Open-top wood gasifiers

Abstract

The technology and economics of a new class of open-top gasifiers for use with diesel engines in dual-fuel mode are described. The performance of systems that range in capacity from 3.7 to 100 kilowatts are discussed, with special emphasis placed on gasifiers at extreme ends of the capacity range. The essential differences and benefits of the new technology are compared with World War 2 closed-top models. Studies indicate that the open-top design achieves diesel replacement values greater than 80 percent and is less dependent on feedstock quality, moisture content, and density. The amount of diesel fuel saved per system among motivated users (mostly small farmers) exceeds 70 percent. A comparative analysis of two gasifier systems: a 5 kilowatt system that runs the village power station in Hosahalli, Karnatka (India), and a 100 kilowatt system that powers a sawmill on the remote island of Port Blair in the Andaman and Nicobar archipelago was undertaken. The cost of installing the larger system, including computerized data acquisition and control systems, was US $625 (Rs 12,500) per kilowatt, with an energy cost of $0.074 (Rs 1.60) per kWh (the cost of energy subsidized by the state is RS 1.25 per kWh).