Air gasification of wood chips, wood pellets and grass pellets in a bubbling fluidized bed reactor

Abstract

Gasification is an attractive method for biomass-to-energy conversion and fluidized bed design is one of the best options for large scale operation. A bubbling fluidized bed reactor was used to analyze the effects of biomass type, equivalence ratio (ER) and temperature for product gas compositions. Wood chips, wood pellets and grass pellets were gasified between 650 °C and 800 °C temperature. The ER was varied between 0.08 and 0.16. Gasification of grass pellets was difficult at 800 °C due to agglomeration and the gas composition was poor compared to wood. The reactor performances improved over the temperature and 650 °C was not sufficient to achieve a reasonable carbon conversion. Nitrogen dilution at higher ERs was counter weighted by improved carbon conversion at higher temperatures. The highest carbon conversion was achieved at 800 °C which were 75.8% and 70.6% for wood chips and wood pellets at 0.15 and 0.16 ERs respectively.