Multi-scale, Multi-modal Imaging of Nanoporous Catalysts.

项目目标：确定各种制造参数对颗粒结构的影响。建立颗粒生产路线与颗粒有效性之间的关系。以更精细的分辨率更详细地研究结构特征的存在，特别是影响颗粒区域之间大规模分子交换的结构特征。为颗粒中那些被证明控制质量传输速率的区域建立一个新的孔隙网络模型。项目总结：提高催化剂颗粒的有效系数是提高催化限制扩散反应产品性能的关键方法之一。这需要详细了解颗粒孔隙结构中限制质量传输的因素，以及制造过程中产生这些特定孔隙结构特征的参数。本研究项目旨在研究催化剂颗粒制造过程与颗粒运输特性之间的关系，这是由一组特定形成条件产生的颗粒结构特征所介导的。它将考虑如何改变制造过程的特定参数导致颗粒结构的特定变化，并确定这些特征对质量传输速率的影响。甲醇合成催化剂球团（铜/氧化锌/氧化铝）通过球团制造，使用滚压或喷雾干燥饲料，已经使用许多不同的表征技术进行了研究。采用综合汞孔隙率法和气体吸附速率实验研究了汞包裹前后质量输运速率的变化。这种方法证明了失去的充满汞的孔隙对吸收速率的影响，从而证明了它们对整体质量运输的重要性。不同的孔隙可能产生于制造过程的不同方面。因此，这些发现可用于颗粒制造过程的设计和优化。计算机x射线断层扫描（CXT）和差示扫描量热法（DSC）也被用来确定汞在小球堵塞空隙中的空间分布。目前对样品进行的初步实验结果表明，颗粒具有非常相似的孔径分布和侵入体积分布。然而，不同侵入压力下被捕获汞的空间分布表明，颗粒的进料特性对孔隙网络的可达性有很大影响。在未来，额外的表征技术，如超极化氙气（Xe-129）的瞬态扩散进入，使用磁共振成像（MRI），核磁共振（NMR）冻孔术和扫描电子显微镜（SEM）都将用于研究样品。

Project Aims: To identify the impacts of various manufacturing parameters on the pellet structure. To establish the relationship between pellet manufacturing route and pellet effectiveness. To study in more detail at finer resolution the presence of structural features that particularly impacting large-scale molecular exchange between regions of the pellet. To develop a novel pore-network model for those regions of the pellet that prove to be controlling the mass-transport rates.Project Summary:Increasing catalyst pellet effectiveness factors is one of the key ways to deliver improved performance of products that catalyse diffusion-limited reactions. This requires a detailed understanding of the factors in pellet pore structure that limit mass transport, and the parameters in the manufacturing process that produce these particular pore structure features. This research project aims to investigate the relationship between catalyst pellet manufacturing process and the pellet transport properties, as mediated by the pellet structural characteristics that a specific set of forming conditions produce. It will consider how changing particular parameters of the manufacturing process leads to specific changes in the pellets structure, and determine the impact of those features on the rate of mass transport.Methanol synthesis catalyst pellets (Copper/Zinc oxide/Alumina) manufactured via pelleting, using either roll compacted or spray dried feed, have been studied using a number of different characterisation techniques. Integrated mercury porosimetry and gas adsorption rate of uptake experiments have been used to study the changes in the rate of mass transport before and after mercury entrapment. This method demonstrates the impact that the lost pores, filled with mercury, have on the rate of uptake and thus their importance to overall mass transport. Different pores may arise from different aspects of the fabrication process. Hence, these findings can be used in the design and optimisation of the pellet manufacturing process. Computerised X-ray tomography (CXT) and differential scanning calorimetry (DSC) have also been employed to establish the spatial distribution of mercury entrapped in the blocked void-space of the pellets. Preliminary results from the experiments carried out on the sample so far show that the pellets have a very similar pore size distributions and intrusion volume profiles. However, the spatial distribution of entrapped mercury following different intrusion pressures indicates pellet feed character greatly impacts general pore network accessibility. In the future, additional characterisation techniques such as the transient diffusional ingress of hyperpolarized Xenon gas (Xe-129) using magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR) cryoporometry and scanning electron microscopy (SEM) will all be used to study the samples.