows what other things might be in use.
    I wish I knew more about chemistry, as the idea that burning up these chemicals at a high enough heat might actually help break them down is intriguing but probably not within my abilities to figure out... I read a statistic that 1.5% of all the worlds trash are these pallets. Thats a whole lot of trees ending up in the landfill...=(
     
  20. Unmutual

    Unmutual Junior Member

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    I just did a cursory google search, but the more I dig, the more confusing it gets especially with people putting out misinformation(one instance was that heat treated(HT) lumber uses chemicals in the process, which it doesn't).

    https://www.cheaplikemeblog.com/environment/dont-reuse-wood-pallets/ - this is more about repurposing them than burning them.

    https://ths.gardenweb.com/forums/load/firepl/msg0810091024630.html - talks about how hot they burn and the problem with pallets chemically treated before 2005.

    https://www.palletenterprise.com/articledatabase/view.asp?articleID=2015 - someone, apparently in the pallet business, talking about health and safety.

    I think one of the best pieces of advice I can give you(and it works with everything, especially for composting): get to know the source. If you're picking the pallets up from dumps, then that's impossible. If you get your pallets from a business, then you're more likely to find an answer.
     

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