Characterization of solid biofuel produced from banana stalk via hydrothermal carbonization

In this study, banana stalk was used as a feedstock to produce hydrochar by hydrothermal carbonization (HTC). The effect of varying carbonization temperature (160 to 200 °C), varying reaction time (1 to 3 h) on yield, and higher heating value (HHV) of hydrochar was examined. With increasing temperature and reaction time, the hydrochar yield varied from 57.8 to 75.3%, whereas HHV varied from 18.1 to 18.9 MJ/kg. The carbon content, energy density, and energy recovery of all of the hydrochars were improved after conversion. The decrease of the O/C and H/C values was in agreement with the increasing coalification of hydrochars with increasing the severity of HTC conditions. The surface characteristics and thermal degradation properties of hydrochars were also assessed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The low ash and sulfur content after the HTC process indicates that banana stalk hydrochar can be a potential raw material for energy production.