Exploiting the effects of mass transfer to boost the performances of Co/γ-Al 2 O 3 eggshell catalysts for the Fischer–Tropsch synthesis
| Autor: | Carlo Giorgio Visconti, Enrico Tronconi, Luca Lietti, Laura Fratalocchi, Stefano Rossini |
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| Rok vydání: | 2016 |
| Předmět: |
Olefin fiber
Chemistry Process Chemistry and Technology Weak mass transfer limitations Fischer–Tropsch process 02 engineering and technology Fischer-Tropsch synthesis 010402 general chemistry 021001 nanoscience & nanotechnology Compact fixed-bed reactors Eggshell catalysts Catalysis 01 natural sciences 0104 chemical sciences Reaction rate Chemical engineering Mass transfer Yield (chemistry) Particle-size distribution Organic chemistry Eggshell 0210 nano-technology |
| Zdroj: | Applied Catalysis A: General. 512:36-42 |
| ISSN: | 0926-860X |
| DOI: | 10.1016/j.apcata.2015.12.011 |
| Popis: | In this work, the performances of a spherical Co/γ-Al 2 O 3 eggshell catalyst characterized by a diameter of 600 μm and an active shell region 75 μm thick are assessed in a lab-scale fixed bed reactor operated at industrially relevant Fischer–Tropsch process conditions. Such performances are compared to those of a powder catalyst obtained by grinding and sieving a fraction of the eggshell catalyst so to obtain powders with a particle size distribution centered in the range 75–100 μm. It is shown that, thanks to the presence of modest mass transport restrictions, the eggshell catalyst outperforms the corresponding powder in terms of C 15+ specific yield. We explain these results by considering the effect of mass transport on the olefin re-adsorption probability and on the H 2 /CO ratio in proximity to the active sites. The former is increased, and results in greater selectivity to heavy hydrocarbons. The latter is also increased, due to the negative order of CO conversion kinetics with respect to CO, and results in augmented reaction rate. |
| Databáze: | OpenAIRE |
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