Gasification to produce electricity?

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dfergx

New Member
Feb 23, 2008
21
Pend Orille County, WA
I am researching a gasifier for my new building. We have 240 acres and tons of standing dead maple. This has always been my first resource fro gasification. But I have not heard anything about a gasifier that produces electricity and uses the excess heat for space heating. any suggestions, tips, thoughts? I found one supplier in denver that made units that looked small enough for my purpose (smallest was 5kW). Thanx
 
Small scale electric generation with wood is a tough nut.

I remember seeing some stuff from Britain when I did a search....

The problem seems to be that turning regular heated water in electric is inefficient - the standard Steam Engine is something like 5 or 10% efficient, meaning your electric would be expensive. To produce electric efficiently, I think you would have to either:

1. Superheat water and use a steam turbine - not for the faint of heart
2. Gasify the wood completely, filter it and use the gas in an internal combustion generator - the total efficiency would be low here also.
3. Use the gas in a fuel cell arrangement - this may be the winner of the three.
Here is a grant which explains the development of a small scale CHP (combined heat and power) biomass plant:
http://gow.epsrc.ac.uk/ViewGrant.aspx?GrantRef=EP/E020062/1

We have some engineers here, including at least one combustion engineer. Maybe someone else will chime in.

Oh, another way....is that they actually have solid state devices which can turn heat to electricity.....very expensive.....but that would be really cool if the price came down.
 
Depends on what size machines you are after but stirling engines are now available in Europe upto 75kw If you want larger than that you have the option of steam technology using boilers and conventional steam engines or turbines. Or go down the woodgas route using a conventional diesel generator converted to gas. You could also produce woodgas by anerobic digestion as outlined by Jean Pain and again use a converted diesel generator to use woodgas.

Small scale plants

http://sunmachine.com/download/datenblatt/datasheet_sm.pdf

http://ztstanzel.com/neu/spm.php?lang=en
 
I didnt know you could measure heat in kW. How does that translate into btus? 100,000 watts of heat sounds like a lot. Although we have a few buildings and could pipe it around a bit.
My other questions is, if the machines are only 10% efficient at producing electricity, isn't most of the lost energy going into heat, through friction? if that heat is getting used to warm a structure doesn't that bring up the overall efficiency of the machine? thanx.
 
I have been working on doing this for geo energy at places like iceland or geo hot spots. There are some new things coming to market soon which look to work well. One of them has been proven to replace the alternator on your truck by taking power from the heat in the exhaust system. I should know in 6 months if this stuff makes production.
 
Thubten

For a commercial installation 100kw is not very big a large domestic boiler could be 55kw which is approx 180k Btu so 110kw is approx 370k Btu. Large school or hotel would probably be 500kw boiler. Efficiencies can vary but 15% electric 60%thermal 25%unrecovered is a typical low pressure steam engine scenario. For high pressure steam engines the mix could be 30% electric 45% thermal 25%unrecovered.

With regard to woodchips for an automated system the material must flow which is why wood pellets are used in the examples quoted. Woodchips have a tendency to stick together and bridge so are more difficult to utilise in automatic systems but not impossible. (REFO boilers are a good example of automated woodchip)

If you want a low tech approach google Jean Pain for a novel way of using woodchips to produce gas and heat a home.
 
google: listeroid and "wood gas" and you'll start to get into some interesting information, some of which comes from the GEK folks and some of which comes from Ken Boak, who's been experimenting with this with some preliminary success in Britain
 
Dave B said:
Wood to electricity at 100 percent efficency. Cut wood, sell wood, buy electricity.

Far better to cut wood and gasify to produce electric for sale to the grid and waste heat to heat your home.

Approx 1 tonne per hour wood produces £250k per annum sales to National grid
 
Como said:
http://www.baxi.co.uk/products/ecogen.htm

Outside the US kw is the normal measure of heat demand, many of the non US Boilers Model Numbers are related to their KW output.

The Baxi Dachs machine would make a good domestic CHP unit for runnning with a woodygasifier for all those who want an off the shelf solution.
 
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