Updraft gasifier for heating and charcoal production?

I am dreaming-scheming of ways to make charcoal, and get something out of the process… I can not see the use in wasting the heat if I am making charcoal…

I have read that an updraft gasifier is useful only for heating applications due to the tar produced… but I don’t understand how the tar-gas is utilized to heat something if it is not used in a spark ignition engine…

Is an updraft gasifier any useful for charcoal-heat production? Or am I better off going in the direction of a batch style retort, that uses exhaust heat to pre heat-dry the next charge of fuel?


I would stick to batch production of charcoal, either openly burning or using a retort.

You could utilize those BTUs by heating water, or like what @tcholton717 does with his little TLUDs to heat his greenhouse in the winter.

In my opinion the most efficient use of the tarry gas when making charcoal is to redirect it to self heat the system. That way you’re stoking less fuel in to complete the charcoal. You could still utilize the heat for other things after it’s leaving the retort.

Exhaust heat from an engine can help dry out wood, but that’s only helpful for a raw wood system. You’d still need to reduce it to charcoal for an updraft gasifier.

For heating purposes, they’re likely using a boiler that draws in the gas where it’s not going to gum something up. It would still need a pilot light or spark source to set it off. An updraft on wood is not a good idea for an engine where valves and other small moving parts will get glued up.


Ok, a batch style is probably easier for me to get my head around… with the exception of the heat exchanger portion.


Updraft is actually more efficient but it requires more cleaning prior to use. The weight/size of the filtration system does not make it as suitable for transportation. (I am sure someone has built one at some point.)

Industrially, they make charcoal in a continuous batch process.
Although allpowerlabs.com has a continuous feed system and while downdraft if you are looking for a more efficient system, it isn’t a bad one to look at.
CharPallet - ALL Power Labs

As far as waste heat, another way to do it is to run a turbine, and typically it is a steam turbine, so you are boiling water to generate the pressure to run the turbine which bypasses the need to clean the gas as much. In europe, they tend to use Lower grade heat for applications like district water heating.


Yes probably something like what you have here, tho I am thinking a horizontal kiln, with an air to water heat exchanger on the exhaust, and a firebox below… all airtight, and insulated.


Just wrap it with a coil. Thats my plan at some point this spring. This will give me encentive to run the kiln as it will produce daily hot water.


I’m thinking basically a wood boiler that makes charcoal… I guess that is a better way to explain it… Then I can have space heating, and a useful byproduct.


Hi Jason , a wood boiler is a excellent way of heating a house and water, and to end up with good engine grade charcoal . I use my wood burning fire that has a back boiler that heats radiators around my 3 story house and every time i refill the fire i take out roughly 3 litres of charcoal , that i use to run generator to charge up battery bank .


Hi Dave,
i’ve got an early EPA ( phase 1 circa 1989-ish) wood stove that is excellent at making charcoal, it does ok until the wood has stopped off gassing and there is a bed of coals, then the heat output crashes and I start getting cold…

if I am around to feed it every 2ish hours, then I would have a continuous charcoal retort… but I was thinking an updraft retort would need less tending… I realize now that it brings it’s own problems that are not worth the effort to solve at this moment.

So some sort of wood boiler that has a way to remove the charcoal, and refill on it’s own… would be ideal…


I heat my house with a forced air and hot water floor heat wood stove that makes char-fuel for 7 months a year and I heat my greenhouse with a hot water/ charcoal producing heater and a Rocket mass heater but none of them refill on their own. All hands on/all the time. I had a wood stove in my ex-shop that I tried to run for hours unattended. That’s why it’s my ex-shop. :face_with_head_bandage: :crazy_face:


I’ve made a lot of retort charcoal in my outdoor boiler: