Oh, also, charcoal can auto ignite. The porous structure realy wants to have something bound to it and it will do so with preety much anything. Oxigen being first… the newly formed “raw” charcoal needs to saturate with oxigen to a point, and this reaction is exothermic and has been prooven to cause autoignition.
I dont know for sure, but lm preety confident thats the case l observed many times. When l open the door of the kiln, and air gets in, after a few moments the charcoal starts to “sing”. It cracks and wines, tiny high pitched clicks. I bet thats the charcoal breathing in the air, causing the structure to change a bit thus cracking
If you get into using TLUDs the biggest piece of wisdom I can give you is; DRY wood. Here in Colorado this should be no problem, but I have messed it up a few times and made a lot of smoke.
This is the way I store my and dry my wood. On the left I have apple wood that is nice for barbecue. In the middle is rough wood of all kinds, including avocado seeds, peach pits, and what ever other fruit stones the house produces. On the right you see old dog food bags neighbors have saved for me. They contain charcoal.
Rindert
This is the result from my full barrel of wood. It more than filled the bucket shown before crushing or screening it with heavy, wet charcoal. I was hoping for twice that amount but probably lost a lot from it smoldering away for over a full day. I’ve gotten more volume than that from much smaller amounts of wood.
This is what I picked out that needs thrown back in the next batch.
I examined my barrel and didn’t really find anything different than it had been so I think KristijanL’s explanation is right. It probably didn’t get enough of the air blocked initially and a glowing coal remained but wasn’t producing enough gases to put it all out so it continued to slowly spread. I should have added a little bit of water earlier when I first noticed it was still hot instead of waiting so long and then drenching it to make sure it was all put out. I did notice (too late) that my dirt that I shovel around the barrel to block the air holes was pretty dry so it probably didn’t seal those holes good enough.
Gary’s barrel just had slots at the base and probably has a tighter fitting lid so the dirt around the base would have a better chance of blocking enough of the air to put it out.
Oh well, if this batch dries, I should have at least 2 hours worth of engine fuel from that little pile of charcoal but it should have made more.
I threw this little shovel full of coals back but, as the temperature gets colder and the furnace is needed more, this could be the best option for the charcoal supply. I didn’t have an airtight bucket/barrel or a bucket of water to dump those coals and they might not have been fully converted but heat for the house and engine fuel charcoal at the same time sounds good.
Hi Brian , I use a few old saucepan’s with loose fitting lids i can place on the pans inside the fire and fill inside so nothing ends up on the living room floor then once full place the lids on and take them outside , there i have a 10 gallon bucket with lid ,i tip the pan full into the larger bucket and then tap the charcoal down with a piece of 2x4 to crush it so i can get more into the bucket works like a dream and never had it burn away , i also choose what wood to burn when i am harvesting engine grade charcoal as normal split cut fire wood takes too long and because i have a wetback i need real hot heat for the radiators around the house so i burn demolition timbers from old houses being pulled down or hard wood pallets ,that way i get at least a gallon an hour of charcoal .
Dave
Thanks again Dave. The saucepan idea is a good idea.
Searching around for more information about using TLUD for making charcoal this helps explain how Rindert’s charcoal maker works. I’m not sure if I really understand it but I think the tin can chimney has the secondary burn holes/slots so it doesn’t need the double (or triple) wall like The MIDGE Gasifier Camp Stove.
The chimney is also there to pull a draft, drawing air from beneath to the burning wood. That’s how the burn moves down, going to the source.
If you run forced air with a bilge blower or some other fan, you don’t need to have a stack on top. Bruce Southerland has done this, and I’ve played around with it.
One thing I’ve done with solid metal drums, is to utilize the 2" bung in the top as the air inlet. Cut out the solid bottom with a drum opener, invert the drum and there you have your air inlets. Make sure to replace the 3/4" bung with a metal plug as well, most are plastic now. I have a grate at the bottom so air can go evenly throughout the TLUD as well. Easy to shut down, just screw on a pipe cap and put a sheet metal lid over.
If you wanted to have a gang of TLUDs running batches you could always get those metal trash cans with lids, and go with the sand method to seal up on the bottom.
Just be careful when the galvanizing is burned off. It’ll be nasty.
Great summation Dave, of how to make good engine fuel grade wood charcoal:
Yes, some is the method.
The but more than half the success will be the actual wood stocks chosen. Garbage woods, poor charcoaling woods IN . . . and you will get garbage (biochar for the garden) Out.
Dave you used the word “wetback” for your home heating system?
That is slang meaning a water heat transferring storage system, yes?
Not some poor illegal into Auz immigrant hiding down in the basement, enslaved, Roman baths like, stoking the heating fires for the elites up in luxury?
For my 3rd small batch I added a section of flue pipe. The wood for that batch was some cut and split pieces of dry 2x4’s and it burned fast with almost no smoke at all. The flames out the top were almost invisible and mostly just heat waves.
This was the result from 3 batches. I dumped each batch into a bucket of water to put it out so it is wet and not a large amount but I really just wanted to test this idea before trying to build a bigger version.
Your not the first to have had that thought, but I haven’t heard of anyone actually doing it yet, one guy is making heat and CO2 for his greenhouse and biochar all at the same time. Link to mentioned discussion.
Hi Steve , yes my fire has what is called a wetback ( old English term for a boiler in the back of the fire box ) fire box size is 24w x 10d x 11H
My More modern wood burning fire has the boiler on the sides and back to steal as much heat from the fire and transfer it to my radiators around the house ,corner to corner i can get 2ft wood in just about but try and keep wood as small as i can so i make more work for my self and of course more fuel for the engines .
I have 2 ways i collect the charcoal if i have a lot of very small coals i can use a small shovel and scoop it straight into the pans from inside the fire , that also gets a fair amount of ash as well , or if its fairly large chunks i use the wife’s old kitchen tongs she kindly donated to me ,but i have to wear welding glove for that as its so damn hot inside .
I was thinking more like what Dave said he does. While the furnace is being used anyway, scoop out some of the hot coals and reload the furnace with fresh wood. Put the hot coals into something airtight and fireproof to go out leaving the charcoal for use as engine fuel.
When I say engine fuel, I’m only talking small engines (for now) like running a generator or the log splitter for a hour or so at a time. I can imagine, on a cold day, being able to collect a scoop or two each time it needs more wood added.
I don’t know if Gary still uses or builds these anymore. It looks like you would have to build it yourself. I’m just planning to swipe some coals from the existing house furnace but something purposely made to make charcoal like the Keystone stove might be an option for a workshop or garage.
Rindert, I’ve been searching for either a down draft gasifier or raw wood gasifier design that wound work with my rather small engines. Did this end up working?
Most of the charcoal designs I have seen are updraft and that is likely the simplest type but I’d like to make my next build be a down draft. I’d like it to be as small as possible but big enough to get me at least half an hour.
I was looking at a mini WK gasifier but it looks like it didn’t work or at least wasn’t finished.
hello brian, on my topics you can see some small charcoal downdraft gasifiers for my mowers, tiller, stationary unit…also kristijan has one on his walkbehind mower…
nice new active people here on the forum…!
I still think I can make it work, at least on charcoal. I now have a 2200 psi pressure washer so I can spray all the tar out of the inside. Will make makes working on it a lot easier I hope. I kind of got more busy with work for a while but should be able to get back to it now.
Rindert
Yeah dont be afraid to be creative. Consider this as the concept, I would strongly encourage you to build the unit out of something more robust than an ammo box. You dont have to build out of a square box you can use round tanks just as well.
