Gasifier Design Idea

Hello everyone,
I am setting up an organic vegetable farm, and my business is quite heavily fossil fuel dependant. To address this, i want to convert my massey ferguson 135 to woodgas, and use it for combined heat, power, traction and biochar.

My idea is to try and optimise the system for charcoal production. I’m thinking that I will pyrolise woodchip in a sealed tank using engine exhaust heat, then pipe the tar gas to an open combustion chamber, optimised for cracking, before it is forced through a charcoal reduction chamber. I will aim to avoid burning charcoal as much as possible, and when I need to refuel i will manually empty the charcoal out of the pyrolysis chamber and fill with wood chip. Hopefully, I can get the balance of the combustion air down to a level where I rarely need to refill the charcoal reduction chamber.

The whole system will be started on compressed syngas, then the shutdown procedure will involve a compressor refilling the compressed syngas cylinder. I made a quick diagram of the concept bellow, excluding the compressed gas part of the system. Orange represents engine exhaust, brown is targas, yellow is combustion, red is syngas, and blue is incoming combustion air. Has anyone tried something like this? Does it seem like a good idea? I am thinking of making the combustion chamber swirl (with the incoming air nozzles) and go through a restriction before entering the charcoal filled reduction zone, and I guess I was going to dimension it roughly on the imbert sizing guide, but then that seems wrong, as the cracking vestle in an imbert is the void space in the charcoal, so maybe it should be significantly smaller.

any advice, or criticism, would be really appreciated


Some details that are not obvious from the previous post:

  1. I think the targas pipe should be heated by the exhaust, to avoid tar clogging, and the exhaust will enter the pyrolysis chamber in the same place that the targas pipe exits the chamber, to get quick gas.

  2. When starting on compressed syngas, I think the syngas should be fed directly into the engine, until the pyrolysis chamber starts producing targas, then perhaps it should switch to feeding syngas into the open combustion chamber, to support the targas combustion until temperatures are high enough for the targas to support the process independently

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I am planning to build a test project on a small petrol generator, before I start working on a spark conversion for my mf 135.

The main advantages I anticipate from this design are better cracking (due to the slow, consistent temperature pyrolysis and open space combustion chamber) and high biochar production.

I’m a tad concerned about compressing syngas in my startup system, as I see that the practice is controversial on here. I’m thinking about other options, duel fuel with diesel, using propane as a startup fuel, that kind of thing.

I think another good way to do it would be to start a charcoal fire in the open combustion chamber for startup (essentially, using my tar combustion/cracking chamber as a down draft charcoal gasifier) and then by the time the pyrolysis chamber is up to temperature and producing targas, the charcoal in the combustion chamber should have burnt out, leaving an open combustion chamber for cracking. This is what I am leaning towards now

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Hi Jono, and welcome, it is always better to start with a proven gasifer design like a Imbert. On this site you can find members with gasifer builds that are working on tractors and have proven to work.
Start there, then after you have what we call the other 75% of gasification experience, you can go and start designing your own custom builds. We want you to be successful on your first gasifier build. So following proven building plans will help you be successful and be DOW with your tractor.


Thanks Bob. That’s probably great advice, and if I were to follow it I would probably build a gek, but I’m afraid I’m just not that sensible.

My idea is loosely based on the gek, at least in terms of using engine exhaust heat to drive pyrolysis. I’m just really keen on the idea of optimising for gaseous combustion, and I’m not sure that building a solid fuel combustion zone gasifier is going to teach me much about the idea.

I have really enjoyed reading through Tone and Ron’s tractor projects too


For good pyrolysis to take place in wood you need minium 400°f to cook the moisture/tars out of the wood with any speed. As it moves closer the the firetube nozzles the temperature goes up to 700°f. At the nozzles and below the temperature goes up to 2000°f plus. This distance is less than a foot of the wood traveling downward. In the top of the hopper the temperature might be only 100°f. The best way for wood to travel in this pyrolysisation prosses is straight downward.
KISS, (keep it super simple)
Exhaust gases are good for drying the wood out before it goes into the hopper to start the pyrolysisation of the wood which needs a way of removing the moisture and tars from the wood to be held in a separate vessel or container to be drained off. Exhaust gases are also good for preheating the incoming air going to the nozzles in the firetube.


Hi jono, if you think useing the waist heat from gasification, too preheat the incoming air, thats axactly how the WK gasifier is designed. Ans it allso is able too get rid of some extra moisture in the design allso, I second what Bob Mac said, start with a proven unit, Wayne Keith has well over 150.000 miles on his wood gas trucks, no problems, once you learn the 75 percent operator rules.


Interesting. Why would you guys recommend a Keith over a gek?

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The gek (with pyrocoil) as I understand it, uses outgoing syngas to preheat combustion air, then dry fuel, then it uses engine exhaust heat to drive pyrolysis. Seems smart to me

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You don’t see that many people power a car or truck with a GEK but plenty of people have scaled down a WK and ran generators, or built to spec and ran their V10 trucks with them.


Hello Jono .

Thanks much for the video .

In 2008 I drove 7500 miles on wood and included on the trip was to compete with that vehicle but sadly it never made it to the starting line on race day.


Wow, what a fantastic event. Did that guy have a biodigester on his car?! Out of the three vehicles I saw, I imagine that you would have won that race

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Hello Jono

The little sports car running on cooking oil was my main competition. The car was governored at just under 50 mph if I remember correctly and would not go any faster if going down hill . Going through Death Vally with open road and down hill grades I could run the dakota up near 90 mph and passed the others including the organizers .

The race (rally) had a lot of rules ( for liabilities I guess pages and pages ) ) and although I got to the finish line a couple hours before the sports car the rules was pulled on me and penalized for speeding . Also I blew a trailer tire that cost me some time .

Did win second place and an award for best machine.

If one loses a race I can’t think of a better way than going too fast :blush:


You sound like a drag racer Wayne :rofl:


Nothing worse than Nerds Wayne.

There was a series called the Prisoner in the late 60s.
The protagonist drove a 7 like that, and he wore a suit like that.

Too many rules in a contest like that.
Its not fair when you demonstrate you significantly outclass your competition and get a penalty for going too fast.

The series is about a Spy who quits his job without telling his handlers why…
He wakes up in Wales ( I believe scary enough thought eh ? ) and everyone has a bad tailor and is forced to ride around in mini mokes in a town full of spies who can never leave until they revel all their secretes…

So you were right to drive 90 mph and avoid those guys HA HA…


With all of the fine print rules and regulations they had the cards stack up against you Wayne, because they knew people in Alabama don’t like or use Laws and regulations that you need a Philadelphia Lawyer to decipher things to understand. The key word was Rally race.
One second over the finish line to soon can cost you the win. But we at DOW knows who the real winner is. I will bet you not one out of those people who were in the race are still driving on that same fuel today except one person. The every day Rally Racer and winner Wayne Keith.


A race is a race to me. As long as you didn’t sabotage another car and follow the course that’s a clean win.


The second morning of the race was real cold and the organizers delayed the start a couple of hours because the veggie cars could not get started. They took their fuel in the motel room and was heating it in the bath tubs.

I should have yelled foul because the times were published. Me and the wood burner could have been down the road about a hundred miles .

I could have used that $5000 :frowning_face:


Rally racing is different. From point A to point B you can not go over the speed limit in time to get there. No matter what seed you drive. If you have a flat tire, you will have to make up the driving time you lost. So you can drive over the speed limit to do this. If it is 10 hours driving time to point B you better not get there in 9 hours and fifty minutes. You will get penalize for it. Who ever gets to the 10 hour driving time will win. There is a lot of mathematics in this kind of racing. But now with new driving gps computers it does the figuring for you as you drive. No need for a navigator next to you. A classmate of mine use to Rally race and wanted me to be his navigator. I never did it.