Abstract:

The catalytic cracking unit is an important efficiency generating unit in the refinery. The flue gas turbine recovers the heat energy and pressure energy in the regenerated flue gas and drives the main fan to do work. In this paper, the flue gas turbine of 0.8 MM TPY catalytic cracking unit is a two-stage moving blade structure. Due to the frequent scaling of rotor blades, blade roots and other components during operation, when the scale suddenly falls off, the machine set vibration exceeds the standard, and the unit is forced to reduce the load for online scale removal or stop to replace the rotor, which has a serious impact on the long-term, high load and stable operation of the unit. In the double stage to single stage transformation of flue gas turbine rotor, many new technologies such as twisted high efficiency blades with large enthalpy drop of dynamic and static blades, new moving blade roots, and sealing cooling of blade roots have been applied. After transformation, the vibration value of flue gas turbine has been stable for a long time at about 25 μm, running well. The application of new technology has further improved the efficiency of flue gas turbine. The electric/generator has changed from the original power consumption to the state of less power consumption or even power generation, saving about 6 900 MW·h of electricity every year, with remarkable energy saving effect.

Key words: catalytic cracking, flue gas turbine, large enthalpy drop, dynamic and static blades, moving leaf roots, sealed cooling, diffuser

摘要：

催化裂化装置是炼油厂重要的创效装置，烟气轮机回收再生烟气中的热能和压力能，带动主风机做功。文中0.8Mt/a催化裂化装置烟气轮机属于两级动叶片结构，由于转子叶片和叶根等部件在运行过程中频繁结垢，当垢物突然脱落时，造成机组振动超标，装置被迫降低负荷进行在线清垢或停机更换转子，对装置的长周期高负荷稳定运行产生了严重影响。烟气轮机转子在双级改单级改造中，应用了动静叶片大焓降弯扭高效叶片、新型动叶叶根、叶根密封冷却等多项新技术。改造后烟气轮机振动值长期稳定在25μm左右，运行良好。新技术的应用使得烟气轮机效率提高，电动/发电机从原来的耗电转入少耗电甚至发电状态，每年节电大约6 900 MW·h,节能效果显著。

关键词: 催化裂化, 烟气轮机, 大焓降, 动静叶片, 动叶叶根, 密封冷却, 扩压器