Woodgas stove soot problem

[norbre_hu]

Hi,

I've made a small woodgas stove but I have a problem with it.
It works well, I can boil 0,5L water in 5 minutes with 1,5-2 handfuls of wood , but it produces lot of soot, my pot's side became full of it.
As I read, soot is because imperfect burning (not enough heat, or air).
I used 3-10mm diameter branch chopped 15-20mm long, what dried in a room for two weeks.
Wood is driftwood from the rivershore (mainly soft wood).
Last time I've added more air holes to the inside and outside cylinders too, but same effect.
Outside tempetarure was around 0°C.
Once I've measured, the flame temperature is about 500°C.
Does it needs more air holes, drier wood, different type of wood or the problem's root is elsewhere?
Images are here:
google drive

thank you

 

[billycoen]

Put a bit of washing up liquid on the pot,easier to clean later.

 

[dean4442]

It might be that there's a bit too much moisture in the wood? Just a guess to be honest, another possibility could be that it's stuffed too full therefore not letting air flow through.

 

[gra_farmer]

I often get soot, and not worried to much. I do find that hard Woods burn cleaner

 

[crosslandkelly]

I think the outer can needs to be a larger diameter, to allow a more uninpeded gasflow.
These are the sizes that I used.

I still get some soot, but these are not a perfect gasifier.
Hope this helps.

 

[norbre_hu]

Put a bit of washing up liquid on the pot,easier to clean later.

I will try, thank you

 

[norbre_hu]

It might be that there's a bit too much moisture in the wood? Just a guess to be honest, another possibility could be that it's stuffed too full therefore not letting air flow through.

I tried to add more holes to get air in, but maybe that is not enough :/ Maybe the moisture who knows.. someone gave advice, there is more resin in the softwoods and this can cause more soot.
I will try harder woods, and I will buy firewood from a store instead of collecting from forest, just for the test.

 

[norbre_hu]

I often get soot, and not worried to much. I do find that hard Woods burn cleaner

Yes I will try, maybe the key is harder wood, several people have mentioned it.

 

[norbre_hu]

I think the outer can needs to be a larger diameter, to allow a more uninpeded gasflow.View attachment 72061
These are the sizes that I used.
View attachment 72062
I still get some soot, but these are not a perfect gasifier.
Hope this helps.

Hmm.. interesting idea. I have this size of cans, I will try to see what is the difference.

 

[Ch@rlie]

I have a comercially purchased one some where, it has a battery powered fan under the inner can, when they are burning efficiently you will get a flame burning which is coming from the holes you have made around the top inner can, thats the secondary burn where its burning the hydrogen gases off, Ive not used it in years, but If I recall correctly I still got a slightl sooty build up on the pot. wasnt thick coated like on an open fire.
I used to take it fishing in winter and used to burn wooden cat litter pellets, the lake I was fishing was surrounded by willow so useless to burn any fallen stuff, the wooden cat litter pellets were fantastic for heat and cooking.
As others have said washing up liquid smeared on the pot definately makes the clean up easier.
I made a few before purchasing one, and found having a large hole instead of multiple around the outer base worked better because you can rotate it to face the wind direction and get forced air flow in, also made it easier to blow in there to help it along if needed rather than it blow in and through the base and bypass the area you wanted.

 

[norbre_hu]

I have a comercially purchased one some where, it has a battery powered fan under the inner can, when they are burning efficiently you will get a flame burning which is coming from the holes you have made around the top inner can, thats the secondary burn where its burning the hydrogen gases off, Ive not used it in years, but If I recall correctly I still got a slightl sooty build up on the pot. wasnt thick coated like on an open fire.
I used to take it fishing in winter and used to burn wooden cat litter pellets, the lake I was fishing was surrounded by willow so useless to burn any fallen stuff, the wooden cat litter pellets were fantastic for heat and cooking.
As others have said washing up liquid smeared on the pot definately makes the clean up easier.
I made a few before purchasing one, and found having a large hole instead of multiple around the outer base worked better because you can rotate it to face the wind direction and get forced air flow in, also made it easier to blow in there to help it along if needed rather than it blow in and through the base and bypass the area you wanted.

great ideas, thank you

 

[Erbswurst]

In my opinion a pot with bail that you can hang under a tripod is the best option anyway.
Austrian army mess kits you can currently get used for 10 €.

 

[C_Claycomb]

Some years back I was quite keen on this kind of stove. I bought a Fritz Handel Bush Buddy stove and made two larger versions more suited to Bushmoot car camping with my mum. Soot built up on pans with all of them. I tried a few things to get a cleaner burn and spent a fair while reading on-line. There were other folk at the Moots then that had various similar stoves, including the Wood Gas Stove LE, which used a battery driven fan.

The conclusion was that without a fan it was not possible to get enough air in to get complete combustion. Also, by placing a relatively cold pot in the flame combustion zone, rather than way up near the top of the flame, you are bound to get soot, almost condensing on the pot. Fire is a chemical reaction after all and if you cool it mid way through it follows that you will get un-reacted products.

I used very dry wood, it helped, but didn't solve the soot.

 

[Ch@rlie]

Some years back I was quite keen on this kind of stove. I bought a Fritz Handel Bush Buddy stove and made two larger versions more suited to Bushmoot car camping with my mum. Soot built up on pans with all of them. I tried a few things to get a cleaner burn and spent a fair while reading on-line. There were other folk at the Moots then that had various similar stoves, including the Wood Gas Stove LE, which used a battery driven fan.

The conclusion was that without a fan it was not possible to get enough air in to get complete combustion. Also, by placing a relatively cold pot in the flame combustion zone, rather than way up near the top of the flame, you are bound to get soot, almost condensing on the pot. Fire is a chemical reaction after all and if you cool it mid way through it follows that you will get un-reacted products.

I used very dry wood, it helped, but didn't solve the soot.

Pretty sure its the Wood Gas LE that I purchased, still have it packed away somewhere.
quick search in youtube, looks like the original add is no longer shown but found this You Tube video here.