Jocielys Rodrigues

Ruthenium promotion of Co/SBA-15 catalysts for Fischer-Tropsch synthesis in slurry-phase reactors

The aim of this work was to evaluate the catalytic properties of a Ru promoted Co/SBA-15 catalyst for Fischer-Tropsch synthesis (FTS). The Ru promoted Co/SBA-15 catalyst was prepared by wet impregnation method and was characterized by X-ray diffraction, X-ray energy dispersion spectrophotometer, N2 adsorption-desorption, temperature-programmed reduction and transmission electron microscopy. The Fischer-Tropsch synthesis using the catalyst was carried out to evaluate the catalyst activity and its effect on FTS product distribution. The synthesis was carried out in a slurry reactor operating at 513 K, 20 atm, CO: H2 molar ratio of 1: 1. X-ray diffraction showed that the calcined cobalt catalyst did not modify the structure of SBA-15, proving that Co was present in the form of Co3O4 in the catalyst. The addition of cobalt in SBA-15 decreased the specific superficial area of the molecular sieve. Fischer-Tropsch synthesis activity and C5+ hydrocarbon selectivity increased with the addition of Ru. The increases in activity and selectivity were attributed to the increased number of active sites resulting from higher reducibility and the synergetic effect of Ru and Co. Ru/Co/SBA-15 catalysts showed moderate conversion (40%) and high selectivity towards the production of C5+ (80 wt%).

Rapid Synthesis of Mesoporous Molecular Sieve SBA-15 by Different Techniques with Microwave Assistance

Mesoporous molecular sieves SBA-15 were prepared by using two different procedures taken from the scientific literature. In the first procedure, a hydrogel was prepared with the molar composition: 1.0 TEOS: 0017 P123: 5.7 HCl: 193 H2O with stirring at 35 °C. In the second procedure a hydrogel was prepared with the molar composition: 1.0 TEOS: 0017 P123: 8.14 HCl: 168 H2O with stirring at room temperature. In both procedures the samples were synthesized in a microwave. The samples were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), nitrogen adsorption-desorption analysis, and scanning electron microscopy (SEM). The analysis of XRD and nitrogen adsorption-desorption showed that the samples prepared with stirring at 35°C presented a higher ordering degree, an increase of crystallinity and larger volume of adsorbed nitrogen. The differential thermal analysis reveals that the SBA-15 presented high thermal stability, and the SEM revealed fiber type morphology consistent with this type of material.

Preparation and Characterization of Catalysts Fe/SBA-15 for Fischer Tropsch Synthesis

In this study catalysts Fe/SBA-15 were prepared for Fischer-Tropsch Synthesis. SBA-15 samples were synthesized under acidic conditions using triblock copolymer Pluronic as a template and tetraethyl orthosilicate as a silica source.The molar composition was: 1.0 TEOS: 0017 P123: 8.14 HCl: 168 H2O. Fe/SBA-15 catalysts with different iron loading (15 wt. % and 20 wt. %) were prepared by wetness impregnation of relative SBA-15 with the desired amount of aqueous iron nitrate. The obtained catalyst were characterized by X ray diffraction (XDR), nitrogen adsorption-desorption and energy dispersive X-ray spectrometry (EDX). After impregnation of Fe the XRD profiles were almost unchanged and exhibited the high diffraction peaks of SBA-15 at low angles. The analysis of nitrogen adsorption-desorption was observed that the values of specific surface area decreased as the concentration of metal impregnated increased. And by the EDX analysis verified that the iron contents obtained are close to nominal levels of iron.

Synthesis and Characterization of Molecular Sieve SBA-15 and Catalysts Co/SBA-15 and Ru/Co/SBA-15

A series of mesoporous materials have been synthesized in an acid medium, with various structures, such as SBA-15. These materials have many properties which make them potential catalysts. Among these we highlight their high surface areas and pore walls relatively thick, resulting in a greater hydrothermal stability. This work aims at the synthesis and characterization of molecular sieve SBA-15 with molar composition: 1.0 TEOS: 0.017 P123: 5.7 HCl: 193 H2O and Co/SBA-15 and catalysts for the reaction of Ru/Co/SBA-15 Fischer Tropsch process. The materials were characterized by the techniques of X-ray diffraction (XRD), chemical analysis by X-ray spectrometry, energy dispersive (EDX) and Nitrogen adsorption (BET method). X-ray diffraction showed that the calcined cobalt catalyst did not modify the structure of SBA-15 and that Co was present under the form of Co3O4 in the catalyst. The addition of cobalt in the SBA-15 decreased the specific superficial area of the molecular sieve.