Charcoal vs. Wood gasification

General Discussion
#241

What Matt sayd, if water injection is set good, in my experiances charcoal is superior as a clean, reliable and efficient motor fuel. If there is no water added, pure charcoal gas or even charcoal gas with added EGR is preety much junk.

Ofcorse it all depends, as always. For a vehicle like a tractor like Tone has and with an limitless supply of wood chips, l wuld never concider to make it charcoal powered. Same with a generator.
For cars, motorbikes, mowers etc l think charcoal is far superior.

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#242

I will agree with you Matt in your findings and tests that you have done.
At home charcoal is easy to fined because we are making it for use. If you make good glass like engine quality charcoal from a retort like Tone is talking about this is even better then like charcoal from a fire pit that I have done, it is softer less calories then the harder glass like charcoal.
But if you want to drive some where. The high quality charcoal needs to be taken with you for fuel, to going and coming back. Unless you take a retort with you.
Wood you can find all most any where to burn in a wood gasifier. This makes a wood gasifier it more easy to use on the open road for going greater miles out of reach of prepaired good engine grade charcoal. Yes the lesser grade charcoal is available by just building a fire and make some in a fire pit. That is if there is not some burning restriction in place at the time where you are at…
So if you can make a retort that could make the higher grade or engine grate charcoal while you are traveling on the road this would be wonderful. But the problem is smoke. People these days freeking out at the sight of smoke, calling the Fire Deparment and all that. Some places you have to have a permit to have a fire. Can you pass a retort off as a smoker for meats. Lol. Yes, I you can, and I have one. But mine is not portable.
So it bring us back to fuel and how much can you carry when traveling on charcoal. The good thing is it is less weight per calorie of btu used.
This is because of the steam added making more CO2 and H2O to convert to CO and H2, with less nitrogen. There is a lot less weight in a charcoal gasifier equipment to haul around. Building it is easier for a charcoal gasifier. Running it is easier by far.
It has been proven by Giorgio, you can drive and make fuel has you drive in Arginetina South America. Have not heard of anyone doing this in the USA yet.
Bob

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#243

Ha! Ha! Finally, an honest man, Tone.
Of course the high sugars sap, and that concentrated into pitches in raw wood has lots of energy power.
Of course the tricks of it is safely converting these into real useable internal combustion engine shaft power.
Some are willing to pursue this as a challenge.
Others prefer not to.
Go the charcoal easy way.

In truth local conditions are far above in importance, dictating on which way to go. NOT cold calculating energy maths.
Here are “local” conditions:
You must fit the whole system unseen discrete in an on-the-road vehicle.
Well . . . charcoal then. Like Kristijan did on his Mercedes car. Ben Peterson did on his classic 1st generation Mustang car. All hidden in the rear trunk (boot) and under the hood.
Locally you have NO superior charcoal making hardwoods. Only conifer trees. Well raw wood for woodgas then. Make the shoe to fit the foot. Can’t go fully discrete then. But you can go nearly 100% visible to others, smokeless.

“But Steve! You will tar up and destroy the engines piston rings!” Utter nonsense. Piston rings been proven many times to be cleaned up in place with commercial carbon cleaners, kerosene washes. Even commercial acetone. Restored in place to back to the base conditions you started with. You will Tar up and stick valves! Sure. Free them up. Repair any damage as needed. Then Learn NOT to do that by Operator hammering learned basics!
What you read here on the DOW by true exclusive “woodgas” driver-users J.O., Woodrunner, Jacob, Marcus, Wayne Keith and others. They’ve had to learn to know to leave the gasifier in the optimal state before shutdown. Have learned to know to check their throttle plate for stickiness before engine starting up the next time.

Only a very few will learn to be aircraft pilots or true responsible boat operators. Lots of pre-education there. Then lots of e-v-e-r-y time pre-checks, and operational attention needed.
Same. Same. Working system woodgas operators requires this same dedication. True Baristra levels of attention. Or a good percolator pot coffee makers. Sights, sounds, smells and a developed feel for all-is-right.

Charcoal using is for the lazy. And the want to be inattentive. The turn-key operators. One button electronic drip coffee makers.
Steve Unruh

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#244

Build a cross dual fuel and you have a choice. The more I run on chip fuel the more this design amazes me. I am now learning the internal dynamics of how the fuel is processed in the cross drafts. It is not as straight forward as you may think. The fuel process stages are just re arranged a bit and I am starting to think this is a superior design over traditional Imbert down drafts as the flow is very stable. Stable flow equals stable and consistent process. The fuel to the back of the hopper is where the first stage drying process and heat from reduction is more local. As the fuel migrates to the front combustion chamber is dry and ready to be processed, the fuel to back that does not make it to the front just replenishes reduction zone. This char insulates the reduction zone and because this is a cross draft there is no grate packing and the fuel is reduced to nothing.

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#245

Bob, a onboard mobile charcoal kiln is a good idea. Actualy, you own one too… its called a wood gasifier :wink: if you look at it, a wood gasifier is a charcoal gasifier with a in built charcoal kiln.

In theory this is great, but as we all know there is small print everywhere

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#246

One of the major things I like in your design is it is square and not round. This makes it more compact for small vehicles when it happens
In your vehicle.
Making it round is for easy building of the unit for us that do not have all the equipment like you do to cut pieces out. Barrels, tanks are very handy less building parts to make and the costs of materials.
When you say less grate packing are you talking about the direction the nozzle is poing at the grate. You do have a grate or not?
The proble with my first build was it got to hot on the exit gases. And my hopper design was not correct, should of made a stright downward drop of charcoal. Also the worm hole that would from above the nozzle causing heat to move up into the hopper. I see you have corrected these problems by design. The water vaccum tube injection on the intake is great. That creates steam to go through the nozzle is the best seen so far.
Bob

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#247

Bob I think one good addition to a Round form factor cross draft would be to have a large plate in front of the grate. This would not only add a heat flywheel, but also prevent clinker from clogging the grate since it would terminate on the plate as well as forcing the gasses to go around and scrub some more on charcoal. It wouldn’t work as well for a more raw wood leaning system though, I think.

Pedricks used their plates as a way to prevent nozzle burnout(large heat sink).

Eddy Ramos has done a similar idea but for updrafts with his high silica content block above the nozzle, forcing the gasses to go around and widen the flow.

I’ve seen some crossdraft gasifiers that have a built in drop box/expansion zone, attached to the outside of the gasifier. I would warrant that’s a necessity with a vehicle designed system. One of the Brazilian fellows on here linked a video showing one with that idea in mind. I’ll link it later in this comment if I can find it.

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#248

Yeah the boxed architecture and “V” shaped combustion / reduction chamber are extremely important in my design.,

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#249

Yeah they have a removable grate. The grate is not subject to gravity or flow packing, this has nothing to do with the nozzle. In the two years Ive been testing, Ive never encountered grate clogging, and the fuel in both raw fuel mode or charcoal both reduce to nothing. However this lower chamber will accumulate dust, clinkers and small fines over time. So you do need to clean that out once in a while. But you do get like 20 to 40 hours of run time before that needs servicing. This is why the new ones have a clean out door and the grate can now be removed through this access point. Just pop it out and push the whats inside out through this clean out. Re install the grate and your back in business.

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#250

Yes Kristijan my WK Gasifier does make good Charcoal bur not enough to keep a Charcoal vehicle on the road driving daily. Unless I am driving my WK Gasifier every day. It all goes back to what you have discovered, for daily driving on Charcoal you need to make lots of Charcoal made in advance and have it stocked piled. No difference then DOW you need a pile of ready to go dried wood chunks. Fuel making and preparation and stock piling is the key no matter if it is wood or Charcoal.
Small engines Charcoal and bigger engines wood. Not to say you can’t do it in reverse.
For top quality engine grade Charcoal your retort is the way to go. For just Charcoal lower grade and easy to make the fire pit will do.
This is what I am trying to develop a Charcoal gasifier that will run a vehicle down the road with the minimal effort. Call me lazy or more efficient I don’t care. Lol. This is where the Flute design might make the difference or Matt’s single nozzle cross diagonal design might work for a every day driving vehicle. We know the up draft, down draft. Cross draft, and diagonal gasification works. But making it really a KISS design that works. The stealth mode is all important too. Or disguised in plane sight.
Bob

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#251

Cody, yes the big flywheel plate is a good idea. I tried to insulate this area and that did not work well. But a big plate with heat sink type fins on the back side could possibily work and then let the gases go through the vertical grate behind it.
Now I am thinking maybe a cross diagonal downward flow using a double flute nozzle design in a barrel with a ash/clinker clean out hatch below the nozzles. The gases are going under the big heat sink plate that can also be clean out. Making it all again KISS in design.
Good news is I now have 32 free 55 gallon barrels to work with. No shortage of material on this.
Time to do some drawing. Thanks for the idea.
Bob

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#252

Bob, l was reffering to the WK gasifier directly. It produces its own charcoal wich it then gasifyes in the firetube.

What l ment to say is every wood gasifier can be described as a charcoal gasifier that makes its own charcoal out of raw wood feedstock on the fly.

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#253

Still, l like the controll that you get with a charcoal gasifier more over wood.

And there is one wery important aspect noone mentioned yet.

Runing a well made wood gasifier and a well balanced charcoal/water gasifier will produce about the same quality gas with the same power on the engine. HOWEVER a charcoal gasifier needs litle to no restriction, less drag, more gas to the engine.
Also it will never bridge and is real hard to constipate, except if not balanced right, read slag formation.

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#254

Let’s say that charcoal is mostly just carbon, which needs a temperature above 600 ° C for gasification, which is achieved by adding air where only 21% of oxygen is left, mostly nitrogen, to maintain this high temperature and add water vapor to produce hydrogen it requires a lot of the energy we get from charcoal. This whole process is quite wasteful and despite a well-insulated gasifier it produces a gas with a high nitrogen content, unfortunately. Gasification of dry wood is another story, pyrolysis takes place at lower temperatures and high-calorie pyrolysis gases and water vapor are formed. Part of the water vapor is removed, and the rest is converted into combustible gas, in addition, tar gas is also converted into a lighter hydrocarbon, probably methane. The result is a gas with a much higher energy density, and we can’t even compare the energy we get from a certain amount of wood against the energy from the same amount of wood turned into charcoal. Probably a ratio of more than 1: 5, … I’m just thinking …

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#255

Yes,yes,yes, to what you are saing here Kristijan. But the problem I see with the WK Gasifier is size and weight. Don’t get me wrong, I love my WK Gasifier it is great on my Dakota truck.
With Charcoal there is no water / tar to dump out. This is a problem when traveling. At home no problem, but out of town you have to dump the tar/water every 50 miles or so when refilling with wood. This is a hard fact. This is why I am building a big tar/water condensation tank on the jeep build.
If I am going to put a gasifier on the back of my car it is going to be light weight. That means it will be a charcoal gasifier.
Bob

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#256

Yes Tone, I have had the super dry wood in my WK Gasifier. Less then 3% because of the very dry area I live in at times. Wow talk about easy to drive on and hardy any water to dump out after driving. Really great power. But this is not the normal for most people driving on wood. Heck some are glad they have 20% to 30% wood to drive on and they do it very well. This where the WK Gasifier can shine on when DOW.
The last time I ran my charcoal gasifier I started it up and then dump damp charcoal into the hopper. It ran good producing good gases. When the run was over I had moisture on the hopper lid. I was impressed I did not have to add any water into the nozzles intake.
Bob

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#257

Okay Cody here is a drawing from what I got on what you were saying. I know I know one more of Bob’s drawings but it is a lot cheaper to draw then to build and then try to work the bugs out.
This is all inside a 55 gallon barrel with a extention filler lid on top.

20220601_141503
20220601_1415031600×1200 325 KB

I call it my Double Sided Flute Barrel Charcoal Gasifier.
There is 8 nozzles in one tube so it will be able to run a larger engine, and not over heat. I am using Matt’s water injection to make steam for more CO and H2 gases. Hoping it will run cooler too.
Bob

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#258

Tone, do not get me wrong. I love both wood and charcoal gasification, they both have their applications and they both can be more efficiant with one application over a nother. None is worse or better thain the other in specific circumstances.

This sayd, plese forgive me to share my wiews on the subject you described.

Yes, wood does start to pyrolise at a lower temperature. But we may split this pyrolisis products in 3 parts. Lets call the first one the endothermic ones, (H2O, CO2) and the second ones exothermic ones (methanol, acetic acid, tars, methane… ), and the third is just carbon (charcoal).
There is always an exess of water in wood wich shuld ne dealed with, boiled off, then condensed, this requires energy.

Then we have the reaction of newly formed charcoal with the rest of the water and all the CO2 produced, (wich can be up to 50%vol in pyrolisis gas!). This is just the same as a charcoal gasifier.

Then we have the “exothermic products”. They do crack some in the glow zone but the vast majority will meet the air on the nozzles and oxidise, burn in to basic components CO2 and H2O plus heat, what happens to them is whats in one paragraph above.

When those “exothermic products” do crack (down to methane) they will always produce soot. In other words, a soot making gasifier will make more methane and vice versa. You have prooven that yours does make almost no soot, wich is no surprice as you introduce oxigen 3 times, wich can only mean that those pyrolisis gas products burn completely down to CO2 and Water, wich then “cracks” down to CO and H2.

So, in short, unfortunaly a good tar free wood gasifier will only produce about 5% methane, tests show. Not enaugh to realy make a difference.

All in all it all comes down to the carbon to water ratio. To much water, the high heat capacity steam robs the gasifier of energy. Too litle, gasifier starts producing poor gas, as you have shown with your tractor. The perfect amount is hard to hit, and every wood gasifier has a sweetspot where it runs best, some with hopper half full, some near empty… this is whats hapening.

But with charcoal, you got controll Thats a big plus for me. It is possible to “program” and adjust your performance perfectly.

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#259

The first prototype of what is today the DXF-S3 had an internal water tank. First lesson at least with my design is you cant have the water tank integrated as the water will boil. This is why it is a separate piece now and there is 1 inch gap between it and the front of the unit, plus we are using 1 inch thick ceramic fiberglass lined to the front of the gasifier.

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#260

Okay thanks Matt, it’s good that you have done some of the work for me. I will make the change on that water tank.
Bob

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