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Gasifier Blog 2

Our previous gasifier had all the problems that we now know are associated with a FEMA style gasifier. It worked to a degree but seized up the engine after the first one hour run. This blog will document our next gasifier which we hope will address the problems with the first gasifier. 

Files from the Midwest Renewable Energy Fair presentation.

posted Jun 21, 2014, 5:18 PM by George Adams   [ updated Jun 21, 2014, 5:28 PM ]

The page of links to wood gas resources is attached below along with a PDF version of the presentation.

Cheap Valve 2

posted Nov 11, 2013, 9:35 AM by George Adams   [ updated Nov 11, 2013, 9:51 AM ]

Martin Payne on the charcoalgasifiers yahoo group has made a couple of valves for his Motofier. A small motorcycle run by a charcoal gasifier.


Martin has modified the valve I described in a previous post with some improvements. The disk is left flat but is made in a slight ellipse which helps to make a better seal in the pipe. He also used JB Weld to lock the disk to the cotter pin. On the plastic pipe he also added a small washer where the cotter pin is bent to lock it in place. 
This is the end view of two valves.
Outside of the plastic valve. Notice the washer where the cotter pin is bent.

Below is a PDF file from Martin which shows a way to make an ellipse for the disk. I have added another PDF of some ellipses made in Google Sketch Up. These ellipses are either 10% or 20% wider than the circle I started with. 
I have also added the Sketchup file. I know just about nothing about Sketchup and anyone else out there that knows Sketchup can do a better job of this.


Grain Cleaner for sorting wood chips

posted Aug 25, 2013, 6:53 PM by George Adams

It has been a busy summer and I'm getting behind on posting updates on the gasifier. For the most part the gasifier has been ignored but a few things have been done.
Back in May I bought a grain cleaner along with Pete Stanaitis from the Baldwin area. I have been fixing it up and experimenting with sorting wood chips. Pete made the video below of sorting 23 five gallon buckets of chips. 
It doesn't do as good a job as sorting by hand with screens and fingers but it is much faster. I think the trick for making chips that work in a small gasifier is to chip up only material that is free of branches and twigs. A minimum diameter of 2 or 3 inches would be best.
Our experiments and repairs included replacing the outside screens with 1/2" by 1/2" screen on the upper outer drum and 1" by 1" on the lower half. The inner drum was replaced with 1" by 1- 1/2" mesh. The motor, wire and switch were all replaced. A missing wheel was replaced. I also added a chain and S-hook to the bottom of the lower end support so a hand trailer mover could be used to wheel the cleaner back into the garage after use.
On the to do list is to find an auger to feed the chips into the machine, build separators for the under side to keep the four sizes of chips separated.  Pete is working on fixing up a snowmobile trailer so he can easily get the cleaner back to Baldwin.

I still need to write up the following;
My methods for drying chips
The pneumatic ejector for starting the gasifier. Two versions
New woodgas mixer/carburetor connections. Two versions
The improved connection for the O2 sensor.

Future projects include adding an alternator to the small engine to create a load and charge 12 volt batteries.
Getting the Case 446 lawn tractor running on woodgas.
Fixing up the Arduino code so the servo can properly mix the air and woodgas and fix the problems with the remote control.

A cheap valve

posted Apr 4, 2013, 9:19 PM by George Adams   [ updated Sep 28, 2013, 10:36 AM ]

Since both the air and wood gas come into the engine through the same opening there needs to be some way to get a proper mix. This is done with a valve, an old engine carburator or a ball valve. The first engine I used a carburetor as can be seen in the pictures below. I didn't have another one and didn't want to pay for a new ball valve. I figured I could just make something cheaply. It didn't need to be as tight as a carburetor butterfly valve. It did need to stay put once moved. It needed to fit 1" steel or PVC pipe. I wanted it possible to disassemble and not be welded in place. No welding would be best since I don't have a welder. Any purchased parts needed to cost much less than just buying a valve. The pictures below show what I came up with.

Gasifier Valves

A 1" steel or PVC pipe is drilled through the center using a 1/8" drill bit and a doweling jig designed for wood. Getting the hole right in the center helps a lot in making a good valve.
A disc cut out of aluminum flashing using a tin snips. The size is just a bit larger than a quarter.
I purchased 2" by 1/8" cotter pins for 23 cents each. These are used to hold the disc.
The disc is placed between the two legs of the cotter pin and centered. A line is drawn on either side of the cotter pin on the disc. The disc is bent on each of the line at a 45 degree angle in opposite directions. This forms a slot for the cotter pin and keeps the disc from falling out.
With the disc held in place with a needle nosed pliers then slide the cotter pin through the 1/8" hole in the pipe.
Check the fit and movement of the disc.
The eye of the cotter pins I was using were just a bit smalled than a 10 32 machine screw. I tapped the eye and screwed in a 10-32 screw adding nuts on both sides.
A spring was added to put some tension of the cotter pin. The ones I used were leftovers from a facet repair kit for the kitchen sink.
Lastly put a bit of pressure on the head of the cotter pin and spread the ends of the cotter pin apart.
A PVC version of this value was added between the air cleaner and the gray plastic box on the generator. 
The two steel ones are for a future Simple-Fire charcoal gasifier.

Gasifier will run an engine

posted Mar 6, 2013, 2:31 PM by George Adams   [ updated Mar 25, 2013, 5:27 PM ]

Gasifier2 skills day

The first successful running of the gasifier happened on March 1 and it was demonstrated on March 2 at the Traditional and Green Skills Day in Prairie Farm WI. The first run lasted about a half hour with some of that running unattended. The gasifier only ran once at the skills day for a short period of time. The flare did work well for most of the time but the flame was clear enough that it was hard to see. The O2 sensor was not working correctly so its control of the servo was disconnected and moved manually. A fair amount of work still needs to be done to make things look nicer and to make it run reliably.

More pictures are on their way.

Gasifier on the trailer

posted Jan 29, 2013, 2:53 PM by George Adams

Here is the more or less completed gasifier bolted onto the trailer. The cyclone is also bolted on at its base. The red cooler/filter is just supported at this point by the inlet pipe but will be strapped to the side bar. This week the trailer got its turn signals and brake lights and wiring fixed. We still need to get a fan/blower to suck air through the gasifier and get one of two small engines running that will be powered by the wood gas.

These are the only pictures of the gasifier with its lid in place. It is spring loaded. It was made from horse shoe iron and heated by my daughter Morgan in her horse farrier forge and bent by her.

Making charcoal for the gasifier

posted Jan 28, 2013, 3:24 PM by George Adams   [ updated Jan 28, 2013, 8:23 PM ]

The gasifier will run on dried wood chips but for testing purposes I wanted a fuel that wouldn't make tar and foul up the engine before we got the set up all figure out. Charcoal has the stuff that makes char cooked out of it. Making charcoal can be a pretty wasteful process where a barrel of wood chunks are heated up by an external source. The chunks get hot in an oxygen poor environment and give off gas. The lack of oxygen keeps the wood from being completely burned to ash and leaves charcoal behind. The charcoal burn hot and clean which works well for cooking, smelting bronze and in gasifiers. I've been making charcoal this winter in my Finish style masonry stove. The fire that heats my home warms up the wood chunks. The gas given off get blown into the flames of the fire and helps to heat the house. I get clean charcoal and heat without waste. 

The gas given off is flammable and poisonous. It can contain carbon monoxide. Pressure can develop in the can if the vent holes get plugged or if they are too small. You don't want it to explode in your fireplace or poison your family. After removing the can from the fire make sure it is cooled well below 400 degrees F all the way to the core before the can is opened. If the charcoal is exposed to oxygen before it has cooled down it will start to burn or smolder. Dump the finished charcoal in a metal bucket until your are 100% sure it is cool. Once cooled down I have been storing the charcoal in a large plastic bag inside a 30 gallon plastic barrel.

I have made charcoal in very small batches in a one quart metal paint can. It has a couple of small holes drilled in the lid. I have used it many times but the last time the holes must have gotten plugged and the top popped off. The lid is a nice safety feature. With the added oxygen the top layer of the wood chunks burned to ash but some charcoal remained in the bottom of the can. A one gallon metal paint can would also work if you could find one.

Gasifier cooler and filter

posted Jan 28, 2013, 2:24 PM by George Adams   [ updated Jan 28, 2013, 2:58 PM ]

Below is a slideshow of the cooler. This is first attempt at making a cooler from junk and I have no idea if it is going to do enough cooling of the gas. It will eventually be painted black to help radiate heat. If need be we will add fins or another cooler. It is made from an old cement sprayer which is turned upside down. The original top will serve as a way to get condensed liquid out of the bottom. The hole where the pump handle was has been replaced with a bolt and washer to seal it up. The 5" rubber washer was cracked and a replacement was made from silicone. The 1/2" hole where the sprayer hose was attached was removed and replaced with a bolt. The inlet pipe for the cooler isn't as fancy at the one for the cyclone. It comes in level instead of pointing down 15 degrees.

The parts of this cooler were cut out with a CNC plasma machine. If anyone else wants the .DXF files I can provide them.

The cyclone

posted Jan 27, 2013, 6:34 PM by George Adams   [ updated Mar 1, 2015, 8:21 PM ]

The purpose of the cyclone is to remove as much ash and other particles from the wood gas as possible. It needs to be sized to match the air flow of the engine it will be used with. A big engine needs a big cyclone and a small engine like the 7 to 10 HP engine we plan to use need a small cyclone. Ours is 4" in diameter and 16" tall. This design is based on information from several sources. 

Basic dimensions

 This was the starting point for both the sizing and proportions for the cyclone.It is from information on pages 183-188 from the government document on gasifiers from 1981 available at The title is State of the Art Report for Small Scale Gas Producer - Engine Systems. 

Modification for dust collection

Bill Pentz has built and tested cyclones for wood dust collection and made many changes to make his cyclone work better at getting fine particles out of the air stream. His web pages are fascinating
Now at
His modifications made for smaller units that use less power to operate and do a better job of removing particles than any of the major manufactures. Some of his changes have been added to many other commercial dust collectors. I have added some to our design hoping to make a better cyclone.
Thanks to the woodgas group on yahoo for guiding me away from the too large cyclone I was going to make and referring me to the appropriate size for our engines.
The parts for this cyclone were cut out using the CNC plasma cutter at the Prairie Farm High School Tech Ed room. Thanks to the school for letting us use the machine and opening the shop to the community through their Community Education program.
Thanks to Wayne Ayers for doing the very nice TIG welding job on this cyclone and the cooler/filter unit.

Assembled and Drawing

Here is the assembled cyclone and the drawing we used for dimensions.

The gasifier

posted Jan 27, 2013, 6:02 PM by George Adams

A few of these posts are being done months after the work was done. The gasifier is a slightly modified design based off a design called the Victoria. 

After spending several months read posts to the woodgas group on yahoo this design looked like it would be fairly easy to build and should handle the chipped wood we have available.
This is our gasifier before the lid was added and before it was painted. Our is 8" in diameter where the Victoria was made from 6" pipe. At this point the CNC machine wasn't working so the discs and donut shapes were all cut out od sheet steel with a 4" grinder. The end product looks OK but isn't all that precise. Thanks to Greg Wright for doing the welding and to Morgan Tartakoff for bending the metal for the lid handle.(picture yet to be taken).

The air jets

This looking down into the burn tube of the gasifier. There are three pipes about 5" above the restriction opening and a fourth a bit lower that points to the center of the restriction. The opening in the pipes is 1/8" for now.

How it works.
The top portion of the gasifier is filled with wood chips or chunks of wood. For testing purposes we have made up a bunch of charcoal we will use in place of the wood chunks so we won't need to worry about making tar as that has been burned out in the making of the charcoal.
The chips at the bottom of the pile are ignited and air is pulled using a vacuum down through the air jets. This created a very hot fire in a small space. Smoke is created an sucked out of the lower section. The smoke contains carbon monoxide, nitric oxide, hydrogen, ash, water vapor and other gases. This gas is run through a cyclone to remove ash and then a cooler to condense out moisture and a final filter to get anything missed earlier. The gas is then mixed with air and fed into the carburator of an engine. This wood gas/air mixture can replace the gasoline/air mixture and run an engine at 50% to 75% of the power it would have if run on gasoline.

More pictures of the completed gasifier will be in future posts.

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