Biomass Gasifiers

The departing comment of the last article left me teasing you with the idea of a wood-powered vehicle. Perhaps some of the readers thought I had finally went over the edge (if they hadn't already felt that way before!)

But the fact is, wood-powered vehicles are old news, big-time old news. Due to the scarcity of petroleum, during WWII Germany was running approxiamately 1 million vehicles on charcoal and wood. Let me write that number out: 1,000,000.

What happened? After the war when gasoline and diesel again became readily available, Germany, like the rest of the world, found it a whole lot simpler to refine crude oil than gasify biomass. So the 1 million “wood gas” (as the system is named, but also “producer gas”, “holz gas”, “air gas”, or “blue gas”) vehicles became a blip in history, so little a blip that most folks do not even realize they existed.

With the revving up of oil prices, interest in reviving the technology has also picked up. But so far, oil prices have stayed just below the line of what it would take to get folks moving by wood-powered vehicles once again.

As with solar ice-makers, the technology to make this happen is already here. In fact, I reiterate that it has been here for a century. The damper on its use has been cheap oil, which will soon come to an end. How long will it be before we see $10 or even $15/gallon gas? I do not know, but I suspect that those of us without much white in our beard will see it before our generation passes on.

The principle behind making wood gas is not that complicated. In simple terms, wood and coal (or other biomass) lets off gas as it heats up. In a wood stove, heat is put to firewood, which heats up the wood to the point of it emitting gas, which then burns and creates more heat, which in turn heats the wood more, which makes it put out more gas. And on and on it goes, until the fuel is used up.

Now, to make a wood gas vehicle, you simply heat wood up until it releases its gas, and then you suck the gas off and burn it in your internal combustion engine.

The most common way this is achieved is by a funnel-shaped bin filled with chips or sawdust. A fire is started at the bottom of the “funnel”. As your engine sucks air from the top of the funnel, the heat is pulled up into the sawdust, which releases the gas “stored” in the fuel. As the fire burns at the bottom, the chips/sawdust flow down. When the bin gets empty, more fuel is added at the top.

Very simple, right? Then how come people do not use them any more? A very simple answer: it is easier to pull into BP and pump gasoline into the tank and peel away.

Wood gas vehicles need to be “started” about 20 minutes before enough gas is produced to supply the engine. And, generally speaking, the fuel should be in consistent sized pieces to facilitate it “flowing” in a typical canister-type gasifier. Which means you cannot just throw that maple tree trunk in the gasifier and speed away.

In spite of these drawbacks, wood gas systems are currently powering vehicles and stationary engines in many parts of the world. One system in Paraguay is supplying all the power for a sawmill as well as generating electricity for a nearby village. Some university students built a gasifier from a fire-extinguisher and used it to run a motorcycle, in the 1980's. They were able to obtain a 20 miles/pound “wood-mileage”. For a large vehicle like a pickup truck, it takes about 2lbs/mile. So a 40lb hunk of hickory would take a pickup about 20 miles. Feasible? Absolutely! And very clean-burning on top of that! Wayne Keith of Alabama has put thousnads of miles on his pickups with the sawdust from his sawmill. He is currently making a coast to coast run with one of them for Auburn Univeristy.

Now for my real brainstorm. Ready?

Gasifiers work for with any biomass. And road apples are biomass. Get the connection? Whoever comes up with the first “wood-gas” vehicle in Holmes County will have all the free fuel he may need. A simple scoop that drops down as the vehicle passes over road apples is all that is needed to collect the fuel. A little auger then takes it to the top of the fuel bin and drops it in.

I can guarantee the builder of this system that he will achieve nationwide celebrity!

Any takers on this brainstorm? As with the solar icemaker, I'll root for you!