Woodgas generator in Australia

Gidday to everyone at Drive On Wood.

I am an Australian and just about to start building a gasifier based on the GEK designs with a TOTTI. It will used to run a 5KW Quicksilver(Generac) generator set. This generator was made as a marine generator, the engine is a Nissan 1.235 Litre single overhead cam running at 1500 RPM. I believe the same engine was used on 7.5 and 10 KW versions of the generator. So I have plenty of power up my sleeve to allow for for wood gas and still get 5KW from the generator. The mechanical governor on the engine is setup to only open the carburetor about 1/3 of it’s full potential.

As I will never be using more than around 10HP to get to the maximum output of 5KW. Mostly it will be running at around 1.5 to 2.5 KW I am planning to reduce the hearth down to around 50mm (2") as the 75mm GEK is designed for up to 10KW. From my research I believe the larger size will be asking for problems. Fuel will be wood chips and I am planning to put a 2 RPM spiral agitator from the top right down through the all the zones to the grate. Similar to the GEK TOTTI I am also planing to run the engine exhaust into the pyrolysis zone through a chamber made of 2 tubes around 150mm and 200mm diameter. This is to recover the waste heat to help increase the heat in the gasifier to keep temperatures up due to the low power output required.

Has anybody got any thoughts on my ideas(hopefully I won’t get shot down in flames :)), this is my first attempt at woodgas, but I have been researching this and thinking about it for about a year now.

Thanks in advance


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Gary, I started you a new thread. Welcome to the site! Sounds like a good project.

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Welcome GaryH.
Your engine to electrical output on woodgas assumptions sound to be spot on.

I do not personally make wood chips. Ran wood chippers and never wanted to invest in one for myself. Too much maintenance. Too fuel hungry to power and then to have to double and even triple screen/sort to get usable gasifier chips would drive me nuts. For a small system I’ve found that I could irregular chunk up with 1/3rd the mechanical and people power imput and have a much higher % final tree/limb/branch wood utilization. That’s just me.
Even so I have operated with supplied sized screened chips in modified Imbert gasifiers. Non-screened out fines will gasses flow cog up the whole system at each step right on down through the char bed just above the grate. Those who have tried mechanical stirring down through the 1200-1400C oxidization zone at the air nozzles have always had heat equipment failures in the moving metals. Before that happens the mechanical forced movement will break down the fragile char chunks too fine causing worse gasses flow packing problems.
With properly sized screened chips for the hearth size you will not need a down in the hearth stirrer at all.

I’ve only ever operated GEK I and II’s on chunks. These had 2 7/8" and 3" restirction openings. I found that I really wanted a 4 inch 100mm restiction opening for the least MATERIAL flow through problems.
Above the nozzles in my strong opinion now most of the fuel chunk/chip bridging/capping/glueing/sticking problems are due to lack of moisture control and too little allowed up there HEATS to keep everthing hot and flowing.
The GEK III and IV with the Hot TOTTI was to introduce more heat to solve these problems. The GEK IV as I read it is to allow screened chip fueling with automation. I have never personally operated either of these so I’d leave it up to others to comment on the effectiveness of these later systems. Video evidence says yes. I even “think” I’ve read they have come to prefer the 100mm restiction. And they do Video operating these at low power levels.

Best result in any small gasifier is to externally as New Zealander Doug Williams showed years ago was to use engine heats to pre-dry down the incoming fuel wood batches.
Sure use the high quality engine exhaust heat as Mr Wayne does into the primary gasifier air or as you propose and GEK/TOTTI/Jim Mason into the internal fuel zone. Same results. Engine exhaust heat is a quality woodgas fuel derived heat source to put back into the core process.
But don’t go blowing off and wasting the also valuable engine coolant heat. Use that forced, warmed DRY air flow to do your fuel wood pre-drying. A fair to factor back in woodgas drived normally wasted blown away, utilizable energy also.

Steve Unruh

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Hi Chris and Steve,

I have available all the wood chips I need for free, all I have to do is collect them from not far away, saves the guy with the tree lopping business paying dumping fees. I can carry 5 cubic metres in my trailer, so will just cost me a few dollars in fuel and some sweat to load it. I will look at wood gas on the road after this project, I want to make some investigations first about emissions and the law here.

Thanks for the input Steve especially about stirring, I see Stainless steel has a melting temperature around 1500 degrees C.

The Generator I have is a Marine setup with water cooling and heat exchanger in the exhaust manifold. I am planning to leave it on to see how it operates at first, if the exhaust temp is reduced too much I will have to make my own manifold to replace it. The engine is from an early model Nissan Micra that where not sold in Australia so getting a used manifold is not possible. My plan is to use the coolant heat and run a copper coil as for drying heat.

I will look for the videos etc regarding the 100 mm restriction and low power requirements.

Hello GaryH.
Well good deal then. Depening on the fellows actual chipper type and how much leaf and needle is in the chipped stock you should be able to get at least 20% to as high as 40% screened sorted out as usable gasifier fuel.
Internet search up Greg Manning a Canadian fellow who has made up a tilted drum sorter for doing this.
For chipped fuel information in small gasifiers Dutch John has much to say on his site under his “MicroGasifiers” download:
Look up the member file of Brian Ham here. Read back there on his “Most Recent Posts”. He is building for running chipped sorted wood fuel also.

Steve Unruh

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Did I hear someone say chips? This is what we have been running for fuel. We do screen for dust, but that’s pretty much it.

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Steve U. I am attempting to make a gasifier that will run on chipped/shredded brush and branches but I have no idea if/how well it will work out. :stuck_out_tongue:

Post in question is HERE.

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Okay I have started building the gasifier, I have some Stainless steel and have made the hour glass. I have decided to go with a 75 MM restriction and see how that works. It only took a few hours to cut out and weld up so will be no big problem to play with different sizes later.

Has anybody tried building a GEK buy cutting all the steel with a jigsaw or grinder? My thoughts are to do this without cutting the tabs that locate the parts together to save on time with cutting. I am getting prices to have them cut with a CNC Plasma but I expecting that to not be cheap, hopefully i will get quotes back for it tomorrow.

Also has anybody got the CAD files for the TOTTI? The GEK people are redoing there website and a lot of stuff from there is not available at present.

Thanks for the link Steve to Woodgas.nl, I found that site a long time ago and been influenced a lot by his site as to what works and doesn’t work. It was his site that had me thinking I should go to a 50 MM restriction, but his designs don’t use the exhaust heat in the reactor.

The woodchips I have access to has a variety of types but I will trying to get the Eucalyptus wood chips where I can, it is a dense native hardwood, I believe it has become a weed in many parts of the world.

Gary H: Too bad a gasifier breaks down the volitile oils in the wood it burns. Otherwise, nobody around you would ever have any sinus or chest congestion! :slight_smile: For those that don’t know, Eucalyptus oil is the active ingredient in “Vic’s Vapo-rub” and many other cold/flu remedies.

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As far as I know the Eucalyptus oil is extracted by steaming the green leaves. It is in the wood too but if you get a few leaves and scrunch them up in your hand the smell is quite strong. I have spent a lot of time in Thailand and Eucalyptus is a weed there, the smell of burning Eucalyptus took my mind straight back to the land of OZ.

Good Morning GaryH.
Well it is very good now that you have declared, your engine, loaded use of it and fuel wood source. All should be doable.
Here is an incomplete list of people I know of gasifing with screened wood chips of some type to get you started.
Here’s some of the GEK type system users I know of here:
Jim Mason the GEK developer is now a member here on the DOW.
Richard “Pepe” has modified into a GEK configeration.
Terry Grzyb has built and operated GEK based units on both an 18 hp B&S riding lawn mower and now a Ford Ranger pickup 2/3L four cylinder:
Open up his “Recent Posts” for his started up topcs on these projects.

Non-Gek system wood chip fuel users:
Arvid Olsen “Another Victoria based build”

Detailed pictures from the inside out on this current system building up. He now builds and sells chipped fueled systems also.
Tomas McDaniels - Chinese gasifier stove modifed for engine useage

Matt Ryder details much on his commercially available Vulcan systems here:
“Vulcan Power Station”

“This is Vulcan”
same address prefix and body - suffix cahnge to 230
And now his new to be released kit version here - suffix change to 923

Larry Dobson has only ever used screened wood chips on all of his gasifier works as far as I know. His members page has his web site info in his Bio:
He has an evolving now opened up design he posts up diagrams and his reasoning on.

Any one of these fellow can be directly contacted through the Contact function on thier members pages. See a members name in blue anywhere here and you can click on it and jump immediately to thier members page.

So . . . many ways to make wood chips work for IC engine fueling to make a shaft turn for power for a purpose.

Steve Unruh

Apologies to anyone I’ve left out. The Old gray brain just ain’t what it used to be.
Ha! HA! Gives you good reason to chime in on this. S.U.

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Finally I have completed the drawings for my version of the TOTTI. Just waiting now for the parts to all be cut so I can start welding it all together. Hopefully in a week or 2 I will have a working gasifier. Is it appropriate for me to post my cad drawing on here? What I have done is used all the photo’s and information I can find to draw up what should be very close to the GEK version. I have tried signing up on their site but have not got a response back in over a week to say I am a member therefore I can not post anything there to ask if they had drawings available. Is GEK still functioning, many links on there site are dead also? The link on Drive on Wood is for GEK plans is also dead.

Once I get all the parts Plasma cut I will start posting photos of my build progress. In less than 4 weeks I will be living completely off grid, would be nice to have the Gasifier operational by then.

Has anybody here found a way to automatically control carby mixture? I found ways to make a meter to connect to a oxygen sensor, but I don’t have the eletronics know how to take it to the next step.

Hello Gary.
I am in central Wisconsin, USA and I have no trouble getting to the GEK gasifier website.
I just downloaded the V4_2 Build parts drawings in dxf format and they do translate pretty well to my Turbocad TCW format.
Here’s the link that worked for me:

The website is very much alive as far as I can tell.
This works for me.

I do know that our hosting service has had trouble with Russian bad guys hijacking Australian addresses in the past. The hosting service then shuts dpwn (almost) all communication from your country while they patch up their code.

Pete Stanaitis

Hi Pete,

The site mostly works but links to pages such as http://www.gekgasifier.com/products/authorized-representatives result in
“APL Authorized Representatives
We are in the process of migrating content to our new website. This page is a placeholder and will fill with more complete content soon.”

There are many more that come up like this including links to the DXF files for the Hot TOTTI.

All the files are there for the basic 4.2 GEK, fortunately, obviously a lot of work gone into getting it to that stage. Certainly a big help for me to build something that has been refined to the stage it is at.


Gary, thanks for the heads up on broken links. They seem to be shuffling things around.

You are more than welcome to post your CAD files here.

Hi Chris tried to upload but got this message.

“Only files with the following extensions are allowed: png, gif, jpg, jpeg.”

Hi Gary,

Try uploading it in the Files section: http://driveonwood.com/forum/files

DXF files are available here http://driveonwood.com/content/gek-gasifier-totti

This is the file I am getting my parts cut from at the moment, as they are untested at this stage there may be some modification required. If you plan to use them please contact me to check.

I have been promised that all the parts for my gasifier have been cut and will rolled today.

Getting all the parts plasma cut is only costing about a hundred dollars, certainly well worth it. I have seen some on you tube trying to cut out GEK parts with a nibbler or jigsaw. It would end up costing nearly the $100 in blades let alone the time that would be needed. It only takes the plasma cutter less than 2 hours to cut all the parts.

So there will be a few days of welding ahead for me :slight_smile:

>carby mixture
I’ve been kicking the idea around that the choke and it’s coil type control from an old Toyota should be able to control air/fuel ratio. Just a thought.