Analysis of environmental impacts and energy derivation potential of biomass pyrolysis via Piper diagram

Abstract

Biomass is an important renewable resource commonly used to derive energy for various applications. This study analyses the environmental impacts of biomass utilisation and conversion including pyrolysis and bio-oil hydrotreatment. The analysis was performed on 70 biomass samples using process simulation software and Waste Reduction (WAR) algorithm. Results showed that energy content, yield, product distribution and the environmental impacts are highly influenced by the lignocellulosic (cellulose, hemicellulose, lignin) and elemental (carbon, hydrogen, oxygen) compositions of biomass. Lignin-dominant biomass is found to produce char-dominant products whilst severely affecting two of the environmental impact categories, and cellulose-dominant biomass contributes mostly to six other impact categories whilst producing oil-dominant products. Hemicellulose-dominant samples produce gas-rich products with mild environmental impacts. Moreover, carbon- and hydrogen-rich samples exhibit positive relationship with higher heating value whilst oxygen-rich biomass have lower heating values. Such correlations were systematically presented on a Piper diagram in order to distinguish the potential and impacts of each biomass sample in pyrolysis. Albeit green, not all biomass samples are environmentally friendly during pyrolysis. The developed Piper diagram provides a straightforward, yet comprehensive, understanding, characterisation and illustration of the potential of biomass in achieving specific engineering, economics and environmental objectives based on fundamental characteristics of biomass.