I was a little hesitant to point this out because I thought: that is so obvious, that anyone who does not understand is not going to be able to discuss anyway.
But, what is meant by pyrolysis?
I see that the word is of Greek origin: Pyro - πῦρ - fire, fever Lysis - λύσις - separation
Based on the translation it means: fire-split.
According to the Webster dictionary Pyrolysis is chemical change brought about by the action of heat.
As discussed on this form, Pyrolysis is chemical change brought about by the action of heat in absince of oxygen. Which is followed by oxadative combustion in the engine.
I have here a kind of fancy grill called Cobb I used to cook my dinner on:
Am I correct to say that the orange arrow in the photo points to the pyrolysis zone?
Does anyone else call this “smolder” or “smoldering?” which refers to the process of burning slowly with no flame, like on a charcoal grill until you remove the lid and it flare up.
Please let the record show that I ask this question on evening of January 6 2024.
I think your cooker is using oxidative combustion, as you put it, burning the charcoal with oxygen in the air to produce heat and CO2. Pyrolysis with an external heat source probably produced the charcoal that the briquettes are made from. Often the two are combined, with some of the wood or other biomass being burned to produce the heat to pyrolyse the rest of the material. For wood gas for engines, carbon monoxide, hydrogen, and methane are the main end products. Less heating can produce wood alcohol and other liquids, including tars.
No. Smoldering wood is partly pyrolising but not charcoal. Charcoal is preety much just pure carbon so nothing to split here. All it does is slowly oxidise.
Welcome to the DOW JoePA.
Your foods cooker shows venting holes in its top cover yes?
How the charcoal combustion heating process is partially controlled, I expect.
Slowing the released food steam moistures to internally foods cook too.
Now to me the only pyrolysis taking place is that heating cooking off of the moistures in the foods.
So yes indeed pyrolysis is fire splitting out with heat the factors that can be readily volitized out of a composite solid.
Good fuel grade wood charcoal and this should have already been done.
Your charcoal shown in the illustration is not pure wood charcoal but a commercially made cooking fuel with binders and often added in fine wood particles to give the food a smoky flavoring.
Now the step past pyrolysis is wood fuel torrification. Done on wood fuel chunks and large chips. Those having been surface heated through pyrolysis driving out. To surface charring. That charring actually the remaining cells carbons still remaining with a cellular mineral framework intact.
Then making these into mini-self containing “reduction” gasifier units.
In your food analogy . . . foods first high heating quickly surface seared sealed. Then slower self-steaming cooking from the insides.
Ha! Ha! See? In real-use the phase steps are flowing and should be continuous. The steps phases expanding and contacting with needs usage demands. And the use up of the available fuel mass. Flowing one into another until all that remains if the true mineral ash.
Conceptualizing in steps is just a convenience.
Useable, workable results needs flows understandings and appreciations.
Solid fuel to energies music.
In my case, and most here; the solid fuel beginning is wood. What I can grow as mine on my property.
IMHO only your own site grown wood-for-fuel is a true Freedom fuel.
All other obtained woods can; and will be compared to other fuel energy sources. Dribbled out for your use. Regulated. Taxed. Controlled by others.
No manner of detailed understanding of wood-to-enrgy will break this vicious cycle of keeping-you-dependent.
From the discussion of pyrolisys in the context of wood-based-gasifiers I understand that two processes occur in woodgas-reactors: incineration and pyrolisys. But, only pyrolysis produces the gaseous fuel that we want. Combustion/Incineration is required to generate heart for the pyrolisys reaction.
Therefore, oxygen-concentration in the reactor is the fulcrum between pyrolysis and incineration, because incineration AKA combustion AKA buring is oxidative and pyrolisys in not. (Please correct me if needed)
But, what if we could separate the processes of incineration and pyrolisys with an expiremental apparatus?
I am in contract with a YouTube Pyrolysis Reactor Designer and Operator: NatureJab ( https://www.naturejab.com/ ) His design uses magnetron heating elements (from microwave) to drive the pyrolysis reaction on plastic waste. Because plastic is petroleum byproduct, his effort focuses on recovering a liquid-fuel not unlike gasoline.
However, he has agreed to put wood-chips in his reactor as either a partial or full-load as an expirement.
From such an expirement, what would you be most interested in?
What might we determine? And, what part of the reaction is not well understood?
I’m looking for input from wood-gassers, has anyone put plastic in their reactor?
Thank You For Your Consideration and Happy New Year!
If you take a look at the back of HWWT, the reports from Auburn show they did do a test of mixed wood and plastic. It’s also here in the free library:
You’ll still need wood to maintain a char bed and not all plastics will play nice. I’d stick to HDPE and LDPE aka milk jugs, garbage bags, soda bottles and caps. I do a little bit of 3D printing and when I get my WK done I’ll probably toss in my failed prints, especially my PLA since they’re plant based anyhow.
Ben Peterson was working in this area. I can’'t find anything related right now but I’m not that good on a computer. I"m sure someone here can help. My area of interest is self sufficiency. I never saw a way of coming up with enough plastic to make it feasible to produce useable amounts of fuel.
Exactly, and like Mike said Wood is the freedom fuel.
I see it as a “well, if it works and I have some then cool” kind of attitude to adding stuff other than wood to a gasifier. I think Edmundo Ramos also has added plastic with his charcoal but don’t quote me on that.
I’m not a soda drinker anymore so I don’t exactly have a steady supply of bottles, and you’d probably want to shred it so that’s just more work. If I’m out and about I’d maybe toss a bottle or two in to not litter. Make sure you take the caps off or you might hear it go boom in the hopper.
I think HDPE is more useful as something to melt down and re-use since you can melt it in an old toaster oven. I’ve seen neat stuff made out of milk jugs and caps, like knife handle scales.
Hi JoeSPA
one of the overlooked factors in conversion from solid fuels to gaseous fuels is the cells structures that grown woods have. Far more complex going on than just thermal-chemically breaking to elemental oxygen, hydrogen and carbons. Then recombining into fuel use chains.
I’d thought of pointing this out on @Kellyian “Gasifier for running on MDF”.
Observe the glowing cells layered stacks in the gasses in-out gasses exchanging going on in the lower hot burning charcoals:
Click on the picture and expand out to really see this.
At certain conversion rates you can see a pulsation cycling “breathing” occurring.
Also see the glass edges now smoked up door glass.
Made by a few pieces of OSB (oriented strand board). It at least has some remains grain structure in the shaved, been compressed woods strands. And a much lower percentage ratio of homogenous resin binder glues that any HDF or MDF furniture materials.
The proof of my beliefs is burning for fuel actual wood plywood scraps; versus raw wood split and chunks; versus even OSB/HDF/MDF. Plywood is ok; almost complete grain layers structure left in the thick sheets layers. Not so bad.
The others are pita sooting, blackening, all insides coating.
To burn for heat or fuels cleanly, completely fossil coal; homogenous plastics and resins requires they be particularized / shredded to make greater surface reactive edges as they are non-porous. And still then needing forced air to add enough extra oxygen to even begin to chemically balance out their excessive carbons in the plasticizer resins glues.
Still . . . using any wastes as fuels means you are Urban dependent on those wastes being generated.
You convert yourself to being a cockroach solution for others excesses and lazinesses to generate your consumable inputs.
Cockroaches, and other wastes converters like maggots and worms never get Hero awards. Tolerated at best. Always shunned and bad-mouthed. Aggressively killed off at worst.
Grow your own trees and brush and then you are fuel input Independent. Only way to be truly Free.
Steve Unruh
I, and I believe that most users of this forum, have the goal of obtaining quality gas from wood, suitable for use in an internal combustion engine. One of the processes that occurs in a gasifier is also the so-called pyrolysis, if I type the word “pyrolysis” into an online search engine, the first result is the following text:
“gasification and thermal decomposition of wood (pyrolysis): at higher temperatures, gases (oxygen, hydrogen) are first released from the wood, followed by the thermal decomposition of the wood (cellulose, lignin,…) into a gaseous state. Pyrolysis is an endothermic process (uses energy), while combustion is an exothermic process (releases energy)”
If you look at the gasifier sketches in more detail, you can see that the air inlet nozzles are placed low in the area where the charcoal is mainly located, where the oxidation of the charcoal mainly takes place, which glows white in this way and thus creates the conditions for the conversion of pyrolysis gases. At the same time, part of this radiation spreads upwards and heats the wood above this area. This expansion and also the direct oxidation of hydrogen and oxygen, which is released from the wood, create conditions for the expansion of a large amount of new gases, which in turn relatively raises the pressure in the gasifier, which automatically reduces the flow of fresh air,…
If we think like this, we cannot draw a line in our method of gasifying wood that would determine the limit above which only pyrolysis would take place without oxidation and also the release of carbon atoms, everything above is intertwined.
Mr. Steve recently mentioned the simplicity of the “Joni” gasifier, where our friend uses a very shallow area with charcoal and states, as far as I understand, that all three processes (pyrolysis, oxidation and reduction of gases) take place directly in a narrow area, this is also proven in his contributions. Well, Mr. Wayne (and I) use a large supply of charcoal in his hot tube, which provides the ability to run for long periods at low load, or even sudden full loads, without fear of running out of charcoal for reduction.
Its way more complex. But most of all, the gas we use to power our engines is not pyrolisis gas. In fact, we struggle as hard as we can to avoyd it as its full of tar. Thats the tarry, smelly sticky hopper gas. Only after it has passed trugh a hot bed of carbon it transforms in to clean useable gas.
Tom, same here about the plastic. But l live next to a cemetery and in our country we got a nasty habbit of lighting big parafin candles in plastic covers over the graves. Looks nice but horrible for the enviroment… well, about a fifth of the wax ends up in the bin and the huge bin does fill up fast. While the plastic cover is PVC its useless, but the parafin is pure and l am figuring out how to use it for a long time now.
Occasionaly l see a liquid parafin candle with like a pint of oil still in, thats basicly the best diesel you can get. But the majority is solid wax. Was thinking to melt it and impregnate charcoal with it for a gasifier. Shuld make wery potent gas, needs testing
Yes, this can be observed by watching the vacuum ratio between rails and hopper during a hard accelleration. Starting from a normal 3:1 ratio, I sometimes find it increasing to 6:1 when pushing things hard for a while.
One famous author once said - “there are so many variables…”
I don’t recall him mentioning this fenomena, but that may be due to his superior hopper condensing ability, which will take care of most of the excess steam created, even during a hard pull.
Another variable is the increasing heat of the gasses passing the restriction. They will expand and take up more room, which will also contribute to the increased vacuum ratio. Very hard to tell which variables are affecting things the most.
I remember Kristijan once reporting - I think it was one of his waggon box gasifiers - when he let go of the pedal down to idle, smoke started to back out his air inlet. I’ve never experienced that much positive pressure, but my air-mix can be thrown off some. After idling for a while and things cool down, I need to richen the air-mix back up to keep the engine from stalling.
Just thinking out loud here - confirming your statements.
Hi Jo, smoke coming out the primary air inlet happens me all the time, more after pulling hard.
I use it a lot for tailgaters, it’s interesting to see how much smoke-smell they stand.
The old blue volvo had a very tight check-valve flap in the primary inlet, and not much resistance through the bad filter lead to, when down to idle, the positive pressure filled the secondary piping backwards, pushing the air out. This leading to stall, after some seconds, or, when taking of again. Therefore i like using double, in series secondary air valves, one coupled with throttle.
This phenomena is mostly a Imbert-thing, i believe, the WKs big char, and heat reserve would deal with this, and “even out” the fluctuations.
What do you think?
Well, as I mentioned before - there are so many factors involved. Funny enough I have more of the varying pressure (air-mix) sympthomes on the huge WK-inspired Volvo gasifier. The Mazda truck has a smaller Imbert-inspired charbed, but with less sympthomes Still, I’ve never had smoke backing out on either of them unless I shut down the engines. But then again - different engines and different setups. On the truck I have huge 120 liter filter barrel. It may even out both pressure differences and gas quality some.
I see Don just chimed in. I think with enough smoke the finger isn’t necessary I’ve had hopper puffs in situations like that (white smoke) and even some intake events (blue smoke). The proplem is you cant rely on them happining at the right time
Hehe, that is only when they get enough of the smoke, and passes me. But only if the honk, and behaves as $ssh#les.
But i am very nice in traffic mostly, sometimes im ready to give a real close tailgater and honker the “evil eye”, just to be surprised when they pass me, it’s just because they want to film the wood powered car, and wawing, giving thumbs up
Sometimes it’s a benefit to live in a country where some knows what woodgas is…
(In my opinion…)
Still, I’ve never had smoke backing out on either of them unless I shut down the engines. But then again - different engines and different setups. On the truck I have huge 120 liter filter barrel. It may even out both pressure differences and gas quality some.
I’ve had hopper puffs in situations like that (white smoke) and even some intake events (blue smoke). The proplem is you cant rely on them happining at the right time 
