Activity of alumina-silica-supported NiMoS prepared by controlled mixing of alumina into SiO2 hydrogels for HDS of gas oil

Abstract

Alumina-silica-supported NiMoS composites were examined in single-and dual-layer catalyst beds in a high-pressure (5 MPa) flow reactor to achieve ultra low sulfur (10 ppm) diesel fuels. Three types of alumina-silica composite supports were prepared by co-precipitation to control the particle size and arrangement of alumina and silica. SiO 2 content influenced the catalytic performance, and the maximum conversion was ~27%, regardless of the preparation conditions. Alumina crystal size controlled the acidity and surface area of the support, key factors influencing catalytic performance. NiMoASA-2(27), prepared by procedure 2, achieved 4.5 and 3 ppm S at 345 and 360°C, respectively, in the single bed reactor at a liquid hourly space velocity (LHSV) of 1 h-1. NiMoASA-2(27) achieved the best performance of the supports examined in this study. The double-layer catalyst bed contained commercial CoMoS (LX6) and NiMoASA-2(27) in the first and the second beds at 345 and 360°C, respectively, and achieved 5 and 2 ppm S, indicating better performance at higher temperatures. The reaction order for the hydrodesulfurization (HDS) of refractory sulfur species was close to unity over NiMoASA-2(27), which was significantly higher than that of the commercial CoMoS catalyst. Alumina-silica-supported NiMoS in the second bed of the dual-layer catalyst bed achieved less than 10 ppm S for refractory sulfur species with ~500 ppm S.

Calibration of the X‐Ray Photoelectron Spectroscopy Binding Energy Scale for the Characterization of Heterogeneous Catalysts: Is Everything Really under Control?

“…Silica–aluminas (SiO 2 –Al 2 O 3 ) are highly important as catalyst supports in various industrial processes. SiO 2 –Al 2 O 3 ‐supported catalysts are used in a broad range of important chemical reactions, including olefin metathesis (MoO 3 /SiO 2 –Al 2 O 3 ),8 hydrocracking (Ni–W/SiO 2 –Al 2 O 3 ),9 nitrosation of cyclohexane (Co 3 O 4 /SiO 2 –Al 2 O 3 ),10 ammoxidation (V 2 O 5 –MoO 3 –P 2 O 5 /SiO 2 –Al 2 O 3 or TeO 2 /SiO 2 –Al 2 O 3 ),11 and hydrodesulfurization (HDS) of gas oil (Ni–Mo–S/SiO 2 –Al 2 O 3 ) 12. Pd/SiO 2 –Al 2 O 3 formulations are well recognized for hydrogenation reactions13 and methanol synthesis 14.…”

Optimization of silica content in alumina-silica nanocomposites to achieve high catalytic dehydrogenation activity of supported Pt catalyst

“…A further increase in the silica content, dilutes the active alumina and in turn does not support the elevation of the dehydrogenation process as was evident from the slim activity exhibited. Nakano et al [20] proposed a series of alumina-silica supports for deep hydrodesulphurization (HDS) reporting that the SiO 2 content was of an influential effect on the catalytic performance, revealing a better performance by around 27% regardless of preparation conditions.…”

“…Dispersion and arrangement of nanoparticles in the alumina/silica oxide composites were important factors governing the hydrodesulphurization (HDS) reaction [20]. Jien et al [21] used carbon nanoparticles (with different structures), carbon nanotubes and traditional carbon materials as supports to prepare platinum catalysts and measure their activity in cyclohexane dehydrogenation.…”

Catalyst Stacking Technology as a Viable Solution to Ultralow Sulfur Diesel Production

“…Two related articles published in 2011 by Park, Nakano et al. studied the deep HDS over NiMo catalysts supported over amorphous silica–alumina (ASA) in single-bed and double-bed catalytic systems. , In all cases, the first catalytic bed was filled with a conventional CoMo catalyst that is normally used to desulfurize gas oil to under 500 ppm sulfur content. The ASA supports of the three NiMo catalysts evaluated were synthesized by different procedures and had markedly distinct properties in regard to the specific surface area, pore volume, acidity, and strength of acid sites.…”