The reactive adsorption behavior of thiophene over the reduced NiZnO/Al2O3-diatomite adsorbent was characterized by in situ Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) technology was used to investigate the phase change of sulfur species in the reactive adsorption desulfurization (RADS) process. The results indicated that S–M bonding of thiophene on the metallic Ni sites was first decomposed to form Ni3S2 while formed C4 olefins were further saturated by hydrogen to form butane which was released back into the process stream, followed by the sulfur transfer from Ni3S2 to ZnO to form ZnS in the presence of hydrogen, and then the new formed Ni sites could participate in the adsorption of thiophene once again. The muticycle fixed-bed tests showed a good prospect for adsorption desulfurization over the NiZnO/Al2O3-diatomite adsorbents. Thermogravimetric and differential thermal analysis (TG-DTA) together with XRD was used to reveal the regeneration mechanism. The XRD results indicated that the formation of NiSO4 species led to an increase of the amount and the strength of Lewis acid sites in the regenerated adsorbents and, thus, temporarily improved the removal performance of the adsorbent for thiophene.

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Attrition resistance is a key design parameter for catalysts used in slurry phase Fischer–Tropsch (F–T) reactors, especially for industrial-scale reaction. It is well-known that iron F–T catalyst particles undergo physical attrition and chemical stresses caused by phase transformations. Here we report on attrition properties of a Fe–Cu–K–SiO2 catalyst used in a pilot-scale stirred tank slurry reactor (STSR) under low temperature F–T reaction conditions. The wax-free catalysts were characterized by SEM, EDS, BET surface area measurements, and a Mastersizer 2000 for particle size analysis. The results show that, after 408 h of reaction in an STSR, the particle size reduction due to erosion/abrasion and fracture was apparent. Large reductions in the Sauter mean diameter (93.45%) and the volume moment diameter (71.67%) were observed. The increase in the fractions of particles smaller than 5 and 10 μm was 18.25 and 30.11%, respectively. We concluded therefore that the catalyst underwent more severe attrition in industrial application and the attrition was mainly caused by the fracture of larger or smaller particles. Further study is needed to improve the catalyst attrition resistance.