延迟焦化装置空气预热器水热媒节能改造

克拉玛依石化公司150×104t/a延迟焦化装置加热炉热管空气预热器存在露点腐蚀和快速失效的问题,分析其原因和北方冬季严寒的天气条件有关:尽管烟气外排温度高于露点温度,但烟气侧底部热管管壁温度低于露点温度。对此,提出了采用水热媒技术的解决方案。实际改造过程中,为降低投资成本并满足除氧水系统压力的要求,采用了扰流子水热媒组合式空气预热器。改造完成后,烟气外排温度从改造前的234℃降低到152℃,降低了82℃;热空气温度从改造前的100℃升高到256℃,升高了156℃;热效率从改造前的87.35%提高到90.74%,提高了3.39个百分点;多回收烟气余热1901.31kW,每年节能54.76GJ,节约燃料费用121.3万元。该技术的成功应用,彻底解决了热管空气预热器存在的露点腐蚀和快速失效问题,可以保证装置长周期高效运行。

Using Heat Medium Water Technology to Raise Energy Efficiency of Delayed Coking Unit Air Preheaters

The heat-tube air preheater of the heating furnace of PetroChina Karamay Petrochemical Company＇s 150×10^4t/a delayed coking unit suffered two major problems-dew-point corrosion and fast failure.Technicians attributed this to the cold weather in winters in the north.Although the temperatui＇e of flue gas emitted was higher than dew-point temperature ,the temperature of the wall of the heat tube of the flue gas system was lower than dew-point temperature.These technicians proposed heat medium water technology as solution.In upgrading the unit,in order to reduce investment and meet the pressure needs from the deoxygenated water system,technicians introduced combined turbolator heat medium water air preheaters.After the upgrade,the temperature of flue gas emitted dropped to 152℃ from 234℃ ;the temperature of hot air rose tO 256℃ from 100℃;the heat efficiency rose to 90.74% from 87.35%;an additional 1901.31kW of residual heat was recovered from flue gas and 54.76GJ of power and 1.213 million Yuan of fuels were saved annually.The upgrade resolved the dew-point corrosion and fast failure problems for the heat-tube air preheater once and for all, allowing an efficient and long-term operation of the delayed coking unit.