Can you run a wood gasifier on charcoal?

So in continuing weighing of options with regards to attaining a stable fuel supply I have come to a crossroads. Can a dedicated wood gasifier, say like a WK; be run on 100% charcoal with no other modifications?

In practice, that would be running wood for a week or so, and then running the hopper down and refilling with charcoal and carrying on with no hard changes to the system.

Is this possible? If so, it could be a great benefit to those trying to take advantage of a wide, diverse selection of fuel sources.

Yes it will work - at least for a while. My main concern would be managing the heat while running just charcoal without any modifications like water or exhaust injection. Wood naturally supplies the moisture used in the hydrogen endothermic reaction in a wood gasifier.
Wood gasifiers automatically make the charcoal that you would otherwise have to make yourself if you wanted to run just charcoal.


Thanks Don, that is what I figured seeing as though everything below the nozzles is charcoal anyway right?

I don’t think it would be too hard to rig up a steam injection system to inject through the air nozzles when running char, maybe an exchanger using heat from the grate area, or exit gas stream?

I would benefit from being able to use both

You might need to experiment some, but I think you could just soak some percentage of the charcoal in water, or pour a measured amount of water in the hopper with the charcoal. You could also quench the charcoal with water, and store it slightly damp. The WK and most wood gasifiers are designed to condense excess water anyways, and the steam will distribute itself evenly as the charcoal heats up. Doing this, I think you could get by with no steam injection system or other modifications.

If the hopper exceeds 250 F, you’ll need to add more water. You will also notice a drop in power if the water runs out, due to the lack of hydrogen.

Bigger pieces and as “undercooked” as possible will be better. What kind of charcoal would it be?

And, just curious, why are you trying to do this?


The wood would be “scrap wood” that has nails and other foreign stuff in it, wood that does not lend itself to making pellets or chips/chunks. I can get quite a lot locally for free, and I figure it could be made into charcoal just as easy as any other wood since nails and other contaminants would either be destroyed or are easily removed by transforming to charcoal and crushing it during processing.

The ability of running charcoal in a wood gasifier would allow me to utilize this scrap wood for fuel along with more suitable woody fuels like tree limbs, straw, and logging residues that I have available to me.

The whole idea is based on the assumption that nails and so on would be easy to separate out after the wood has been turned into charcoal.

You could add some green wood with it.


Depending on the nail size, it may be easier to just run it, and clean the nails out of the gasifier occasionally. I did this for awhile to use up some pallet scrap wood. Can be a pain sometimes but certainly works.

Making charcoal and especially trying to sort the nails etc. sounds like a lot more trouble to me, and you’ll need to handle about twice the material per mile.


Yep, I’d definitely pass on this fuel supply if possible, but want to keep as many options open as possible. I might need to use it from time to time, so it is nice to see that if I go with a wood gasifier, that charcoal could be used as well with minimal mods to the unit if I want/need to.

Funny, l was asking myself the same question. The greenhouse heater will be designed to produce charcoal while operating. It shuld make quite a larhe quantity so l was thinking of how culd l make my future gasifier dual fuel. We will see…


If you heat with wood that is the best place to burn wood with nails. A wood stove just handles the nails with no issue. I have sifted the ashes to sort out nails before so I could put them on the garden the other choice is to dispose of the ashes where you don’t plan on driving… but my two cents would be to burn the stuff with nails for heating the house and use the better fuel for a gasificer if possible.


Yes, it works quite well. I set up my screening table on the path between the house and the barn, so every time I make the trip I can “do a little”. I use a large scoop shovel to spread the charcoal on the screen, then push it back and forth with a brush so the fines fall through into a collection bin. Then I pass a heavy-duty magnet through the charcoal to collect nails and screws, etc. Then I sack the charcoal until I run it through the grinder. After grinding, it goes back on the same screen to sift out the fines, and to collect even a few more nails. Then the charcoal goes into sealed drums labelled “engine grade”. Even then, sometimes there are nails in the slag that forms around/above the charcoal nozzle. Just as with solar panels or water leaks, doing a little bit all the time adds up to a lot.
We have been under an outdoor burn ban almost all Summer, and I have a good supply of dead limbs and sticks loaded into the barrel, and covered so if Tropical Storm Harvey brings some rain, I can make more charcoal.


Thanks guys. I heat with Pellets, season #13 coming up, and for same reason as I need to stay flexible with gasifier fuel too - no woodlot.

I can think of a few ways to take nails and so on out of the char, and would probably try to work some magnetic device into the exit of the char grinder to collect the metal as it falls with the ground up char.

Good morning Will.

If your gasifier has a stainless steel grate ( non magnetic ) I see no problem with using fuel with nails mix in . It would require a little maintenance after about a pound of nails are used by dropping a magnet down the hopper and bringing out the nails .

Personally, if I had a bag of wood at my truck with a few nails mixed in and a bag of wood 100 feet away nail free, guess which I would use .


Thanks Wayne, I recall your pics of the welded together nails pulled from your grate. The wood I’m talking about is pretty loaded with nails so I’d be hooking the artwork out of there on the regular :slight_smile:

Could you use the moisture in some exhaust gas to cool the reactor down when running on charcoal?

I suppose you could run your metal detector over the charcoal pile to verify that you got all the metal out. What makes me think of this is that right now I have to go out into the yard and metal-detect for some bird feeder hangers that some raccoon just knocked into the long grass!

Pete Stanaitis


I really like that statement :smile: