城市污泥过热蒸汽与热风干燥特性  

Drying characteristics of thin layer sewage sludge in superheated steam drying and hot air drying

作　　者：张绪坤[1] 姚斌[1] 苏志伟[1] 孙瑞晨 罗俊[1] 吴起[1] 邢普[1] 

机构地区：[1]南昌航空大学机电设备研究所,南昌360063

出　　处：《环境工程学报》2015年第10期5049-5054,共6页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(51168038)

摘　　要：为研究城市污泥过热蒸汽和热风干燥特性,研制了一套常压内循环式干燥实验装置。以4 mm和10 mm污泥薄层为研究对象,在160~280℃温度下进行过热蒸汽和热风干燥特性实验。实验结果表明,随着温度升高过热蒸汽与热风干燥时间越来越接近,当温度达到280℃时,过热蒸汽干燥与热风干燥时间大致相同;过热蒸汽干燥初期存在凝结过程,4mm和10 mm污泥在160~280℃下凝结量范围为3.39~1.07 g和9.71~3.62 g,凝结现象的出现导致干燥速率出现负值,但随着温度升高凝结过程对整个干燥时间影响愈来愈轻。从干燥结束后污泥的表观形态可以观察到过热蒸汽干燥的污泥表面裂纹密集、质地疏松,没有发生燃烧炭化的现象,能够避免污泥干燥时可能发生燃烧和爆炸的危险。In order to study the drying characteristics of the sewage sludge thin layer in the process of superheated steam drying and hot air drying,the internal-circulation drying test-bed under normal pressure was built to carry out the superheated steam drying and hot air drying for the sewage sludge thin layer with a thickness of 4mm and 10 mm,respectively at 160—280℃. The results showed that the drying times of superheated steam and hot air will be more and more near along with drying temperature rising,the drying times of superheated steam and hot air are approximate at 280℃. Because of steam condensation at the beginning of the superheated steam drying process,the mass of the samples increases due to superheated steam coming to the cold surface of the sludge. Thus,the steam condensation mass for the sludge thin layer of 4 mm and 10 mm at the temperature 160—280℃ can be obtained respectively as 3. 39—1. 07 g and 9. 71—3. 62 g. As a result,the drying rate at the beginning of the superheated steam drying process will be negative number. The increase of the mass of condensation water and drying time was greatly influenced by the temperature of superheated steam,the higher the temperature,the smaller the increase. The results were also compared with those of hot air drying,the superheated steam drying was found to be most suitable drying method for drying sewage sludge as not oxidized and burnt after superheated steam drying even at high temperatures.

关 键 词：干燥 过热蒸汽 热风 污泥 

分 类 号：X705[环境科学与工程—环境工程]