Hydrochar Production from Cacao Pod Husk by Hydrothermal Carbonization Process

The project aimed to produce hydrochar, an energy product, from wet biomass using hydrothermal carbonization, a process operating at subcritical water condition using cacao pod husk (CPH) as sample material. The abundance and lignocellulosic nature of CPH make it a potential candidate for the production of an alternative fuel substitute to natural coal. Increasing the calorific content with improved energy and mass density properties were the primary aim of the hydrothermal carbonization (HTC) of CPH into hydrochar fuel pellet. Using a prototype 20 L HTC reactor, two main parameters, temperature and reaction time were subjected to evaluation of their effects in the hydrochar output. The reaction severity as affected by either temperature or reaction time showed significant effect in the resulting mass yield (MY), higher heating value (HHV), and energy yield (EY). An increasing HHV was observed as temperature and reaction time increases. The HHV increases from 18.65 to 24.68 MJ/kg as the treatment combinations progresses from 180 °C - 6 h to 220 °C - 12 h. This is equivalent to an increase in energy densification from 1.10 to 1.45. In terms of added energy, the resulting value showed 10 % to 45 % increase per unit mass of material. The HTC process increases the calorific content of the biomass after conversion even at the lowest temperature and shortest duration by more than 1 MJ/kg as compared to its fresh or raw state.