Any Wood Gasifier users/builders out there?

[veggie]

For years I have dismissed wood gasifiers. Mostly because my attention was with diesels and alternative fuels. A recent dive into gasifiers has me intrigued.
I have begun to assemble documents and videos on building these units for gas production to drive a small generator.
I can get a good supply of wood chips.
One obstacle with wood gas powered generators seems to be the modulating of the air/gas ratio under varying engine loads.
This can be overcome using a Lambda exhaust gas sensor tied to a microprocessor and a throttle servo valve which constantly adjusts the mix based on exhaust oxygen.
Is anyone here operating a wood gasifier ?

[Tom Reed]

A friend of mine converted my old Briggs 4KW generator to wood gas. It worked ok, but took a lot of fiddling to keep running.

[mobile_bob]

i have also been long interested in wood gasification

so much so that i bought one of the chinese gasifiers years ago from George over at utterpower.com

i like your idea of using some sort of microcontroller scheme to monitor exhaust gas O2 content and adjust the mix to keep things in stoic or near so.

a couple of other thoughts i had rattling around inside my head way back when

1. if, one was to power an alternator charging batteries, then having to have steady rpm for 50 or 60hz output would be of no concern, and/or

2. if, one was to use the wood gas as a constituent fuel in a dual fuel/pilot injection system in a small diesel engine, then then diesel faction of the mix would shift up and down as needed, and could in theory make for a prime mover that could keep a steady rpm, or so it would seem to me.  if the wood gas ran lean then the diesel injection would increase and keep the rpm steady, if the wood gas ran richer, the diesel injection would decrease and also keep the rpm steady.


i think there is a lot that might be interesting to work with and study about using perhaps both 1 and 2 above, and maybe even with  your control system as well.

as for wood chips, i recall in the pac nw, wood chips were easy to find... and even around these parts would not be that difficult to come by.

old pallets broken down and ran through a chipper would not be hard to do, a small gas generator, a skillsaw, and a small chipper in the back of a pickup truck, with maybe a small trailer and one could certainly come up with a lot of clean chips in a saturday afternoon.  a lot easier than cutting trees, bucking them up and splitting into firewood too.

asplunh, comes through town here about every year or so and will gladly bury you in wood chips if you let them,,, the only problem  with their chips is they have a lot of bark and the chips are green, so one would have to do some sorting and drying of those chips, but they are free and they will deliver.  i have had them drop here from my garden use,  i think i could setup and sorting table and process a lot of clean wood chips for a gasifier, which would be easy enough sitting in a chair on a nice afternoon.  the only issue then is spreading them on a tarp or maybe a screen to dry them?

edit:   GEK gasifier, all power labs (search google and check out what they have been up to for over 10 years now)
bob g

[Tom Reed]

I've been thinking about gasification too. The concept of a homestead system with the gas used for cooking and possibly hot water too. I met with a friend of mine who is a real engineer and built a 4kw Birggs powered system with a wood chunker and all.

My idea is to compress the wood gas and use standard lp gas regulators to supply fuel to the engine. Apparently, when wood gas is compressed the CO and H separate. During WW2 busses were run with bags of wood gas on the roof. So easy peasy, a nitro cellulose bag full of Hydrogen, what could go wrong?

Instead of a bag, one could cut the top off of a couple of poly water tanks with a smaller one to fit inside the other. With the larger tank filled with water and the smaller tank upside down inside the larger tank and also filled water, wood gas could pumped into the top of small tank. As it is filled the smaller tank would float and make a large volume of low pressure gas.

This type of design might allow a larger gassifier to run at peak efficency on an occasional basis, perhaps using standard size firewood.

Anyway just a thought.

[veggie]

mobile_bob

I was intending to use a small diesel engine with diesel fuel pilot ignition.
This allows a lot of dual fuel flexibility (or even tri-fuel if you include cooking oil)
I do have a 10HP Briggs IC if I decided to go with a gasoline engine.
Your comment about driving an alternator makes a lot of sense, eliminating the need for tight rpm control.