Characteristics and kinetics of biomass tar cracking in a micro fluidized bed

Abstract

This study is devoted to investigate the characteristics and kinetics of biomass tar cracking in a micro fluidized bed reactor for liquids (MFBRL). The carbon balance and conversion were measured to estimate the performance of MFBRL, and the results showed good reproducibility and reliability. H₂, CH₄ and CO comprised the vast bulk of the producer gas and the total volume fraction of them increased from 69.85% to 93.62% (973–1173 K). Kinetic parameters, including reaction order, pre-exponential factor and apparent activation energy, were studied with the isothermal method. The reaction orders varied greatly with temperature, suggesting that temperature significantly affected the reaction mechanism. The pre-exponential factors for H₂, CH₄, CO and gas mixtures were in the range of 2.37 × 10³ to 2.87 × 10⁵ S⁻¹, while the apparent activation energies ranged from 62.96–100.2 kJ mol⁻¹. Compared to the fixed bed experiments, the derived results were obviously higher, indicating the kinetic parameters were more suitable for describing the intrinsic reactions.