This is basicly what l preach too, but with a slightly different turn. I find it easyer to mix a bit of charcoal in. It achives a similar resault, the averidge water content (not just moisture but chemicly bound too) will drop.
Trunt be told, most cases those procedures are not needed. But there comes a time where you need to squeeze the sistem tight or make it as light as possible, so iliminating condensatiin devices, condensate tanks and stuff like that realy makes things worth wile to take measures in optimising the fuel.
To me, the advantage of a raw wood gasifier is that you are torrifying the wood as part of the gasification process. To torrify it as a separate exercise or to take it all the way to charcoal seems to negate the one advantage of raw wood. My 55 gallon drum rocket stove wood dryer will take chunks down to a very dry state but it’s a lot of extra work to do it and probably wouldn’t be sufficient to fuel a daily driver. My issue with charcoal is the lost energy in the production of it. All that heat serving no purpose. I think that my as yet untested greenhouse heater will be able to use most of the heat generated by the charcoal making process and I hope to find ways to capture even more of it as I tweak it. My Rocket Mass Heater in that GH absorbs pretty much all the heat generated. The temps out the flue are in the 70-80F range.
Agree. But to have the drying process on the gasifier isnt free either. You still need energy to power the process. Something has to boil off the water and run those convection currents in the hopper and this energy comes from the gasification process. This energy is a loss that culd be used to power the gasification process instead, making richer gas.
Does a few more calories matter on your big 300hp trucks? Nah… maybee a bit says Bob. Does it make a difference when you want a in the trunk of a sedan, or a motorbike gasifier, where bulkyness, weight etc are huge factors? Hell yes.
Not to mention our vehicle engines, you probably put on lawnmowers over the pond. Barely good enaugh stock, letalone woodgased… you need to scrape power everywhere you can
Kristjan has written very well, but let me add a few thoughts. A large gasifier has inappropriately less heat loss compared to a small one (quadratic function), and a large engine has a much higher efficiency than a small one, so I think that when making a small gasifier, special efforts should be made to preheat the air, concentrate heat in the hot zone and fuel preparation. Again a sketch showing the system by preheating the intake air and thus maintaining the metals at a tolerable temperature, I will try to make something similar these days.
Is the hexagonal nozzle a rock drillbit, it looks like one? If so, what is the coneshaped top, is it just a turned piece that is threaded in to the drillbit or is a piece of special metal? Now that I think of it perhaps it is the piece of the drillbit that is fastened to the drill, that usually has that mushroom shape and just made round at the top.
I like the simple design, but still trying to figure out where the reduction restriction area opening is. This is usally below the upper nozzles and it holds the wood up some keeping the extra added wood weight from pressuring downwards that would crush the fragile charcoal or cause it to maybe pack down too tight.
The other thing I see is there is no ash cone that will form for heat protection of the firetube unless you are planning on using shielding around the nozzles, or unless it forms between the grate slots and moves upwards?
Question: how big is the diameter of the upper nozzles area? And how tall from the nozzles to the bottom to going out the grate slots at the lower nozzles?
Where will all the extra moisture and tars that are made going to go? I only see through the gasifier system. I do not think you can keep it really hot enough to burn the extra water moisture and tars.
This is my thoughts from what I have read about Imbert gasifiers.
I would add some kind of upper hopper tubing for extra moisture and tar collection system for a condensation tank to drain off the extra tars/water.
Also a restriction opening below the nozzles to form a ash cone protection.
The heated hopper sides, I really like for more Pyrolysis of the wood above the firetube nozzles. Adding all these things together makes for a really high gasifier in heigth. This could be a problem in some cases.
Bob
A lot of questions, but I write very slowly. Cody, the gas will flow through these slots, the larger pipe will also be cut out, and there will be airducts for the air supply to the lower nozzle, which will cool the metal and will be super overheated to the middle nozzle. Johan , the nozzle is made of a drill and above is welded and scraped (see article 439). Bob , from what I use the lower nozzle in my tractor , I no longer detect a tight area below - even the opposite - the narrowing occasionally detects a “void”, so I recently increased the diameter of the upper nozzles from 4mm to 5.5mm (the lower nozzle has a 5mm inlet). Here I will do an attempt to gasification a mixture of charcoal and wood (or super-dry wood , which I do these days) without a condensation zone and even without a limiting plate, as the sketch above shows. The combination of a medium nozzle and side nozzles should create a layer of very hot area down here, and the fuel will run without barriers, well, together we’ll see how it works.
Okay the lower nozzle will supply more air that will comsume the charcoal below into ashes and out the grate falling down below. The extra water moisture will be turned into Hydrogen this will increase heat in the lower area. Any extra tars will be cracked by this extra heat in this area is what I think you are trying to accomplish here.
So by the time the very dry wood and charcoal gets to this part below the upper nozzle it is all torified wood and pyrolysis is completed and turned into charcoal because of the nozzles blasting into this area.
If you use very very dry wood and more of a charcoal mix. I can see this working then.
Similar to what @Matt Ryder is doing with his units using mainly charcoal with a little dry wood mixed in.
With yours having a multi nozzle upper lower nozzle stages this will make the process very complete hopefuly.
Bob
tone, interesting project! is it for your grass-mowers? your bottom nozzle design could also be interesting for bottom nozzle updraft design , because of slag build up aside.
Wow Tone, it seems by the video it is working. Was it going through the filter too running the tractor? Ofcourse I know you have more testing to do with it how long it will last. What vehicle are you planning on running it with. Another TS Gasifier build.
Bob
I also noticed in the video when I stopped it. I think I counted 11 upper nozzles. Was there a reason for 11 nozzles and not 10 or 12 ?
The straight down sides will never cause wood to hang up on anything, lots of likes on this.
Bob
Bob, I drilled the upper nozzles (4mm holes) in the area between the slots for the gas outlet, there are 11 slots below, so also 11 nozzles. I must say that the air jacket surrounding the hot zone is raised higher than in the sketch, for more preheating of fresh air to the upper nozzles, but you can imagine to what temperature the air entering the lower nozzle is overheated.
Tone how did you build the air jacket at the slots. I’m looking for a way to build your grille (heat exchanger/air inlet and grille) in a simple way. do you use stainless steel for these grates?
So do you want the lower nozzle air to be cooler if possible so the colder air would have more moisture in it?
I can see where this would be good for making more Hydrogen in this area.
Bob
The “air jacket” is a slightly larger tube that surrounds the inner tube, the bottom is cut out just like the inner tube and here the edges of those cut out slots are riveted inward and I welded it together, sorry I don’t have a picture. Bob, with the use of dried wood there is no lack of moisture, we only need a high temperature in the reduction area, which enables us to return the energy in the preheated air, well, the air below is really extremely warm, I think it reaches a temperature of more than 600°C when it reaches the lower nozzle . The negative pressure, which works in the direction from the center to the outside, allows hot air to blow between the bleached coal, into which superheated steam and tar gases from the top descend, the result is a visible, rich gas with hydrogen and methane.
I have a hard time understanding how the different levels of nozzles work.
If the top nozzles produce co and co2, doesn’t the oxygen from the nozzles below burn up the co gas that is produced further up?
