催化裂化再生器二级旋风分离器料腿顶端结垢分析与对策

Analysis and countermeasures of fouling on top of feed leg of FCCU regenerator

中国石油天然气股份有限公司锦州石化分公司第三套催化裂化装置再生剂中0~20μm筛分增加后,第二再生器(二再)一级旋风分离器入口催化剂密度上升,二再二级旋风分离器料腿顶端开始结垢,后期二再主风分布管损坏,烧焦罐返混偏流,催化剂循环量受限。针对性提高二再主风流量后,二再二级旋风分离器入口线速从24.2 m/s上升到25.68 m/s,催化剂细粉冲刷料腿顶端并不断结垢,最终造成二再少量跑剂。对二再二级旋风分离器进行改造,灰斗直筒段延长200 mm,灰斗锥体段锥角由11.9°减小至11.4°,有效避免了料腿顶端结垢的问题。提出将二再主风分布管改造为主风分布板,并加衬耐磨衬里,可提高运行周期,预防因二再主风分布器损坏,二再烧焦罐返混偏流。

After the 0~20μm sieving in the regenerant of the third FCCU of PetroChina Jinzhou Petrochemical Company increased,the inlet density of the first-stage cyclone separator increased,and the top of feed leg of second-stage cyclone separator began to foul.When the main air distribution pipe was damaged,the backmixing and bias flow occurred in the coke burning drum,and the catalyst circulation was limited.After increasing the main air flow rate,the inlet linear velocity of second-stage cyclone separator increased from 24.20 to 25.68 m/s.The fine powders of catalyst scoured the top of the feed leg and continuously fouled,resulting in a small amount of catalyst loss.The second-stage cyclone separator was transformed.When the straight section of the ash hopper was extended by 200 mm,and the cone angle of the ash hopper cone section was reduced from 11.9°to 11.4°,the problem of fouling on the top of the feed leg was effectively avoided.It was proposed to transform the main air distribution pipe into the main air distribution plate and add wear-resistant lining,so as to improve the operation cycle and prevent backmixing and bias flow of the coke burning drum due to the damage of the main air distributor.