摘要
针对现有用于流化床换热器固体颗粒的密度高、强度低、不耐磨等缺点,采用溶胶滴球-热油柱成型法,制备低密度球形ZrO_(2)/SiO_(2)/Al_(2)O_(3)复合陶瓷颗粒,研究ZrOCl2溶液和硅溶胶加入顺序、n(Zr)/n(Si)/n(Al)对所制备复合陶瓷颗粒的微观结构及物化性能的影响,评估所制备颗粒在流化床传热中应用的可行性。结果表明:n(Zr)/n(Si)/n(Al)为1∶1∶60,先滴加锆源再滴加硅源合成混合溶胶,由此制得的氧化铝基ZrO_(2)/SiO_(2)/Al_(2)O_(3)陶瓷颗粒的形状近似为球形,其平均直径为1.5 mm,干湿颗粒密度分别为1740和2170 kg·m^(-3),远低于普通陶瓷颗粒的密度(2400~2900 kg·m^(-3)),较低的密度有利于流化床的均匀流化,从而有利于流化床强化传热和防垢除垢;干湿单颗粒抗压强度分别为116.0和115.7 N,完全能满足流化床操作对固体颗粒强度的要求;此外,所制得的颗粒还具有出色的耐磨性能和耐酸碱侵蚀性能。综合考虑颗粒的形状、大小、密度、机械强度、耐磨及耐腐蚀性能等,可以预期,所制得的氧化铝基复合陶瓷颗粒能很好地应用于管式换热器的流化床强化传热和防垢除垢。
In view of the shortcomings of the existing solid particles used in fluidized bed heat exchang-ers,such as high density,low strength and low wear resistance,low-density spherical ZrO_(2)/SiO_(2)/Al_(2)O_(3) composite ceramic particles were prepared by sol-gel and hot oil column curing methods,and the effects of ZrOCl_(2 )solution and silica sol addition sequence and Zr/Si/Al molar ratio on the microstructure and physicochemical properties of the prepared composite ceramic particles were studied,and the feasibility of the application of the prepared particles in fluidized bed heat transfer was evaluated.The results show that the as-prepared particles with a Zr/Si/Al molar ratio of 1∶1∶60 have a dry granule density of 1740 kg·m^(-3) and wet granule density of 2170 kg·m^(-3),much lower than that of the normal ceramic(2400~2900 kg·m^(-3)).The lower density is beneficial to their uniform fluidization and distribution in the heat exchange tube bundle,and hence ensures the effectiveness of preventing/removing scale and en-hancing heat transfer.Besides,the particles with a mean diameter of 1.55 mm present good wear and corrosion resistances,and dry and wet single particle compressive strengths of 116.0 N and 115.7 N,re-spectively,which are high enough for the fluidized bed.Comprehensive consideration of size,density,mechanical strength,and wear and corrosion resistances,the as-prepared spherical composite ceramic particles are suitable for fluidized bed,especially in a tube heat exchanger for preventing/removing scale and enhancing heat transfer.
作者
俞璐琦
马红钦
罗心悦
高君宇
谷星朋
刘嘉豪
YU Luqi;MA Hongqin;LUO Xinyue;GAO Junyu;GU Xingpeng;LIU Jiahao(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China;Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology,Tianjin University,Tianjin 300072,China)
出处
《化学工业与工程》
CAS
CSCD
北大核心
2024年第4期138-146,共9页
Chemical Industry and Engineering
关键词
溶胶-凝胶法
制备
氧化铝基复合材料
球形颗粒
流化床传热
sol-gel
preparation
alumina-based composites
spherical particle
fluidized bed heat transfer
