Experimental Study on Sewage Sludge Direct Drying in Granulating Type Rotary Drum Dryer

The granulating type rotary drum sewage sludge direct dryer was designed,and the influences of operation parameters,including the flow direction of sewage sludge and hot flue gas,the rotary speed of drum body,the obliquity of dryer,and the rotary speed of mixing spindle on dryer performance and drying effect were studied.The results showed that counter flow style is better than parallel flow style;2.5° obliquity is better than 5° obliquity;the optimum drum rotary speed exists when the obliquity is fixed;and high rotary speed of the mixing spindle is advantageous to sludge drying.Evaporation intensity A and evaporation coefficient α were two important parameters for dryer performance discussed based on the experimental data.The operation parameters of drier had great effect on A,but little effect on α.