Influence of dry explosion combined with acid-spraying pretreatment on physicochemical and pyrolysis properties of Hybrid Pennisetum

A method of “dry chemical thermomechanical pretreatment” by combining dry explosion with acid-spraying was carried out for Hybrid Pennisetum (HP) to improve energy efficiency and reduce the negative environmental impact. The physicochemical and pyrolysis properties of HP treated by acid-spraying, dry explosion (DE), and acid dry explosion (ADE) methods were analyzed. The results showed that the DE process can efficiently disrupt the complex biomass structure through the removal of hemicellulose, the dissolution and relocation of lignin, and the dissolution of amorphous cellulose. Moreover, the reaction intensity of the DE pretreatment was significantly enhanced with acid-spraying. The higher heating value of HP treated by ADE 210 °C increased from 17.85 to 21.23 MJ/kg, while the pyrolysis activation energy declined from 48.31 to 38.79 kJ/mol. The ADE pretreatment improved fuel properties and pyrolysis characteristics of HP with the bond conversion of C–O to C–C/C = C. This research supplied an effective and eco-friendly method of dry explosion combined with acid-spraying for improving the fuel and pyrolysis properties of lignocellulose biomass for thermochemical applications. This method can resolve the problem of high energy consumption and waste liquid production for industrial application process.