[atiff]

Not sure exactly how 'correct' this is, but an idea..... Based on a book I was directed to by this forum.

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Stefan backed up, wiping his dirty hands on an old rag as he cast a critical eye over the metallic contraption in front of him. Everything seemed right, so it was time to give it a try.

At the left-hand, an old lawnmower engine had been converted into an electrical generator. They had initially run the coils by muscle power to prove they had generating capability, and the engine drive-shaft was geared way down for this first test. It could always be adjusted later to give the output they needed; or they could use a bigger engine. That was the real plan, if this test unit worked.

On the opposite end was the gasifier. It had taken them almost three weeks to hand-tool or salvage the right kinds of parts from the ruined warehouses and former workshops. Several more days of trial-and-error experimentation had followed, trying to tune the nozzles and feeds and everything else, before they had been able to get a reliable flow of gas running from it. In the beginning, they just burnt it off at the output pipe, learning to control the output better. But for Stefan and his partner, Johan, it had been a great success. And one that would not have been possible without....

Stefan's eyes drifted over to the book on the rear table. A bit over 100 pages thick, it provided hope for the town in the message on the cover: "Wood gas as engine fuel". Before that book had been found, Stefan had never heard of the Food and Agriculture Organization of the United Nations, but he would be singing their praises forever more if this worked....

He turned back to the middle section of the contraption. Filtering; that was the problem. The raw gas was too dirty to use in an engine. They had already ruined one figuring that out. The first filter system they tried had not stood up to the heat of the gas, and had failed. The second had worked for a short time, and then the cloth filters had gotten blocked with tarry residue and stopped the gas flow. Because the gasifier was hard to get started, they couldn't always be stopping and starting it around a filter change. And you couldn't change the filter quickly, because they got too hot. So they had come up with this.

The gasifier output pipe led to a pipe junction, controlled by a directional tap. Two pipes led out the back, to an identical pair of filter units, and then to another directional tap which rejoined the flows leading into the engine. They knew the cloth in the filters would only last maybe an hour or two at best, but if they could change redirect the gas and change one set of filters out as the gas ran through the other, they could keep the engine running continuously. It would be manpower-intensive, but not as hard as trying to generate the same kind of electrical power using muscles, or as wasteful as using grains to make alcohol fuel.

Stefan gave the nod to Johan, and he fired up the gasifier. Stefan kept an eye on the pressure gauge and after a good 15 minutes, it was ready to go. Stefan moved over to the engine and reached for the starter cord. The second pull, it turned over and burst into life. Johan let out a whoop, and Stefan smiled; but they still had the filters to test.

Each man moved to the tap at their end of the filter apparatus, and on the count of three, slowly turned them from one extreme to the other. The engine stuttered, but kept going. It took a few seconds before Stefan let his smile return and grow bigger. Johan pumped his fist, and then the men shook hands. Very soon, and for the first time in two years, they would have lights on again in their little town...