Tone, is that a mesh over the glowzone?
The problem l see with the mesh gasifiers is how to prevent ash buildup.
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I think the only way that makes the most sense to add charcoal particles to a nozzle would be to replicate a sandblaster venturi.
Issue lies in now you have two hoppers to manage. Hard to tell how big to make the dust hopper, or how to tune it to nozzle size. The venturi would aid in atomizing water, but may backfire metaphorically because itâll mix with the dust and turn to a carbon mud in the air pipe. Maybe it could be mitigated if you used a water cooled nozzle and had a small delivery tube near the end. Or in a downdraft style use slightly moistened charcoal.
Iâve heard from some that moistened charcoal bridges very easily.
Iâm honestly convinced for charcoal either keep it a simple updraft and do your due diligence in fuel prep, or build something like a Mako downdraft with a ring of replaceable nozzles.
Itâs good to sequester that carbon dust back into the soil. Apparently cats like it for kitty litter too.
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Isnt that the thing from the Kalle âmanualâ Chuck refers to?
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I did a little experiment with dust.
I fueled up with 1/2 inch charcoal that was cleaned of 1/4 minus. Then I added some 1/4 minus into the fuel bed something like this;
I wasnât precise in measurement or placement but Iâd estimate the dust was 10% of the fuel load.
It didnât plug up, which might mean a lot of the dust was consumed.
Donât know how useful it is, but it might let me use some of my dust in my updraft gasifiers.
I think Iâll try a few different configurations of âdust loadingâ and see what happens.
I should probably point out that this is a modified âupdraftâ, sort of a side draft, but the gas exit is 360 degrees. Gasses travel up between the two vessels which makes a pretty good cooler.
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So the air is coming in from the bottom big nozzle and gases go up the barrel side. Is it loaded from the top? Yes I see a side up draft gasifier. A barrel in a barrel design gasifier. I like it KISS Keep It Super Simple.
If the nozzle would be placed higher it would be a down side draft gasifier. With charcoal dust placed in the top it would go strait down to the nozzle with the center charcoal flow. Some might migrate to the side.
Bob
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IS there a cheap enough type of glue that would make char dust pellets, or spray char dust on demand maybe?
Yeah, there is a hatch at the top of the inner vessel for loading.
Based on the glowing char pattern when you open it up hot, I suspect the flow is something like this;
One interesting consequence of the very large volume the gases flow through, between the barrels, is that very little dust ends up in the course filter. The gas flow is very slow and doesnât seem to carry much junk with it. I ran the same gasifier as a straight updraft before adding the liner and it produced significantly more dust without it, all other things being the same.
There is soo little dust in the filter Iâd say it would be fine for 20 hours or more.
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Hey Kevin, yeah, pelletizing is a sure fire way of using the dust, eh?
There are quite a few conversations about that topic around hereâŚ
Totally doable (and would make a premium fuel) but it would take more tools and equipment which would end up more complicated. Iâm trying to stay with ultra-simple.
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chuck, how do you feed the dust inside? only by engine sucktion?
maybee some fotos?
thanks giorgio
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Chuck, this way of exhausting the resulting gas certainly has many good properties, all of which you mention, but we must not forget that it creates good insulation around the middle, which means a lot to the quality of the gas. There is a lot of talk about the durability of nozzles in charcoal gasifiers, well, here I would add my opinion, well preheated air, which is supplied through the nozzles, cools the tips of the nozzles better than cold, because the volume of this air is larger and it moves the oxidation process a little further from the nozzle , the high temperature of the inlet air also means that we need less burning of coal to achieve gasification
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You might want to skip the gasifier and just use direct injection. There are a couple examples of car engines that run on coal. And according to this paper, which has like 1 paragraph on charcoal, it has less mineral content then coal and better for the engine. Then they also tried pulverized biomass and said that could work as well. But they are using big engines and some of them are the 2-cycle diesels judging by the table of contents. I did not look to see what they are using as injectors. It is rabbit hole, I donât have time to dive into right now.
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Video of the little 16 gallon charcoal gasifier with the âbarrel-in-barrelâ cooler;
https://youtu.be/scej5s_P74k
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I did another dust experiment where I filled the hopper 80% with clean 1/2 inch charcoal then filled the rest with fines and dust.
The run was pretty much normal. At the end of the run the dust was almost all consumed and what remained looked a bit like this;
There might have been a little more dust in the course filter.
Internal flow;
Even though the exit for the gas is horizontal, the gasifier will tunnel up through the fuel bed if no vibration is supplied. I suspect the hot gases flow upward fairly strongly from the reaction zone.
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Hi Chuck , i really like your builds and i know you must be thinking out side of the box when designing and building them .
About 6 years back when i was running horizontal nozzles i had a time when after relighting the old char would always take way longer than running from fresh charcoal ,and so on start up i would light the old char up and straight away start feeding in charcoal fines and dust allowing the pull of the fan to take in as much as i could it certainly helped getting the gasifier going a bit quicker , and i then decided what i needed was an auger feed separately from the air intake nozzle , i thought of using big masonry drill bits and then thought of using a electric mincing machine as that had a variable speed drive motor attached and also a barrel of sorts that could be easily made into a extruder of sorts as long as you donât allow the dust and fines to pack up, but sadly thatâs as far as i got due to life getting in the way again .
Dave
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Hey Dave,
Funny how everyone ends up exploring the same solutions as we encounter the same problems. Makes you wonder if there really is anything new under the sun:)
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Here is a little demonstration of crushed/powdered charcoal and the density gains.
A 4x6cm cylinder was filled with fine charcoal and compressed in a 20 ton press.
(40,000 lbs/ 1.76in_ sq=22,727 psi)
The volume changed from 75.4cc to 22.6cc, a 3X gain in density.
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This may not be completly applicable, but it would be interesting to make powdered charcoal pucks and see how they burn/gasifiy
The first hakf of the video is what I mean with âpucksâ the rest is of interest I guess if you want to make your own black powder like I plan to some day
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Probably really well if you use the potassium nitrate binder:)
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I tryed making my own charcoal pucks before, but they were to crumbly to test in a gasifier. 3 times as dence thugh⌠this has potential, specialy for mobile aplications like motorbikes etc.
Regarding black powder. Fastest powder is just ballmilled and wettened with water and 10% alcohol then pressed trugh a corse sieve and dryed. Presing it to pucks makes it denser but slower. Depends on what you need realyâŚ
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