Abstract:

Since March 2021, the phenomenon of after-burning has continued to occur in the regenerator of 800,000 TPY FCC unit in a refinery. This paper discusses the phenomenon from multiple aspects such as coke burning temperature, catalyst residence time, and oxygen partial pressure, according to the coking theory of coke burning drum, and comparing the operating parameters of multiple sets of the same type units. It is pointed out that the short residence time of the catalyst in the coke burning drum causes incomplete combustion of the catalyst, and the large amount of CO generated encounters excess oxygen in the dilute phase, leading to after-burning of the dilute phase of the regenerator. When the coke burning drum storage capacity is increased to 45 t/h, the residence time is extended to 81 seconds, the dilute phase temperature of the regenerator is reduced to 721 ℃, the temperature difference between the dilute phase and the dense phase is reduced to 20 ℃, and the phenomenon of after-burning of the regenerator is effectively controlled.

Key words: FCC unit, regenerator, after-burning, coke burning temperature, residence time, oxygen partial pressure, Crosser grille

摘要：

自2021年3月，某炼油厂800 kt/a催化裂化装置再生器持续出现尾燃现象。根据烧焦罐烧焦理论，对比多套同类型装置的运行参数，从烧焦温度、催化剂停留时间、氧分压等多个方面进行了探讨。分析发现：烧焦罐内催化剂停留时间过短影响了烧焦效果，造成催化剂燃烧不完全，产生的大量CO遇到稀相过剩氧，导致再生器出现尾燃现象。当烧焦罐藏量增至45 t/h时，停留时间延长至81～90 s,再生器稀相温度降至721℃,稀密相温差降至20℃,再生器尾燃现象得到有效控制。

关键词: 催化裂化装置, 再生器, 尾燃, 烧焦温度, 停留时间, 氧分压, Crosser格栅