hello brian, on my topics you can see some small charcoal downdraft gasifiers for my mowers, tiller, stationary unit…also kristijan has one on his walkbehind mower…
nice new active people here on the forum…!
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Brian M,
You may not have seen this yet. It might be what you are looking for in a down draft charcoal gasifier:
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I still think I can make it work, at least on charcoal. I now have a 2200 psi pressure washer so I can spray all the tar out of the inside. Will make makes working on it a lot easier I hope. I kind of got more busy with work for a while but should be able to get back to it now.
Rindert
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Yeah dont be afraid to be creative. Consider this as the concept, I would strongly encourage you to build the unit out of something more robust than an ammo box. You dont have to build out of a square box you can use round tanks just as well.
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Yeah, That’s where I’ve come down too. I like old propane tanks and water heaters for material.
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One thing me and Rindert didn’t do is follow the dimensions 100%. It is very dimension sensitive. Also the grate is meant to be fixed. One big thing to keep in mind as well, is any gasifier that Joni has brought up require high velocity at the nozzles. You do this by making the orifice tip like a jet. Say you want a 10mm nozzle, drill out 10mm and behind it drill it out a little bigger.
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I found a better barrel with a lid that I’m guessing is maybe 15 gallons.
Trying to shovel the hot coals directly into it instead of blocking the holes in my water tank burn barrel.
I chopped it up as I was filling it using the shovel and looks like this will have a lot less wasted waiting for it to go out while continuing to smolder. No smoke getting out after closing the lid. Plus, this will be dry so should be usable as soon as it cools and gets classified and ground to engine grade size.
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Brian , when you first load up that drum with glowing charcoal leave the lid loose don’t what ever you do make it air tight to start with wait till the coals stop glowing before sealing up the lid air tight ,other wise it will burn up any oxygen inside and create a vacuum and collapse the drum .
Dave
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I don’t have the clamp for the barrel’s lid and it doesn’t have a gasket so it won’t seal completely air tight but good enough to keep the coals from continuing to burn.
I misjudged the angle it needs to get the charcoal to go down the screen so this ended up shorter than I intended but it separates the finer (1/2" and smaller) from the charcoal I will still need to grind. I’ll still have to screen the fine stuff once more to get the ashes and biochar out.
This screen can also be used to get the rocks and bigger clumps out of my compost pile.
This is the fine pile from yesterday’s barrel of charcoal.
This is what I got just from separating the charcoal without any grinding besides breaking it up with a shovel. I’m figuring there’s 2 hours worth of generator fuel in that bucket ready to use. Probably a gallon worth of biochar. That isn’t even counting the 3 or 4 buckets of bigger charcoal that could either be ground finer or saved for forge, foundry, or BBQ use.
The better barrel to put the glowing coals into was the key to having a practical system for making my own fuel. Gotta go find a lemon now.
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Brian,
If you are using a 1/4 inch (4 mesh) screen for the fines, you will be ok and reclaim more engine fuel using 1/8 inch (8 mesh) screen. That is what I use and haven’t noticed any negative issues.
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The hardware cloth in the new screen is 1/2 inch and my little screen is a little over 1/8 inch. I would like to have 3/4 inch as the biggest screen but I don’t have any that size. A few bigger than 1/2" pieces got mixed in with this engine grade bucket which should be fine but I think I could recover more of the bigger pieces to mix in if I get a 3/4" screen and eliminate even more grinding.
I’m still researching and hunting through my scrap trying to decide on a down draft charcoal (or wood) gasifier but my simple fire gasifier is working good enough that I’m not in a big rush to use up my scrap until I decide exactly what I want to build.
I have a 20# propane tank sitting here just waiting for a use but it’s starting to look like a filter for the simple fire if I can figure out a good way to seal it but still be able to clean or replace whatever filter material I use. The bucket filter I have now is working but the 20# tank might work better if/when I put this on a base or cart.
Thinking something like this might an option for the 20# tank. Maybe upside down so the threaded opening could be used as a drain.
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My grinder batteries went dead but got the propane tank cut.
Kind of crude cell phone drawing but this is my plan.
The tank will be upside down so the threaded part where the valve was will get a 3/4" pipe plug to drain any condensation or to drain it if I just wash out the filter media.
It will be raised up to access the drain but I won’t know the length of the legs until I get it together.
I want to go out of the gasifier, through the condenser, and then into the bottom of the tank (formerly the top). The gas outlet will be on the removable top section where I’ll hook up the hose to the engine. I thought about making the gas outlet at the side (and still might) but it will probably be a plastic hose so being on the removable lid shouldn’t be a problem.
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I discovered a problem with my plan. My nozzle still isn’t easily replaceable but that can be fixed with Tom’s suggestion. The problem is the way I have been cleaning out the charcoal is to just flip it upside down. I won’t be able to do that if I keep adding to this or mount it on a base.
Here’s one solution.
The link in that post goes to some pictures of Giorgio’s clean out port. Large pipe fittings and pipe caps are expensive and I can’t tell for sure but it looks like Giorgio’s version isn’t threaded. Where my clean out port would go is in one of the hottest places on my gasifier. Would woodstove gasket rope and high temperature silicone handle the temperature at the bottom side of my gasifier? I’m thinking a section of square tube welded on the side unless I find something better.
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If the nozzle isn’t pointing directly at that area, and you leave a gap for ashes and charcoal to help insulate you’ll be fine.
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I have a couple of simple fires without any clean out as well Brian. They are small and I just suck the char out of them with a shop vac when I want to clean them out.
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Back to burning liquid fuel for my generator.
Probably still some life left in the nozzle but it did melt.
I chopped a hole in the side to get to the nozzle and as a clean out port. My square tube was only 3 inches so I decided to build my own.
Should have used the grinder instead of the torch to cut the pieces but…
Hours later it’s getting closer. I still need to figure out how I’m going to make a door for this and will likely have to do more grinding to get the door to seal.
My water trap jar came off and might not go back on. It was hard to get it sealed airtight and the last couple runs there was only a few drops in it.
I still want to turn the propane tank into a filter but hope to get this simple fire gasifier working again so I don’t need to burn gasoline to do all the grinding, cutting, and welding it is going to take.
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Make a piece with double lips to act as a channel for the stove rope.
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I won’t know if this works until I get some stove rope and more silicone but it sits on here without rocking.
I still need to clean it up and round the edges but I want to see if it seals before getting too much more work into it. My homemade box was welded inside and out but I’ll need to check it for leaks too.
Looks like I used about a pound of flux core welding wire today but I have close to a 5 inch square opening to reach inside instead of just using the 3 inch square tube I had that I was thinking of using.
I only tacked the lip for the stove rope. Hoping the silicone and rope seals it good enough. Hopefully I can be back running on charcoal gas soon.
This will make cleaning it out and changing the nozzle a lot easier.
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on my gasifiers i do not use silicon for the rope, i have the double lips higher, so the rope stays from alone inside…on the two ends of the cut i make some windings of adhesive stripes…til now the stripes are keeping up with the heat…i tried this because not having silicone here…
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I found an old piece of stove rope and had a partial tube of silicone left so I put it together.
I figured silicone and charcoal dust wasn’t making a big enough mess so I smeared some grease on the surface of the new box.
I’m hoping that stops the silicone from sticking to the surface so it will come back apart. I reinstalled the old nozzle first so, if I don’t have any leaks, I can get this running again soon before seeing if it will come back off without messing up the seal.
It looks like it could work. I was worried I didn’t leave enough of the bolt sticking up on the right side.
Will have to wait for the silicone to cure before testing it. Half of the tube I used was already solid so I guess it’s a good thing I used it up instead of trying to save it.
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