Characterization of Bio-coal Made via Hydrothermal Carbonization of Mixed Organic Waste

In this study, a mixture of sewage sludge, paper sludge, and food waste was hydrothermally carbonized to produce a renewable solid fuel. Hydrothermal carbonization (HTC) does not need a drying step, so it is a proper method to make biofuels from wet feedstocks. Fuel properties of the bio-coals produced via HTC of mixtures of sewage sludge, paper sludge, and food waste with different ratios were characterized. As the ratio of food waste in the mixture was increased, the content of fixed carbon and heating value were increased. Coal banding analysis proved that the ratio of carbon/ hydrogen/oxygen of the bio-coals were similar to those of a low-grade coal.