基于多产化工品的重油原料烃类结构导向研究

STUDY OF HYDROCARBON STRUCTURE ORIENTATION FOR HEAVY OIL FEEDSTOCK TO PRODUCE MORE CHEMICALS

石油炼制的化工转型及中间基原油供给比例持续增大的趋势均愈发明显,中间基劣质渣油中硫、氮、重金属等杂原子含量高,稠环芳烃、胶质、沥青质等难裂化重组分多,对多产化工品途径带来挑战,需通过加氢等前处理工艺进行改质。基于重油分子水平组成、烃分子结构结合催化裂解反应化学研究,提出多产化工品的优势原料烃类组成结构为链烷烃、一环~四环环烷烃及烷基苯,需要渣油加氢与催化裂解两个单元很好地耦合。中间基渣油加氢改质的方向为稠环芳烃超深度加氢饱和并适度裂化。从分子水平表征中间基渣油加氢前后烃组成结构的变化显示,中国石化石油化工科学研究院以烃类结构为导向,采用加氢过程实现了多环芳烃、噻吩型含硫芳烃、胶质、沥青质的深度加氢饱和,定向转化为链烷烃和环烷烃尤其是一环~三环环烷烃等可多产化工品的优势烃类结构,进而与高选择性催化裂解技术耦合可实现劣质中间基渣油多产低碳烯烃和BTX(苯、甲苯、二甲苯)等化工品的目标。

The chemical transformation of petroleum refining and the proportion of intermediate crude oil supply have a tendency to increase continuously.However,the content of heteroatoms such as sulfur,nitrogen and heavy metals in intermediate base inferior residual oil is high,and there are many hard-to-crack heavy components such as polycyclic aromatic hydrocarbons,resins and asphaltenes,which bring challenges to the way of producing more chemicals and need to be upgraded by pretreatment processes such as hydrotreating.Based on the research of heavy oil molecular level composition,hydrocarbon molecular structure and catalytic cracking reaction chemistry,it is proposed that the best raw material hydrocarbon composition structure for chemicals production is paraffin,cycloalkanes and alkylbenzenes,which needs a good residue hydroupgrading coupling with catalytic cracking.The direction of hydrogenation upgrading of intermediate residue should be super-deep hydrogenation saturation of condensed aromatic hydrocarbons and moderate cracking.The changes of hydrocarbon composition structure of intermediate base residue before and after hydrotreating characterized by molecular level showed that the polycyclic aromatic hydrocarbons,thiophene-type sulfur-containing aromatic hydrocarbons,resins and asphaltenes were directionally converted into the dominant ideal hydrocarbon structure by deep hydrotreating for producing more chemicals,such as paraffins and cycloalkanes,especially monocyclic-tricyclic cycloalkanes.Furthermore,the coupling with highly selective catalytic cracking technology can achieve the goal of producing more chemicals such as light olefins and BTX from inferior intermediate base residue.