Abstract: According to the data of desulphurization wet flue gas of an 800,000 TPY FCC unit and the local meteorological conditions in winter, the flue gas de-plume process is designed with the temperature-humidity chart. The flue gas cooling and reheating de-plume scheme is suitable for a wider ambient temperature range, with more effective de-plume and more significant water-saving effect. Therefore, the flue gas cooling and reheating de-plume scheme is determined. Thermal calculation and comparison between indirect heat-exchange cooling and direct spray cooling are carried out. The results show that direct spray cooling has high heat transfer efficiency and large heat transfer area. Within the scope of process design, the circulating water amount of direct spray cooling is only 40%~60% of that of the indirect heat-exchange cooling. Direct spray cooling can significantly reduce the system energy consumption, operating costs and equipment investment. Direct spray cooling is a more economical and efficient flue gas cooling scheme.

Key words: FCC unit, desulphurization wet flue gas, de-plume process, indirect heat-exchange cooling, direct spray cooling

摘要： 根据某800 kt/a催化裂化装置湿法脱硫烟气数据和当地冬季气象条件,按温湿图进行烟气脱白工艺设计。烟气冷却再热法脱白方案适应的环境温度范围更宽、脱白更有效、节水效果显著,确定采用烟气冷却再热法脱白方案。进行了烟气间壁换热冷却与顺流喷淋冷却两种冷却方式的热力计算对比。结果表明,直接喷淋冷却换热效率高、换热面积大,工艺设计范围内,直接喷淋冷却的循环水量仅为间壁换热冷却的40%~60%。喷淋冷却能显著降低系统能耗,减少运行费用和设备投资,是一种较为经济高效的烟气冷却方案。

关键词: 催化裂化装置, 脱硫湿烟气, 脱白工艺, 间壁换热冷却, 顺流喷淋冷却