降低催化裂化汽油烯烃含量技术措施探索

为满足国Ⅵ(A)标准车用汽油生产，某公司4.8 Mt/a催化裂化装置（MIP工艺）通过优化工艺条件以降低稳定汽油烯烃含量。结果表明：在第一反应区出口温度提高4 ℃时，稳定汽油烯烃体积分数下降2.4百分点；在平衡剂微反活性提高2.8个单位时，稳定汽油烯烃体积分数降低4.6百分点；在粗汽油回炼量为15 t/h时，稳定汽油烯烃体积分数降低1.3百分点；在稳定汽油终馏点提高4 ℃时，稳定汽油烯烃体积分数降低0.3百分点。降低催化裂化汽油烯烃含量技术措施的方向主要是增强氢转移反应和小分子汽油烯烃选择性裂化反应，都属于二次反应，由此会导致焦炭产率增加。大型炼油企业应综合考虑汽油调合池组分，以综合效益为目标选择合适的催化裂化稳定汽油烯烃含量。

TECHNICAL MEASURES TO REDUCE OLEFIN CONTENT OF FCC GASOLINE

In order to reduce the olefin content in stabilized gasoline of FCC unit (MIP process) to meet the national VIA standard of vehicle gasoline, the optimization of operation conditions was carried out in a 4.8 Mt/a FCC unit. The results showed that the volume fraction of olefins in stabilized gasoline decreased by 2.4 percentage points by increasing the temperature of the first reaction zone by 4 ℃; the increase of micro-reaction activity of the equilibrium catalysts of 2.8 units led to a reduction of olefin content by 4.6 percentage points; recycling the crude gasoline at a rate of 15 t/h resulted in a reduction of olefin content by 1.3 percentage points, and increasing the final boiling point of stabilized gasoline by 4℃ would decline the olefin content by 0.3 percentage points. The main principles of technical measures are to enhance the hydrogen transfer reaction and the small molecule olefins cracking reaction. These reactions are secondary reactions and result in a high coke yield. The large oil refining enterprises should take the blending pool of gasoline into consideration and choose the appropriate olefin content of the stabilized gasoline to get the comprehensive benefits.