Products distribution and kinetic analysis on gaseous products during fast pyrolysis of two kinds of biomass pellet

Abstract

Biomass can be converted into high value-added products via rapid pyrolysis. Extruding biomass into pellets not only promote the energy density and combustion characteristics but also benefit for storage and transportation. In this paper, a thermostatic tubular reactor combined with online mass spectrometry was used to determine the pyrolysis characteristics of two biomass pellets, PP (pine pellet) and BP (bark pellet). The kinetic parameters about the formation of primary gaseous products were calculated by the iso-conventional method. The results show that with the pyrolysis temperature increasing from 600 °C to 850 °C, the yield of the gaseous products of PP increase from 12.48% to 21.11%, while the yield of tar and char decreased from 70.62% to 64.05% and 16.9% to 14.19%, respectively. The gas yield of BP increased from 12.10% to 16.99% and remained stable with the further increase of temperature. While the yield of char decreased from 30.86% to 25.09%, and the heat value increased from 11.01 MJ·M−3 to 13.21 MJ·M−3 from BP. The volatile content of the PP was higher than that of BP, resulting in a higher heat value of the gaseous product. The activation energy for the formation of H2 from PP and CH4 from BP was higher than other gaseous products, with the value of 52.52 kJ·mol−1 and 59.57 kJ·mol−1, respectively. This work provides basic information on the thermal behavior of biomass pellet.