Something i know affects this, is i mostly drive on not perfectly dry wood, as im a little short on space, the amount of moisture releasing could be enormous.
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I have already written that shortly after I started using wood gas in my tractor, I noticed that thick smoke started coming out of the air inlet every time I went down a slope or took off the gas after a heavy load. , so I installed a non-return valve , well , I still check the effect of the overpressure several times by opening the chimney , where smoke is visible. Even if there is no additional air to maintain the layer of glowing charcoal (for a short time), there is no fear that the temperature in the hot part would drop significantly, since a lot of oxygen is released during pyrolysis, the overpressure of which pushes it down into the glowing charcoal. Intensive cooling of the upper part of the gasifier, which also causes intensive condensation of catean gases and water vapor, which means a decrease in pressure inside and thus the constant entry of fresh air into the process, if we take this to the extreme, the gasifier becomes a heater just like a central heating boiler. We want to get as much good gas as possible for the engine to operate, so a compromise is needed in the balance between the intensity of condensation and the humidity of the gas at the outlet of the gasifier.
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Indeed, l had problems with any stelth gasifier build. Small super insulated hopper meant that soon the whole hopper went in to pyrolisis mode. This produced potent gas when driving but idle was impossible.
Here l have to disagree Tone. This is a huge problem and it absolutely will cool down the charcoal lair. You may not notice it that much because your gasifier is big and has a big mass of charcoal but in my small stelth gasifiers it was like someone poured water in the gasifier as soon as l went to idle. And indeed thats exactly what happens. Yes, oxigen does come as a product of pyrolisis but unfortunaly mainly as water. This steam will react with hot carbon to make extremely potent gas, but its also extremely endothermic and with no aditional supply of energy (no fresh air intake) the resault is a dead gasifier.
Only practical way to get around this was a wery high idle, in the 2000rpm range. I tryed air cooling the hopper via powerfull fan and this complicated things alot. Wet charcoal is the way to go for such project as it does not show any of this effect
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Kristjan, such discussions are very useful, it is good to have a discussion about the details that go into turning wood into gas. Understanding these processes is essential so that you can build a gasifier adapted to this task.
Now, when we talk only about pyrolysis, I can highlight some characteristics:
-wood consists of carbon, hydrogen and oxygen atoms bound to each other in various bonds
-when we heat the wood, it starts to dry and at about 150 Ā°C all the moisture evaporates from the wood
-when we heat the wood to 200Ā°C - 250Ā°C it starts to smoke, which means that some of the bonds between the atoms in the wood structure start to break
-if we know the process of cooking charcoal, where we get only carbon from the wood, I can say that first mainly hydrogen and oxygen atoms start to be released, Kristjan calls this āchemically bound waterā. Now we have come to the key point where opinions differ, I think that the oxygen and hydrogen atoms are released separately, but if the conditions are right (high enough temperatureā¦above 500Ā°C), they can also immediately combine into H2O, which means combustion and additional high heat, which also tears apart the carbon atoms and forms tar gases.
So what happens when we have a layer of glowing charcoal below, and very dried or torrefied wood above? My opinion and experience show that here, for quite some time, very high quality gas is produced without additional air. The condition is the airtight closure of the non-return valve on the air inlet, which allows the pressure to rise throughout the entire gasifier system, including the filter and cooler. It is also interesting that the condensation of excess steam becomes more intense at higher pressure (another automatic phenomenon that has a positive effect on the operation of the gasifier). However, the engine requires a good gas mixer that is not too bothered by this fluctuation in gas pressure.
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What the four of you ToneS, KristijanL, JO, and GoranK are describing are actual working conditions wood gasifiers.
Practical guys putting a system to practical daily usage.
That means from a cold condition starting up; to a stabilized continious operation.
And as an organic solid wood fueled system, HOW from the previous full operations running state-of-conditions, the gasifer system was left by the operator; determines just how difficult, and long, of tars making, that next from cold starting up to stabilized will be.
The step-by-step; must-understand down to the molecular level approaches to understanding, will be L-o-n-g, t-e-d-i-o-u-s and lose the patience of most all of your supporters.
What works better is to make something work in any fashion. Then improve, improve, improve on that beginnings.
Then the fellow able to do that; has the difficulty of separating out what was actual system successes and failures/limitations; versus also growing/learning capabilities operator enabling efforts.
Because a good operator can make blue flare gas out of a long piece of metal pipe.
Yeah. A short show-off stunt, yeah. Frankly what most all only have the patience for. YouTube moments. Then they skip/flitter off to another feat of interest. Frankly most people are butterflys in this modern enabled world.
Rare, rare, will be the individual to months after months grinding out, true able-to-work, working systems, accepting that the working operator will be the key to it too. Too many will then waste much efforts, time, and resources digitizing it. Automating it. Dehumanizing it. And call that progress.
Steve Unruh
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First simple gasifier I built produced a sustained nearly invisible blue flare however mists of water vapor came with it. It wouldnāt run a damned thing. Thatās why I donāt give a damn about seeing peoples flares. If itās not running an engine itās a space heater.
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Iām with Tom.
Showing me a flare is like sitting still and reving the car motor. It may sound real mean but lets see if it will smoke the tires or put some wind in your face 
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Mr. Tom and Mr. Wayne, you always surprise me with your original comments, which only a person with extensive knowledge and experience is capable of. I really like it because there is no malice or mockery in them, they always joke at their own expense.
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Iāve written some questions to NatureJab via email regarding setting up this expirement, his replies below:
I have heard about you and your reactors on YouTube in the last 30days, but I understand that you have been building reactors for years. Would you share your story's beginning: where were you and where did the skills to build your first reactor come from?
I started in high school when I was in the 10th grade. I began gardening with the intent of self sustainability in a grid down situation. Through gardening, I learned about composting and became very good at it. I also learned that you can do a lot with almost every type of waste, plants waste, wood waste, etc. however, I would always find myself picking plastic out my compost pile and having nothing to do with it, but to throw it away, I was in an environmental science class and I was shown a video of the ocean, plastic problem, and a turtle that has a straw in its nose, and I also learned how less than 5% of plastic is recycled and this made me mad because studying nature there should be no such thing as waste. Everything is energy or fertilizer for another thing
So I began to research what plastic was why it was not recycled and different solutions. I was in a welding program my 11th and 12th grade year and learning how to weld and put together. Metal ended up being an integral part of my journey through my research, I found the process of pyrolysis, which allows you to turn any organic material, including plastic back into fuel. Itās basic building blocks. Being a welder as soon as I found this possible I immediately put together my first reactor, which was around the size of a crockpot I have continued my research and innovations since high school and instead of going to university I have continued to constructing to this day five prototypes my latest prototype being 10 foot long and 14 inches in diameter and weighing over 600 pounds
With regard to your current design, can you describe, in general, the process and apparatus you operate?
The general process is that plastic is loaded into an environment that is then vacated of oxygen through a vacuum pump. This plastic is then heated up with microwaves, and without oxygen the plastic cannot burn it instead breaks down into a petroleum vapor made of its constituent hydrocarbon parts.
This vapor is then condensed into an oil similar to crude oil and some vapors that never condensed are collected and compressed as a natural gas alternative. All thatās left of the plastic inside the chamber is carbon, black, and any other minerals.
Wood-gasifiers, which are powered by incineration+pyrolysis can reach 1000deg+. Their by-product is ash, and the main product a gasious fuel comprised mainly of flammable gasses: Hydrogen and Carbon-Monoxoide. Your reactor produces liquid fuel strictly from pyrolysis (no incineration in the machine), and the by-product is black plastic. Besides fuel, can you address differences between the two reactor types?
Gasifiers are different from pyrolysis reactors because even though pyrolysis is an important stage of gasification, gasification has no place in pyrolysis. Pyrolysis involves absolutely no air or oxygen present if feasible, while gasification allows for a limited and control amount of oxygen. A gasification reactor will have some way for air to be drawn in while a pyrolysis reactor will be completely sealed and shut from outside air.
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The Auburn Test from the DOW-Library was a nice read.
According to this report, an increase in methane gas production for the 20%-plastic-trial, but such a little difference that Iām not sure itās significant.
This photo from the report shows an analysis of the gas taken during the run.
Although, I donāt see any measure of steam.
Iām most eager to discover the potentials of microwave pyrolysis to produce cleaner fuels than the wood-gasifiers I am familiar with. That said, I personally have not built any type of reactor, therefor I say your guess is probably better than mine.
Would it be feasible to gain insight into the pyrolysis process by loading the machine with the wood and taking measurements similar to the Auburn Test? Can the Cai ZRA Gas Analyzer and Servomex K1550 Gas Analyzer be rented out?
My guess is that the use of magnetron heating element as oppososd to incineration opens on the possibility to gain a better understanding of pyrolisys through the opportunity to observe the reaction in absence of fire. If that is true, the fist step is conducting each processes independently to determine their constituent reactions.
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I wuld advise you first building a good prooven classical wood gasifier and then decide if it needs upgrades regarding gas cleanlyness.
Its important to know that probably 90% of sistems on the internet is junk. Dont take these as a standard. People think, since we use wood, a āprimitiveā fuel, that the gasifier can also be primitive but that could not be further from the truth. In German, a gasifier is called a āwood carbouratorā and thats what it is. You wuldnt just pour petrol over a intake manifold and expect it to run well. But a goid carb, and a good gasifier in tune with the engine will gladly feed an engine for thousands of hours.
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