Morphology, of catalysts

For FTS process, two main mesoscale phenomena can be summarized (1) the interaction between internal diffusion and external diffusion, which is determined by the texture properties of catalyst and flow type of reactor. Generally, the texture properties, such as the size and morphology of catalyst pellet, always influence the flow type of reactor. Therefore, those should be combined to discuss their effects on FTS reaction (Kim et al., 1989 Lee et al., 2004 Mikkola et al., 2007 Schneider and Mitschka, 1966). (2) The relationship between internal difiusion and the intrinsic properties of active site, which is influenced by texture properties and active phase of catalyst. As well known, texture properties and active phase of catalyst always influence each other, such as the catalyst with low-surface area is always difficult to form highly dispersed active metal particle. The above mesoscale phenomenon significantly affects on the deviation from the ASF distribution of FTS products. 

The morphology of catalysts and their precursors was observed by means of an S-360 Oxford Eng scanning electron microscopy (made in USA). All of the SEM images in this study are taken at the same magnification of 20 pm. 

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