With many projects on the go, finding time to work on the wood gas project is not easy. Over the past two weeks a photovoltaic system had to be set up. However, it gave me the chance to run the car air conditioning fan on the deep cycle battery and the result was much more promising than running the fan on a wall wart. The fan is a little over-powered so I will need to add a potentiometer to slow the fan down.
The fan I constructed from an electric leaf blower, and built a plywood case for, is now running on an old converted 386 PC power supply. The power supply has a +12V and -12V output and I am using this to run the fan on 24V. That fan is a little under-powered.
Interestingly, the car fan doesn't work well on the PC supply unit and the converted leaf blower doesn't work well on the deep cycle battery. Maybe someone reading this article knows the answer why.
The next thing to do is to build a transition for the car fan so that it can be connected to my no-weld gasifier. At long last I might be firing up the no-weld gasifier during the next week or two. I shall buy some charcoal and run the gasifier as an updraught gasifier just to check the seals and the power of the fans. Then the gasifier will be re-plumbed as a downdraught gasifier if the fans are up to the task. Charcoal is to be used as the planned gasifier will be a small one and charcoal is better than wood for that purpose. Of course, charcoal will have to be made on-site in future.
Constructing a centrifugal fan #3
The fan is almost complete. All that is needed now is a way of taming its huge power. Controls for moderating air input and output will have to be constructed.
Update 1 - After discussing my problem with other wood gasers I have changed to a lower power DC supply. With a variable resistor I will be able to find the optimal speed. The next task will be to make a transition for the fan casing so it can be connected to the wood gasifier.
Update 2 - Well, the DC worked but made the fan rotate in the opposite direction. So I converted from AC to DC and from blower to vacuum cleaner. After some thought, I turned the coils round, that reversed the magnetic field and now we have a blower again. Now onto making a transition.
Update 1 - After discussing my problem with other wood gasers I have changed to a lower power DC supply. With a variable resistor I will be able to find the optimal speed. The next task will be to make a transition for the fan casing so it can be connected to the wood gasifier.
Update 2 - Well, the DC worked but made the fan rotate in the opposite direction. So I converted from AC to DC and from blower to vacuum cleaner. After some thought, I turned the coils round, that reversed the magnetic field and now we have a blower again. Now onto making a transition.
Constructing a centrifugal fan #2
The centrifugal fan is almost complete. As the fan runs on 240V AC a lot of care is being taken to make sure the fan does not endanger anyone.
The following photo shows the fan and a plywood former for a length of thin steel that will act as outside of the fan casing.
The next photo shows the rear of the fan with the AC motor. As you can see there are plenty of bolts holding everything together.
All that remains is for the front face and sides of the casing to be completed.
The following photo shows the fan and a plywood former for a length of thin steel that will act as outside of the fan casing.
The next photo shows the rear of the fan with the AC motor. As you can see there are plenty of bolts holding everything together.
All that remains is for the front face and sides of the casing to be completed.
Handbook of Biomass Downdraft Gasifier Engine Systems
I am adding the Handbook of Biomass Downdraft Gasifier Engine Systems to my list of gasification reading materials.This document is available for sale on some websites but it's actually in the public domain.
The handbook covers all aspects of gasifier designing, building and use of woodgas as an engine fuel source.
PDF document - Handbook of Biomass Downdraft Gasifier Engine Systems
Generator powered by updraught gasifier
Here is a simple but very effective gasifier running a generator. The gasifier would appear to use a forced-draught as air input as there is a blower rather than a sucker.
The wood gas is taken from directly above the pyrolysis layer so it would make this an updraught gasifier rather than a downdraught gasifier, which takes gas from below the pyrolysis layer.
Normally, an updraught gasifier is not to be recommended but the use of charcoal rather than wood makes for a cleaner gas. Looking at the flame in the combustion chamber, there is certainly a blue flame there.
Later in the video, we see the wood gas being successfully ignited.
It is good to see such a simple but effective gasifier in operation.
The wood gas is taken from directly above the pyrolysis layer so it would make this an updraught gasifier rather than a downdraught gasifier, which takes gas from below the pyrolysis layer.
Normally, an updraught gasifier is not to be recommended but the use of charcoal rather than wood makes for a cleaner gas. Looking at the flame in the combustion chamber, there is certainly a blue flame there.
Later in the video, we see the wood gas being successfully ignited.
It is good to see such a simple but effective gasifier in operation.
Constructing a centrifugal fan #1
A centrifugal fan is essential for running a downdraught gasifier. However, searching for a fan can almost be impossible or too expensive if you are lucky enough to find one. After purchasing How to Design and Build Centrifugal Fans
enough information is at hand to build a fan from scrap materials.
In the picture below we can see one side of a fan cut out of a piece of plywood. The correct dimensions for the fan required are taken from the book.
In the next picture we can see two plywood framing pieces cut out for both sides of the fan. Below the framing pieces a sheet of light gauge steel has been cut from a vegetable oil can that will act as a shield to protect the plywood.
enough information is at hand to build a fan from scrap materials.In the picture below we can see one side of a fan cut out of a piece of plywood. The correct dimensions for the fan required are taken from the book.
In the next picture we can see two plywood framing pieces cut out for both sides of the fan. Below the framing pieces a sheet of light gauge steel has been cut from a vegetable oil can that will act as a shield to protect the plywood.
Centrifugal fans
Probably the hardest task, when making a gasifier, is the blowing/suction fan. Thanks to the famous Gingery engineering family there is help at hand. How to Design & Build Centrifugal Fans for the Home Shop is packed with everything you need to know about constructing the right fan for the task at hand.There are five chapters; fundamentals, design, construction, testing & measurement and applications.
After experimenting with various fans, that were woefully underpowered, I am sure this new book acquisition will help me to build the right fan. The applications chapter even has details on building a cyclone separator, ideal for cleaning ash out of your wood gas.
The book can be bought from Amazon - How to Design and Build Centrifugal Fans
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