CGO关键组分结构分析及其对FCC反应性能的影响

STRUCTURE ANALYSIS OF KEY COMPONENTS IN COKER GAS OIL AND THEIR EFFECTS ON CATALYTIC CRACKING REACTION

以大港焦化蜡油(CGO)400～425℃窄馏分为研究对象,采用盐酸+糠醛分级抽提的方法富集其中的碱性氮化物及稠环芳烃,采用GC-MS对抽出物进行结构分析,并比较了抽提前后油样的FCC反应性能。结果表明,盐酸抽出相中的碱性氮化物主要是氮杂菲系和氮杂芘系,其中以苯并喹啉系及二苯并喹啉系含量最多;这类化合物与催化剂活性中心结合,使催化剂活性下降。糠醛再抽提抽出相中的稠环芳烃包括荧蒽、苯基萘、菲蒽系、芘系及苯并芘系,其中3～4环的稠环芳烃所占比例最大;这类化合物在催化剂表面缩合生焦,降低了CGO的FCC反应性能。盐酸及糠醛抽余油的FCC反应性能均得到了改善,但糠醛抽余油的改善程度不及盐酸抽余油;碱性氮化物对CGO的FCC反应性能的影响比稠环芳烃大。

400-425℃narrow fraction of Dagang coker gas oil（CGO） was chosen for the concentration of basic nitrogen compounds and condensed aromatics by the extraction of HCl and further furfural,respectively.After that,the possible structure of basic nitrogen compounds and condensed aromatics was determined by means of GC-MS,and the FCC reaction performance of oil samples before and after extraction were reviewed.The results showed that the basic nitrogen compounds extracted by HCl were a series of quinoline,benzoquinoline and dibenzoquinoline,among which the amount of benzoquinoline was the largest.The basic nitrogen compounds could integrate on the acid centers of catalyst and then decreased the activity of the catalyst during FCC reaction.While the condensed aromatics further extracted by furfural were a series of fluoranthene,phenylnaphthalene,phenanthrene,anthracene,pyrene and benzo（a）pyrene,the majorities of which were the condensed aromatics with 3-4 rings.The condensed aromatics could be condensed on catalyst surface to form coke.The FCC reaction performances of HCl and furfural raffinates oils were both improved,in which the former was better than the later.Basic nitrogen compounds had more effect on FCC reaction performance than condensed aromatics.