加氢高压换热器泄漏原因分析及解决措施

Analysis of hydrocracker high-pressure heat exchanger leakage and solutions

针对大庆石化分公司炼油厂260 kt/a加氢裂化装置高压换热器频繁内漏的状况,深入分析造成内漏的原因,主要有:(1)螺栓预紧力不够;(2)温度变化;(3)压力升降。提出了解决措施:(1)消除螺栓内部的残余应力,提高螺栓的抗疲劳强度;(2)将浮头原回弹能力小的齿形复合垫更换为回弹力大的波齿形复合垫;(3)在回装浮头和大盖时,螺栓一定要均匀、对称拧紧,并且要有足够的预紧力;(4)工艺操作平稳,尽可能减少温度和压力上的波动; (5)在浮头和大盖螺栓两侧安装高温碟簧。通过一个周期的运行证明措施切实可行,彻底解决了加氢高压换热器的内漏问题,节省了检修费用,为装置的长周期安全平稳运行提供了有利保障。

The high pressure heat exchangers in the 5 600 b/d hydrocraker in the refinery of PetroChina Daqing Petrochemical Co. ,Ltd experienced frequent leakages. The causes of leaking were analyzed i. e. 1 ） insufficient pre-tightening of bolts, 2） temperature variations and 3 ） pressure fluctuations. The following measures were proposed such as 1 ） relief of internal residue stress of bolts to improve their anti-fatigue strength, 2） replacing the original compound pad with little resilience for the floating head was replaced with the ones with large resilience. 3 ） evenly tightening the bolts in reinstallation of the floating head, 4） stable process operation to possibly reduce the fluctuation in temperature and pressure, 5 ） installing high-temperature dish spring at the floating head and both sides of bolts. One month of on-stream operation shows that these practical measures have eliminated the leaking problems of heat exchangers, saved the maintenance costs and provided a solid foundation for the long-term stable safe operation of the unit.