除氧水管线泄漏原因分析及应对措施

The Reasons and Countermeasures for Leakage of DeoxygenationWater Pipeline in FCC Unit

中海油惠州石化有限公司4.8 Mt/a催化裂化装置自省煤器返回除氧器管线,由于除氧水降压闪蒸而导致汽蚀严重,管线频繁泄漏。装置采用切削除氧水泵叶轮的方法,成功解决了管线汽蚀而导致的泄漏问题。但在解决管线泄漏问题的同时,烟气余热未得到充分回收,装置操作费用每年增加约78万元。装置采用降低除氧器水温的办法尽可能多地回收烟气余热,降低装置操作费用。结果表明,除氧器水温下降1.33 K,年操作费用节省143.69万元。虽然降低除氧器水温可以降低装置操作费用,但还需考虑烟气露点温度和除氧效果等因素,以确定合适的降氧器水温。

In the 4.8 Mt/a FCC unit of CNOOC Huizhou Petrochemical Co.,Ltd.,the pipeline from economizer returned to deaerator was caused serious cavitation and frequent leakage at elbow due to the pressure-reducing flash of deoxidized water.The unit which adopts the method of cutting the impeller of deoxygenation pump,successfully solves the leakage problem caused by pipeline cavitation.However,while solving the problem of pipeline leakage,the waste heat of flue gas had not been fully recovered,and the operation cost of the unit had increased by about 780,000 yuan per year.The method of reducing the water temperature of deaerator was adopted to recovering as much waste heat as possible and reducing the operation cost of the FCC unit.The results showed that the water temperature of deaerator decreased by 1.33 K,and the annual operation cost was saved by 1.4369 million yuan.Although reducing the water temperature of deaerator can reduce the operation cost of the FCC unit,it was necessary to considering the dew point temperature of flue gas and the effect of deaeration to determining the appropriate water temperature of deaerator.