Hydrochar as an Energy Alternative to Coal: Effect of Temperature on Hydrothermal Carbonization of Paper Board Mill Sludge

Abstract

Hydrothermal Carbonization is a thermochemical conversion process in which a biomass is processed under hot compressed air to form carbon rich products called as hydrochar. Hydrochar is a hydrophobic, condensed and friable solid product with a fuel property similar to conventional non-renewable energy sources like coal and lignite. Hydrothermal Carbonization performed with Effluent Treatment Plant (ETP) sludge at a temperature range of 180-240℃ for a time period of 4 hours in a hydrothermal autoclave reactor resulted in the production of hydrochar with good energy values thereby ensuring its utilization as an alternative to coal. The energy properties like higher heating value (15.25 MJ Kg-1), energetic recovery efficiency (69.8%) and energy densification (1.24) were found to increase after hydrothermal carbonization at 220° for 4 hours