Environmentally-Benign Conversion of Biomass Residues to Electricity

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. Biomass-based 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 carbon-neutral, 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 ill-controlled and typically produces considerable amounts of health-hazardous airborne compounds [1, 2]. Thus, an alternative technology for biomass utilization is described herein to address increasing energy needs in an environmentally-benign manner. More specifically, a multi-step process/device is presented to accept granulated or pelletized biomass, and generate an easily-identifiable form of energy as a final product. To achieve low emissions of products of incomplete combustion, the biomass is gasified pyrolyticaly, mixed with air, ignited and, finally, burned in nominally premixed low-emission 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 well-controlled and can be complete. A demonstration device has been constructed to convert the internal energy of plastics into "clean" thermal energy and, eventually to electricity.

Pyrolytic Conversion of Biomass Residues to Gaseous Fuels for Electricity Generation

“…Pyrolytic gasification of biomass requires an energy input that is in the order of 1 MJ/kg [27,28], which is much lower than the energy released during their combustion (in the order of 20 MJ/kg). A laboratory-scale system was designed and constructed to pyrolytically gasify waste solid municipal, industrial and agricultural fuels, including residual biomass, generate a combustible gaseous fuel mix and demonstrate its conversion to heat and, eventually, to electricity.…”