Pyrolytic Conversion of Biomass Residues to Gaseous Fuels for Electricity Generation

Abstract

As petroleum resources are finite, it is imperative to use them wisely in energy conversion applications and, at the same time, develop alternative energy sources. Biomass is one of the renewable energy sources that can be used to partially replace fossil fuels. Biomassbased fuels can be produced domestically and can reduce dependency on fuel imports. Due to their abundant supply, and given that to an appreciable extent they can be considered carbonneutral, their use for power generation is of technological interest. However, whereas biomasses can be directly burned in furnaces, such a conventional direct combustion technique is illcontrolled and typically produces considerable amounts of healthhazardous airborne compounds. Thus, an alternative technology for biomass utilization is described herein to address increasing energy needs in an environmentallybenign manner. More specifically, a multistep process/device is presented to accept granulated or pelletized biomass, and generate an easilyidentifiable form of energy as a final product. To achieve low emissions of products of incomplete combustion, the biomass is gasified pyrolytically, mixed with air, ignited and, finally, burned in nominally premixed lowemission flames. Combustion is thus indirect, since the biomass is not directly burned, instead its gaseous pyrolyzates are burned upon mixing with air. Thereby, combustion is wellcontrolled and can be complete. A demonstration device has been constructed to convert the internal energy of biomass into “cleanâ€‌ thermal energy and, eventually to electricity.