Gasifier for a stove

I had a friend call me today talking about building a gasifier for a stove. the entire purpose of the gasifier would be to turn the biggest wood possible into a gas good enough to burn in a burner for cooking and heating a house. It can have a fan on it and the budget is about $4500 including paying labor. I told him I would get back with him. I am looking for ideas on what style gasifier to go with. The only one I really know in depth is the WK. I was thinking of something like what Joni has but I am not sure how big of wood it could handle. @KristijanL @Matt @bsoutherland @SteveUnruh
The gasifier will go inside as well, for the heating effect of the gasifier itself. It will be vented but a goal is for it to burn completely. I think you will still have to run off tar and water but that might be avoidable as well.
I am mostly thinking out loud here any ideas send then this way.

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I dont know about just running fire wood. Might as well just get a wood stove.

However, this is part of my next journey in development. The plan will be to build a simple gasifier that can run on chunks like a WK. It will supply a set of gasometer for continuous gas supply for gas appliances. However a second application will be to use the raw gas direct in a heater or cook stove. So this would run continuous to supply this heater / stove and I could automate it so that it can stop and redirect the gas to supply the gasometers.

However this would not be placed indoors for the simple nature of a gasifier is when you open the hopper you will release the hopper gases. So that will be your first challenge. A gasifier does not give off all that much heat anyways so Im not concerned with this loss. It will be a thru wall system were the gas is pipe in and into this burner and then vented out a chimney. I may have to use an artificial draft mechanism to make work but I have done this before and could do that with very low power requirement.


The other option is to get an NG / LP fire place insert and just run the gas from the gasometer system. It will already supply the oven / stove so that part is covered. Just a matter if the gasometer system will be able run its cycles while keeping up with a constant heating system. The solution to that is to simply add more gasometers or make them larger.


Through the wall would eliminate the refueling smoke. Also if it way more like a duct for the gas through the wall instead of some small pipe then the gas can come in hot and be cooled inside so that heat is gained there. Is there a way to do it with fans and blowers to make it not smoke when you refuel? I can’t think of any way for it to work but it might be possible.


can someone explain to me the basics of an imbert gasifier?

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Jakob, what kind of KW range are we talking about here? Average family size stove or something bigger?

In my opinion, having a gasifier powered cooking stove will only be feasable in some wery limited scenarios. If they do a lot of wok cooking, absolutely. And also if they plan to have the stove as the only cooking appliance, as l do. Its nice to light and shut the fire off in a matter of seconds/minutes in the summer to minimise exess heat, but in winter, a good clean burning wood stove is hard to beat.

It makes good sence to bring the gasifier as close to the actual stove as possible. Its best if its all connected actualy… Think JOs downdraft boiler. There is no need to light the gas, the alredy hot gas exiting the reduction zone will automaticly combust in contact with secondairy air. I have found gasifier hickups and hassitations that we all know and love also hold true with woodgas burners. Its not nice if your engine stalls on a red light and its not nice to loose the heat when searing a expensive steak, the later is also dangerous! Uncombusted woodgas inside and all that…


Jakob, l wuld argue its quite the same as a WK. Only difference is the desired temperature spots are a tiny bit shifted. A WK draws exess heat from the system and dumos it in the air, therefore making the upper part hot. An lmbert relyes on insulation more, hence the long nozzles and ash cone, and it reaches higher heat lower in the hearth.
Both have pros and cons ofcorse.
If thats of any help.


The bigger the better. I was think at least a 4 inch vent and yes it would be very close to the burner. No chance the gas would have time to be cooled so water or tar is no issue. It will get burnt as soon as it enters the burn chamber.


Family sized.
thanks that helps.
I was reading ben petersons book, trying to understand it better.
What gasifier would you start with?

I like the all in one system probably through a wall or if it is possible to have smokeless refuel all inside.

My only other though is if they wanted to regulate the temperature for cooking how would they do that if it automatically ignites. Could you put burners in a closed in box? that are adjustable?


I wouldnt run gas burners. I would build the burner with a hot plate and just control the entire units flow somehow. If you are going to run any type of gas burner I would think you would want a full filter system.

Maybe think a little differently and build something to make charcoal while it heats and then just build stupid simple charcoal gasifier to run the cooking hardware. You would not need to produce very much charcoal for daily use. It would be a lot simpler and way less complexity. Just modify an existing stove or build something that you can extract the charcoal from.


Start with? You mean for a engine powering gasifier? Probably lmbert.

With a good draft on the chimney it doesent matter, l refuel my stove trugh a 10x11" ( l think) door inside and it doesent smoke. I can leave it open actualy.

If you like l can make a video of the power adjustment and use on my stove. After l get home and get some sleep. Last nightshift, zombie…


I would never go for the idea of a gasifier for heating the house or cooking, for this is a very simple and cheap solution - a wood stove. The other thing is the engine drive, which can easily run a generator, car, tractor, … when you have electricity, you can easily cook with it, heat water, cool rooms, … As for the construction of the gasifier, I am of the current opinion that it is good hot zone design according to WK mode with air supply and preheating through the lower grille, and funnel design according to Imbert mode, so the exhaust gases heat the funnel walls and thus prevent tar accumulation inside and preheat and dry wood, and steam condensation is carried out only on the upper slope part. The entire gasifier must be insulated except for the condensation zone.


I don’t think you can determine much about a heating system without first having some understanding of how the house is laid out and built. Retro-fitting a heating system is much harder that having the house designed around it and maybe in Alabama a heating system is not a huge priority and more flexibility is possible, but in a climate like many of us here have it is of primary importance. My heating system works as well as it does because my house was built around it. I would pay a lot of attention to what Kristijan said.

Just like fuel size in a gasifier, the biggest wood possible is just a bad design. Effecient combustion always requires a oxygen to fuel ratio. When you are just burning off the surface of a mass you are not achieving a good ratio. The downside is to achieve that ratio you must be much more involved in the care and feeding of the thing. With that consideration I’d lean toward the system the Drizzler guy developed.


So what I am gathering from everyone is that he would be better off building a well designed wood stove rather than trying to run through a gasifier?

Does anyone have test charts and percentages for efficiency of gasifiers and wood stoves. I am looking for numbers to show him. @steveunruh I’m not convinced that a gasifier is more efficient. We have a stove in our house that once it is lit burns really clean. It only has natural draft


Hey Jakob

It seems to me cooking and heating a house by gasification would really complicate a very simple process .


Hello Mr. Wayne, we are all trying to explain our opinion in a complex scientific way, and you say in a short sentence more and more precisely, you are a very wise man.


Hello Jacob, I was saying that a well designed woodstove and chimney would beat the socks off of any gasifier process for space and domestic hot water heating.
Wood stoving beat in the raw numbers of fuel wood used.
In the variety and quality of woods used.
Wood stoving beat it the combined labors needed from tree to usable heat.

All factors, and all labors accounted for . . . still a good purpose designed and built wood fueled COOKING stove will beat gasification. For cooking heat control the cooking stove the wood splits are special, the very best sort out just for that purpose.

For practical useful making shaft powers 10-20 horse power and above . . . is where the woodgasifer pulls ahead. Shaft power below that . . . charcoal gasification.
Steam? Stirling? The first all developed out - lacking. The second a never achieving joke.

You will learn you can never sway a wanna’be-a-believer with numbers Jacob.
They are Emotional thinkers and Emotional remembers. Not logic rationalists. EQ, not IQ.

Gasifiers conversion efficiency numbers are in the DOW Library in the U.N., World Bank, and Swedish Papers publications.
Wood stove efficiency numbers are in the manufactures home web sites. QuadraFire. Regal. Lopi. And 20-30 others.

Steve unruh


Jacob. Out of curiosity, why does your friend want to go in this direction. Does he believe that other more common fuels will be unavailable. ( he would be right) There are definite advantages to cooking with a gas fueled burner but not nearly enough to make it sense-able to use wood gas. I know a number of people that have gone back to old fashioned wood cook stoves and after surviving the learning curve are very happy with them. They paid much more for them than the ones I’m linking so I’m not sure how they are selling them here for these prices but it’s just an example.
Stove Cooker Stove Turkish Oven Stove Wood Iron Burning | Etsyk_EAIaIQobChMIyIDIrqSW9gIVNz6tBh0UGwmNEAQYCCABEgKrgfD_BwE_k&utm_content=go_12567673668_122422054991_507253754083_pla-308555950715_c__998036007_413061747&utm_custom2=12567673668&gclid=EAIaIQobChMIyIDIrqSW9gIVNz6tBh0UGwmNEAQYCCABEgKrgfD_BwE

I can also see some reasons to build some sort of hybrid using common fuels with a pressurized delivery system, like a common Coleman camping stove which could also make it possible for a person to produce their own fuels. An interesting video.

Personally, I find this kind of project to be extremely interesting so I hope you and your friend can make it work somehow. Give me $4500 dollars and you can bet I’d come up with something good.


Hi Jacob,
I think you are leaning in the right direction here.
I think home heating, cooking, and engine fuel production are three very different directions. Just because you are good at one of them doesn’t mean you can do them all.
I’ve been trying to figure out how to make a TLUD that would heat my house, AND produce charcoal for a gasifier. The more I think about it the more I feel that it will be better to make a wood burning rocket stove and a wood gasifier. And yup there is going to be a learning curve in each case.


If you think a little beyond just cooking and heating and could create clean gas for other uses. Then you can better justify losses of efficiency on some applications as other applications if ran on gas versus electric counter parts would be far more efficient than any electric driven application from engine drive electric power from gasification. Those applications would far exceed efficiency gains making up for those losses of the other application’s. Then to add I can see where there is also an advantage of simply using a gas stove ran off the this gas if the gas supply could be easy to implement. If such a system could produce charcoal in all of this process then you have easily made fuel for charcoal gasification for engine driven electric power. That is where Im going with the gasometer system and a simple raw fueled gasifier optimized to drop charcoal I see no easier way. If all appliance that are an option to run on gas then you have a huge HUGE efficiency gains as you can use the gas directly without engine losses converting the gas to electric. These appliances then reduce your electrical needs so less charcoal creation is then needed. Combined with some solar this system will hopefully generator a surplus of charcoal daily while fully supplying all gas appliances 24 / 7.

As for heating though, I think a good ole wood stove that is efficient will still be hard to beat as mentioned. A wood stove is a gasifier, its simply doing all the processes in the fire box and without losses of the reactions of a more advanced gasifier. The energy losses are lost in a different way, losses in gases that are not fully converted to combustible gases and flu heat losses. Those things can be overcome with better wood stove designs.

So for me, it Im going to go to the trouble of running cooking hardware on any type of wood gas then Im going to make the system run much more and run all appliances that are available gas fuel counter parts to electric, Then its more justifiable especially if you are making charcoal to support daily electric off grid electric power.