Energy analysis on drying process for hydrothermal-treatment products of degradable organic wastes

With the depletion of fossil fuel resources and increasing effects of serious environmental pollution, more and more attention is paid to energy-saving and environmental protect. This work proposes the combination of hydrothermal degradation (HTD) and superheated steam (SHS) drying in disposal and processing of degradable organic wastes in municipal solid wastes (MSW). Energy analysis is applied to the combined process. The analysis covers the ranges of dryer inlet temperatures of 202.38–234.19°C and feed water content of 32.5–65%. The comparison between the novel efficient combined process and conventional hot-air drying process is carried out. Thermal energy analysis shows that the combination of HTD and SHS drying can achieve thermal energy self-sufficiency (TES) more than 60% by manipulating process variables. Compared with hot-air drying, the proposed system can generate energy savings of 50% for an inlet temperature of 212.83°C and 30%–65% feed water content, and energy savings of 40%–49% for an inlet dryer temperature of 202.38–234.19°C and 50% feed water content.