The developed performance evaluation method of an industrial scale updraft woody and woody-like biomass gasifier using a thermodynamic approach

Abstract

Recently, biomass gasification technology for supplying heat has attracted several energy-intensive industries, such as ceramics and hot mixed asphalt production, as the fossil fuel pricing escalates, and environmental issues dominate the news. It offers higher energy efficiency, raw material flexibility, a wider range of capacities, and lower greenhouse gas emissions. Palm kernel shell is a potential biomass source in Indonesia as feedstock of the gasification process because of its high calorific value, abundance, and being considered as carbon-neutral and sustainable. The gasification process performance should be measured based on carbon conversion efficiency (CCE) and cold gas efficiency (CGE) to guarantee the operation's reliability. This study aims to develop the performance evaluation method of an industrial updraft woody and woody-like biomass gasification system using air as a gasifying agent for supplying heat through a thermodynamic approach. The model developed was created using licensed Aspen Plus v.11 software. The constructed model was validated with several laboratory experiments of previous researchers using various types of biomass considering carbon monoxide and hydrogen contents in the producer gas. The thermodynamic model showed a good agreement with the experimental data assessed based on root mean square error (RMSE) value for H2 and CO being 3.02 and 2.10, respectively. The developed model was implemented to evaluate performance of an asphalt mixing plant with palm kernel shell updraft gasifier as a heating source of aggregate. It was observed that at the operation condition of equivalent ratio (ER) of 0.082, the CCE and CGE were 46% and 38%, respectively. The model dictates that this installation unit should be operated at an ER value of 0.28, which is equivalent to a feedstock flowrate of 990 kg/h and an air gasifying agent flowrate of 1250 Nm3/h to achieve near to 95.20% of CCE and 76.34% of CGE. At the same time, about 50% savings on feedstock was also identified.