The causes of fouling on equipment in FCCU flue gas system were analyzed. It was concluded that the direct cause of catalyst fines deposition was the addition of olefin reduction component in catalyst formulation. The main cause of fouling was the failure to replace the equipment in flue gas system which resulted in over-load operation of equipment. Whereas, design shortcomings of critical-velocity venturi nozzle and the over-specification of fines in flue gas at the inlet of flue gas expander due to failure of cyclone separators were also major factors contributing to the fouling on blades of flue gas expander. After replacement of 1"-stage and 2 -stage cyclone separators, expansion of hole diameter, application of low-velocity nozzle instead of high-velocity nozzle, the fouling in flue gas system has been brought under control. No apparent fouling has been found after 17 months' operation and long-term safe operations of FCC unit and flue gas system have been ensured.%分析了催化裂化装置烟气系统设备结垢的原因,认为所使用催化剂配方中添加的降烯烃成分是导致催化剂细粉牯附的直接原因；而装置扩能没有更换烟气系统设备导致设备超负荷运转也是产生结垢的重要原因；文丘里管型临界流速喷嘴的设计缺点,各级旋分器失效导致进入烟机的烟气粉尘含量超标,也是烟机叶片结垢的主要因素.利用停工检修的机会,更换一二级旋分器、更换临界流速喷嘴并扩大孔径、采用低速喷嘴取代高速喷嘴控制系统催化剂细粉含量,使烟气系统结垢标本兼治.再生烟气系统连续运行17个月,没有出现较明显的结垢现象.实现了再生烟气系统与装置的长周期同步安全运行.
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