Comparison of catalytic and non‐catalytic pyrolysis of ten typical biomass feedstocks to produce aromatics and olefins in a fluidized bed reactor

Abstract

Catalytic and non‐catalytic fast pyrolysis (CFP and non‐CFP) conversion of the ten biomass species into olefins and aromatics compounds were conducted using a fluidized‐bed reactor over HZSM‐5 catalyst and sand as bed materials. The influence of biomass type and composition (cellulose, hemicellulose, and lignin) on the yield and selectivity of pyrolysis products was investigated. There was a great difference between CFP and non‐CFP products yield. The highest aromatics carbon yield was only 1.34% (corncob) during non‐CFP tests. While a remarkable improvement in aromatics carbon yields were 12.12%, 12.52%, and 12.58% obtained from pinewood, corncob, and poplar biomass during CFP tests, respectively. The dominant aromatic compound was benzene with selectivities of 49.6% (bagasse), 46.8% (rice straw), 48.0% (nutshell), and 50.78% (corncob). Moreover, the highest CFP olefins carbon yields were 10.19% (pinewood), 10.69% (corncob), and 9.89% (poplar), compared to highest non‐CFP olefins carbon yields were low as 3.37% (bagasse), 2.85% (rice straw), and 2.82% (nutshell). While the higher carbon selectivities toward ethylene were 50.31%, 59.46%, 54.59%, and 51.67% in pinewood, bamboo, indus, and poplar, respectively. The biomass feedstock rich in cellulose and hemicellulose content produce higher hydrocarbon yields than those with higher lignin content. Thus, biomass composition can be used as markers for selecting biomass and predicting pyrolysis products distribution. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1371–1379, 2018