超声波作用下渣油临氢热裂化反应机理

摘要

采用高温高压超声波反应器对惠州炼化的减压渣油进行超声波作用下的临氢热裂化反应,考察气相产物组成、液相产物组成、反应生焦 SEM形貌及元素分析,探讨在超声波作用下渣油临氢热裂化反应机理.结果表明,超声波作用下的渣油临氢热裂化反应的气相产物收率无明显差别,轻油收率略有增加,生焦率降低;焦炭的颗粒棱角比较圆滑,出现孔道结构,说明在超声波作用下,渣油临氢热裂化反应主要按自由基热反应机理进行,超声波的空化作用可促使渣油发生裂化反应,因此轻油收率略有增加,超声波的机械效应使悬浮在渣油中的生焦前驱物剧烈震荡,阻止其聚合,从而减少了结焦;焦炭中 Ni元素的大量增加说明了催化剂为结焦提供结焦中心.%Using a high-temperature and high-pressure ultrasonic reactor,the hydrothermal cracking reaction of vacuum residue of Huizhou Refinery.The gas product composition,liquid product composition,reaction coke SEM morphology,and element analysis were investigated to discuss the mechanism of hydrothermal cracking reaction under the effect of ultrasonic wave.The results show that there is no significant difference in the yield of gas products in hydrothermal cracking reaction mechanism of the residue under the effect of ultrasonic wave and the production rate of light oil has been increased slightly while that of coke has been slightly reduced.The angularity of the coke particles is relatively smooth and the pore structure appears,indicating that under the effect of ultrasonic wave,the hydrothermal cracking reaction of residual oil is mainly based on the radical thermal reaction mechanism and the cavatition of ultrasonic wave can promote the residuum to have cracking reaction so that the production rate of light oil has been slightly increased.The mechanical effect of ultrasonic wave causes the raw coke precursor suspended in the residue to oscillate violently,so as to prevent its polymerization,thus having reduced coking,the large increase of Ni in the coke indicates that the catalyst provides a coking center for coking.