Here is an interesting article about a trash gasifier, which is still on an commercial not residential scale, but much smaller than usual:
InfoSciTex Gasifier, about this company's truck-mounted trash gasifier.
There was also a Slashdot article on it. The best part of that discussion was this link:
A gasifier Experimenter's Kit - it comes in a variety of assembly levels, the most expensive being over $2,000. If I got something like this, I could perhaps focus on trying to build a catalitic reactor to upgrade the gas.
Update 12 Oct 2008:
I have been very busy with work for several months, and have accomplished absolutely nothing. But, here are some links to people who have more time:
Puffergas -- look at all the links on
this page, some of the good stuff is down a couple of levels
Around Sweden with Wood in the Tank - a Swedish project that uses an old Volvo and an old commercially built gasifier
Wayne Keith has a woodgas powered truck that seems very practical and quite successful
Update 16 May 2008:
There is not much technical information here, but some interesting pictures; it is a pickup that runs off a pretty traditional looking gasifier, which in this case is fed with used coffee grounds:
Cafe Racer Crew
Jim Mason's Woodgas Pickup Truck
Jim Mason's Other Gasifier Experiments
I am glad to see that Jim Mason successfully ran a small 5kw gasoline electric generator off of a simple gasifier, as that is one of the first experiments I had planned.
Update 9 May 2008:
Here's an interesting story that has been making the rounds of various news web sites:
E-Fuel Corporation Web Site
Wired Blog commentary
New York Times article -- seems largely cribbed from the Wired Blog
The summary is, that they sell a standalone self-operating fermenter, into which you put table sugar, some yeast that they say is special and that you have to buy from them, and water, and from which you take 100 percent ethanol. It uses osmosis (they call it "fine filters") to get the ethanol up to 100 percent ( you cannot get that pure via ordinary boiling and condensing distillation), and they say this uses much less energy than distillation. They claim you can produce ethanol for about $1 a gallon, provided that they find a way to use NAFTA to force the US to allow the importation of cheap raw inedible Mexican sugar at 2.5 cents a pound (table sugar normally sells for 20 cents a pound or so).
It seems ripe for abuse in terms of producing drinkable alcohol without paying the excise tax.
They offer no claims as to the amount of electricity it uses. They suggest that 20 percent of ethanol can be lost to evaporation between a central manufacturing facility and a consumption as fuel. They suggest that a fuel with 20 or 30 percent ethanol, the reminder gasoline, might get better mileage than gasoline alone. They also suggest that transporting sugar to the end consumer is more energy efficient than transporting liquid ethanol.
It can operate in a "distillaton only" mode in which beer is fed in. Perhaps the more practicle use of the appliance would be as a distiller for a farmer who had enough agricultural produce to ferment large batches without resorting to buying sugar. If I lived up north and had some sugar maple trees, and had bad sugar sludge left over, I might consider this -- I wonder if it would make more sense to turn contaminated syrup into ethanol, or feed it to pigs.
This seems that is will partly just convert coal (burned in the electic power plant) to liquid fuel. I hope someone who gets one also puts it on a kill-a-watt or similar power meter and posts how much it costs to run.
In looking over those pages, I found the following links describing a more convential ethanol operation:
Farm-scale ethanol fuel production plant
The Butterfield Still
Their FAQ addressed the issue of the ATF licensing related to running a still, and they had a link to a form whereby they claimed you could get a license for distilling less than 10,000 gallons a year.
Interesting link: possible cheap separation of oxygen from air. This is interesting because in a woodgas apparatus, the fuel ( carbon monoxide and hydrogen ) is heavily diluted due to the fact it was produced by introducing air to the feedstock, and the air is only only 20 percent oxygen, so 80 percent of the volume is uselessly taken up.
Of course, this applies to other types of combustion also. If you separated out the nitrogen and threw it away, running an ordinary internal-combustion engine on oxygen and gasoline, it would be able to take in and burn completely much more fuel in each stroke, thus producing more power per stroke and for a particular engine weight. Also, without nitrogen in the combustion chamber, nitrogen oxide pollutants would be eliminated.
I should look up enough thermodynamics to figure out how much energy it should take a perfectly efficient system to separate the nitrogen and oxygen solution.
Interesting link: Smaller, Cheaper Biofuel Reactors
Update 9 July 2007:
I read all the books below. I also obtained and read "Synthetic Fuels" by Ronald F. Probstein and R. Edwin Hicks, published by Dover (1982, 1990, 2006), ISBN 0-486-44977-7. This is the most technical material related to this subject I have read so far, and the book is a real eye-opener.
The main reason why I called it an "eye-opener" is because it gave me a better idea of the amount of heat, energy, and pressure involved in making a fuel that is storeable ( the CO and H2 gas coming from a gasifier is impractical to store and is better consumed immediately in my opinion ). This doesn't mean that it is impossible on a small scale, but a lot more expense, care, and safety would be involved in operating something like that. On the other hand, I have noted that other people are researching into using microwaves to carry out processes like this:
used to break down plastic
Slashdot discusson on the above
I think the first gasifiers may well focus on garbage rather than wood or other "biomass" because our garbage has so much energy-rich plastic. ( I also recently read Heather Roger's book "Gone Tomorrow" which has a lot of interesting information about how much packaging we throw out. )
This device is closer to what I want, but the bio-reactor part seems to require continous addition of liquid yeast, which seems to tie you to a yeast producer:
Purdue developes portable generator turns trash into electricity
The scale of that last one seems more promising also.
As of 20 Oct 2005, I received the books below and started reading them.
As of 16 Oct 2005, I have ordered these books:
Convert Wood into Charcoal & Electricity by Richard H. Buxton and Gas-Engines and Producer-Gas Plants by R E Mathot. I'm not sure what the next step is, I think I need to take the FEMA pamphlet listed below and print it out, organizing it correctly with all the drawings.