Hi Tone
As more i think about it, i see how good your construction of heat exchanger/grate is, this is what science found out should be done, a significant cool down of the gas, directly when it leaves the reduction zone, it’s the correct way to achieve the “frozen equilibrium” when woodgas stays as CO, not re-form in to CO2.
I need to try this in the future, what discourages me is the welding work needed, but 
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Congratulation Goran, on the continued test drives, the hopper juice on the ground, for sure no weeds will be growing in that spot. My dog Marley shys away from that hopper juice stuff, and my wonderfull wife Dana does not like the smell of it ether. It must be that they are not into wood gas like the rest of us. SWEM.
I agree you still need to let all the ash build up good and get things sealed up before getting all your temperature readings and difference readings on your gauges.
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If I did not know better when watching the video of you driving by the trees and fields , I would of thought you were drive in the Northwest part of the USA. Even the stop sign is in the English language.
Or is that the Swedish way to spell stop too. In other countries it is spelled hault.
Thanks for the DOW ride with you Goran.
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My impression was for sweden and most woodgassers in general, it really doesn’t matter, they aren’t going stop anyway. 
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Hi Bob and thanks, we use international standard stop signs in Sweden, the Swedish spelling is: STOPP not much difference.
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It isn’t at all. We use “STOPPP!!!” to provide emphasis in spoken text. For instance, Göran yelled “STOPPP!!!” to try and get Sean to stop at the stop sign while he driving Göran’s tracked machine. However, the Swedish pronunciation of STOPP sounds a lot like the American saying for “You are getting chased by a 3 eyed flaming throwing viking”
I will stop this bad story before it gets worse.
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Hello Goran, this is the answer or reflection on your contribution from a few days ago…
The heat exchanger, which is installed directly at the exit of hot gases from the hot zone, performs several functions:
- preheating of fresh air, where the energy of hot gases and radiation from the hot zone are used
-retention of charcoal in the oxidation process to a size when the flow of gases carries it aside
-cooling of hot gases, well, here you stated something very interesting in your contribution, about which it is necessary to say a few words,…
CO is obviously a rather unstable gas, especially when it is hot it has fragile bonds between oxygen and carbon atoms, is this a sign or consequence of soot accumulating in the pipeline and filter? Does CO change into CO2 and C from which soot is formed? Presumably this happens as soon as the gas leaves the hot zone and hot travels forward? If so, then that explains why my Fergi doesn’t have a lot of soot, there is usually only fine ash and a little soot in the pipeline.
So if this theory about the direct cooling of hot gas is true, then it is necessary to supply as cold air as possible to this heat exchanger (no preheated air, as I have done now), this is good information for planning the next gasifier.
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Tone, this is possible. Althugh now that l think about it, a charcoal gasifier wuld then also produce soot wich it never does.
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If we are already talking about the formation of soot during incomplete combustion (a gasifier is actually a device that converts fuel from a solid form to a gaseous one, and this happens with the help of incomplete combustion), well, if we take for example the incomplete combustion of diesel fuel, where from the exhaust it raises black thick smoke, which contains a lot of CO and free carbon in the form of black smoke, from which soot is formed,… What is different about a wood or charcoal gasifier?
Kristjan, why do you think that the charcoal gasifier does not form soot, my experience is different, a lot of charcoal dust accumulated in the pipeline and filter - soot. When I look at the postings of Giorgio charcoal gasifiers, they actually work very cleanly and produce relatively cool gas, as the oxidation zone is surrounded by a large amount of charcoal,… but if the oxidation zone is close to the exit, when the heat radiates from the glowing charcoal and they temperatures high enough for the coal to gasify, but will soot begin to accumulate in the system? l
This thinking brings me back to the beginning, when I was figuring out how high to install the air nozzles, so that there will be no clogging or that there will be no shortage of charcoal in the hot zone…
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I know this is a “difficult” topic and it’s uncomfortable to go into such details, but these are key things to understand and then build a good gasifier…a particular “sour apple” is the use of soft resinous wood, which is known to cause a lot of problems with soot and tar, here it would be NECESSARY to think about the introduction of a large enough amount of oxygen for the formation of CO in the lower part of the hot zone and then intensive cooling of the gases… The formation of gases from fragments of charcoal means the expansion of gases , which the engine needs to operate, and the heat thus moves closer to the bottom of the hot zone. The expansion of the gases means less system resistance, and the direct heat transfer takes care of cooling and returning energy to the process, so the consumption of wood is significantly reduced, the gas is of high quality and clean,…
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Its not the same. In all my experiances never have l observed a charcoal gasifier of any kind making actual soot. Its the resault of charcoal particles themself. The black stuff you speak of is basicly charcoal dust, but not soot. Its coarser and feels much different.
The actual soot we talk about here is much different. Its extremely fine and feels kinda greasy. Its a resault of carbon rich gases being broken down to carbon, as you described.
Being so fine and basicly pure carbon it doesent cause wear on the engine, while the charcoal dust is much more abrasive. Easyer to filter thugh…
I think you are on the right track comparing soot production to a incomplete combustion of fuels. Its probably how its formed. Thre is not enaugh oxigen to fully burn all the hidrocarbons (tars) in the oxidation zone, so sooty vapours enter the reduction zone where the rest of the tar cracks. This produces even more soot and since there is no oxigen to consume the soot, its passed out in the gas stream.
I think this is the key to your lack of soot, because you DO have a secondairy sorce of oxigen in the reduction zone. The soot can literaly burn away.
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Very, very good observations and conclusions on downstream soots KristijanL.
Years ago I identify FIVE sources and conditions that generated “soots” inside of a gasifier system.
Three of the five you could maybe do something internally about, to minimize formations.
The other two the engine could just eat as free carbons fuel particles.
And yes my friend Tone the first soot forming factor is the wood fuel you are using. Resinous conifers being the very worst for making in system soots and freed blowing char-carbon particles.
I actually do look at area back ground pictures all put up.
Most have mostly types of good hard charcoal making trees. Hardwoods. Any conifers in their home areas are the minor percentages. And often those conifer trees were imported, planted.
So . . . . where am I going with this, eh???
At times I often want to just exchange woodgasing with guys like MarcusN. and JanA. and most western Canadians and Alaskans who only have confir trees too.
We can to the horror of Eastern North American wood heating folks wood heat with these “resinous”, “smoking”, “flaming embers popping” conifer woods. Year after year after year. And live quite happy with our dry-in-six weeks, conifer trees.
The last three years I have even taught myself to heat with the worst of the worst of my local trees - cottonwoods.
Often time here on the DOW I feel like I’ve fallen into a warped-room of pastries makers; only using 92-100 octane Premium gasoline users; only using the very best anthracite coal users. None of these representative of the real world.
The majority make and use whole flour breads and nail and rock soups. Use-run IC engines that will fuel with anything from 85-105 octane. Only use an IC engine system that can eat up wear-safe woodgas made soots.
You know . . . practical people. Making do; with what they do have.
Steve Unruh
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This is a interesting discussion, keep it coming 
As i first mentioned about Tones heat exchanger, i was thinking about some old reports, can’t remember if it was, Tobler, or maybe Finkbeiner?
In the reports they stated how one could “froze” the gas after reduction, by cool it of fast, and a big “jump” down in temperature, someting called “frozen equilibrium” was achieved, in that case the gas was much more stable against “recreating” co2, i don’t remember anything about creating soot or carbon though.
This investigation was mostly a proof that classical Imbert’s could be made to work much better without the lower/outside charbed, which, in case, “boosted” regeneration of co2, by supplying charcoal under a lower temperature.
In this time the lower charbed was much needed though, it insulated the reduction area (cone) it filtered out some particles by acting as a mass filter, and probably most important: it distributed the gas flow more even by act as even restriction around the cone, to avoid channeling or point overheating.
When i draw parallells to Tones construction, i could see how “elegant” he solved this, fast cooling of the gas, heat recycled, evenly distributed, by a air-cooled grate, heat recycled,
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Hi SteveU, i should really try to find a study from “the society of engineers” i got, very interesting study of soft versus hard woods reactions in a gasifier.
There is a great difference in reactive properties on charcoal from hard or soft, in favor to the conifer charcoal. The drawbacks is a softer charcoal is crushed more easily by shaking, and even blasted to pieces by the air jets.
Their conclusion? Mix fuel.
My conclusion? Mix fuel if i have it available, otherwise drive on whats available at the moment, and if needed, adjust my driving to fit the fuel, the gasifier must handle both satisfactory.
The report/study i mentioned is, sorry to say, incomplete, as made around 1950, no one wanted to hear about woodgas then, and much research funds on that area were drawn into.
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Hey Goran I couldn’t help but notice you use a lot of CAC turbocharger hose. How well does it hold up to vacuum on the gasifier?
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Hi Cody, as far they seem to hold up well, has worked good on other builds too.
Now on the volvo, i’ve seen one of them hoses, bend a little to much, and somewhat squezed under the hood, i haven’t noticed it collapsed, but im going to put some “rings” of pipe on the outside to stabilize it some.
An other way in a bad spot is to never have more space between pipes than diameter of the hose, then no “sucking together” is possible.
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Kristjan is probably right about the properties of the black substance that is deposited on the walls, so I could assume that soot is a mixture of hydrocarbons, where carbon predominates, this substance is probably very similar to tar. Why does it smoke? Why don’t they turn into a combustible gas? Is the temperature in the hot zone too low, or are some elements insufficient?
Once, my brother Primož (doctor of mechanical engineering) said, when we were talking about what happens in the hot zone, that for a good gas conversion, it is necessary to push superheated water vapor directly into the “center of the action” … even though we are talking about excess water in the wood gasifier ,… If we think about it better, this is a way of adding oxygen and hydrogen to the reaction, and probably in this way the compound would have the opportunity to react and become a stable calorific gas,…
Goran, thank you for supporting the discussion and thank you Kristjan.
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Tone, we are all “thinking chair experts” here, just throwing out ideas wich is a benefit to us all in the end. And by no means wuld it ever be my goal to be a smartass.
This sayd, l agre with your statement that that soot is a relative to hevy hydrocarbons aka tar but l think its actualy more thain that.
This is all speculative but based on prooven science.
When hydrocarbons are “cracked”, you can imagine this process as the chain of carbons with hydrogen atached to each link gets the hydrogen stripped off. Resault is spots on the chain that are eager to bond to something, so they often will bond to a nearby carbon atom and form a double bond, or even more complex structures like rings or 3 dimensional structures. This is in fact how carbon nanotubes, graphene and the other soccer ball shape (forgot the name) of carbon was discovered. Even nano diamonds have been prooven to been formed by the sooty flame of a candle! Diamond in the end is nothing more thain an extremely orderly form of carbon…
Same exact thing happens when wood is turned to charcoal; hydrogen and oxigen stripped off, carbon now forms a 3D cristaline structure but this one looks wery messy 
This thugh (soot) can only happen in a oxigen deprived enviroment because oxigen will bond to the free spot on the chain much rather thain carbon to carbon… or steam, but this requires more heat.
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G is l belive charcoal. Messed up like most of us here
Anyway, l belive the real, greasy soot is a mix of all the alotropes. All preety much harmless, maybee even benneficial. Graphite is a exelent lubricant…
Edit: l just remembered Mr Waynes anecdote burning plastic in the gasifier. If l remember right he reported weird string like soot. Probably the extra hydrocarbons formed some weird alotropes in there…
Chris, if Goran wishes perhaps you culd split the topic?
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If you are getting graphite, that is just layers of graphene. They make it using chemical vapor disposition in the lab, but you also have metals, nitrogen, etc that can also react with the carbon. I don’t it is all allotropes of carbon.
Bucky Balls are what you are thinking of for the balls.
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