Physicochemical, structural and combustion characterization of food waste hydrochar obtained by hydrothermal carbonization.

A solid carbon-rich product hydrochar, was prepared using hydrothermal carbonisation of food waste at temperatures of 200, 250 and 300 °C. To acquire detailed insight into physicochemical and structural properties, hydrochar samples were characterised using a range of techniques. The carbon content and higher heating value of food waste increased considerably from 39 to 73% and 15 to 31 MJ/kg corresponding to the heating temperature. The blends of hydrochar and coal prepared in three different ratios (5%, 10% and 15%) exhibited different thermal behaviour. The overall results of co-combustion study showed that the activation energy of hydrochar samples decreased from 56.78 KJ/mol to 29.80 KJ/mol with increase in temperature. Hydrochar prepared at 300 °C with coal blending ratio of 10% exhibited the lowest activation energy of 19.45 KJ/mol. Additionally thermal gravimetric analysis of the samples showed that high temperature carbonization can increase the combustion properties of hydrochar.