Bill S simple fire charcoal gasifier

I wasn’t going to build one of these until after I built my truck. Because I seen Al D’s and my brother in law science teacher wants something for his class, I decided to do this now.
My neighbor at work gave me two steel propane tanks. I cut this apart when I cut my fire tube today. I cut it upside down so I can use the gauge opening on the top for the burner tip. Not sure how it will work from the bottom facing up but I guess I will find out.

Cutting propane tanks scares me. How did you do it?

LOL… Cutting propane tanks isn’t that big of a deal really… I typically fill them with water for a couple of days. pour it out and if I can leave them out in the warm sun for a few days… I know I know warm sun… yeah right. once that’s done, drill a hole in the other end and pump air through it for a half hour or so.

In the winter I still fill it with water and then just leave it to freeze outside… once it’s frozen, I cut it with a angle grinder and a cut off wheel…

How did you cut yours Bill?

It scared me too.
Apparently I took a more aggressive approach. It’s been a few years since they were used. I took all the fittings out of the top, filled it up with water twice and shot a hole through the bottom with the plasma cutter with the tank upside down. When nothing happened, I felt all was good and continued. I figured the worst that could happen with all the openings in the top was a slight flame for a short time. I didn’t think that propane can store in the metal itself.

Most of my tanks will sit for a while before I use em.
I do this right after I bring some home…

Remove the valve after its empty.
Turn it up side down and forget about it til it’s needed…
Propane is heavy, it will be gone shortly after.
The smell of the stuff they put in it so you can smell any leaks… (methanethiol)
Will smell for quite a while, it does get in the metal.

Before I go cutting it, I will pass a torch by the open hole… While standing out of harms way. I’ve done this many times. Have yet to see any flame from this method.

If it’s a fresh tank and I’m in a hurry, then I go the water route.

I also used propane tanks and did what bill mentioned pull valve and let sit for a long time they do stink for ever though.

I use propane tanks to, if available…
My trick;… put exhaust from IC engine in the hole and let it run…
otherwise i use the water trick…

Koen, my question is about having the nozzle come straight up from the bottom. Is it not going to be a factor because of the velocity of air and the char that does drop in it just burns up?

Bill, on my proof of concept rig (The one with plastic buckets and vacuum hoses), I noticed some charcoal bits made their way down into the nozzle… about an inch down in or so. I believe they stayed there because of bridging. The unit we’re building now has a 1/2" nozzle vs. the 5/16" nozzle on my POC rig…

My biggest concern is having a bigger hole will invite more “fall through.” If it becomes a problem, we’ve designed the nozzle assembly as a modular piece, so we can try a “dog house” approach, nozzles at 45 degrees angles, etc. In short, the development time would be cut way down because it’s modular.

We are about to have our first test run at the end of the week. I’ll keep everyone posted on nozzle plugging, and if it becomes a problem…

I really hope we can make this arrangement work, however. The force of upwards air “fluffs” the feedstock, thus revealing more surface area for reduction.

The nozzle in normal operation, blows the charcoal upwards, acting as a cutting torch so to speak.
at shut down, without insertion of a rod to block the nozzle, there will be some particles falling out.
I try to keep the airspeed in balance with a certain minimum vacuum in the reactor.
also, engines do not ask for the same amount of air as physically given by their dimension (engine displacement) at their different rpm’s and loads
the smaller the engine, the more critical the changes become to have a minimum good gas quality.

the only reason that i started with the vertical nozzle is the small tube i started with.
For the moment i stick with that , seen the performance and quality gas it gives me.
nevertheless, i do like experimenting and if i see better, i will implement any improvement.

i enjoy sharing my knowledge and experimental results…
for what’s worth it , use it for your benefit or even teach me some new visions…

Thanks Troy,
I think the only way that will be a problem is if it constricts the engine required flow of air. My theory is the velocity through such a small nozzle that what falls in there will be forced out. Also when the engine is stopped, that what is above the nozzle will drop in.
what I am having a hard time visualizing is the fire above the nozzle. Because of the velocity, is it going to be a long piercing flame? So pointing straight up, at what point does the velocity of a single nozzle push the charcoal out of the way? So I see the benefits of coming in at an angle or maybe even multiple nozzles straight up or slightly outwards.

Here is a concept we came up with that would:

  1. provide variable gas flow, based on idle/load, or different engines
  2. normalize air speed on a per orifice basis, which is directly tied to temperatures
  3. prevent most feedstock from “fall through”

The ceramic nozzle manifold would have to be custom made, and the sliding pipe fit would need to be tight.



Understand I haven’t made one yet and understand only the basics.
First thoughts- how would you light it?
Secondly, I like the concept. Like I said, I’m not sure if the charcoal falling in the tig nozzle would stay stuck in there? Would the velocity extract it automatically?
What I also don’t know, Does a 1" nozzle operate a 5hp or a 10hp engine? The difference only being the velocity of air flowing through it? Is there an ideal velocity? If there is an ideal velocity, then this would be awesome.
What program did you use for this drawing? If I can find a decent program, I can show you my idea. Other wise you have to wait until I build it.
I plan on building my truck at work and my charcoal gasifier at home. I have to get both places organized first.
Thanks for the drawing

Now thats what i call creative idea thinking… gives me a wow feeling, good good good…

Bill, the flame will be indeed as you described long streched, as a candle flame…
The heat comes from the amount of oxygen, the airspeed will focus that heat…

the minimum recomended airspeed is 25 m/sec
fire lenght will be then about 150 mm
the focussed heat will cut trough the charcoal as you would do with snow…and hot air, instantly evaporizing the carbon.
focussing the heat prevent the heatloss trough the reactor walls…
you can compare it with your propane torch, the heat is focused to…

a good balance between airspeed, oxygen content and your engine is what gives the power.

Here Al D. is the article about the Kalle charcoal gasifier.
This begs the questions-
1). Is a vertical preferable over the horizontal?
2). If vertical is preferred, Is coming from the top better because everything settles when not running?

Bill, that is the million dollar question… This is where innovation really shines. I’m also curious to know if our upward-pointing nozzle will have problems.

Sorry but the vacuum of engine is able to suck the air from the holes of nozzle? I suggest to admin the quantity of the charcoal with an coclea for increase/decrease the production of syngas. This is the right way for obtain an purified syngas from your gasifier.

Sorry, Marco.

It’s hard for me to understand your English. I realize it’s not your native language, but in order for me to grasp what you’re suggesting, I propose you put together a graphic or diagram for me to look at. I searched for the word coclea, and I pictures of ears, shells, and electronics. A graphic would be nice, explaining all the points you’ve made here, and in other posts.

Plasma sounds awesome, but I need to see what you describe for a better understanding. Thanks!


Oh wait!

Marco, do you mean an auger?

I’m italian. Attached the image modified. Air is sucked by engine from these holes?