[RWL: Gotcha. See note below on possible BLDD to replace TLUD operation - which would keep the bones low.
I’m sharing land with an organic market gardener, and waste cardboard seem to be an abundant resource.
in terms of your questions:
1. The picture with the bones at the bottom was aimed at showing the bottom of the kiln, I don’t tend to place the bones at the bottom as it’s the place receiving least heat, and bones do not seem to char well there.
[RWL: I thought I was looking at topmost layer. Thanks for noting this.
2. I usually start with a bottom layer of sticks, to make sure that the flatness of paper does not block any air intake, the sticks allow even distribution of air. The picture showing the sticks also shows the next layer up of rolled cardboard, starting the stacking from the outside and not yet complete in the center, the sticks are only at the bottom layer.
[RWL: Intresting that you think in terms of layers. I have not previously heard that.
3. Stacking the rolls of cardboard, paper, newspaper works well, and does not seem to matter upright or horizontal.
4. Nut shells or tree bark when available work well as a complete layer.
5. Bones, egg shells, fruit stones, avocado skins and other such material seem to char best scattered evenly through the paper/ cardboard mass in the top part of the drum.
6. In terms of the design of the kiln, I have seen ‘aqueous solutions’ using both of the approaches, the 2nd drum as a chimney or a third of a drum attached to a flue as a chimney, I chose the later as I had the flue and it seemed lighter and easier to remove at the end of the burn.
i followed their design exactly, and I am very happy with it, I have used TLUDs before, and this one is the cleanest burn homemade TLUD I have constructed and used.
7. Regarding the question about my satisfaction with the resulted char... I’m not sure, which is why I shared this material to start with.
its all charred right through, including the bones, has no smell or taste, washes off easily with a bit of water, soaks up liquid well, and powders without effort, but I had not managed to find any information on the structural characteristics of paper/cardboard char, and I had not run any field trials.
i have been using that char in 2 main ways:
1. Mixed with grass clippings or wood shavings in our composting toilets, so every time someone does their thing they add a handful of the mix into the chamber, once full it sits for six months to decompose, red worms are abundant in the chamber too, after six months the compost is used in the garden or as part of seed raising mix.
2. Our family lives from the farm animals and our garden, and urine is an important resource.
my understanding is that each liter of urine has approximately 10ml of N, and that bacteria consumes approximately 5:1 C:N, so I either mix 50ml of humates with every liter of urine, and that’s spread onto the garden / forest garden (diluted).
Or the urine goes into the dry paper and co. biochar to soak for a few days, then the liquid (black urine) is watered into the garden, and the saturated biochar is forked into the garden soil.
i should run some simple field tests.
[RWL: Looks like you are doing everything right. I look forward to hearing what happens as you compare different amounts vs a control.
as well, I read somewhere about a characterisation project? Aiming to link feedstock, pyrolysis method and resulted biochar?
I had not managed to find the database, is this in existence? Common knowledge to this list? How would one get access to the information?
[RWL: There is a H-P Schmidt paper on this I’ll try to find. Also compares good (seasoned) and bad (raw) char.
And has anyone seen some info on the structural characteristics of paper/cardboard biochar?
[RWL: I’ll try to look tomorrow I don’t recall any.
hope I clarified a few points.. :-)
[RWL: Yup. You’re really on to something new I think. New and likely important.
Re the BLDD idea - I will try to send more - but the basic idea is to use your existing 200 liter barrel exactly as is - but light at the bottom. Open (cold top). The needed downdraft supplied by the existing tall (small diameter) chimney a few feet away. Flames to travel horizontally those few feet in a trench in the ground - covered by a piece of steel (on which you could cook/boil something (sort of like a Plancha). I’m claiming not much new equipment needed except the flat horizontal steel plate.
The probable main new problem is getting a fire stated at the base. Second need is for a way to regulate the needed secondary air.
A proposed advantage over TLUD operation is early being able to start with small height of fuel (better draft) and keep adding fuel until the barrel is totally full rather than half(?) full.
I don’t know of this ever being tried. For most of us a major difficulty - but you have most of the gear already.
Again - thanks for doing what you are doing.
Ron. (Not Rob)
which ever you carry