Making my simple fire gasifier

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#23

Hi Brian , welcome along I can see by your posts that you are as excited as i was the day i managed to run a engine on Gary’s simple fire , even to this day many years along i still have a trusty updraft simple fire ready to go at a moments notice .

Tell me what design nozzle have you gone with ? and do you have a wood burning fire in your home ? i am guessing that it might be summer where you are so probably no home heating needed , but one way i manage to add between 25 and 50 liters’ of good engine grade charcoal every day is by taking out the burnt wood as soon as the flames die down i take out the hot coals before every load up of fresh wood , at the moment i am burning hard wood house framing that i get from the demolition of houses , all they charge is for delivery and its all aged dried wood that makes the best fuel i have ever used .

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Enjoy the thrill of making your own electricity or whatever else you choose to do with that Gas .
Dave

15 Likes
#24

My nozzle is really simple. I had a section of 3/4 inch pipe and some fittings so I just welded the coupler on the side of the air tank with a piece of pipe on the inside that goes almost to the center of the tank and a shorter piece with pipe sticking out with a 3/4 to 1 inch adapter just because it was on the scrap pipe I had.

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I didn’t leave a good way to change the nozzle and the top opening is only 3 inches so no chance of reaching inside far enough to change it.

I’ve only fully emptied it after my first burn so I don’t know how it is holding up. I’ll have to cut an access port in the tank when it needs changed but I just wanted to get it working and prove that it was going to work before getting too fancy with it.

I don’t expect that nozzle to last a long time but I’ve only run it maybe 4 or 5 times now and the longest was probably a half hour or slightly over that before it was getting hot enough to start melting my duct tape.

I ordered a piece of 1 inch flexible exhaust pipe for the generator that I might use to add a little exhaust back into the gasifier or I might try rigging up a simple water drip to try to extend the life of the nozzle and add a little more power.

I do heat with wood as well as coal but the furnace isn’t easy to take unburnt charcoal back out of but I have scooped some glowing coals out of it before and dumped them into a bucket of water to get charcoal but that was for a different project.

The grates on the furnace are too big so, unless I’m burning coal, the wood falls through and burns up into ashes. In the heart of winter I try to keep the fire burning and never let it fully go out. It might be possible to collect some charcoal at the beginning and end of the heating season when the furnace isn’t needed full time though.

Oh yeah, on my first visit to Gary I saw he was using a water cooled nozzle but didn’t get to examine it to figure out exactly how it was made. If I remember right, I think it was set up to put the steam back into the fire but he also had the exhaust fed back in so I assume the steam/water vapor wasn’t enough alone to keep the fire cooled. He showed me an old water cooled nozzle made from copper that melter when he forgot to keep the water full but I didn’t ask if his current nozzle was copper or something else.

My own gasifier isn’t real easy to fill and empty so I haven’t taken the time to check the nozzle but there’s a very good chance that a better nozzle would make it work better but it works for now.

I’m hunting for materials to build a different filter and maybe some kind of cooler for the gas but haven’t started anything yet.

Lots of ideas but limited time and scrap. So far, if you don’t count stuff I had, I only spent less than $20 for the pipe cap. The rest was made from scrap parts I had laying around or that was given to me. It probably hasn’t paid for itself yet but at $4 a gallon for gasoline it shouldn’t take long.

6 Likes
#25

You do really need to make that nozzle easily accessible. I’d be willing to bet that your current one is melting badly even with your limited burn time. I’d think about a flute type nozzle for that unit. I’d look up Don Mannes youtube channel and look at the WG generator he built. I’m sure it’s one the site but I’m too dumb or lazy to find it. If you want to stick with a pipe nozzle consider this.

Slips into the end of a pipe coupling. I got steered toward them by Dave the Australian. I think Cody has used them as well. They last.

4 Likes
#26

Yeah I’ve used one. They can press fit into a 1.25" sch40 pipe as well if you’re careful and have a shop press. An arbor press might do it but I don’t know. I pressed the nozzle in halfway so the brunt of the heat would stay away from the pipe nipple.

I prefer the flute style because water drops have time to boil and steam, so the reaction can use it better. When metal gets as hot as it does buried in glowing charcoal, water just glides off without boiling entirely and your drops just land in the reaction. It’s called the Leidenfrost Effect.

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#27

I dumped my gasifier out to look at the nozzle.

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It’s still hard to see even with a light and my camera to look inside the tank through the 3 inch hole but I’m pretty sure I can still see some threads on the pipe so I’m not going to mess with it yet. I did find a lump of metal slag when I dumped it but it was probably from one of the holes I cut.

I found a thread here that probably has enough details to figure out the water cooled nozzle idea. When my nozzle is no longer usable I MIGHT try something like this. That silicon carbide tube bushing might be an option though.

https://forum.driveonwood.com/t/mikes-venture-into-the-dark-side/4675

and this one that shows Gary’s copper nozzle.

5 Likes
#28

Good work Brian , i would have bet my last penny that there would be nothing left of that pipe after 1 hours run but Tom beat me too it !
If i were you i would just carry on and run that as is so you can at least see what will happen and in the mean time start work on a flute style nozzle for speed , cheapness and in keeping with simple ,once your nozzle has melted away just cap off that pipe and drill a new hole and insert a flute nozzle and a water drip and away you go .
I love simple so try that before paying out money for copper pipe or even the silicon carbide that i use that’s still in my gasifier since Aug 2018 .
Here is a link to all types of nozzles we have used

Dave

8 Likes
#29

Brian M.,
I also recommend the flute nozzle as a simple way to make what for me has been a long lasting-nozzle. Also, I started with exhaust return to the air inlet, then added the water drip. I have since eliminated the exhaust return from my three gasifiers. Water and exhaust cooled the reaction too much. The water adds a bit of hydrogen and therefore a boost in power as well the cooling effect to protect the nozzle.

9 Likes
#30

hello brian,welcome in the forum, thanks for your good documentation of your gasifier…recently i have built a water cooled nozzle for my motorcultivator, not tried yet but soon…
also exhaust gas redirection - egr - works well on my mowers, much less slags, will say less heat stress for the nozzle, nozzle keeps up good on engines 250 ccm
ciao giorgio

9 Likes
#31

The engine on my generator is only 212 cc so it isn’t very powerful. A slight boost would be nice.

Since I dumped out all my charcoal, I was wondering if it would be worth the time to crush and screen it to a smaller size.

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The charcoal on the left is the bigger pieces that I had in the gasifier. Nothing huge but some of the flat pieces are over 2 inches long.

The screen is 1/2 inch squares and the little tray has slightly bigger than 1/8 inch holes.

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My grinder isn’t chopping it all up especially flat pieces that might slip through.

The bucket has the minus 1/8 inch biochar. The melted black container has the 1/8-1/2 inch. The rest is the mixed sizes that I dumped out of the gasifier.

It worked the way it was although it heated up faster than I hoped it would. I assume using the smaller screened size would give the gas more restriction and probably keep the temperature of the charcoal gas a little cooler but it means rebuilding my grinder (which isn’t the best anyway).

FYI, the gasifier holds 2 full buckets (about 10 gallons) of charcoal but I’ve been shutting it down after burning about a gallon (maybe less) worth of charcoal because it starts getting too hot. A smaller size might extend my run time?

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If I rescreen my minus 1/8 inch using a window screen, I can recover a good bit of small pieces but I’m not sure if they are too small and should just be thrown in the compost pile or mixed into the engine grade charcoal.

11 Likes
#32

On my simple fires I grind it to a half inch and screen it through a quarter inch screen. You need to get the dust out of your fuel. I once did a video of trying to start one and Matt Ryan immediately spotted the problem of too much dust. For a long time I just made sure it was pretty dustless and had no problems. Now I have started to wash it and then dry it. Seems to work a little better but probably not enough to go through the extra effort. Just trying some trial and error. I would not bother with the window screen or anything that falls through a quarter inch screen. That’s bio-char for me.

8 Likes
#33

Thanks for that reply. I do have uses for the biochar so it won’t be wasted but didn’t want to be separating the best stuff if smaller was better.

I think Gary has a 1/8 inch screen and saves between 1/8 and 3/4 inch as engine grade. I thought I read where others here were saving anything bigger than window screen so I thought I might be wasting some.

I’ve almost got my gasifier filled back up but will need to dig into my stash and grind some more to fill it. I assume I lost the burnt ash (sifted out) and I ground up the bigger pieces a little smaller so it takes more than I dumped out of it to refill it again.

5 Likes
#34

Brian, one thing that I do when making charcoal is I pre sift my charcoal before grinding with a 1/2" screen. Then I sift the dust out of that with 1/8" screen.

The bigger stuff I will grind down and reclassify
I’ve thought about making a two tier sifting ramp, that collects charcoal into two buckets. Engine Grade and Too Big. Dust would just land on the ground to be shovelled up later.

Keeping your charcoal sizes on the smaller end will help increase your fuel density and give you longer run times.

4 Likes
#35

My charcoal grinder has a 1/4 inch screen at a 45 degree angle and what falls thru the screen is 1/8th inch and dust biochar. 1/4 inch to 3/4 inch engine grade charcoal is what rolls down to the left bucket.

14 Likes
#36

brian, eddy ramos, also here on the forum, uses charcoal size from rice corn to olive size…not too much rice size mixed in though…
quick method for charcoal making is burning twigs in a bath tube, of corse not the one in your bathroom…a old scrappy one, here in europe they are from metal, in u.s. i have heard made from plastic, not ideal…
with twigs i get the right size of engine coal automatically without crunching…
i have made a topic of this system here in the forum

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#37

Luckily, on Don’s grinder video, the one for his generator set up came later. I mentioned it earlier about the flute nozzles. All nice and compact.

12 Likes
#38

Just to save some future searching, here’s the start of a lot of good information on some of the designs people have made to grind the charcoal.

[Charcoal Gasifier for Generator - #74 by don_mannes]

I tried slowing down Don’s video to see the grinding mechanism better but just couldn’t catch it. In the link above and in the posts that follow it Don has better pictures and some dimensions and there are other people’s versions.

Thanks Tom for finding Don’s other video. I’m still experimenting so I want my gasifier to be able to be hooked up to other engines besides the generator but that looks like an easy to use, complete unit. I figured that was what a “flute” nozzle was but seeing the glow through the holes confirmed it.

My generator is the only engine I tried running on the charcoal gasifier so far but I’m thinking that a lot of the small engines around that don’t run anymore is because of the ethanol in the gasoline here (in the USA) messing up the carburator. Feeding them wood/charcoal gas should get them usable again.

8 Likes
#39

Brian if you scroll through the Nozzles for charcoal gasifiers part 2 link then you will see a more detailed view of all the nozzles being used that should also give you dimension sizes for you to copy .
On the charcoal size the smaller it is the slightly longer run time you will get on a small gasifier as you will create smaller rat runs for the hot gas to bypass the cooling charcoal helping to keep it cooler longer .
Dave

9 Likes
#40

That charcoal in the picture would run great in my double tube flute down draft gasifier. It can run larger pieces as well mixed in.

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#41

I just bought a set of these TOM thanks for posting- i am sure i find a use for them once i get into char gasifier-i might use them on a insulated burn TUBE wood gasifier testing design. THERE is 5 or 6 sets left.

4 Likes
#42

ONLY 5 left now. I debated on buying one but figured I should get one before they’re gone.

I’m going to keep using the piece of pipe I have in my simple fire since it’s still working but it sounds like this should last longer and I really hope to use this gasifier a lot more once I get it set up better. Right now it works but I want to get it on a cart or at least a base with the filter and probably a water drip as one unit instead of having everything duct taped and spread around.

I got almost another bucket of charcoal from my last batch of sticks but it still needs screened and maybe crushed although most of it was fairly small and broke apart by hand.

Started on another charcoal grinder that will hopefully work better than the welded nuts and bolts on my first test. Only one tooth so far but a quick test powered by a cordless drill looks like it makes it closer to the size I was hoping for.

6 Likes