催化汽油中噻吩类硫化物在新型功能化吸附剂上的吸附行为研究

On the basis of previous research, for the first time, a new-type functional adsorbent with the metal-ions adsorptive active sites that has adjustable characteristics, will be used for deep adsorption desulfurization of catalytic gasoline. The synthetic route of the absorbent is that the silicon-based mesoporous zeolites are used as the main body, and then the surface silicon hydroxyls are modified by using slilyl reagents, and metal-ions compounds are dispersed as the object, using a variety of synthetic methods, optimum synthetic conditions. The adsorption desulfurization performance is investigated by the structural parameters of the adsorbent, and simulated oil with different components by using the intermittent and dynamic adsorptive methods. The interaction between adsorbate and adsorbent is studied by employing FTIR and UV-DRS spectra techniques. The selective adsorption and competitive adsorption behaviors of thiophenic sulfur, olefins and aromatics molecules on the new-type functional adsorbent are investigated by using the IGA/MS coupling techniques, and then determine and modulate the phase morphology of the metal-ions active sites in the adsorbent. The structure-activity relationship between the structure of active sites and adsorptive properties of the new-type functional adsorbent, dispersion of active sites, etc., are researched systematically by using in situ FTIR, IGA/MS, the adsorption breakthrough curve, etc., and combining with the molecular simulation calculation, in order to better understand the essence of the new-type functional adsorbent which has good adsorption and separation performance, for the sake of providing a guidance for the improvement of the synthetic methods of the new-type adsorption material and realizing the depth removal of the thiophenic sulfur compounds in FCC gasoline.

本项目在前期研究的基础上，结合新型功能化吸附剂中金属离子物种吸附活性位可调变的特点，首次将这种新型吸附材料用于催化汽油深度吸附脱硫中。以硅基介孔分子筛为主体，硅烷化修饰表面硅羟基，以金属离子化合物为客体，采用多种合成方法，优化合成条件。选用不同组分的模拟油，利用间歇法及吸附穿透曲线技术，对吸附剂结构参数对吸附脱硫性能的影响进行考察。采用FTIR和UV-DRS光谱技术，研究吸附质与吸附剂相互作用模式。运用IGA/MS测定模型硫化物、烯烃及芳烃分子在新型功能化吸附剂上的选择性吸附和竞争吸附行为，确定并调控吸附剂中金属离子物种活性位的物相形态。采用原位FTIR、IGA/MS、吸附穿透曲线等技术，结合分子模拟计算，对活性位的分散，物相形态与吸附性能之间的构效关系等问题进行系统研究，以更好地认识新型功能化吸附剂具有优良吸附分离性能的实质，为这类新型吸附材料的合成方法的完善提供指导，从而实现催化汽油中噻吩类硫化物的深度移除。

催化裂化（FCC）汽油中ppm级噻吩类硫化物（尤其是噻吩和短链烷基噻吩）的超深度脱除一直是困扰汽油进一步清洁化的难题。选择性吸附脱硫技术是一种极具应用前景的FCC汽油超深度脱硫技术，其面临的核心挑战主要是辨析吸附剂活性位物种和构筑有效吸附活性位。本项目以Y、MCM-41和SBA-15分子筛为研究对象，全面获悉了分子筛中非骨架物种和B酸活性位的化学形态和分布规律，进而在吸附剂中定向设计、构建和调控有效吸附活性位。在系统开展相关理论研究的基础上，研究发现通过巧妙控制金属物种负载量和焙烧温度以及有效吸附位的激活条件，可实现改性分子筛吸附剂中活性位物种化学形态的有效调控。基于以上理念，本项目成功开发出系列Cu(I)-Y、CeY、Cu(I)-NH4Y和Ce-SBA-15优良吸附剂，其穿透硫容量以往文献报道最大值均有明显提升。并从理论上分析证实了产生上述效果的本质是最大限度地实现了分子筛中有效金属物种吸附位的形成，如Cu+，Ce(OH)2+，[Cu-O2-Cu]2+，[Cu-O2-Cu]2+等。此项目研究成果对未来制备高效超深度脱硫吸附剂具有非常重要的理论和实践意义。