Retrofitting existing coal power plants through cofiring with hydrothermally treated empty fruit bunch and a novel integrated system

High-potential biomass residues from the palm oil industry such as palm kernel shells and empty fruit bunch (EFB) must be utilized with the appropriate technology to optimize its economic benefit and minimize the environmental impacts. In this study, the cofiring behavior of hydrothermally treated EFB (HT-EFB) with coal is analyzed in terms of thermal behavior including temperature distribution and the composition of gases produced (CO and CO2) through computational fluid dynamics. Several HT-EFB mass fractions are evaluated, i.e., 0%, 10%, 25%, and 50%. To complement this research, an experimental study is conducted to validate the simulation results. In general, an HT-EFB mass fraction in the range of 10-25% seems to be the most preferable cofiring condition. In addition, an integrated system is also proposed and evaluated including coal drying, HT treatment of EFB, cofiring, and power generation. Very low energy consumption during coal drying and HT treatment of EFB can be achieved. Finally, the net power generation efficiency of the proposed integrated system is approximately 40% including coal drying and HT treatment of EFB processes.