Stabilization of Pt in SiO2–Al2O3 Microspheres at High Mechanical Resistance, Promoted with W Oxides for the Combustion of CO

Abstract

This study shows the development of a combustion promoter for the oil-refining process called fluid catalytic cracking (FCC). The investigation of a catalyst prepared for the combustion of CO composed of 0.05 wt% Pt supported on SiO2–Al2O3–0.5 wt% W microspheres with high mechanical resistance, promoted with tungsten oxides (WOx) that can inhibit the sintering of Pt, is reported. The addition of WOx in SiO2–Al2O3 inhibited the decrease in the specific area when calcined from 550 °C to 950 °C. SiO2–Al2O3 support in the form of calcined microspheres with average diameters between 70–105 µm were produced by spray drying, using two atomization discs with vanes of different geometry: a straight rectangular blade disc (DAR) and a curved rectangular vanes disc (DAC). The DAR disk produced whole microspheres, while the DAC had hollow and broken microspheres. The microspheres were characterized by XRD, SEM, optical microscopy, N2 physisorption (BET area) and fracture resistance tests. The Pt catalysts were evaluated by TPR, H2 chemisorption and CO combustion. The catalyst of 0.05 wt% Pt/SiO2–Al2O3–0.5 wt% turned out to be the most stable. A thermal stabilization effect was observed at contents lower than 1 wt% W that allowed it to inhibit the sintering of the Pt catalyst.