用于低阶煤热解的过渡金属/沸石纳米复合催化剂的设计制备与构-效关系研究

Catalytic pyrolysis is one of the primary approaches of coal efficient and clean utilization, and the design of new-type catalysts with higher activity and selectivity has become increasingly attractive. Here, we propose a systematic study on oriented synthesis and structure-property relationship investigation of transition metal/zeolite nanocomposite catalysts used for catalytic pyrolysis of low-rank coals with process intensification and composition adjustment of pyrolysis products. The top-down strategy, which is widely used in the synthesis of nano materials, will be employed to obtain zeolite nanoparticles by a fragmentation method including sonication induced crush and disassembly of bulky zeolite crystals, and a suspension of highly monodisperse zeolite nanocrystals with a similar paricle size will be subsequent purification by density gradient centrifugation (DGC) method. Moreover, referenced by the bottom-up strategy, which is another effective method for the construction of nano materials with novel structures, the obtained zeolite nanocrystals will be used for the assembly of new-type catalysts for the pyrolysis of low-rank coals with transition metal nanoparticles by the particular physical combination or chemical treatment. Furthermore, the catalytic pyrolysis performances (rates, apparent activation energies, product selectivities and effectiveness factors) of transition metal/zeolite nanocomposite catalysts will be compared to conventional catalysts with single component. It can be expected that the research we propose here will not only promote the practical process of catalytic pyrolysis of low-rank coals, but also demonstrate a proven strategy in the exploitation of novel catalysts for bulky molecular reactions involved in coal utilization, heavy oil upgrading, and also biomass conversion.

催化热解是当前煤炭高效清洁转化的重要途径之一，而新型热解催化剂的设计与开发是其技术核心。本项目拟制备过渡金属/沸石纳米复合催化剂用于低阶煤热解强化耦合目标性产物定向调控。在技术层面，通过对块体沸石分子筛进行“自上而下”（Top-down）的结构拆卸，结合密度梯度超速率离心分离，获得单分散的等径纳米级沸石颗粒，经由物理/化学结合作用与过渡金属纳米颗粒进行“自下而上”（Bottom-up）的结构组装，构筑兼具金属活性与酸活性的新型煤热解催化剂；在理论层面，综合评价多孔催化剂传质强化和多中心协同催化效应对低阶煤热解反应效率、产物结构与组成的影响规律及作用机制，系统建立起过渡金属/沸石纳米复合催化剂参与低阶煤热解的定量构-效关系。项目成果可以提供出一套从“功能-结构-合成”之间的关系入手，进行煤热解催化剂顶层设计的方法与理论，从而推动煤催化热解技术的实用化进程，具有重要的科学意义和广阔的应用前景。

催化热解是当前煤炭高效清洁转化的重要途径之一，而新型热解催化剂的设计与开发是其技术核心。本项目研究以分子筛为材料研究基础、煤催化热解为开发体系，从理论研究、合成设计和过程开发三方面入手，对低阶煤热解挥发分催化改质及新型热解催化剂结构设计进行了系统、深入的研究。.分子筛合成控制方面，采用超声手段拆卸3DOm-i结构的分子筛和介孔二氧化硅，获得了可单分散的等尺寸纳米级分子筛和介孔二氧化硅颗粒的制备工艺；综合运用软模板、硬模板以及外延生长等合成策略，获得了一系列新颖结构的多级孔分子筛。（过渡）金属/分子筛复合催化剂开发方面，通过原位合成以及后处理复合等手段，获得了以Ti、Cu、Fe、Ga和Zn等（过渡）金属与CHA、MEL、MFI和BEA等骨架结构的分子筛相互复合的双/多功能催化剂材料及其制备方法。低阶煤催化热解过程研究与热解催化剂开发方面，综合优化了催化剂的结构（骨架结构、孔结构、酸性结构、形貌结构以及（过渡）金属与分子筛的复合形态等），并设计开发出高轻质芳烃收率、脱氧降酚性能优异的新型Ga掺杂的多级孔分子筛催化剂。.项目成果提供了一套从“功能-结构-合成”之间的关系入手，进行煤热解催化剂顶层设计的方法与理论，从而推动煤催化热解技术的实用化进程，具有重要的科学意义和广阔的应用前景。