Sunday, May 25, 2008

Jono and I Pass Biogas

I have been experimenting with a "backyard batch biodigester" for a month or so. Essentially, it's a big barrel full of rotting food and water that is deprived of oxygen. Bacteria eat the food, and produce methane. The methane can be burned, theoretically, and can even run a generator to produce electricity. That's where I'm headed with this - electricity production for the developing world.

The digester is really producing now. I could see the barrel swelling this afternoon, so I bled off quite a lot of gas. I tried to light it, but I don't think that's going to be possible without a burner of some kind to control the oxygen mixture. I measured 8 liters and then got tired of measuring, so I let it just bubble away. My guess is we produced about 16 liters in 24 hours. The Texas heat is helping a lot. The optimum production temperature is about 95-100 degrees. It hasn't been that hot outside yet, but I leave the barrel in the sun, so I'm sure it gets plenty warm inside.

Jono helped me video some of it (video is now a verb), it was his first camera work! He says some cute things in it, listen carefully. However, what I say in the video doesn't make a whole lot of sense. What I meant was that I tried to hook up the grill to the biodigester, so I could provide cooking fuel to the burner. But I couldn't figure out how to disconnect the hoses without destroying the grill, and The M might have frowned on that!

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