FCC装置主风分布管喷嘴磨损的气相流场分析水

ANALYSIS OF THE GAS-PHASE FLOW FIELD FOR THE EROSION OF NOZZLES OF PIPE DISTRIBUTOR IN FCCU

用FLUENT流体计算软件对FCC装置再生器树枝状分布管喷嘴流场进行了计算,分析了喷嘴发生磨损的机理。对喷嘴流场的计算表明喷嘴磨损是催化剂颗粒造成的,属于气固两相流冲蚀磨损。由于某些喷嘴的压力降偏低和流场存在偏流,造成催化剂颗粒倒流至喷嘴内部或分布支管内部。催化剂颗粒流经喷嘴时,斜向冲击内壁产生冲蚀磨损。磨损首先发生在喷嘴内壁局部区域,形成圆弧状磨损痕迹,再将喷嘴磨穿,逐渐扩大为整个喷嘴,磨掉喷嘴。这些分析结果可为主风分布管的设计提供帮助。

Gas flow field in the nozzles of distributor is simulated by using a commercial software, FLUENT, to understand the erosion inside the nozzles in FCCU. The computational result indicates that the erosion of the nozzles is attributed to the impact of the catalyst particles. Some catalyst particles are entrained into branch pipes from nozzles due to the low pressure drop in some nozzles and uneven gas flow of nozzles along branch pipes of the distributor. When these particles flow through nozzles their impingement against the internal wall of nozzles results in erosion. It is initially a pit erosion, which develops into a hole and finally wears out the entire nozzle. The analysis results provide very good information for the design of the pipe distributors in FCCU.