Temporally and spatially resolved operando characterization of hydrogenolysis in wax-filled Fischer-Tropsch pellets using magnetic resonance imaging.

当周期性地加入纯氢或稀氢时，瞬时费托合成(FTS)可以提高相对于所需液体产物的活性和选择性。这归因于氢解反应排出了充满液体的催化剂孔，在氢解反应中，长碳链被添加的氢打破，使它们更容易蒸发并从催化剂床中逸出。总体而言，长链烷烃在FTS催化剂孔中的氢解反应还很少被研究。这并不是最不重要的原因，因为传统的分析方法，如气相色谱或质谱仪，只能对反应堆出口气流中的产物进行定量。因此，本项目旨在利用时间和空间分辨的OPERANDO磁共振成像(MRI)来研究氢解的传质过程。非侵入性核磁共振测量应能够表征整个气孔耗尽过程中反应器和球团内部的质量和相变。通过这种方法，将对填蜡Fischer-Tropsch催化剂中孔的排空和氢解的动态过程有一个系统的了解。

A transient Fischer-Tropsch synthesis (FTS) can lead to an increase in activity and selectivity with respect to desired liquid products when pure or dilute hydrogen is added periodically. This is attributed to a draining of liquid-filled catalyst pores by the hydrogenolysis reaction, in which long carbon chains are broken up with the addition of hydrogen, allowing them to evaporate more easily and escape from the catalyst bed. Overall, the hydrogenolysis reaction of long-chain alkanes in FTS catalyst pores is still little studied. This is not least due to the fact that classical analytical methods such as gas chromatography or mass spectrometry can only quantify the products in the outlet stream of a reactor. Therefore, this project aims to investigate the mass transfer processes of hydrogenolysis using temporally and spatially resolved operando magnetic resonance imaging (MRI). The non-invasive MRI measurements shall allow a characterization of the mass and phase transformations in the reactor and pellet interior during the entire course of pore depletion. In this way, a fundamental understanding of the dynamic process of pore emptying and hydrogenolysis in wax-filled Fischer-Tropsch catalysts will be systematically developed.