Co-hydrothermal carbonization of pineapple and watermelon peels: Effects of process parameters on hydrochar yield and energy content

Abstract

This research determines the effects of temperature, residence time and mixing ratio on hydrochar yield and energy content from the co- hydrothermal carbonization (co-HTC) of pineapple and watermelon peels. The research assessed optimum conditions for higher hydrochar yields and energy content as well as the synergistic effects of pineapple and watermelon peels on the co-HTC process. Results show that hydrochar yield decreased with increasing temperature and residence time. In contrast, energy and carbon content increased with increasing temperature and residence time. Pineapple peels showed greater hydrochar yields and energy contents than watermelon peels. The optimum conditions for co-processing are 180 °C, 120 min and a mixing ratio of 70:30 for pineapple and watermelon peels respectively. Synergistic effects occurred during the co-HTC of pineapple and watermelon peels with a decrease in hydrochar yield and an increase in energy and carbon content.