Cracking steam

Has anyone here tried to feed a small and steady amount of steam into the combustion zone of a charcoal gasifier? I’m curious if this was done in a manner which would yield two things; first, to keep the temperatures in check, and second, to introduce Hydrogen – and some extra BTU’s – to the final gas flow…

This has probably been addressed before, but I haven’t been able to find the answer here, or on the Yahoo sites. Any insight on this would be greatly appreciated. Thanks!


Look in my Topic

my latest design runs with water, basicely i only gasify if water is present…

Koen, I love what you’ve built… Great work. Is there any point in this long chain of posts that addresses steam specifically? Maybe towards the end?

I’ll read it all today… Just curious about the steam specifics, and where to find techniques.

will look for ya, have adressed this issue more then once, the effect of hydrogen.
also have some documents posted in my other topic, the importance of gas contents

Troy: Welcome… Back… (I see you posted over a year ago)

Koen, and a few others, have had good success with water/steam injection into a charcoal gasifier for H2 production and heat tempering. Another option is to partially route some of the engine exhaust back into the inlet. This provides more than enough H2O vapor, as well as recycles the CO2 from the engine, which makes even more CO gas, further tempering the reaction.

Hi Brian,

Yeah… It’s good to be back. The Yahoo forums aren’t quite what they used to be, and this place is on fire!! Literally :slight_smile:

Yes, I am very familiar with routing a portion of the exhaust into the combustion zone (Gilmore style)… I was specifically interested in steam cracking and the effects of Hydrogen, simply because I am trying to arrive at a faster flame front in my overall gas flow. Plus, I have long term plans of re-routing the exhaust gasses into an algae pond. Willie Smits does this in Indonesia, and then pyrolyzes the dried algae for biochar usage, or just for composting… Pretty neat stuff. But, I don’t even have the land yet to set this up, so in the meantime, the exhaust gasses may suffice.

For anyone interested in my build, here are the details:

  • Going to build a DrizZleR (kind of an open-top hybrid biomass.charcoal gasifier)
  • V-trough open-top hopper with feed auger
  • Pyrotouch fuel level mechanism
  • Refractory hearth with little or no restriction (not a monolithic casting… 4 fit-together pieces)
  • No grate… Closed basket type reduction (GEK v.5.0 style)
  • Cyclone w/ fins
  • Super-sized liquid-cooled condenser… Way overkill (on purpose) to get the exit gas temps to drop as rapidly as possible… Hopefully reach ambient.
  • Media filter aluminum pot scrubbers (gas will be much cooler by now, so no worries about melting aluminum)
  • Arduino-powered servo motor on the carb
  • O2 sensor on the exhaust
  • Running an Onan 4kW - 1800 RPM

Since the DrizZleR doesn’t require pre-heated air at the nozzles, I have all this heat that I need to do something with. I don’t want to blow it off to atmosphere with a radiator. I’d love to figure out how to thermally use as much of it as possible… Hence, my inquiry into steam cracking.

With wood gas, i could probably expect 2.3 - 2.5 kW out of this small unit with the woodgas derating. But if I can deliver ambient temperature gas to the engine, it will be more dense and more combusible with the higher H… 1800 RPM should be perfect. I don’t want to mess with advancing the timing if i don’t have to…

My build starts next week… Will keep everyone posted on the progress…



This isn’t my generator, but it’s the same model, and hopefully what it will look like once I get it cleaned up and painted. These are available on Craigslist all over the Country… and for cheap!! I bought mine for $200.

Built to last 20+ years and 1800 RPM. In my opinion, it is an unnoticed gem for small-scale units…

I’d keep an eye on those aluminum pot scrubbers. I remember seeing that someone had their aluminum intake manifold on a car turn to swiss cheese soon after they started running woodgas. I’ve also seen people using aluminum cooling rails that still looked brand new years later. I guess it just comes down the grade of aluminum, but I wouldn’t expect high grade stuff in pot scrubbers.

I have an Onan 2.5kw (Thought it was 1800rpm but actually 3600rpm). I got mine at the junk yard for 40$ and just needed the points sanded/cleaned. During my cleanup/repair process, I lost a little spring that controls the gas pump in time with the govenor. It runs great… for 30 seconds and then sputters out after using up the residual gasoline in the carb bulb. I still need more piping and a good supply of quality charcoal to get it running on a Simple-Calle I built out of an 8 gallon propane tank.

Hi Brian… The aluminum pot scrubbers would be used in the media filter, after the condenser… My condenser will be overkill, so I’ll make sure the temps are close to ambient. Will upload some drawings shortly…

Hi Troy, Yes, things are a little slow on the Yahoo site. I’ve been busy helping the kids set up house, working and getting firewood put away so it can dry over summer. Need to stir the pot over there and soon.
Anyhow to the point of your question on steam. Go ahead and add it to a charcoal gasifier until you get water condensing in the filter. This is an indication that you are not cracking all the water and it is just being converted to steam that drops out later. I have pretty much abandoned the use of a water drip because there is usually enough humidity in the air which in turn supplies the water. Recycling the engine exhaust gas also adds more water. I’ve run the charcoal generator on very damp days where enough water condensed in the gas line to the engine that it had to be poured out to keep it from obstructing the flow of charcoal gas.
If you are using wood for the fuel like you outlined for the DrizLer, then forget adding more water to your oxidation zone. The wood will have an over abundance of water. Let me make a suggestion to use a heavy wool blanket material as a dust filter. Works well for me and is easy to clean. May be easier to use than aluminum pot scrubbers and will not be affected by acids or alcohols in the wood gas.
By all means keep us informed of what you discover.
Gary in PA

If you only going to use charcoal as fuel, then you can avoid heat loss by using updraft and having an sufficient high layer above the glow.

The shown picture is one of my idea’s to take advantage from the heat retention with the charcoal.

Last time that i drove with my current set, the temperature was never more then ambient, tha amount of water used was equal as the amount of charcoal ( Kg to Kg ) the filters where bone dry

I am now using the stainless coil (3/4") on the outside of the small diameter reactor pipe (5")

The drawing is showing an coil on the inside of a larger pipe.
Maybe this can lead you to even better idea’s ?


Using steam in certain amounts will lead to corrosive accids
First they react with any iron, and second they love to eat aluminium…
so make sure you have an steel wool filter before the aluminium pot scrubber… :wink:

Gary and Koen,

After some serious thinking, I’ve decided to abandon the idea of building DrizZleR – at least for now – and move onto a charcoal gasifier. The only reason for all the condensers was to condense the tar out of the gas stream. The DrizZleR is more of a hybrid than a true woodgas imbert, but it still needs to crack hydrocarbons, and tar will always find a way to mess things up, even on the best of system designs.

Additionally, I’m moving to the tropics in July (Puerto Vallarta), and biochar has no better poster child as it does in tropical soil. Sure, there are pros and cons with biomass and charcoal, but I really like the idea of not having to worry about all the “downstream” sub-system components with wood gas. I know that colder gas flow is denser, and I’ll still try to reach ambient temperatures, but once I let the idea go that I had to go the direction of woodgas, everything got easy…

I’ll still be using the Onan 4kW 1800RPM genset… My rig will look something in the middle of the Gilmore gasifier, and the Koen green waster gasifier… probably go with 8-12 inch pipe/tubing for the reactor/hopper, and 1 inch pipe to match engine displacement at – slightly more than – idle speed.

Thanks guys for all the work you’ve done in blazing these trails… I intend on pushing the envelope as well.

No more ideas of aluminum either :slight_smile:



Hi Gary,

I was actually referring to all my Yahoo accounts (wood gas, charcoal, bio energy list, etc.) I really prefer this site too… much more user-friendly.

See my new post on going 100% charcoal now… pretty excited by it, actually. I even own two 55-gallon charcoal retorts, and have made biochar many times. I guess I bought into the whole “charcoal has less inherent energy” mindset, which is partially true… But if you consider the other applications of using that latent heat (and pyrolosis gasses) for useful purposes, then it’s an even wash, I would say.

The new “context” for me is that I need both biochar AND gasifier fuel… Everything that falls through the sieve is for the compost heap. Everything else is for generator. Later, i plan on decoupling the ICE and generator so that if I don’t want electricity, I can use the engine to drive a V-belt on other mechanical systems, like a hammermill, or pelletizer, etc.


Hi guys,

In a charcoal gasifier, does it matter if air is sucked in through multiple nozzles vs. a single nozzle?

For my 4kW Onan, I am going with 1-inch pipes, so the area of a 1-inch diameter circle is .79in². I’m wondering if there would be any impact on performance if that air was divided into multiple smaller ceramic nozzles. There is a guy in my town that makes glass-blowing nozzles, and these would fit my design:

Any insight into the combustion/reduction zone performance in this scenario would be greatly appreciated. Thanks!


Multiple nozzles means “multiple hot zones”
1" pipe seems large for 4 Kw power

The data below is from “old knowledge” but they do work perfect for me
I try to convert as much as Co2 as possible

Multiple nozzles , i am trying to build as in the picture with the multi nozzles, might be adaptable for you…

Glas can melt at low temperatures, make sure your nozzle don’t…
I use ceramic body’s from electric fuses, have them in different sizes, they withstand high temperatures ( 2000°C) where as everything else melts already :wink:


I like your idea of the vacuum-reacting nozzles… Is this your own idea?

What size is the piping for your unit? It seems to me that you might consider sizing the piping for the maximum foreseeable gas flow in m2/second, just so the pressure drop in a smaller pipe would never be the weakest link. Also, with slightly over-sized piping, the gas will slow down a bit, which means better cooling, better particulate drop-out, and denser gas at the final exit point. So even on your rig, 1-inch piping might be perfect.

This old knowledge is priceless. I realize that my tuyere should be less than half the diameter as what I thought I needed to get the densest gas (according to the gas composition vs. air blast velocity table)

Really nice work here, Koen…


Yes the nozzles are my idea
The nozzle size…
Smaller nozzles-higher velocity’s-higher temperature-higher conversion-less co2 in the gas-less temperature in the exiting gas…

a strange circle but very noticable

I controle the reaction temperature with water…
The hotter the coil gets, the more water gets to high temp steam, the less dense the air gets, the less oxygen is available for the reaction ( air gets more spacious ) automaticly balancing itselves…

Depending my setup, i can make my gas so rich that i will need more air for the engine … ( 1" for the gas and 1" for the air intake and still to little air :wink: )

My sizing :
10 mm nozzle using now, can use 8 mm and 6 mm as well
Testing testing testing :wink:

for the multiple nozzle setup i want to use 7 nozzles of 4 mm
the total surface equals the 1 nozzle of 10 mm
1 in the center, 6 surrounding the middle one , in 2 stages of three
each nozzle having its own weight adjustment…