Combined Heat and Power (CHP)

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SteveJ

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Nov 19, 2007
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CO 9000ft
Not feasible or Not tricky, Pook?
 
With what little I know about steam power, I'd have to agree with that. Not to mention the danger of an explosion.

I was thinking that somebody's figured out a way to generate electricity with heat or wood gas, instead of a conventional steam turbine or steam engine. I think you can use wood gas to run a Stirling engine, but that's about the extent of my knowledge on that. Or maybe some sort of gas turbine. Running a gasifier feels like running a jet engine at times.

I looked at Seton's website, but didn't see any details, so I have no idea what he's building. I also heard somewhere that Wood Mizer is working on a wood-fired generator of some sort, presumably something that burns slabwood and sawdust.
 
During WWII, wood gasification was used extensively as a source of fuel for conventional internal combustion engines. There may still be a current body of knowledge on this in eastern Europe. Basically, you have a primary combustion chamber that substitutes for the carburetor (for those of us old enogh to know what a carburetor is).

Absolutely no reason that couldn't work to power a generator, although I don't know what the problems are in terms of throttling, filtering, and so on. Plenty of tractors worked this way up until the late 1980s.
 
Running an engine on wood gas is a tough thing to do. The engines need frequent rebuilds due to ash and acids and tar and generally all the junk that comes out of gasified wood. Also the gas doesn't have a regular composition so the engines can't be in a highly tuned state since they might only work some of the time.
 
slowzuki said:
Running an engine on wood gas is a tough thing to do. The engines need frequent rebuilds due to ash and acids and tar and generally all the junk that comes out of gasified wood. Also the gas doesn't have a regular composition so the engines can't be in a highly tuned state since they might only work some of the time.
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I rather expected that was the case, but I have no first-hand experience. I met someone once who had talked with a lot of Eastern European farmers - each had their own contraption. Perhaps there's a design that would work better than I'm thinking. It's possible, at least. Efficiency isn't so much an issue, since we're heating with it anyway. You could even mix the exhaust with fresh producer gas and burn it to reduce hydrocarbon emissions.

A generator is ideal since the load is relatively constant.

We just need to get a retired Czech farmer on the forum to tell us how it's done.
 
i read a book on making charcoal. the guy had a stove and heated up some chunks of wood with it. then he would colect the off gases and either feed them back into the stove or run them through a sereies of filters and use them to power a small briggs and straton genset.
 
OOPs, The whispergen site is no longer active, but, if I remember right, it is a dishwasher size unit that makes heat and electricity combined but I think it may run on nat gas or propane. Not RE.
 
I always thought that these systems, CHP, were simply piston or turbine generators that capture the waste heat of combustion to heat water, or air for the home. Nothing profoundly different than warming up your garage by placing the petrol fired genset in there while making your electricity.
 
We will be using two Bellis and Morcom steam engines to produce 600kw of electric and the waste heat to heat an old Market Hall. Problems with steam are largely overcome by using a thermal oil steam generator which converts thermal oil at 260C to 300C into steam at 150PSI. The fuel used is woodchip derived from forestry brash. There is no reason why this technology cannot be scaled down for use with a boiler similar to a woodgun with automatic woodchip feed so long as it can cope with thermal oil.
 
renewablejohn said:
We will be using two Bellis and Morcom steam engines to produce 600kw of electric and the waste heat to heat an old Market Hall. Problems with steam are largely overcome by using a thermal oil steam generator which converts thermal oil at 260C to 300C into steam at 150PSI. The fuel used is woodchip derived from forestry brash. There is no reason why this technology cannot be scaled down for use with a boiler similar to a woodgun with automatic woodchip feed so long as it can cope with thermal oil.
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Love to see that in operation!! Must have taken a lot of engineering to pull that off. I wish you well.

I have to wonder whether this will work on a small scale as having a 150 Lb boiler means you will probably need a stationary engineer on site to run it. I have seen a Chiptec boiler setup here in MD, and they had a 1st class engineer (with an open mind!) on site to run it. Fascinating setup, though.

My understanding is that you need a large demand for thermal energy as well as electricity to make it pay off, at least with fossil fuels. It's hard to generate electricity cheaper than the electric company, or everybody would be doing it!
 
Redox

Engineering is off the shelf and not new technology. The steam engines were built in 1937 and still generating 600kw when we removed them from site to transfer to the new site. Using a thermal oil steam evaporator overcomes the requirement for an engineer on site (UK Regs) And any woodchip boiler will do so long as it can safely raise the temperature of thermal oil upto 260C-300C. The thermal demand we normally work on a ratio of 4:1 so our 600kw generated will drive a district heating scheme of 2400kw assuming well insulated homes requiring 24kw per home then that would equate to 100 homes. As for electric cost it all depends on the price of the woodchip which at present is very low using forest brash or £20 per tonne using round logs.
 
Might be worth a plane ticket to see it. Any possibilty of some snapshots?

District heating is a European "thing", but then, you are paying $8.29/gal for diesel if my calcs are right.
 
District heating used a lot in scandinavia the uk is 20 years behind with a handfull of schemes .I have tried putting a photo on my avatar of the engines used you can see the scale from the steps of the ladder sorry photo seems to be to big I will try and reduce pixels.
 
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