重油催化裂化装置再生烟气线路技术改造及效果分析

TECHNICAL TRANSFORMATION AND EFFECTIVENESS FOR REGENERATION FLUE GAS SYSTEM OF RFCCU

中国石化北京燕山分公司2.0Mt/a重油催化裂化装置在上一个周期的运行时间超过1 100天,再生烟气线路存在如下问题:烟道内多处衬里裂缝或开裂、高温取热器入口3处膨胀节腐蚀开裂,导致运行末期局部超温;高温取热器及余热锅炉存在积灰结垢现象,取热能力不足,导致运行末期余热锅炉出口温度高于200℃;高温取热后蒸汽过热器管束多处因碰撞造成硬伤,一条管束爆裂;烟机入口管线及临界喷嘴管线多次泄漏。检修期间对再生烟气线路进行了技术改造,大面积更换及修复衬里,更换膨胀节,对烟机入口管线材质进行升级,增设四级旋风分离器及临界喷嘴免维护系统,在余热锅炉出口增设复合相变换热器。改造后烟气外排温度降至150℃,再生线路无超温现象,在长周期高效经济运行方面取得了良好的效果。

The 3rd RFCCU with a capacity of 2.0 Mt/a in SINOPEC Beijing Yanshan Co. ran for more than 1100 days last operation period. Some issues arose in the flue gas regeneration circuit system at the end of the period. Cracks were found in the lining of the gas flue and local ultra-temperature due to three expansion joints being corroded at the inlet of high temperature heat removal device; the outlet temperature of waste heat boiler was more than 200℃ （design, 180℃） resulting in scaling; one tube bundle exploded and many nicks left; the inlet pipeline of flue gas turbine and the critical nozzle leaked several times. Multiple technical transformations were adopted during the maintenance this year. A large area of linings and five expansion joints were repaired or replaced, material of the inlet pipeline of flue gas turbine was upgraded, and the 4th cyclone separator and a composite phase change heat exchanger were added in the waste heat boiler exit. The operation results reveal that the outlet temperature is reduced to 150℃ and no ultra-temperature parts in the regeneration flue gas system is observed, resul- ting in an efficient, economical and long-period operation in RFCCU.