Hydrothermal carbonization of miscanthus: Processing, properties, and synergistic Co-combustion with lignite

Abstract

Abstract Hydrothermal carbonization (HTC) is an evolving technology that converts biomass, such as Miscanthus, into high energy solid fuel known as hydrochar. The reaction time and temperature of HTC significantly influenced the hydrochar physical and chemical properties. The hydrochar has better fuel properties including higher yield, carbon content, heating value, and lower ash, and lower nitrogen content. The hydrochar obtained at 260 °C and reaction time of 30 min was co-fired with lignite in varying quantities with two different heating rates (20 and 40 °C/min). The composition of gaseous products released from the combustion of lignite and hydrochar was studied using thermogravimetric analysis (TGA) coupled with an FTIR. The thermal behavior of the hydrochar and lignite under combustion conditions was studied by means of TGA. The addition of hydrochar to lignite increased the total burnout, shortened the combustion range, and significantly enhanced the combustion efficiency of blends due to synergistic interactions between them. Furthermore, Kinetic studies indicated that activation energy follows a descending trend upon increasing hydrochar ratio in blends. The study revealed that hydrochar co-combustion with lignite is a cost-effective, sustainable, eco-friendly, and promising alternative for energy generation.