Biomass pyrolysis chemistry and global kinetics at high heating rates

The initial step of biomass thermal conversion involves the primary decomposition of the lignocellulosic matrix that is composed of three interconnected polymeric materials: cellulose, hemicellulose, and lignin. Pyrolysis mechanisms typically include a superposition of the kinetic mechanisms for the individual components of the biomass material. The validity and development of these mechanisms is currently being investigated [1,2]. A reliable description of the global kinetics of biomass pyrolysis is the building block for accurately describing the high temperature chemistry that occurs in developing biomass thermochemical conversion systems. These accurate chemical models of biomass gasification and combustion can be used as input in systems analysis models to adjust engineering parameters such as gas velocities, particle residence times, and heat transfer rates to optimize the design and performance of developing gasification technologies. A new continuous feed, laminar entrained flow reactor (LEFR) has been recently built and characterized for determining biomass pyrolysis kinetics, gasifier tar production rates, and alkali metal release rates. This reactor is capable of heating rates on the order of 103-104 K/s, typical of heating rates found in developing gasifiers and in industrial boilers. This reactor has been coupled to a molecular beam sampling mass spectrometer (MBMS) system to follow the chemistry of the gas phase products as they evolv