延迟焦化加热炉抑焦剂对焦炭形貌的影响

摘要

在高压反应釜中以辽河重油为反应原料,分别在460℃和500℃下进行模拟延迟焦化反应,考察了添加及未添加抑焦剂情况下,结焦率、气体组成、模拟蒸馏组成以及4组分的变化情况.采用SEM、偏光显微镜和XRD等手段分析了抑焦剂对焦炭形貌的影响.表征结果显示,加入抑焦剂后,焦炭的结构参数基本不变,焦炭的宏观形貌有所改变;抑焦剂使焦炭外表变得多皱褶且不规则,孔隙和裂缝增加.实验结果表明,加入抑焦剂后,在反应温度分别为460℃和500℃时,裂化气中甲烷含量的降幅分别为14.96百分点和11.94百分点、结焦率分别下降了3.06百分点和12.85百分点、汽油+柴油馏分含量增加、4组分分析的液体收率增加.%Delayed coking was simulated in an autoclave with the Liaohe heavy oil as feedstock at 460 ℃ and 500 ℃ separately.The coking rate,gas product composition and liquid product SARA composition (saturated hydrocarbons,aromatics,resin and asphaltene) were investigated with/without coking inhibitor.The morphology of the forming coke samples were characterized by means of polarizing microscope,SEM and XRD.The characterization indicated that,after the coking inhibitor was added,the coke crystal structural parameters,namely layer diameter and average layer distance,were not changed basically,while the coke morphologies were changed.On the coke surface,crease and irregular shape appeared,and pores and rips increased.At the same time,under the reaction temperature of 460 ℃ and 500 ℃,after the addition of coking inhibitor,the methane content in the cracking gas decreased 14.96 percentage point and 11.94 percentage point,and the coking rate decreased 3.06 percentage point and 12.85 percentage point,while the yields of gasoline and diesel oil in the simulated distillation increased,the liquid yields in SARA analysis also increased.