Study on the Kinetics of Shell Powder Intensified Drying Process of Sludge

Abstract

Based on the problems of large yield of sludge, low degree of shell resource utilization and large mass transfer resistance of sludge drying process in China, the drying characteristics and water migration rules of shell powder quenched sludge are studied in this paper. Single-factor and orthogonal experiments of drying temperature, thin layer thickness and mixing ratio are performed, and the results are fitted to the drying kinetics model. The results show that the drying process is best when the mixing ratio is 10:1; The degree of influence of each factor is: thin layer thickness > mixing ratio > drying temperature, the optimal process is: mixing ratio of 10:1, drying temperature of 160°C and thin layer thickness of 6 mm; The Midilli and Kucuk model in the kinetic analysis can better describe the water migration in the sludge. According to Fick’s second law and Arrhenius equation, the fitting equations of pure sludge and mixed sludge at 100° C -160°C and 6 mm are obtained, shell powder quenched sludge has greater effective diffusion coefficient and smaller activation energy than pure sludge, which shows that the addition of shell powder can optimize the drying process of sludge.