Water softening by induced crystallization in fluidized bed

作     者：Yuefang Che Rong Fan Danfeng An Yujie Cheng Hazel Tan 

作者机构：School of Civil and Environment Engineering Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants University of Science and Technology Beijing Beijing 100083 China. 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2016年第28卷第12期

页      面：109-116页

核心收录：

学科分类：080706[工学-化工过程机械] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070305[理学-高分子化学与物理] 0807[工学-动力工程及工程热物理] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 

基　　金：supported by the China National Critical Project for Science and Technology on Water Pollution Prevention and Control (No. 2014ZX0710-012) 

主　　题：Fluidized bed Induced crystallization Hardness Softening capability Quartz sand 

摘      要：Fluidized bed and induced crystallization technology were combined to design a new type of induced crystallization fluidized bed reactor. The added particulate matter served as crystal nucleus to induce crystallization so that the insoluble material, which was in a saturated state, could precipitate on its surface. In this study, by filling the fluidized bed with quartz sand and by adjusting water pH, precipitation of calcium carbonate was induced on the surface of quartz sand, and the removal of water hardness was achieved. With a reactor influent flow of 60 L/hr, a fixed-bed height of 0.5 m, pH value of 9.5, quartz sand nuclear diameter of 0.2-0.4 mm, and a reflux ratio of 60%, the effluent concentration of calcium hardness was reduced to 60 mg/L and 86.6% removal efficiency was achieved. The resulting effluent reached the quality standard set for circulating cooling water. Majority of the material on the surface of quartz sand was calculated to be calcium carbonate based on energy spectrum analysis and moisture content was around 15.994%. With the low moisture content, dewatering treatment is no longer required and this results to cost savings on total water treatment process.