NNI-1型C_5/C_6烷烃异构化催化剂长周期运行分析及建议

ANALYSIS AND SUGGESTIONS FOR LONG-TERM OPERATION OF NNI-1 C_5/C_6 ISOMERIZATION CATALYST

中国石化海南炼油化工有限公司0.2 Mt/a C5/C6烷烃异构化装置以连续重整装置的拔头油为原料,使用NNI-1催化剂,采用一次通过流程,不设脱异戊烷塔和稳定塔,经设在连续重整装置内的脱丁烷塔稳定处理后作为汽油调合组分。该装置于2006年9月开工投产,截至2015年3月已连续运行3个周期。长周期运行分析结果表明:前两个周期中NNI-1催化剂具有较高的异构化活性及选择性,C5异构化率为60%左右,C6异构化率为80%左右,C6选择性为15%左右,产品辛烷值基本达到技术指标要求(RON≥78);而在第三周期运行中,催化剂积炭增加等原因导致其异构化活性及选择性降低,异构化产品辛烷值提升能力呈现逐步衰减的趋势,提高反应苛刻度已不能弥补催化剂活性下降造成的产品辛烷值降低。为保证装置长周期运行,建议择机停工对催化剂进行再生,或是直接换用与装置原料性质匹配的异构化催化剂。

The CCR reforming topped oil is processed as the feedstock in a 0.2 Mt/a C5/C6 alkanes isomerization unit with once through mode and NNI-1 catalyst. The process has no de-isopentane tower and stabilization column. The isomerized product is stabilized in the debutanizer of CCR unit and used as a blending component of gasoline. The analysis for the first two cycles shows that the NNI-1 catalyst has a good performance, higher activity and stability. The RON of the product is greater than 78, the isomerization rates of C5 and C6 are over 60% and 80%, respectively, C6 selectivity is about 15%. While in the third cycle run, the decline of the isomerization activity and selectivity becomes obvious, the prod- uct octane is gradually lowered, and increasing the reaction temperature is not able to overcome the decrease of catalyst activity. In order to ensure the long term operation, the catalyst regeneration or switching to a super acid catalyst is suggested.