Wood-Gas Generator Motors

Here's a little basic info about wood gasification for generating electricity. October 1, 2010

Question
I have read past postings on using wood-fired gasification units for generating electricity. The one drawback was that it might not be economically feasible. I am in Ontario and with the pending combining of G.S.T. with the provincial tax, I believe I will be paying more for fuel. Gasoline is not exempt from road tax if used off road, however diesel is. Presently gasoline is approximately $4.00 per US gallon.

A 3.1 litre engine and transmission was given to me, and I have one generator, single phase, and a 3 phase 30K generator. The engine has cruise control. I would like to build a gasification unit to fuel the generator/engine setup. I have an airtight woodstove which I would add air for burning. What size unit would I need to place the wood in, to produce enough fuel?

Forum Responses
From Professor Gene Wengert, forum technical advisor:
About 20 years ago, Virginia Tech forestry department had a gasification unit that powered a diesel that ran a generator. I do not have the publications, but maybe you can contact someone there.


From contributor S:
There is a very active gasification generator group of folks. If you search youtube you can find many of their videos, which will give you the link to the respective web sites. I have looked at some of the designs which are sized based on the amount of power you need to develop. I heat my home with a wood gasification boiler. It's not too difficult to produce the gas. I have plans to make a gas generator to fire a small foundry furnace.

From the original questioner:
I had been concerned about safety with the gas. What type of piping do you use? And where does the unit itself sit in comparison to your house? Another system I had thought of was distillation for wood alcohol. It appears that storage would be easier.

From the original questioner:
Today Canada Forest Management encouraged the further use of forestry products in a speech regarding capture of the various chemicals available. One product that comes to mind is wood alcohol. Has anyone tried to build a distillation unit and a means of fermenting the various parts of trees?

From contributor S:
The wood gasifier I use makes hot water, but you could also have one make steam. Then use the steam to turn the generator. There are many biomass fueled steam generators that you could purchase.

The gasifier I plan on making for the foundry will produce a gas that will not be very hot, so piping is not an issue. If you look at the various solutions, you will see that some filtering is done to the gas before it is consumed by an engine.

Heat is the number one energy requirement for residential or small farms, so you may be better off using wood or a biomass fuel to meet your heating needs. Lights are not expensive compared to the energy necessary to make the hot water or the heating we all use.

But reading your post again, I see you want to run a generator. So look at the solution posted on the web - drawing and plans are there for each load size or HP of engine. The designs are pretty easy to make.


From Professor Gene Wengert, forum technical advisor:
Wood gas can go directly into a diesel engine. Before turning the engine off, regular diesel fuel must be run through. Wood gas cannot be transported very far, compared to propane or natural gas, or even coal gas. Gas generators were common in WW II, especially in Europe. They (wood or coal gasifiers) are not especially efficient and easy to use (low BTU gas; residue issues; low BTU per pound for wood compared to coal); it is easier to heat directly in a boiler or use propane or natural gas, hence the lack of interest in using them today. They do work, however.

From contributor B:
This is a topic I find very interesting and have been reading about for a while. Go to the Biomass Energy Foundation at woodgas.com for some great reprints and lists of current publications on the subject. The Handbook of Biomass Gasifier Engine Systems by Thomas B. Reed and Agua Das is a good place to start. Another good group doing a great deal of open engineering is The Gasifier Experimenters Kit (G.E.K.) group.

All gasifiers are pretty design specific to their feedstock. And though I too am hoping to build one, I would buy one in a second if I could find a design that I believed in and could afford. The G.E.K. designs are all made from mild steel and small. The key to a good gas unit for engine operation is to build one that makes clean, tar free gas (the fuel gasses are hydrogen and carbon monoxide). Tars are cracked at temps > 800C so a good unit might run as hot as 1200C. That is too hot for mild steel. Startup and acceleration seem a little slow for real practical work vehicle applications to me, so I'm working on the generator application. One of the problems is, after you work out all the engineering for the gasifier, you need to automate it or babysit it. It is all possible, but a great deal of figuring and testing. It has been done and the folks who have done it want a pretty penny for their work. One unit I found that looks good, it took me a week to get a price out of him. For a manual unit that will operate a 20Kw generator 24/7 you are looking at $20,000; $50,000 with the automation. That is a great deal of incentive to work it out.

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