DIY Trough Style Biochar Retort

Finished this the other day,  haven't fired it yet.

Interesting. Is that an old pressure tank from a well water system? Or a water heater?

Sweet! That looks like high quality work.

I was just looking at an old pressure tank, trying to figure our something better to do with it than "big blue overgrown stump simulator".

Please, if you can, post pictures and results of your trial runs.

That there was a gas fired water heater.
They are easier to get for free than a 55 gallon drum, at least around here.
Chlorine and fluoride are the only likely contaminants.
I went back and forth on whether to use an electric heater instead, but in the end the gas water heater has a central chimney and that opens up interesting options.

I've made char in trenches, and liked that, but wanted something more  portable.
Ideally I would quench from a tank of rainwater into the retort, then pump it right back into the tank.
Then I can roll it over and empty it right onto board or maybe a tarp.

If I like it I probably will take this one to the yarden and make second one for my backyard.
I would like a cleaner edge on my next one, I might use a higher grit wheel in the angle grinder.
How high a grit would you recommend?

That design looks familiar :p

In my version the opening was wider. Let me know how your narrow opening burns. I suspect that it may choke the fire a bit, and you might want to go wider. Or have the fuel above the opening - perhaps with a wire grill of some sort - and as it burn the embers can drop through to the chamber beneath.

It might need to be opened up a bit.
Do you have a link for your trough?
I am actually worried the threaded openings will let air in past the flame front and ruin the char.
I considered cutting them out,  but I want them for drains.

Me and the kid reducing  a wet pile of brush to char:

I love how everyone is creatively experimenting with new designs. I am interested to see how this one works out for you, William.  When I used the angle grinder on my 55 gallon drum, a spark caught my T shirt and lit it on fire while I was grinding.  I wasn't hurt but I ended up with a big hole in my T shirt.  Oh well.
John S
PDX OR

I figure this is about 20 to 30 gallons.
I didn't have a board handy so now I'll need to scrape it out of the mud.
I plan to shovel it into buckets to get a rough accounting of how much was produced.
Where should I use it?
-Worm bin?
-Chicken bedding?
-Chicken composting yard ?
-In with the fermented  grain?
-Some other place?

Mixing it with fermented grains could help spread it to all the other places, and inoculate it at the same time, plus it will encourage me to up my fermented feed game.

I have used mine so far around the dripline of fruit trees. I just started to put some in the raised beds for vegetables. I also put some in the half-barrels with my herbs like licorice and thyme.  They seem to prefer more alkalinity and the biochar can help with drainage as well, which is absolutely crucial for so many herbs.

I like your ideas of getting a two-fer out of it, William.  Mixing with fermented grains and then putting it somewhere inoculates it so there's nutrition in it.  Maybe the birds would peck out the grains and mix their poop in it.  Then it would be even better, and you could put it on whatever plants you wanted to experiment with.
John S
PDX OR

William Bronson wrote:
Where should I use it?
-Worm bin?
-Chicken bedding?
-Chicken composting yard ?
-In with the fermented  grain?
-Some other place?

Mixing it with fermented grains could help spread it to all the other places, and inoculate it at the same time, plus it will encourage me to up my fermented feed game.

All of the above? I just got into making it on a small scale again. I'd quite because the system we were using wasn't working all that well and my supply of free sawdust dried up. I'm still not sure where I'll get materials long term, but in the short term I've got them and permies helped me find a short-term system to make it in small quantities while using the heat to help warm the house.

So I'm - 1. adding it to compost piles - a lot before the cold weather came, but less composting happening now. The worms free-range.
2. I've got two lots of birds who are being deep-mulched for the winter and I'm adding a bucket of char spread over the bedding every 2 days or so. Some of the birds are bound to ingest some of it, but they'll definitely poop on it!
3. Hubby wrecked an area of the field by leaving some birds on it too long (he thinks in "time" rather than "quality of the plants" when shifting his chickens and I didn't realize that he didn't know that that area was too fragile). I've covered it with coffee sacks to protect it from the rain and I spread biochar before the sacking. As soon as we get enough sun, I'll add some seed, but we're so cloudy/ low light at this time of year, the seed will just rot right now.
4. I try not to add it directly to plants or beds without putting it through the compost first as when I did, it seemed to suck up too much of the nitrogen in the short term. But once composted, I use the finished compost in paper pots for annuals I start in the spring, so that inoculates my garden areas on a pot by pot basis.

What I *don't* do is spread it on the surface without covering as we are in a high forest-fire risk zone and I've been led to believe that will increase the heat of a fire if it goes through. I *don't know* if that information is accurate or not, but it's one I'm not willing to test. There are so many easy ways to get it under soil/mulch/bedding, that I'll take that approach for now.

Mike's Half Drum Biochar Burner

I'm sorry, I commented about my half drum burner then totally forgot to find the link for you!

Jay=
I would check on Craig's list. People in our area are always trying to give away wood. Trees grow too fast here!

John S
PDX OR

Michael, that is a nice clean build!
Edible Acres did half drum build, but like mine, it's a lot rougher.
https://youtu.be/lOSDwp20EKM
Yours seems to be truly a half barrel, which lends itself to your dump and  smother extinguishing method

I might try that with an electric water heater,  since there isn't a chimney to complicate things.

Sad note on the fermented grains.
I had been fermenting oats in a lidless bucket since spring, without incident .
Today I found three small wild birds in the bucket, dead as could be.
It seems they might have landed on the grain,  thinking it was solid,  and drowned / froze.
I feel bad about this.
I had always hoped mice would jump in  and drown,  but I never anticipated it happening to the little  birds, who are partners to me in ways mice are not.
The bucket is in the greenhouse now,  lesson learned.

We certainly had fund making it. The drum was coated with a layer of dirty oil on the inside. I was wary about taking an angle grinder to it full of flammables, so I though it would be a good idea to have a small bonfire and chuck the intact drum on top to burn off the oil and paint. I took off the various screw threaded caps and figured it would be enough.

Turns out that what I was actually making was a rocket. It got hot enough to vapourise the oil inside which ignited with a huge bang, and fired a jet out of the bungholes. The whole thing was propelled 20ft sideways off the fire. I had figured there was a small chance of something going boom so I was tucked behind a tree. I was left wishing the tree was further back. It was LOUD.

When I recovered the drum both ends had domed outwards, which actually made for a better shape for the finished burner!

John Suavecito wrote:Jay=
I would check on Craig's list. People in our area are always trying to give away wood. Trees grow too fast here!

Consider yourself very lucky John! I can't even get the tree-trimming trucks to dump it any more - too many people on their list!
This is complicated by Hubby's chicken/duck/egg business. We're so wet in the winter, we tend to have to park their portable shelters and deep mulch them, so everything generated on our property that isn't large enough for firewood, goes through the chipper/shredder. Yes, it's noisy and messy, but we use everything we produce, and do have at least one friend who lets us pick up her hedge trimmings to shred for our use. It's still legal for people to burn stuff like that in open piles, which is such a waste. If they'd at least do a pit and biochar it, it wouldn't seem such a waste.

If you have a rack or a pickup, there would certainly be people giving away wood if you hauled it.

Just a thought.
John S
PDX OR

Here are my collected gleanings:

The benefits of doing a trough full! I'm doing the "pot in the wood-stove" technique and as fast as I get it made, I'm putting it in one of the duck runs under fresh bedding as it's been so damp I'm hoping the biochar will stop the runs from getting smelly.

I cut out the central chimney, plugged the threaded holes and mounted it on wheels.
I tried to make the drain pipe also be a tuyere, but that was too complicated.

I like seeing the innovations you all are making.  I'm not on acreage, so I'll probably never use the idea directly, but you never know when you are going to be inspired by something, even if you forgot where it came from.

John S
PDX OR

Last nights burn was semi successful.
Good times with the kid, for sure, so a solid win.
It was also my first time smothering rather than quenching.
I'm exploring the idea of making fuel for a charcoal gasifier, and wet char is not ideal in such a system.

The results were soft, half baked and oily.
This could be because the feedstock was a random collection of punky old branches and brittle pallet pieces.

To smother the fire I fashioned a two piece cover from another water tank.
I used a watering can to cool off the exterior, followed  by a blanket and more water.

I have a wood fired bar-b-cue grill shaped like a 55 gallon drum turned on its side. It has a chimney that can be closed off. Could I make bio-chat in that?

Heather Sooder wrote:I have a wood fired bar-b-cue grill shaped like a 55 gallon drum turned on its side. It has a chimney that can be closed off. Could I make bio-chat in that?

If you did the system where you put a smaller container full of wood (with some holes drilled in it to release the pressure) inside the B-B-Q with wood around the container, I would think it would work.  People often use 5 gallon metal paint cans as the small container, but there are also some small metal drums that are small enough to go inside a 55 gallon drum. It would be an interesting experiment.  Hopefully some more experienced biochar permies will have experimented with something like this. I don't know if the BBQ could be used as is with no second inside container.

@William - trough style burns work better on skinny feedstock. Those thicker heavier pieces probably need considerably longer at temperature to char right through. I'd be chopping/splitting smaller, or reserving those heavy pieces for burning in the house stove.

Heather, I think it would work, but only if there are no openings other than at the top.
Any significant amount of air that enters from the bottom will allow the charcoal to burn into ash.