Since 2016,the outlet pipeline of the feed heater to fractionation column in fluidized catalytic cracking and delayed coking diesel hydrogenation unit started to vibrate.In order to alleviate vibration,the E-205 outlet pipeline was fixed to the steel beam of the fractionation frame,and vibration of the pipeline was alleviated.However,since May 2017,the vibration of the E-205 outlet pipeline was intensified,leading to vibration of the whole fractionation frame,and the frame vibration drove the reflux tank,the attached pipeline and the relief valve of the stripper vibrating.T he reasons were analyzed:the unit blended straight-run diesel and produced the grade Ⅴ of the national standard diesel led to the increase of the light naphtha components generated by cracking in the hydrogenation reaction.The light naphtha components gradually accumulated within the stripper which caused the increase of the light components in the fractionation column feed,the rising of vaporization rate of medium within the E-205 outlet pipeline,and the increase of gas phase velocity,thus led to pipeline vibration.Through the implementation of the technological transformation,the recirculation oil of the stripper was changed to the hydrocracking unit stripper,the light components were transferred from the stripper,and the vibration was obviously alleviated.%2016年以来,催焦柴加氢装置分馏塔进料加热器E-205出口管线出现振动,为减轻振动,将E-205出口管线固定到分馏框架钢梁上,管线振动情况得到缓解.但从2017年5月开始,E-205出口管线振动加剧,带动整个分馏框架振动,从而带动汽提塔塔顶回流罐及附属管线、安全阀振动.分析其原因为:装置掺炼直馏柴油及生产国Ⅴ柴油导致加氢反应中裂化生成的轻石脑油组分增加,轻组分在汽提塔内逐渐累积,造成分馏塔进料中轻组分含量增加,E-205出口管线内介质气化率上升,气相流速增加,导致管线振动.通过实施技改措施,将汽提塔回流油改至加氢裂化装置汽提塔,将轻组分从汽提塔转移出去,振动情况明显减轻.
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