絮凝体形态学和密度的探讨Ⅱ-环境科学学报.PDFVIP

第 20 卷第 4 期 环 　境 　科 　学 　学 　报 Vol . 20 ,No . 4 2000 年 7 月 AC TA SCIEN T IA E CIRCU M STAN T IA E J uly ,2000 ( ) 文章编号 2000 　　　中图分类号 :X13 1. 2 　　　文献标识码 :A 絮凝体形态学和密度的探讨( Ⅱ) ———致密型絮凝体形成操作模式 ( ) 王晓昌　西安建筑科技大学环境与市政工程学院 ,西安 　7 10055 ( ) 丹保宪仁　北海道大学 , 日本札幌 ,0600008 摘要 :论述了致密型絮凝体形成操作的两种模式 :脱水收缩和逐一附着 ,前者通过长时间机械搅拌进行 ,后者通过上向流造 粒流化床操作进行. 实验结果表明,两种操作均可生成接近于球型的致密化团粒 ,但脱水收缩条件下生成的团粒仍具有颗粒 有效密度随粒径增大而降低的特点 ,其分形维数为2 40 —2 47 . 而逐一附着条件下生成的团粒密度基本上与粒径无关 ,可认 为其分形维数接近于3 . 通过讨论上向流造粒流化床操作条件 ,并将实验得到的致密型絮凝体密度和常规絮凝体密度进行比 较 ,说明用该方法实现逐一附着型絮凝操作是促使絮凝体致密化的有效途径. 关键词 :絮凝体密度 ;脱水收缩 ;逐一附着 ;造粒流化床 A study on the morphology and density of flocs Ⅱ. Operation modes f or compact floc f ormation ( WAN G Xiaochang 　 School of Environmental and Municipal Engineering ,Xi ’an Universit y of Architecture and Technology , Xi ’an 7 10055) ( Hokkaido University ,Sapporo ,0600080 ,J apan) TAMBO Norihito 　 Abstract :Two operation modes for compact floc formationmechanical syneresis and onebyone attachment were discussed ,t he former being realized by longperiod mechanical agitation and t he later by t he fluidized pellet bed operation . Experimental result s showed t hat sp herical pellet s of high density were obtained by bot h met hods. However ,t he pellet s formed by mechanical syneresis still showed a tendency of decrease in t heir densit y wit h increase in particle size ,and t he fractal dimension of such kind of pellet s was about 2 . 40 — 2 . 47 . In contrast ,t he pellet s formed t hrough onebyone attachment had almost identical densit y reg