Advantages and optimization conditions of heat pump sludge drying: A review

^a Shanghai University of Electric Power, Shanghai 200090, China
^b School of Mechanical Engineering, Tongji University, Shanghai 200092, China

^* E-mail address: gaonaiping@tongji.edu.cn.

Abstract

The integration of heat pump technology into sludge drying combines heat pumps with traditional convective drying techniques. The process of moisture and apparent morphology changes during sludge convective drying is succinctly summarized from literatures. The analysis also covers the effects of drying conditions, including temperature and airflow velocity, on the energy consumption of heat pump drying. Leveraging the precise and independent control capabilities of heat pump dryers, various heat pump intermittent drying methods are compared. By adjusting drying conditions at different stages of sludge drying, a balance can be achieved between rapid external moisture diffusion and reduced energy consumption of the heat pump system.