Comparative analysis of energy, exergy and economic performance in biomass gasification: a process simulation study

Abstract

Thailand possesses substantial biomass waste from industrial and agricultural sectors, which can be converted into chemicals and fuel through gasification, a thermochemical process that transforms biomass into fuel gas. This study examined five biomass types: rice straw, rice husks, corn cobs, rubber wood, and sugarcane bagasse, employing thermodynamic, energy, exergy, and economic analyses to assess investment viability through biomass gasification process modeling using ASPEN PLUS V12.1 software. The analysis evaluated the impact of operational variables such as gasification temperature, steam-to-biomass ratio (S/B), and equivalence ratio (ER) on process efficiency. Results indicated that increased gasification temperatures positively affected hydrogen production, with optimal temperatures ranging from 800-900°C, an optimal steam-to-biomass ratio of 1, and an ideal equivalence ratio between 0.1-0.2. Energy and exergy analyses revealed varying equipment efficiencies: decomposition units achieved 54-71% and 38-42%, coolers reached 58-75% and 54-75%, and gasifiers attained 87-96% and 68-76%, respectively, while other equipment exceeded 80% efficiency in both analyses. Economic analysis demonstrated high potential for rice straw, corn cobs, and sugarcane bagasse due to short payback periods and positive Net Present Values (NPV), whereas rice husks proved economically unfavorable with negative NPV and extended payback periods exceeding project timelines. The study's benefits include reduced prototype plant construction costs, improved production planning, and time savings by eliminating trial-and-error approaches in biomass selection for gasification processes.