Wall-scaling prevention in cryogenic external cooler of ammonium chloride solution by liquid-solid fluidization  

作　　者：Yusu Zhu Yongli Ma Mingyan Liu 

机构地区：[1]School of Chemical Engineering and Technology,Tianjin University,Tianjin,300350,China [2]State Key Laboratory of Chemical Engineering(Tianjin University),Tianjin,300350,China

出　　处：《Particuology》2024年第11期120-132,共13页颗粒学报（英文版）

基　　金：supported by the Natural Science Foundation of Tianjin City(grant No.22JCQNJC00550);Open Research Fund of State Key Laboratory of Multiphase Complex Systems(grant No.MPCS-2021-D-06).

摘　　要：A double-tube cooler with liquid-solid circulating fluidization operation and corresponding parameter measuring system are developed to avoid fouling of inner walls of heat exchange tubes in a cryogenic temperature external cooler of ammonium chloride solution in soda ash production.Wall-scaling prevention performance of the cooling process is experimentally evaluated using convection and overall coefficients,enhancement factor,wall temperature and fouling resistance.Effects of different volume fractions of added particles,particle size,superficial liquid velocity,and cooling medium temperature on heat transfer are examined.Under present conditions,convection coefficient of liquid-solid flow inside the tube of external cooler is higher than that of the liquid phase flow,increased by 0.7–2.8 times,enhancing cooling performance obviously.Convection coefficient initially increases and then decreases as the volume fraction of added particles increases,reaching its maximum value at a volume fraction of 2.0%.The wall-scaling prevention effect of glass beads mainly depends on the volume fraction of added particles;optimal anti-fouling effects are achieved when adding particles at a volume fraction of 2.0%,regardless of changes in superficial liquid velocity or cooling medium temperature.This study lays a foundation for industrial applications of this new technique of fluidized bed external coolers.

关 键 词：FOULING Liquid-solid circulating fluidized bed External cooler Two-phase flow Ammonium chloride 

分 类 号：TG14[一般工业技术—材料科学与工程]