title: Experimental study on agitated drying characteristics of sewage sludge under the effects of different additive agents.
abstract: Drying experiments of dewatered sewage sludge (DSS) were conducted on a agitated paddle dryer, and the effects of additive agents, i.e., CaO, pulverized coal (PC), heavy oil (HO), and dried sludge ("DS" through back mixing) on the agitated drying characteristics of DSS were investigated. The results indicated that CaO can significantly increase the drying rate of DSS. The drying rate at CaO/DSS (mass ratio)=1/100 was 135% higher than that of CaO/DSS=0. Pulverized coal has no obvious effect on drying rate, but the increase of PC/DSS can promote breaking up of sludge lump. Heavy oil was found to be slightly effective in improving the drying rate of DSS in the examined experimental range of HO/DSS=0-1/20. It is also found that HO can reduce the torque of the dryer shaft, due to its lubrication effect. Back mixing of DS was found to be effective in alleviating the unfavorable effect of the lumpy phase by improving the mixing effect of the paddle dryer. There was a marked increase of drying rate with an increase of the DS/DSS in the experimental range of DS/DSS=0-1/3.
authors: School of Environmental Science and Engineering, Donghua University, Shanghai 201620, China. Electronic address: dengwy@dhu.edu.cn.
authors: Wenyi
authors: W
authors: Deng
authors: School of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
authors: Yaxin
authors: Y
authors: Su
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry; D003031:Coal; D003890:Desiccation; D009821:Oils / Q000737:chemistry; D010087:Oxides / Q000737:chemistry; D012722:Sewage
chemical_list: D017610:Calcium Compounds; D003031:Coal; D009821:Oils; D010087:Oxides; D012722:Sewage; C016538:lime
keywords: Additive agent; Drying; Sewage sludge