降低FCC装置NO_x排放的工程技术

基于FCC装置NO_x生成机理的研究,开发了降低再生烟气中NO_x排放的工程技术:新型高效汽提技术和低NO_x再生技术。工业应用表明,FCC装置汽提器和再生器主风分布器改造后,焦炭中氢质量分数下降了27%,汽提效率大幅提高;再生器主风用量下降了9%,分布管压力降下降了20%,再生器密相温度较改造前下降约10℃,密相温差由改造前的15℃左右下降为3~7℃,烧焦效率提高。在原料油性质和反应再生系统操作条件变化不大的情形下,再生烟气NO_x质量浓度由改造前的397.5 mg/m~3下降至235.6 mg/m~3,降低了40%。改造后,产品总液体收率提高了1.03百分点,年创收超1 000万元。该工程技术的实施降低了再生烟气中NO_x含量,是一种降低FCC装置NO_x排放的新途径。

Engineering technologies for reducing NOx emission of FCC unit

Based upon the formation mechanisms of NOx in FCC unit,a process of low NOx emission of regenerator flue gas has been successfully developed which is characterized by high-efficiency stripping and low NOx formation.The commercial application of the process shows that,after revamping of the FCCU stripper and main air distributor of the regenerator,the hydrogen in the coke is reduced by 27％,the stripping effi ciency is greatly improved,the main air requirement of the regenerator is lower by 9％,the pressure drop of the distributor is decreased by 20％,the temperature of the dense bed of the regenerator is 10 ℃ lower than that before the revamping,the temperature difference of the dense bed is dropped to 3 ～ 7 ℃ from 15 ℃ be fore revamping,and coke burning rate is improved.Without big changes of feedstock properties and operating conditions of the reactor and regenerator systems,the NOx in regenerator flue gas is reduced to.235.6 mg/m3 from 397.5 mg/m3 before the revamping,which is a 40％ reduction.After revamping,the total liquid yield is raised by 1.03％ and annual economic benefit is over 10.0 million Yuan.This process,which reduces the NOx in the regenerator flue gas,is a good process for the reduction of NOx emission of FCC unit.