Tuyere-less charcoal gassers

After abusing my download limit across the world wide web (and youtube) I have seen two talented individuals by the names of Chris Seymour and Jeff Davis (Hi guys), using simple charcoal gassers which appear to have no tuyere into the reaction, just an opening into the reactor. Really liked the skinny reactor on Chris’s tractor which just seems to have 3 to 4 small holes in the side of the base. Also loved the front mounted reactor on Jeff’s tractor too, which just seems to have a single hole bored in the base of it. Can anyone shed any light on this please. It seems just too simple to be true that a gasser is as simple as a “bucket with two holes in it”. It may certainly help me decide on a route to go for my first charcoal gasser, as obtanium in the shape of 1" BSP pipe and fittings is harder to get hold of than I anticipated, And I’m a part time scrap metal dealer!

1 Like

Neil, I saw Jeff’s tractor at Argos and was impressed with its simplicity. The gasifier is just a 20lb propane tank turned upside down with the valve removed. Around the valve hole inside the tank is some refractory cement which surrounds the hole and also covers the threads to protect against heat. A water pan is fitted below the nozzle to catch any burning embers at shutdown or big bumps and experimentally add hydrogen (steam or vapor).He cut about a 6 inch hole in the bottom which is now the top and welded a standpipe above the hole with an airtight lid on top and a gas outlet on the side near the top which leads to his cooler pipes surrounding the standpipe. The gas goes from the cooler to the filter and then to the engine. Here are some pics of it.
Pic #1 -Inverted propane tank
Pic #2 Pan under nozzle
Pic #3 Fill pipe and cooler pipes
Pic #4 Setup mounted on tractor
Don Mannes

Don, that is sooooo helpful! I did wonder how having the reaction zone right on the edge of the reactor affected things. After what can happen to a mild steel tuyere I feared that the inlet hole would just melt away in the heat. I had thought that maybe cement was a good and cheap solution, didn’t want to mention it first in case I was revealed as hopelessly guessing at solutions.

Neil… is there any good reason why you want to start with 1" BSP? I want to try scaffolding pipe in the next evolution- it’s everywhere, and about a pound a foot to buy. Tuyere meltdowns are a minor issue at the moment- the questions that need to be answered are… Can you moderate the combustion zone to whatever temperature you want? You can? So what temperature do you want? Ceramic kilns happily run at around 1400C, and the thermocouples are mature technology, soooooo… what’s the maximum temperature for a mild steel tuyere? What’s the minimum temperature for good gas?

Hi Brian and Neil,
There are ways to make a charcoal gasifier without a steel tyere. Jeff Davis has a hole in the bottom of his gas generator where the air enters. On the inside of the generator this hole is lined with clay to a depth of maybe 1 to 2 inches. The clay protects the steel shell and since the air blast is upward, there is no metal to oxidation zone contact. No need for a steel tyere. Such is the advantage of this design. Downside is dumping out the contents of the generator for cleaning will likely cause the clay protecting ring to also fall out. Possibility of hot charcoal falling out of the “nozzle” is very real, especially if the generator is shaken as can happen on a mobile unit. This design is actually more simple than the steel nozzle I am using, but as in most things, there are plusses and minuses.
How hot does your oxidation zone need to be? This is a quote from the FAO wood gas for fuel publication.
“The reaction rate decreases with falling temperature. In the case of the water-gas equilibrium, the reaction rate becomes so low below 700°C that the equilibrium is said to be “frozen”. The gas composition then remains unchanged”
In otherwords, when the temperature of your charcoal drops in the range of color called “red” (1300F), any water entering in will not be split into hydrogen and oxygen. You must keep the temp of the charcoal in the “bright red to orange” range to complete the water to gas reaction.
Charcoal can easily go into the “white” range that easily melts steel. Exhaust gas can be used to moderate this temp. I have brought the temp of the oxidation zone down to a dull red (about 1100F) with too much exhust gas. I use my eye to adjust the oxidation zone temp and therefore need to look at the fire. A thermocouple would be a nice addition to the system, but it also adds more bells.
Until later in PA

Hello chaps.

1" bsp pipe and fittings seems to be used in small gasser setups with good success, it is pretty universal and modular and in theory, pretty easy to find for free. Having just moved site at work the demolition and refit has left a few interesting bits in the skips. Today I managed to nab a few lengths, a tee piece plus a gate and ball valve, all of the 1" steel variety. For a first attempt gasser I would ideally like to just copy someone’s working model. Then there should be a good chance I got it right (within reason). I like Gary’s simple fire but with a budget of £0 and no suitable pails to hand, I was looking at Jeff’s design. I happen to have 4, 13kg propane cans cluttering up the place, plus a few lengths of exhaust pipe too. I understand that there is pro’s and con’s of every style setup. I can see the bottom entrance inverted propane can setup could potentially light whatever is under it!

However, in good news I managed to afford a proper reactor welding mask this week, and am collecting a free petrol lawn mower on Friday. Project material and supplies keeps trickling in…

1 Like

Neil, you have all the parts to build a Simple-fire. Here is a photo of mine. I welded a stainless steel Baine Marie into the top as a hopper, but that really was not necessary. The puff-lid was not required either. Just put a hatch on the top so you can reach in and unscrew the nozzle which is one inch pipe wrapped in some thin stainless sheet. Or, at the bottom, you can mount the nozzle on a hatch so you can take it out without removing all the contents of the propane tank. To make a hatch on a curved tank, just use an angle grinder with the thin cut-off disc, and cut a square. Then lay some straight angle iron in the curved parts to make a flat sealing surface. Of course, if you have multiple tanks, you can use one as a parts unit, and just cut out a larger section from one, and slap it over the hole in the other. The most important detail is in the proper sizing of the charcoal which needs to be larger than 1/8" and less than 3/4". You can buy hardware cloth and screen your charcoal. (Put the fines and ashes in the compost pile.) Without a charcoal grinder, just use gloves and bust it with your fingers. Don’t use any charcoal with brown wood which will be easy to see once you start busting it up. Good charcoal will literally explode when you crush it. Don’t douse your wood with water unless you live in the desert! Once the tank is loaded, just stick a propane torch in the inlet nozzle for a few seconds, and it will take right off. When you are done, put a pipe cap on the inlet and outlet, and it will be ready to use next time. Don’t skimp on the filtering. Those little lawnmowers will run for quite some time on very little charcoal. Of course, then you need to find a good use for a lawnmower engine… Oh, if you sort through your charcoal and find pieces that are not good enough, just use some of it in a TLUD cook stove towards the end of the cooking session, like for simmering. What comes out of the TLUD is usually small and well done charcoal, after you dump it into a sealed can and let it cool off. It will need to be screened over the hardware cloth, for sure. Good Luck.

Hi Neil, Thank you for the very nice comment! Tuyere-less is a fine way to go for a inexpensive start to gasification. This type of gasifier can last if Mr. Gilmore’s advice is taken. A char coal gasifier can easily go white and into meltdown mode. If you are going for engine grade fuel, a good choice is using engine exhaust metered in and regulated by a thermocouple, safe and simple. Experimenting with a bit of steam from an exhaust jacket can work and can split better. Be careful messing with steam it is more of a handful but the reward is extra hydrogen and pure oxygen with less chance of over watering the reactor. you can put a water drip in instead of steam, but just be careful not to add too much water and hurt the reaction.

We mixed the air with the exhaust gases very well before sending the mixture into the reactor with a nice sized box attached to the exterior of the reactor. this box is sturdy and thick on the reactor side. it also works well to heat the incoming mixture of air and inert gases.

1 Like

Such great advice. Joining DOW was a good move. There is only so much information you can gather from background reading. Chris, your charcoal truck setup is a beast. It really demonstrates the power available using charcoal. Thank you all for some really top notch advice. As to the pending lawnmower, it’s a test bed for now. I have a 125cc motor bike and a Landrover that just scream “project” whenever I see them, but start small and if I torch an engine, it’s not a big or valuable one.

It’s imprinted now that charcoal gassers must have an “addition” to regulate and add hydrogen to the reaction. I had a thought, so please add your collective knowledge to it. I considered passing the inlet air through a water bubbler before hitting the reactor. This would add water vapour (how much I don’t know) and also act as the blanking cap to the air inlet. No suction on the outlet, no air gets through the inlet. I’d been watching the vapour lock on a demijohn when I had the idea. Also, maybe use a little generated power from the engine, attached to a pair of plates in the water bubbler to produce pure hydrogen and oxygen. Like I said, it was a thought.

OK, the petrol lawn mower turned out to be electric (bummer), but it’s fetched £25 for the project fund on Gumtree.

However, Freecycle did come up trumps with this little beauty. Had bees stood in a garage for 4 years. New fuel and it started second pull! This is British engineering at its best. Now for a Yankee designed charcoal gasser…

The nice thing about a charcoal gas producer is that just about anything will work. Pro’s and Con’s sure but all good.

The bottom inlet is about 2" on my producer. For me the larger diameter made it extremely consistant. I’m on my third tweak, not sure how this one will hold up. Can’t wait to try the fourth

1 Like

Here’s a like to the fourth tweak. Getting ready for Argos. Never can tell, with me, if I’m going forward or backwards… Can’t keep me out of the woods so it’s on the Forestry Forum. A bit of cross pollination.


1 Like

Hi Gary

First things first: really appreciate your youtube material - it has opened my eyes to charcoal gasifiers. I am quite ashamed that after being an avid armchair enthusiast for wood gasification since 2013 it has taken me nearly 2 years to “discover” charcoal gasifiers.

Just a note on something I am wondering about:

In a number of posts I have read the following phrases: “cracking” water (steam), water-gas equilibrium, water thermal disassociation, water splitting, water-gas shift reaction and many more.

From what I read the actual thermal splitting of water into Hydrogen and Oxygen is a rare bird with very few water molecules “splitting” at temperatures around 1000 deg C (only 3% at 2200 degC and 1 in 100 trillion at ambient temperature)

The water-gas shift reaction seems the likely source of Hydrogen generation when introducing water into a gasifier: C + H2O = CO + H2

Not that it really matters much as the water cares little for our theories, it just does its thing!

Reason for me pondering the above is that I am currently thinking about practical ways to up the gas energy content. Recirculating the engine exhaust is great, but just like air it introduces Nitrogen as a passenger, dilluting the gas energy content.

Getting my components together for my own build, so hopefully will soon be able to temper my musings with some practical experience.

Apologies if the above has been discussed here or elsewhere, there is a lot of reading on this forum and I am quite a bit behind!


Engine exhaust replaces some of the incoming fresh air and so the actual nitrogen content entering/going through the reactor is the same or less.

Also, @SteveUnruh wrote up (somewhere) a nice bit on the fact that nitrogen, CO2, and other inerts may not carry energy themselves, but do help the engine use the energy stored in the woodgas. I believe it’s because they absorb the heat energy and expand more (or more smoothly?) than the base CO/H2.

Hi Chris red, I can’t tell you what to do and there are many contradictory statements out there but I think your first ambition should be to build the best unit you can before you try to increase the power of the gas. There is no such thing as a free lunch is the most common answer to gas enrichment. By that I mean if you took a true energy accounting of your end product straight co produced in a standard charcoal gasifier with exhaust reinjection for control of temperature would win. You could inject steam but steam takes energy, drip water and you need the btu’s to make steam, make H and O and inject that; another huge energy consumer. All of those are possible but have energy costs and add complexity. The complexity might be warranted in some cases but start easy and grow into it. My two cents of course. Best regards, David Baillie


Dear Brian

Will hunt down SteveUnruh’s post for sure.

I agree absolutely that the inert gasses are not without virtue. What expands within an IC cylinder would be the combustion products (water or steam and CO2 plus extras) and then of course the Nitrogen. The “penalty” with Nitrogen is that it is a gas so during the compression stroke it is rather expensive to compress. You get most of this back during expansion (ignoring entropy generation) so the Nitrogen acts very much like a spring. The advantage of a steam circuit as an example is that compression occurs during the liquid phase (rather inexpensive) and only after compression do you get the phase transfer from liquid to gas. The fuel fed into an IC engine undergoes a “similar” process. So as I understand the process the Nitrogen takes up the place which could have been used for more fuel-oxygen components. Basically the metal parts are now bigger or rather, the same pieces of metal produce fewer horses.

Of course an excellent comment that I have read somewhere on this forum is that the above is all good: more metal producing less power, especially for a stationary application, burning a cleaner fuel simply means that the metal will last that much longer.

I guess my desire for Hydrogens is “fuelled” by a vision of a motorcycle-side-car application, what’s the use of all this if you can’t flaunt it!

Thanks again for this forum and the knowledge shared so freely!

Dear David

Sound advice and I am taking it. I’ll just get a slightly bigger older motorbike then!

1 Like

Mentioned post can be found here: The NEED and Effects of Expansion Gases within an IC Engine Cylinder

ChrisRed, those were exactly my thoughts when I searched out a motorcycle with a single carburetor. I found a Year 2000 Honda Shadow VLX600. The other option I considered was a Harley-Davidson 883 Sportster, which also has a single carb through year 2006, and then it went to fuel injection. I found some information on building a utility sidecar on the Adventure Rider Motorcycle Forum under “hacks” and “some assembly required” Hack build links in Some Assembly Required | Adventure Rider
My idea was to build a charcoal powered rig to drive 25 miles round-trip to the grocery store, so I mounted a Simple-Fire (using a 20# propane tank) on the sidecar frame, leaving space for the cyclone and filter, and a cage for groceries. About that time, we purchased an electric car, and I started installing more and more solar panels, and the sidecar project took a back seat to solar electric and clean sine wave charcoal powered generators that could charge my electric car. That is where it is at…lots of ideas and unfinished projects. Meanwhile, I’m making charcoal every chance I get. Hope this helps.

Wow, really impressed with the link you sent with your reply. Great builds!

Took me forever to complete a water-cooler for my TIG torch after I had all my cables and air-cooled torch stolen some time back. At least I can weld again. Standing on the driveway I have 90% complete Gelandewagen (off-road vehicle) rebuild and various other half-completed small projects lying around besides.

Think I’ll start with just the gasifier - mounting it on a bike as a future option … sticking to David’s advice!