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

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。

ANALYSIS AND SUGGESTIONS FOR LONG-TERM OPERATION OF NNI-1 C5/C6 ISOMERIZATION CATALYST

Topped oil of CCR unit has been used as feedstock and used the once through process，do not set up the isopentane and the stabilize column, has been adopted in the 0.2Mt/a C5/C6 alkanes isomerization unit.Through debutanizer stabilized in the CCR unit as the blending component of gasoline.Analysis of the parameters in the first two cycles showed that the NNI-1 catalyst has good performance, higher activity & stability and the requirements of production have been met. RON greater than 78，the rates of C5 andC6isomerization are over 60% and 80% respectively. C6 selectivity is about 15% ，reached the technical requirements.The third cycle running data indicated that increasing the reaction temperature has not been able to overcome the reduction of catalyst activity, RON of the feedstock has been increased by 2-3 units and the rates of C5 andC6isomerization are about 50% and 70% respectively. C6 selectivity is low10% .Therefore recommend propose of a long-term running.