【作者】 刘显成； 卢春喜； 时铭显；

【Author】 LIU Xian-cheng, LU Chun-xi, SHI Ming-xian (Department of Chem. Sci. and Eng., University of Petroleum, Beijing 102249, PR China)

【机构】 石油大学(北京)化学科学与工程学院；

【摘要】 在一套φ600 mm×7000 mm半圆形的大型有机玻璃两段环流实验装置上,采用FCC催化剂,在导流筒区表观气速0.101-0.670 m/s,环形区表观气速分别为0.049 m/s和0.099 m/s范围内,测定了导流筒壁与颗粒床层之间的传热系数、床层密度和颗粒环流速度的分布规律.结果表明床层密度和颗粒环流速度是影响传热的主要因素,而这两者的变化规律完全由导流筒区和环形区的气速来调控.传热系数随导流筒区气速的增加而增加,适当增加环形区气速能显著改善传热效果.实验结果表明,两段环流取热器比目前工业催化裂化装置使用的外取热器有较高的传热系数.通过理论分析,给出了两段环流取热器的传热系数关联式.更多还原

【Abstract】 Heat transfer between gas-solids suspension and both interior and exterior surface of a 1.0 m height draft tube in a 7.0 m high, 0.6 m inside diameter airlift loop heat exchanger was studied with FCC particles. Heat transfer coefficients were measured using six miniature cylindrical heat transfer probes that inserted in different axial localities for the wide range of superficial gas velocity (0.101≤vi≤0.670 m/s) in draft tube region and superficial gas velocity in annular region v0=0.049m/s and 0.99m/s, respectively. The bed density and particles circulation rate were also measured by optical fibers at the same conditions. The results show that heat transfer is largely governed by solids concentration and particles circulating rate. Heat transfer coefficients were increased with superficial gas velocity in the draft tube, and increase gas velocity in the annular region can properly improve the heat transfer status. The heat transfer is higher than any kind of heat exchanger now used in Fluid Catalytic Cracking Unit (FCCU) nowadays. Computational formulae of heat transfer coefficient are regressed according to the experimental data.更多还原