Kalle charcoal gasifiers

Thanks to Gary and his insight I built a nice little Kalle Gasifier a few weeks ago.
If I can get a chance I will be installing it on a small generator (soon). Before I do, I just wanted to pass by a few problems that I had and see if I am going in the right direction.
Discription: gassifier body is made from a ten gallon air tank. The air inlet pipe is 3/4 inch dropped inside a 2 inch outlet pipe. the nozzle is a ceramic mig nozzle attached to the end of the inlet pipe about 4 inches from the bottom of the inside of the tank.

Since Gary is the only one that is working on one of these I was wondering if the nozzle was big enough? During the run I noticed the temp rising on the tank but I was using straight air from a compressor to fire it. I assume this added to the heat problem. To me it just doesn’t seem like I am going to be able to supply enough air to maintain combustion.

Any thoughts?

I like Steve Unhurs opinion, The minute you get woodgas run it through an engine
Make shour it is a 'THOW WAY " engine… Find out what makes it run , and what
makes it fowl…If you have 2 inch wood chuncks or 1/4 inch pellets you can come up
with a gasifier that will satisfy your needs… Every time you run your system you
think of something that could be better…And that is what makes use survive

Hey thanks for listening DausieR.
Engine running sooner versus later is also a Gary Gillmore technique with his charcoal gasifiers systems.

Hey JeffA. I have only very limited direct experience with charcoal gasifing. But I did have your same overheat problems as you when I did try. Kept over heating the walls and nozzles destruction and had very poor engine power. Once i learned better I then had a local charcoal fuel making situation unresolvable.

“I Think” you primary problem is forced air blowing into the charcoal hearth. You are pushing in too much O2 resulting in over oxidized heating to get an out flow past the internal char bed flow restriction. Using a compressed air source use this down stream of the reactor through an ejector nozzle assemble to draw flow the system. ( Yes I know head/book people will say it should be the same sucking or blowing - try it both ways - you will see five different ways in an actual gasifer system it IS NOT the same!)
Also on a true Kahle cycle system you must have the % of inert high CO2 internal combustion engine exhaust flow into the drawn in primary air supply to cool the core reactions and add more combustion produced (now without the internal heat) CO2 and water vapor H2O, for the gasifier internal fueling gases to be converted to gasifier out, CO carbon monoxide and H2, IC engine fuel gasses.

Gary will see this, and I am sure and be able to give you the hard numbers on all of this.

Steve Unruh

Jeff Allen, So you are building what Gary calls the “Gilmore Gasifier”. There are three or four others that have been built and documented in the photo section of the Yahoo charcoalgasifers group, moderated by Gary Gilmore. The one that I have used a 2" schedule 40 outlet pipe with a 1 1/4" pipe run down the center of it for an air inlet. At first, the inlet pipe was too short, so we just welded another piece on to it. When that burns away, we will cut it off and weld an extension… At first, we thought it was not flowing enough air, but the problem was an air leak elsewhere. Martin Payne just flared a second unit just like the first unit, but with some modifications, and is getting a very large flare using two bilge blowers in series. Does your MIG nozzle also have the 3/4" inside diameter? Gary’s Simple-Fire unit runs a 1" inlet and outlet pipe for nozzles, and the air inlet nozzle is just wrapped with some stainless steel thin sheet. You can reach in and unscrew the nozzle (or replace the wrapping) which is just a regular pipe nipple cut in half.
Most of the Gilmore Gasifiers are using a 30 gallon barrel for the reactor. If you are indeed building a Kalle unit, does that mean you are incorporating a movable air inlet nozzle?
Are you making your own charcoal? Welcome, and please keep us informed of your progress.
Ray Menke, in South Central Texas.

Hey all, thanks for the comments…
I do have a bildge blower to use on the output side. I was thinking that blowing the air in was probly disrupting the combustion area too. The nozzle does have a 3/4 inch ID, however I lied about the type, it is actually a plasma nozzle. I only had to file the threads on the pipe a bit to get it to screw on.
If I get a chance this week end I will try hooking it up to the generator.

I am making small amounts of charcoal now but one of my major projects is a charcoal kiln. I keep getting dragged away from it for one thing or another. I have already invested a bunch of money in 3/8" lazer cut parts (doors, floor etc. and stone for this thing. The kiln is a modified version of an Adams retort. I have a really good supply of wood here in rural Virgina to produce fuel from.
I will try and get some pics out this weekend.
I sure to appreciate the comments!

BTW if anyone is bored…

Hi Jeff,
Welcome to the amazing world of charcoal gasifiers. Rule #1 is use well cooked charcoal and rule #2 is do not force air into the air inlet. By pushing compressed air into the air inlet, you create a mini blast furnace. Yes, the charcoal gas exits as fast as you push compressed air in, BUT, the velocity is much greater than an engine sucking would create. There fore excess heat. If the engine sucking created too much heat, then the air inlet, outlet and reactor must be increased. Your are using a 3/4" nozzle so your engine HP should be no more than say 10HP.
Why did you use compressed air to start up the reactor instead of using the bilge fan? The fan is very adequate for starting the unit so am just curious what you were thinking. Just helps me understand what people are thinking so I can better understand the issues as they see it.
As for making charcoal, it is very easy with just a steel drum with a lid. No need for doors, stone, brick or other fabrication. I don’t want to throw water on the work you have already put into your kiln, but it it is not necessary. I have made very good charcoal by bulding a fire in the bottom of a steel 55 gallon drum. As the wood burns down, I add several more logs. As they burn down, add some more and keep repeating. Use dry wood and add the next round of wood a little before the previous load has turned to coals. Over several hours and a dozen times of adding wood, you will have a barrel half full of hot charcoal so put the lid on and let the coals cool off. Open it up 12 hours later and remove the charcoal. Any unburned pieces go back in the next batch. This is the simplest way to make charcoal, but takes a fairly vigilent eye. Go to youtube and search on “Gilmore charcoal” to see the way I use most of the time. You can also go on the yahoo usergroup charcoalgasifier and look at the files section for more info on making charcoal and the operation of a Kalle gasifier. (check out the files section of this forum too. I forget if I had the charcoal info posted :slight_smile: )

Another important aspect of the charcoal in the Kalle gasifier is to grind it to a certain size. This is catagorized as “Fine” charcoal. I must not pass a 1/8" screen but must pass a 3/4" screen. The small charcoal size is extremely important to the operation of a Kalle style gasifier. It you are using larger size charcoal, the reactor will heat up as the hot gasses find easy passage through the course char.
Keep it up and let us know how you make out.
Gary in PA

Hi Gary, I Shure do appreciate the input!
I have seen most of your YouTube videos and really appreciate the time you have spent putting them out there!
…Guess I need to get used to the reply method of this forum. I just spent a bout 20 min writing a reply and lost it! (rats!)
I see I broke at least two of the rules. I didn’t have my charcoal sized right. I wasn’t using large chunks but they sure weren’t within the 3/4" spec. As for the air compressor, I took a shortcut! The blower is just sitting there, I was afraid I was going to burn it up so I thought better of putting it on.
I have been making charcoal in a small barrel up to this point. My biggest problem is the burn bans here in Virginia. I had to come up with a method to completely contain the process. The kiln or “retort” I am building has the fireside underneath and the process side on top. The volatile gasses are piped down into the fireside to a burner. The startup is a wood fire underneath.
The kiln should hold between 1/2 and 3/4 of a pick-up load of wood.
I didn’t get a chance to change my set-up this weekend; maybe I can spend an evening or two. …just got to get back on that horse, setbacks seem to take the wind from your sails if you’re not careful (and stubborn!) :slight_smile:

Hi Jeff, Just lost my past 10 minutes of typing!!! I hate when that happens. Just got to get back on the horse! Virginia tech is playing around with charcoal production too, but they are using the old smokey kiln. If we want to make charcoal, it really needs to be smoke free or society will shut it down. Anyhow, here is the link http://frec.vt.edu/charcoal/
Keep experimenting. There is a lot of satisfaction running an engine on home made fuel. Yesterday I mowed the cornstalks in my garden using nothing but a charcoal powered Gravely. Neat!!!
Are yoy anywhere near Winchester, VA.

Hello, did you make moveable grid for you gasifier ? sS mentioned in making kalle gasifier ? As far as I understood - without moveable grid it will grid clog with small particles of charcoal, but without it - it will ruin the gas filter.

I am looking for kalle gasifier too, mainly to avoid tar from badly made charcoal. And for small applications. I will try to run a small diesel engine ~250cc, 5 hp on mixed mode.

Hi Gary,
I agree, we need to be as smoke free as possible. So far I don’t have any complaints from the neighbors out here in the country. If anyone complained I would think it would be about the old high sulfur coal I burn in my forge. (To be replaced with… charcoal) However, if I fired up an “ole smokey” I am sure someone would call the fire dept on me… lol.
Winchester Va is a good ways from me, about 2.5 hours I think. I am just outside of a small town on Rt 17 called Tappahannock. We are about an hour drive to the north east from Richmond.

hi Jeff,
after reading the description of the original Kalle gasifier i am finally realizing what a great design it was. did you attempt to re-create it, or have you made something that is a modification?