催化油浆在自分散型纳米团簇量子点催化剂存在下缓和加氢稳定化反应耦合蒸馏脱固研究

Over 7.5 million tons of catalytic cracking slurry oil (SLO) is annually produced in China. Because of its high content of aromatic components, SLO is widely believed to be an important potential feedstock for manufacturing high-value petrochemical products, such as needle coke. However, this promising utilization is heavily undermined due to its high solids content of more than 0.2%. Distillation is an important potential solution to removing solids from SLO. However, research work indicated that SLO’s thermal stability is quite low, which is represented as coking phenomenon when SLO is exposed to the normal distillation temperatures encountered by general crude oil samples. Therefore, although the lighter fractions can be distilled to bring forth solid-free SLO, its yield is rather low. Furthermore, if the solid-free SLO is heated up to a temperature of higher than around 300 ºC, its thermally unstable molecules would chemically condense to form nano-sized and ultra-dispersed coke fines, giving rise to a so-called secondary pollution. By delving into the molecular composition and structure of SLO, this project is intended to elucidate the molecular basis leading to instability at relatively elevated temperatures as a first step. Then, by using trace self-dispersed nanocluster catalyst under mild reaction temperature and pressure, the stabilization via hydrogenation of unstable molecules is explored. Furthermore, both the synergistic effect among different catalysts and the stabilizing mechanism via catalytic hydrogenation are focused on, which brings enhancements in both conversion and selectivity of the stabilization reaction of SLO via catalytic hydrogenation, coupled with hydrogen consumption reducing. Thus, a novel method based on new theory for efficient removal of solids from SLO can be established. This innovative research will help to fashion a brand new hydrotreating process, and open a new pathway for solids removal from various secondary cracked heavy oils, carrying both important scientific significance and application potentials in a range of fields including oil processing and carbon material preparation.

我国年产超过750万吨的催化油浆（SLO），富含有芳烃，是针状焦等高值化工产品的潜在原料。但是，SLO中0.2%以上的固含物阻碍了本身的高值利用。蒸馏是实现SLO脱固的重要潜在方法，然而研究显示，SLO热稳定性差，在通常油品蒸馏温度下就会结焦。因而尽管通过蒸馏可蒸出部分馏分，即脱固油浆，但是收率偏低；并且在后续处理时一旦受热到约300℃以上时，脱固油浆中的热不稳定分子将缩合生成超分散纳米尺度的焦粉，造成二次污染。本项目从SLO的分子组成和结构入手，揭示其受热稳定性差的分子基础，进而探索痕量自分散型纳米团簇催化剂在温和的温度和压力下对不稳定分子的加氢稳定规律的影响，同时重点研究不同催化剂间的协同效应和加氢稳定机理，提高加氢稳定转化率和选择性，降低氢耗，最终构建高效的SLO脱固新型理论和方法。研究创新加氢精制工艺，开辟二次裂解重油脱固新途径，在油品加工、碳材料制备等领域都有重要科学和应用价值。

催化油浆富含芳香烃，是制备橡胶填充油、针状焦、碳纤维等高值产品的重要潜在原料，但前提是脱除其中含量高达0.2%～1%的固含物。通过蒸馏有望实现高效脱固。油浆在蒸馏加热到300°C时就开始缩合生焦，极大抑制了脱固油浆收率的提高。因此，本项目围绕确定催化油浆热稳定性差的分子基础，设计合适的化学反应体系，在蒸馏之前凭借较缓和的化学反应条件使不稳定的油浆分子得以靶向稳定，即烯烃被加氢饱和而脱除，提高稳定化反应的程度，进而抑制蒸馏生焦，提高脱固油浆的拔出率，极具科学与现实意义。.本项目首先以某催化油浆为原料，某常压渣油作对比，通过测定不同温度下的生焦趋势、沥青质沉淀起始点、烯烃含量以及光学显微镜观察对催化油浆的热稳定性进行考察，明确了合适的蒸馏温度，初步分析了烯烃与催化油浆热稳定性的关系；其次通过溴价法、二烯值法、紫外光谱法、核磁共振氢谱法、色质联机等方法对催化油浆中的烯类化合物分布进行了测定，同时利用烯烃模型化合物深入探究烯烃与催化油浆热稳定性的关系；而后利用模拟油浆和烯烃模型化合物及油溶性催化剂对油浆加氢稳定化条件进行优化，揭示油浆在加氢稳定过程中催化剂之间的协同效应和加氢稳定机理；最后，将真实催化油浆在最优条件下开展加氢稳定化实验，评价其中烯烃脱除效果，而后对脱烯烃后的催化油浆热稳定性进行探究，并对其进行蒸馏脱固，从而获得收率高且性质优的脱固油浆。.结果表明，催化油浆和常压渣油相比，其热稳定性更差。油浆中存在烯烃和共轭烯烃，含量分别为21%和6%左右，不同组分和不同馏分之间烯烃的类型存在差异。催化油浆的≤500°C馏分含烯烃58种，共轭芳香烯含量最多。烯烃尤其是比较活泼且分子量较大的多环共轭芳烯烃能促进油浆生焦，增加其热不稳定性。油浆加氢稳定后的烯烃和共轭烯烃脱除率分别高达90.50%、91.25%，有效抑制了蒸馏过程的生焦现象，脱固油浆收率提升32%，固含量满足针状焦制备要求。