Things that make me go Huh

I have questions. So many questions. An old man with a brain like a five year old.

I’m trying to understand the reaction that moves wood into charcoal and then into wood gas fuel. I guess that all the tars and most of the moisture bakes out of the wood as it transforms into charcoal As that breaks down you are left with fuel that is essentially carbon, hydrogen and oxygen. I guess that the hydrogen and carbon are combined as methane. They are the only flammable elements I see. Oxygen is just an accelerant. Carbon monoxide is the end fuel as I understand it so I’m not sure where the hydrogen went. Also I don’t under stand how carbon monoxide is a burnable fuel when Carbon dioxide is used in a fire extinguisher.


Producer gas A gas mixture containing carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2) and nitrogen (N2). In the USA, producer gas is a generic term referring to wood gas, town gas or syngas. In the UK, producer gas, also known as suction gas, means a fuel gas made from coke or other carbonaceous material.
and the source said it is patented

A gas mixture containing carbon
monoxide (CO), hydrogen (H2),
carbon dioxide (CO2) and nitrogen
(N2). In the USA, producer gas is a
generic term referring to wood gas,
town gas or syngas. In the UK,
producer gas, also known as suction
gas, means a fuel gas made from
coke or other carbonaceous material.
Air is passed over the red-hot fuel
and carbon monoxide is produced in
an exothermic reaction which reads
2C + O2 # 2CO. The nitrogen in the
air remains unchanged and dilutes
the gas, so it has a low calorific value.
The gas may be used to power gas
turbines which are suited to fuels of
low calorific value.

Wood gas
The product of thermal gasification of
biomass (e.g. coal, wood chips,
sawdust, charcoal) in a gasifier or
wood gas generator. It is the result of
a high temperature reaction (> 700
degrees C) where carbon reacts with
steam or a limited amount of air
producing carbon monoxide (CO),
carbon dioxide (CO2), hydrogen (H2)
and methane (CH4). It can be filtered,
purified or scrubbed and used to
power internal combustion engines,
gas turbines, Stirling engines or fuel

Read Jim Masons explanation in detail. It is all in there.
Not easy to truly understand this. Refer back again and again until it does become clear.
Read his Combustion as our talked about here on the DOW: Oxidization. And drying is actually step before pyrolysis. And some here will say torrification: a “browning” of the wood. In a raw wood gasifier actually then part of pyrolysis.

My explain is a bit cheeky over-simplified intentionally. 'Cause that’s all some (most!) ever want.
You want more now TomH.
And that is good. Very good.


What is carbonic oxide?

(Chem.) a colorless gas, CO, of a light odor, called more correctly carbon monoxide. It is almost the only definitely known compound in which carbon seems to be divalent. It is a product of the incomplete combustion of carbon, and is an abundant constituent of water gas.

Thanks for the response, Henry and Steve. I started thinking about this after getting into the back of the Driveonwood book which I never bothered with before because it was’nt about building. In the analysis Wayne had done the only readings on the analyzer were Hydrogen, methane, CO2, CO and O2. I’ll study the Mason information.
As far as I can understand the whole mechanism of wood gas production is generating as much heat as possible to break the combined molecules down to their basic atomic structure. The trick being to do this in such a way this heat can be generated without melting down the materials in the gasifier itself. In all the types of engines I’m familiar with which I guess is limited to IC and turbine, power is always dependent upon packing as much O2 in with the combustible fuel. Not cost effective but has anyone tried pumping pure 02 through the nozzle of something like a simple fire? I’m guessing that would overhead the container but if it were built with a sacrificial liner there would be enough time to see how much extra power was generated. I guess that could be measured with Koen’s set up though I always find torque a more important value than HP for most tasks.

I guess this is getting kind of long but I’m trying to figure out what can be effectively added to the gas production process to make enhanced power. When I was building motorcycles it was fairly easy to ramp up the compression ratio into the 11 to 1 range but that became an issue because timing was not easily altered as it is on a car or truck. 11 to 1 will run on 93 octane gas but is much happier around the 100 octane rating. We used to dump an octane booster into the tank to get there. Well, actually at that time Sunoco had a 97 octane pump but you weren’t always going to find a Sunoco station. Anyway I never looked at what was in the booster can but now I’m guessing it was just Methanol. This is why I am interested in injecting methanol into the nozzle rather than just H20. My main interest in wood gas is that I can make it myself which makes me more self sufficient. By the same token small amounts of methanol can also be easily made by anyone with very little apparatus. I have messed with ethanol back in the days when MEN was all about it, but do not think I could grow enough corn to make it’s production feasible. Black Diesel is feasible and sourcing the basic materials is not overly difficult and again methanol is needed. So we are back at wood gas.

An overview by Steve Unruh

So here is my current evolved explanation: Wood gasification is running smoke though a hot bed of charcoal.

Period. That’s it.

I think above Steve pretty much nailed it :slightly_smiling_face:

I like to think of gasification as a wood heater being forced to burn backwards.


Ah, You are saying KISS it. I understand but I’m more a CTCOOI. (Complicate the crap out of it) kind of guy. Then after chasing my tail for a long time I usually end back at simple.

1 Like

OK Mr. Tom let me try this one .

( hot char eating smoke and farting gas :smiley: )


Wayne, that is the best explanation of how to make wood gas yet. I give it a 10 score.


O.K. TomH, you have stated your goal . . . that is good.
You want a better “drop-in” engine fuel.

Now good wood gasification is an understanding and applied use of three over-lapping areas.

Chemicals transformations.
Heat energy producing’s and management.
Pressure differences as indicating actual flows of the different gases through out the system.

Shhh. Here is the short cut secret . . . kinnda’ ignore the chemical side of it.
Hit it with progressively bigger heat hammers. Heat hammer it until you do have metals failures. Do NOT back off the heat hammering or you will lose the chemical transformations. Rebuild to manage the heats erosions and wears.

Now it is the pressures differential useable knowledge is why I am personably here on the DOW to learn.
Only a few placed in the world has this working knowledge of systems pressures. The India Institute of Science: I’ve seen pictured banks of six and eight pressure manometers.
Folk operating the Humferys slit throat Powerhearth systems. Confidential operators are telling me these are using up to eight pressure points for systems control.

But the only place actually talking about systems pressure are Wayne Keith and WK operators and those here emulating this kind of working knowledge.

Sheee. All I ever been allowed to work with was only allow ONE pressure/flow monitoring point.
Not enough for system state/status and control.
6-8 point is obssesive…
3 points just right. Now I know. Thanks to the WK DOW guys.


Now specifically making the best drop in engine fuel out of wood . . . it is charcoal.
Then half of mine and Jim Masons explanations are just gone.

And on the engine side of it the answer is many times over proved to be the same: makeing the engine better for that one specific fuel.
Methanol only racing engines.
Meth-alki racing engines.
Elsbett raw vegi-oil eating engines. Heat and pressure hammer those long tight carbon-hydrogen chains.
The big cargo ship IC engines eating most any kinnda’ industrial wastes oily crap. Heats and pressures hammering.
Oil and gas fields engine eating the raw wet, acidic straight out of the well-head-gases.
IC engines eating landfill gas raw.
IC engines eating all kinds of Industrial off-gas “wastes”.

I think you are working at the wrong end of it man. For DIY it’s the engines side that can be done.
Steve Unruh


Hi Tom,
I’ll give it a try…
The least complicated form to explain:
1:Gasification is changing the solid or liquid state of a matter into gaseous state by the means of applying heat
2: Wood is not actual one matter only, its a combination of many components
3: each component will act/react with each other during the gasification process, some minerals present in the wood will create a different reaction to form again a different gas mixture…
( iron minerals in contact with heat , Hydrogen and CO, will form CH4, CH5, CH3 and a lot more ) this as example…
4: if the process id slightly different, the outcome in general will be different to a certain extent…
Different materials, different heats, different timing…= different gasses

If you break down all matters into chemical components, you end up with a bunch of C’s, H’s and O’s…
Water turns into H2o = 1 H and 2 O’s
CO2 turns into 1 C and 2 O’s
and so on…
In the gasifier , where as carbon is omnipresent, all C’s will try to unite with an O, to form CO

If there are no more free O’s available or no more O’s to be stripped from other components, then the process is in balance and will halt if no more O’s being brought into the process.

The endproduct at that point is CO gas, Hydrogen gas, solid carbon and some minerals, ashes…

If there is no more C available but a lot of O’s, then the process is not in balance

The endproduct at that point is CO gas, Hydrogen gas, CO2 gas, H2O in steam form, ashes, minerals

In both cases you can or will have some Methane ( CH4) formed where as a C melts together with a number of H’s
This depends the kind of matters present and how the total process proceeds ( temperature, pressure and time dependend)

I hope this helps you a bit in the desired direction…


I do understand. Power equals wood gas times volume. Bigger is better. Not really a huge weight difference between a 350 and a 454 and even though less weight means less standing inertia to move, the bigger engine overcomes this with pluses. Better to concentrate on building a better, hotter, more durable gas producer. Wayne did that. There’s been some tweeks in the last twenty years but the system is basically the same. When he started he could have just built another Imbert. Proven tech. He was looking for a better system. Is the gas we are producing the best it will ever be? Maybe. Not really my wheel house. I mostly stick things together that other people thought up first. My default setting is the time I spent trying to milk an extra 10 horsepower out of engines that someone thought up a hundred and thirty or so years ago. I am enjoying the discussion. Being a mental shut in this is my main contact with the world of humans.

I was responding to Steves post, not your Koen

1 Like

Yes, that is helpful Koen. Then as long as there is a carbon source, eg a column of charcoal in your gasifier then it has a place to park that oxygen and break down the molecular structures in the char. That being the case is there a limit to the amount of O that the charcoal can utilize or is the only problem that the containment vessel will feed itself into the process by at least partially shifting into a a different state by liquifying.

As @SteveUnruh already said, it seems you are working at the wrong side of the whole system. Thinking about the gasifier as a chemical transformation working at equlibrium, you always get mix of outputs related to this equlibrium. There is certain upper limit for calorific value of producer gas comming out of the best tuned gasifier. So everything for more power must take place after the gasfier :nerd_face:


I’m not taking the blame for my line of thought. I’m blaming whoever brought up using oil soaked corn cobs for fuel.

1 Like

Hi Tom, I too read the oil soaked corn cobs, but let’s think about this. Where does oil come from, from deep in the ground where it cost a lot of oil/gas energy to find it, to get it out of the ground, to process it. Not free at all now is it. Or oil from plants, again cost of oil/gas price of planting, water, labor, processing to make oil. Again not free.
Let’s talk about free scrap wood or trees, that will go to a landfill or just be burned up. You get it make it into fuel for your gasifer. If you have a gasifer truck it is free except for the sweat off back. You don’t have to go to the gym and work out. One more membership savings. Best of all it is Carbon neutral. I look at it now, as solar powering my truck in a round about way. Wood is the best for gasification, the harder the better.


I agree Bob though I’m not sure they weren’t talking about perhaps bio-oil, but again very few people have the ability to press oil out of various plants. A large part of my time is spent processing fire wood. Split cordwood to fuel the two wood stoves I run; and then branches and limbs I chop up to make charcoal and to feed my Rocket heater. Now I have another heater I’m getting ready to put into operation. That’s a lot of wood. They are currently logging off the Maple on the property next to mine. I’ve been looking at the slash they leave from the tops. A lot of three inch and less branches. I’ll be hacking that stuff up until I can’t stand the sight of it for another minute. Plenty of twigs and branches will be left to degrade and feed the soil so all the eco-police wannabes can KMA if I want to convert the rest into a heat source. As you stated. It’s carbon neutral if done properly with at least nearly complete combustion. I think the gases coming out of my rocket heater are mainly water vapor. The heater I use in my house runs so hot that there is never anything coming out of the chimney except heat waves. Same goes for factory engineered stoves with catalytic converters. Methanol is also just birthed from converted wood fibers. Still not entirely convinced that the easily separtated oxygen atoms in it would not enhance wood gas production but I do defer to the many people here on the site with many, many more years of experience in producing and using wood gas. As usual I’ve been up since about 2.30 AM so I just need something to occupy my brain. I’ve gotten too old to spend a lot of time thinking about naked women now.

1 Like

Well since this is 100% armchairing . . . here’s the direction of engines I was referring to TomH.

Pause this and read the comments and you’ll find that VW/Audi has been using five valves on their cars for years.
I have no interest in their cars; but they are bottomed out, used cheapish. Especially with notorious tanked VW auto trans. Get it direct from an disappointed owner happy to have it just gone. Bone it out down to just what you do want.
Now as a stationary generator engine . . . on woodgas . . .
I also had a picture of the Yamaha five valve single cylinder head. I could not get it off of reddit to load.
Nobody said you had to operate a Yamaha motorcycle engine at high rev’s. Could be tuned for 2800-3600 RPM . . . on woodgas, generating, pumping, compressor compressing, refrigerating.

Now to BobMac’s point. You are a Premium member. Go back and review your Have Wood Will Travel book. Specifically the very controlled tests comparing straight gasoline; against straight woodgas; against wood boosted with 20% by weight plastic. Pages 173 to 190. Specifically page 182. Straight wood beat all other mix combinations in useable driving efficiency. Beat gasoline. Efficiency is what you put in versus what you got out in useable shaft energy. You do size the engine for your actual gross power needs. On the fuel you intend to feed it.

Armchairing booster mixes is just that: armchairing.
The jury’s not still in session. They already voted and went home.


Good morning and Merry Christmas Mr. Tom .

For some reason I was thinking we were about the same age but I guess not ? :slightly_smiling_face: