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On the topic of biochar  RSS feed

 
Posts: 109
Location: Council, ID
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Thanks! My thoughts exactly, low tech then, low tech now. Overall a little less carbon capture, but better than none.

Fascinated by the self perpetuation thing, I have seen this elsewhere, but so hard to believe! Are bacteria actually creating more charcoal, or is the charcoal migrating from the leftover patch into new soil?
 
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Well, bacteria don't create charcoal and charcoal can't travel under its own power, so that would indicate that either humans were involved in the spreading of the charcoal (which is how the terra preta was created in the first place) or worms are moving tiny chunks in their bodies and then depositing it away from where they ingested the bacteria laden biochar/ charcoal.

On Buzzard's Roost I have one area of terra preta that is part of an experiment to find out just how the biochar gets into so much soil.
So far it appears that the movement vertically and horizontally is accomplished with the help of the earth worms.
The particles being moved are smaller than grains of fine sand and they can move almost a foot overnight, indicating that they are part of the worm poop cycling of the soil.

Redhawk
 
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Location: Mims, fl
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About the only contribution to biochar from nature would be lightening.
Cultures throughout history have used designated dump sights for waste that included broken pottery, char, shells and bones.
But only a few burned areas on purpose for planting. And fewer still realized that burning was helpful to their crops.
 
Bryant RedHawk
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Quite true Keith, and I doubt lightening could ever come close to forming enough char. I've been in the California Mountains right after a forest fire and not found anything remotely looking like terra preta.

In the case of the discovery of terra preta, it was obvious that the spreading of the charred waste materials was done on purpose since it was found over large areas that contained evidence of farming activity over a very long period of time.
The initial terra preta finds were separated fields of various sizes which indicates they were indeed created on purpose.
Such fields would have been able to feed a large population over a long period, just as with the Aztec, Mayan and Inca Cultures, Agriculture was key to their success and longevity of the society.

Several Native Cultures burned fields after the harvest so the land could be used the next growing season, in these areas there is little evidence of terra preta like soil.
The terra preta is over a foot thick and it isn't just biochar, the black soil is very full of microbiology and that is, I think, the key to the regeneration of the terra preta stories.
That's why I'm doing my own experiments with a small patch of (quite new, only three years old now) terra preta like soil.
I want to see if the regeneration stories could be caused by the spread of the soil microbiota, I currently don't have enough data to form any opinions on the regeneration theory but I do have evidence that the actual char can be spread by earthworms.


 
J W Richardson
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Powdered charcoal is so pervasive, and it colors so easily, it makes sense the the worms or even water flow would spread it, so not actually regenerating but being spread. That sounds like sense. I think the word regenerating is what threw me.
 
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Hi All

I have been making and using Biochar since 2005, started one of the worlds first Biochar businesses (Black Earth Products - Australia) and have built and used every method for making char under the sun, including large format industrial gasifiers and tested almost every feedstock too

1. In general forget about using retorts of any style, they are fire explosions just waiting to happen, seen that first hand.

2. Unless you are an engineer, really handy or can buy a biochar maker, a Tlud (top lit up draft) gasifier requires reasonable about of knowledge to run and you need a really dry chipped/sized feedstock to make the work well.

3. Open burning or cone charring is by far the easiest and safest way of making Biochar as long as you can run a small to medium fire/bonfire in your backyard, you can char damp or chunky feedstock if that's all you have.

As an example I am Workaway (woofering) working in a remote part of Portugal in an area that was hit by a massive firestorm 4 months ago, the owner wanted all the dead trees on the land cut down, cropped up for firewood with the crowns/tops burnt. We are re-planting many trees, re-setting up his vegetable gardens and making lots of compost, so lots of potential to use biochar. So how do I make Biochar without anything other than lots of fine branches/tree crowns, a rake, a hose and a lighter??

1. Start smallish and keep the open bonfire under 1m3 at all times, light from the top of the pile to reduce start up smoke.
2. Have all the feedstock close by so you can keep feeding it and keep a hot flame all the times which will reduce emissions. Small twigs and branches will char quickly and large logs can take quite some time to char so would be better split of use elsewhere.
3. By constantly adding to the fire you to tend to build up a pile of hot coals at the bottom which keeps increasing in size.
4. Biomass/wood/feedstock goes through three main stages when burnt.
(First) releasing the volatiles, (the oils, resins and some carbon) this occurs at about 450 deg C. Most of the resins release as smoke which is really flammable and if you keep a good flame will burn up producing very little smoke and emissions. Much of the physical strength of the biomass is lost and the carbon or hot coals crumbles to the bottom of the pile as you add feedstock/wood from above.
(Second) burning the carbon content once the resins have been released, this needs lots of oxygen to occur and if you have a pile of hot coals, most of the oxygen is used up from the above fire and the carbon will not be lost to ash, which is the final step if you do not interrupt this stage.
5. Let the fire burn down so you have just a few visible branches left and a small amount of flame, then using a hose/water quench the char pile and interrupt the final combustion process, until it no longer produces any smoke or stream, using a rake pull all the char open so you can hose the bottom of the pile thoroughly, it is easy for the char to reignite and burn to ash so water down really well and keep the pile wet. Note, do not breath in the white stream that is produced from this quenching as it is loaded with high levels of carbon monoxide, try and work and stand upwind. Wear full length cotton clothes, a hat, leather gloves and work glasses.
6. You can leave some of the hot coals and fire to restart a new batch which is what I did so I could break for lunch.
7. You can break down the produced biochar into smaller chunks by slowly adding biochar to a wheelbarrow and the top of a hammer or a brick to smash it down or let nature do that for you over a few years in your soil.
8. Inoculate your biochar with compost and or any biological or high nutrient additives that you want. I always keep biochar moist and you can never add too much water to it.
I used 1x 75lt bag of commercial bagged compost mixed into a large 0.5m3 pile of biochar and watered heavily, have left for a week before I dig it into the vegetable garden soils.
I used about 200 litres of straight biochar layered through 2x 1000lt composts. Biochar layers are generally less than an inch/20mm thick.

Biochar is a very long term structural soil improver that will stabilize into a black soil/loam over a number of years, after 10+ years of adding biochar/compost and organic matter my light colored acid sandy soils were jet black and full of worms, productive life with a neutral pH.














 
open-char-making.jpg
[Thumbnail for open-char-making.jpg]
Pics of my open bonfire char making
 
Posts: 43
Location: north-central Maine
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Great description! It seems that close tending of the fire is an essential, and the inclusion of proportions will be a guide as I start out. The reason for lighting the fire on the top had never been pointed out to me, but makes sense. (So different from the way we were taught to make campfires.)

Craig
 
J W Richardson
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Thanks Barry, for explaining about the limitations of the higher tech approaches. No more guilt here!
  A a kind of coffin sized pit a foot or so deep accentuates the top burning aspects if you have a permanent location, less oxygen to the coals as they are below ground level and air flow not so good there. Coffin sized because it is really easy to cut most small stuff the that size, less cuts. I find that I do not have time for much besides feeding the fire when burning, it goes fast!
 I start with a small fire in the pit and add gradually to that rather than top burning an intact pile, as I want to be able to control the height of the flames due to trees nearby.
 Credit to that guy in hawaii, previously mentioned in other biochar threads...I will find his info...
 
J W Richardson
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I have read that biochar has to be made by heating wood in the absence of oxygen, so that charcoal made by throwing water on a fire is not the same. I have no idea whether it's true that one is actually better for the soil as biochar than the other.
 
J W Richardson
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Hi Rebecca!

  I found this quote from a study in Nepal...maybe it is the other way around?

The most toxic compound among the PAH-16 used as benchmarks by the environmental authorities in many countries is benzo(a)pyrene. Concentrations of benzo(a)pyrene were 0.01–0.06 mg/kg (Table 1), well below the Norwegian maximum tolerable risk (MTR) level for soils where 95% of art diversity is protected (0.5 mg/kg)[41]. In addition, PAHs in biochar are only very sparingly bioavailable, often less than 1% [28]. Due most probably to the optimized out-gassing under the fire front the PAH EPA16 contents were low (2.3 to 6.6 mg kg-1). However, while both water quenched metal cone biochars would qualify for EBC premium quality (< 4 ±2 mg kg-1), the soil snuffed biochar would only entitle for basic quality (< 12±4 mg kg-1). It can be assumed that the hot water vapor that penetrates from bottom to top through the biochar layers during the water quenching process has an activating effect and may expulse PAH containing gases out of the biochar pores [42]. This activating and tar reducing effect can also be seen in the nearly 50% higher specific surface area of the water quenched eupatorium char (215 m2 g-1) compared to the soil snuffed char (149 m2 g-1).
 
J W Richardson
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Link...http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0154617
 
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I am always happy whenever Redhawk is posting on a thread I like because I know I'm going to learn a lot.

I am using 55 gallon drums, which I can get for free off Craig's list in my home town . TLUD because it seems I can make lots of biochar more quickly than with retort.  Many retorts have tiny inner chambers, and I also found it very difficult to find the inner chamber.  Other systems are inefficient.  TLUD is efficient, partly beause the fire is funneled into going straight up quickly.     I found this video to be extremely helpful:

https://www.youtube.com/watch?v=YIbGkmt1VdE

I did everything in it, except for cutting the hole on the top of the stove.   I think you can draw a circle around your chimney on the top of the barrel and cut into it with your angle grinder.  My chimney was a bit different, but those were the parts I could get.

You have to see when the fire settles down and then douse it with water.   It makes fantastic, light, metallic sounding biochar.  I simply grind it with a simple 2 x 6, with another piece attached to the bottom so it's wider there. I wear gloves.  

Then I have inoculated it with urine, sea water, compost, rotten fruit, or anything else nutritious that was around and that I could use.  For a month.  Then I put it in the garden.

I am excited.  Healthy soil and declining carbon in the atmosphere = Less climate change and better food.

Let's use the wisdom of previous indigenous peoples' civilizations as a tribute to them and their ingenuity.

John S
PDX OR
 
Posts: 17
Location: Algarve, Portugal
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Bryant RedHawk wrote:

The Retort is probably the most efficient method with a TLUD being a close second, the reason is there is more complete combustion, which does sound contrary to logic.



I have to partly disagree with you here Bryant, at least for homescale/low budget systems that is.
TLUDs are actually more efficient than retorts because all your biomass turns to char, even the match you use to light your column, whereas with retorts you need a primary fuel source to carbonize the stuff in your retort.

In more industrial units like the one from the Living Web Farms video you can do a continuous burn with multiple retorts where the process energy of one retort starts the process on the next and then you can even condense a lot of the gasses down to py-oil so that would be many times more efficient.

So really it is a matter of scale which system is more efficient and of course it also depends if you are using the process energy.


Personally I prefer TLUDs and in particular those that get water quenched at the end of the process because the water quenching partially activates the char and immediately turns it hydrophilic rather than the hydrophobic state it has when it gets out of a retort.
Quenching also helps remove some ashes that might form in a TLUD if the biomass is packed quite loose. (this small amount of ashes is still only a fraction of the ash produced by the fuel that is burnt in a simple retort system)


Something I'm planning to build is a TLUD fired retort. Why would I want to do that you ask? To condense the gasses coming out of the retort and harvest some wood vinegar.
 
Martijn Macaopino
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Angelika Maier wrote:BTW my husband makes biochar simply in a drum by observing and managing the fire. It's a bloke thing I am interested only in the end product. He says it's easy.
The real nice thing about biochar is that it uses all the garden wastes which are not suitable for the compost including thorny blackberry canes all that wooden debris.
For Aussies: do it aoutside the fire season or get permit.



You can cut a 55 gallon drum in half lengthwise as well and use it as what is called a flame trough kiln, either just a half barrel of the two halves connected if you have longer materials to char.
The image below is of a commercially available flame trough kiln found on the website of Byron Biochar
 
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