Fast pyrolysis kinetics of lignocellulosic biomass of varying compositions

Abstract

This study is focused on evaluating the apparent kinetics of fast pyrolysis of different lignocellulosic biomass viz, rice straw, pine wood and empty fruit bunch. The goal of the study is to investigate the effect of biomass composition on kinetics, time evolution of pyrolysis vapors and the production of major bio-oil components during the fast pyrolysis of biomass. The isothermal mass loss data were generated at different pyrolysis times between two and sixty seconds in the temperature range of 400–700 °C. The data generated were then analyzed using various reaction models, viz., first-order model, diffusion models, contracting cylinder model and Avrami-Erofeev model to determine the rate constants and the rate parameters. Kinetic compensation effect was established using a large number of kinetic data reported in the literature to validate the results. The time evolution of major functional groups in the pyrolysates was analyzed using in-situ analytical pyrolyzer coupled with Fourier transform infrared spectrometer (Py-FTIR), and evolution of the volatiles was observed in time range of 5–60 s. Increase in pyrolysis temperature led to faster evolution of volatiles as evidenced by the shifting of maximum rate of vapor evolution to shorter time periods.