影响混合二甲苯收率及质量的因素分析

Analysis of Factors Affecting Yield and Quality of Mixed Xylene

结合某石化公司130万吨/年连续重整装置生产过程中的实际情况,探讨了影响混合二甲苯收率及质量的原因并提出了优化措施。结果表明:影响装置二甲苯收率主要原因是重整进料性质,装置二甲苯月收率大于18%时,加裂重石脑油掺量均大于25%,故在生产过程中需关注原料组分的变化,及时调整进料量。当催化剂氯含量偏低时,部分烷烃及环烷烃未转化为芳烃,使得二甲苯产品非芳烃含量增加,因此再生催化剂氯质量分数控制在1.1%~1.3%。适当提高脱庚烷塔灵敏板温度以降低混合二甲苯中甲苯及非芳烃含量,同时调整二甲苯塔操作尽量回收二甲苯提高二甲苯收率,目前混合二甲苯收率为13.82%。为解决该重整装置重整汽油干点较高影响汽油调和的问题,提出对重整装置二甲苯塔增设塔侧线抽出线。同时通过改变两个白土罐前后串、并联顺序保证混合二甲苯质量持续合格,并且提出重整生成油液相加氢项目以改善二甲苯产品溴指数控制难的问题。

Based on the actual situation of 1.3 million tons/year continuous reforming unit in Huabei Petrochemical Company,the causes affecting the yield and quality of mixed xylene were discussed and the optimization measures were put forward.The results show that the main reason that affects the yield of xylene is the nature of reforming feed.When the monthly yield of xylene is greater than 18%,the content of cracked heavy naphtha is greater than 25%,so it is necessary to pay attention to the change of raw material composition and adjust the feed amount in time.When the chlorine content of the catalyst is low,some alkanes and cycloalkanes are not converted into aromatics,which makes the non-aromatics content of xylene products increase.Therefore,the chlorine content of the regenerated catalyst is controlled within 1.1%~1.3%.The temperature of the sensitive plate of the deheptane tower should be appropriately increased to reduce the content of toluene and non-aromatic hydrocarbon in the mixed xylene.At the same time,the operation of the xylene tower should be adjusted to recover xylene as far as possible to improve the yield of xylene.At present,the yield of the mixed xylene is 13.82%.In order to solve the problem that the high dry point of reforming gasoline in No.3 reforming unit affects the blending of gasoline,it is proposed to add the side line extraction line to the xylene tower of reforming unit.At the same time,the mixed xylene quality was guaranteed to be qualified continuously by changing the sequence of the two white clay tanks,and the project of oil phase hydrogenation for reforming generation was proposed to improve the problem of bromine index control of xylene products.