碱性氮化物对催化裂化过程的影响及反应化学研究

采用小型固定流化床装置,考察了以喹啉和7,8-苯并喹啉为代表的碱性氮化物对大庆减压蜡油催化裂化过程的影响,探究碱性氮化物在催化裂化过程中的转化及产物中的氮分布规律,并采用分子模拟的方法研究其在催化裂化过程中的反应化学。结果表明:碱性氮化物的加入会导致反应转化率下降,并影响产物分布;喹啉和7,8-苯并喹啉在催化裂化过程中发生烷基化反应的可能性最大;在氢转移反应过程中,喹啉分子中的氮环更易被饱和,进而发生开环裂化反应生成苯胺类氮化物;7,8-苯并喹啉优先饱和中间的苯环,故能发生开环裂化反应生成氨气或脂肪胺,但不会生成苯胺类氮化物;烯烃和氨气可发生环化缩合反应生成苯胺及五元氮杂环化合物;小分子氮杂环化合物可发生烷基化、环化缩合反应生成大分子氮化物。

EFFECT OF BASIC NITROGEN COMPOUNDS ON FCC PROCESS AND RELATIVE REACTION CHEMISTRY

In order to study the influences and reaction chemistry of basic nitrogen compounds in FCC process，the model compounds of quinoline and 7，8-benzoquinoline were used to investigate the conversion rules of N-containing compounds and nitrogen distribution in FCC products by fixed fluidized bed（FFB）.The reaction chemistry of samples were studied by molecular simulation.The results showed that the addition of basic nitrogen compounds reduces the conversion and influences the product distribution.Quinoline and benzoquinoline are most susceptible to alkylation.In the process of hydrogen transfer，the nitrogen ring in the quinoline molecule is more easily saturated，and then the ring-opening cracking reaction generates aniline nitrides； while for 7，8-benzoquinoline，the benzene ring in the middle of the molecule is most probably to be saturated first by hydrogen transfer reaction，and then be converted to aliphatic amine or ammonia，but not generate aniline.Aniline and five element nitrogen heterocyclic compounds are generated by cyclic condensation reaction of ammonia with olefins.The macromolecular nitrogen compounds are produced from small nitrogen-containing molecules by alkylation or cyclization-condensation reactions.