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 b...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.展开更多
基金supported by the Shanghai Natural Science Foundation (No. 11ZR1400700)the Fundamental Research Funds for the Central Universities (13D111315)
文摘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.
