A techno-economic comparison between two design configurations for a small scale, biomass-to-energy gasification based system

Biomass has great potential as a clean and renewable feedstock for producing modern energy carriers. This paper focuses on the process of biomass gasification, wherein the synthesis gas is subsequently used to produce electricity. A comparison between the most promising design configurations for the industrial application of gasification based, biomass-to-energy cogenerators in the 100–600 kWe range is presented. Mass and energy balances and material and substance flow analyses drawn for each design solutions are based on the experimental data obtained from a pilot scale bubbling fluidized bed air gasifier, having a feeding capacity of 100 kg/h and operated with a commercially available, natural biomass. Measurements taken during the experimental tests include the syngas complete composition as well as the characterization of the bed material, the entrained fines collected at the cyclone and the purge material from the scrubber. The techno-economic performances of two energy generation devices, a gas engine and an externally-fired gas turbine, have been estimated on the basis of the manufacturer's specifications. The study concludes that the internal combustion engine layout is the solution that currently offers the higher reliability and provides the higher internal rate of return for the investigated range of electrical energy production.