Thierry, I tested the steam extraction on my gasifier, which I used to drive the electric generator, the exhaust pipe was straight up, just like on the tractor, it extracted the tar gases well, but soon, due to the relatively cold exhaust gases, dirty tar started to flow water that seeped down the outside of the exhaust pipe and showered the surroundings. The upward facing exhaust is not suitable for this, but I definitely prefer the condensation process.
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I am surprised, I thought that the extraction of excessive vapors from the hopper, during periods of engine idling, would have been more efficient with the venturi system vs. condensation
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Now the evenings are long and Fergie has no real work at the moment, but I started a âminorâ renovation. I will try to install a centrifugal speed regulator, the vacuum regulator works quite well, but it is not particularly precise, the mechanical one will probably be more precise. I took this gear with weights from an old Mag engine and installed it on the alternator pulley, I still need to make a lever to transfer the force to the flap,âŠ
Hereâs another picture of the propane system and the wood gas mixerâŠ
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Tone, your Fergie is a true flexi-fuel vehicle 
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Very interesting Tone, a great idea to put the regulator on the alternator pulley
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Iâll give some thoughts on gasifier moisture, specifically charcoal gasifier moisture. If we are dealing with a gasifier that prepares gas for a working engine, which can work with a small load or with a large one, the amount of moisture that travels through the hot zone must also be adapted to this. I will list some good thoughts:
- the âdownwardâ process is the most suitable, so that it can maintain a suitable humid atmosphere inside
- it is necessary to overheat the moisture as much as possible and push it into the âcenter of the actionâ, that is, into the glowing coal zone, where free carbon atoms are released and where there is a lot of âsurplusâ energy
- if we are talking about a coal gasifier, where there is no fear of tar formation, it is good to capture the moisture from the top of the gasifier, mix it with fresh air and âblowâ this mixture into the center of the hot zone
- I imagine that it is possible to achieve some kind of automatic humidity regulation, if we have a cooled cover above and a chute to collect condensation, where at increased load, this water can evaporate again and raise the humidity concentration, thus cooling the process and giving strong gas
- the wood gasifier almost always suffers from the âtoo much moistureâ syndrome, but we are lucky that water vapor is the lightest gas and stays under the hood, so we can easily drain the excess, even to maintain the âworkingâ temperature, much less air is needed, since the energy is released during pyrolysis, but it is necessary to prevent the penetration of tar and water vapor with the shape of the hearth
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Very well thought out, and stated Tone.
The sun just came out after two days of winter fogs here . . . so . . . a brightening joke:
Automatic Compensating Controlled Staged Downdraft Wood Gasifier
ACCSDWG
Sorry my German genes get the best of me sometimes.
In the 1940âs they topped out with four letter acronyms. So very clinical cold; needing a code book.
Opps. I think they would have said, Wood Gasifier Downdraft Controlled Staged Automatic Compensating
Toneâs System is much better. How I will remember.
Joniâs System
WKâs System
Stephen Abadessaâs System
Regards
Steve unruh
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I have been thinking about this for a while and have talked to Kristijan about when he was gasifing his Mercedes on wood. But were thinking the thoughts getting tar into the center of the hot lobe area for more energy.
Al flick made a hopper lid that collects this tar a drips it into the center of the hopper. He said he has no problems with tars.
On the Charcoal down draft gasifier I been thinking of something a little different.
How about making the hopper like a wood gasifier with cooling condensation tubes on the side to collect extra water. Then use 30 % or a little more in the charcoal. With added moisture and no problems with tars, the extra moisture will be forced through the charbed like in a wood gasifier. But not to much because the extra moisture would be collect by the condensation tubes.
We also talked about a way to bring the moisture from the top of the hopper down to the nozzles by the use of orfice type nozzle jets.
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Iâm thinking the same way Bob. As I have mentioned, I wash down my charcoal now to get rid of any residual ash but to work in an updraft I have to dry that charcoal back down. I know Kristijan recommended fairly wet charcoal in a downdraft. I have my larger charcoal unit Iâm currently running updraft but that one could be converted to downdraft. When I get caught up on splitting and stacking my fire wood Iâll experiment with that.
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Hmm l think in case of a downdraft wet charcoal gasifier, there isnt much more to be done to be completely honest. It is quite self regulatory.
We want same composition gas at idle and full power. This means, proportionaly, always the same ratio of charcoal and water must be consumed no matter the gas demand. This is the problem with wood gasifiers. They produce roughly the same amount of steam all the time (via pirolisis in the upper part) but the gas demands varies. This leads to problems we all know as hesitation, gas flooding etc.
A wet charcoal gasifier hasnt got this problem. At least not nearly as much as a wood gasifier.
There are 3 ways to heat things. Conduction, Convection and Radiation.
If the charcoal is of right size, aka engine grade, the particles are so close together they dont alow much convection in the hopper to carry heat upwards.
The porous light weight, loose touching particles seck at conduction too.
But the real shine comes from charcoals ability to absorb radiation. Its black. So any radiation gets stopped in its tracks right at the edge of the glowzone.
Try this, and lm not kidding. You can push your finger in the hopper of a runing gasifier. Its gonna be preety much cold untill the wery last inch or so next to the glow zone.
So, charcoal will only emit as much mosture as it needs at the moment.
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Well said Dr. Leitinger!
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dr. Kristjan, as always, provides expert arguments that must be taken into account. If we imagine a coal gasifier, where the coal is gasified in the form of a sphere surrounded by excess coal on all sides, and the engine sucks the gas downwards, there is a possibility that moisture can avoid conversion, since there is a lot of space on the sides between the cold coal. Giorgio recently posted pictures of his system with a water-cooled nozzle, but the idea came to me that the water cooling could be carried out inside the gasifier, where the steam would condense on the lid and collect back in the chute, and the âexcessâ steam would be picked up from the top by the venturi effect and pushed through the air into the glowing area. One more important thing should be taken into account when gasifying coal⊠coal needs an inappropriate amount of air for gasification than wood, and look how much we try to preheat the air when gasifying wood, but we neglect this with coal. My guess is that charcoal needs at least 3 times more air for gasification than wood, but if I could do this with an integrated heat exchanger, I would probably get a very interesting gasifierâŠ
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No doctorate involved 
Tone, in this case l agree. I tried central nozzles only once and decided l dont like them all that much. Indeed, moisture does creep trugh the charbed. But a clasical ring nozzle style doesent seem to have this problem. For the double flute l will let others to say how it behaves as l only run it a couple of hours my self.
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In the book-story/movie The Wizard of Oz the âWizardâ carnival flim-flam man awarded the Scarecrow with a Doctorate in Thinkology.
Ha! We seem to attract again and again that type here in newbies. Thinking to better fuel gasses.
Kristijan you have earned your Doctorate of the Dirty Hands.
Takes lots of sweating the details along with the woods; grinder and welder holed clothes; and even a few flash Woofs hair-singeâer to earn that.
Runaway thermal events are stepping stones Graduate level working.
S.U.
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Hi Chistian
I didnât know that to use wet charcoal it had to be graded (1/8, 3/4). I tested wet charcoal that I had simply sieved (1/4 to remove the ashes) and I I had a lot of difficulty lighting a torch
Do you think the gas didnât ignite because too much steam was released?
Thierry
Note: my gasifier is downdraft
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the classic arrangement of nozzles in the form of a ring is certainly a good choice, but we have to admit that here a lot of energy is lost in the hot tube, which quite closely surrounds the glowing coals, while the single nozzle creates a very hot sphere of glowing coals, which is well thermally insulated from the rest of the coals , and there should be a slight upward flow of gases and steam in the gasifier, which would provide the venturi effect of the fresh air pipeline. There is also a simpler option to install a piece of fireclay chimney pipe below, which can withstand high temperatures, thus preventing the passage of moisture past the hot zone.
There is little progress on the tractorâŠ
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Tone, my gasifier has a central nozzle. It also has a small 6-hole 4mm nozzle on the grill (like your gasifiers). Shouldnât this little nozzle break the water vapors into h2?
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My DownDraft gasifier was leaving a lot of moisture get through the hot zone. I switched to just a single nozzle instead of the flute nozzle but I think the main thing that helped was to use the engine grade charcoal instead of the bigger pieces I was using. I think there was too big of gaps between the pieces of charcoal that was letting the moisture pass through without getting converted to hydrogen.
My generator was running pretty good even with the bigger sized charcoal but I was condensing a lot of moisture from the gas and the gasifier side and top was getting really hot. The smaller sized charcoal helped keep the heat where it was needed.
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Yes, this makes sense about the sizing of the charcoal keeping the hopper cool. Well then there is no need to install hopper condensation tubing, just keep the water ratio under 30% and it should be fine. If the temperature runs hot in the hopper, with engine grade size Charcoal, it is to dry or you have run out of Charcoal in the hopper. KISS Keep It Super Simple.
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Also on sizing Charcoal if it is all one size I feel this is not good. Better to be popcorn size all the way down to 1/8" sizes to fill voids. Maybe only 10% popcorn sizes. If you have 1 to 2 % larger sizes it should be okay but something like 15 to 20% in larger sizes I have found out the hopper runs alot hotter. I still have been getting good gases in my double flute gasifier. But my firetube is square and is insulated and is small and straight down to the grate. Nozzles 20° downward pointing.
I have never tried any upwards angles. I think I should try this, because many here are getting good results from doing it.
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