PERFORMANCE AND CHARACTERIZATION OF SUPPORTED IRON NANOCATALYST IN FISCHER-TROPSCH REACTION

Fischer-Tropsch synthesis (FTS) has received considerable attention as it offers alternative route to produce liquid fuels and chemicals from abundant energy sources other than crude oil such as natural gas, coal, and biomass. The objective of this work is to synthesize, characterize and study the performance of supported iron (Fe) nanocatalyst with Fe particle less than 30nm in Fischer-Tropsch synthesis. Supported Fe nanoparticles have been formulated using impregnation and precipitation methods. Fe nanoparticles loading (3, 6, 10, 15 wt %) were deposited on silica (SiO2) and alumina-silica (Al2O3-SiO2) supports. The effect of alkali promoters such as potassium (K) and copper (Cu) on the physicochemical properties of the catalyst has been investigated. The physicochemical properties of the catalysts were studied using N2 physical adsorption, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and H2 temperature-programmed reduction (TPR). The FTS performance of the synthesized catalysts was examined in a fixed-bed microreactor at atmospheric pressure and various reactant ratio (H2/CO), temperature, and space velocity. The size of Fe nanoparticle was affected by the Fe loading, synthesis technique, and the type of catalyst support. More uniformly distributed and smaller particle size was obtained at lower Fe loading. The 6%Fe/SiO2 synthesized via the impregnation method had Fe average particles size of 8.6±1.1 nm, as measured by TEM. It resulted in CO conversion of 54% and C5+ selectivity of 20% at 523K, 1.5H2/CO v/v ratio, and 3L/g-cat.h. Under the same reaction conditions, 6%Fe/SiO2 prepared by precipitation method with Fe average particles size of 12.8±4.2 nm resulted in CO conversion of 45% and C5+ selectivity of 8%. The CO conversion trend correlated to the size of Fe nanoparticles where the results show that catalysts with average particles size less than 9 nm yielded in CO conversion >50% as well as higher selectivity of C5+ and olefins, and lower selectivity for light hydrocarbons (C1-C4) compared of those of larger particles

PERFORMANCE AND CHARACTERIZATION OF SUPPORTED IRON NANOCATALYST IN FISCHER-TROPSCH REACTION

Fischer-Tropsch synthesis (FTS) has received considerable attention as it offers alternative route to produce liquid fuels and chemicals from abundant energy sources other than crude oil such as natural gas, coal, and biomass. The objective of this work is to synthesize, characterize and study the performance of supported iron (Fe) nanocatalyst with Fe particle less than 30nm in Fischer-Tropsch synthesis. Supported Fe nanoparticles have been formulated using impregnation and precipitation methods. Fe nanoparticles loading (3, 6, 10, 15 wt %) were deposited on silica (SiO2) and alumina-silica (Al2O3-SiO2) supports. The effect of alkali promoters such as potassium (K) and copper (Cu) on the physicochemical properties of the catalyst has been investigated. The physicochemical properties of the catalysts were studied using N2 physical adsorption, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and H2 temperature-programmed reduction (TPR). The FTS performance of the synthesized catalysts was examined in a fixed-bed microreactor at atmospheric pressure and various reactant ratio (H2/CO), temperature, and space velocity. The size of Fe nanoparticle was affected by the Fe loading, synthesis technique, and the type of catalyst support. More uniformly distributed and smaller particle size was obtained at lower Fe loading. The 6%Fe/SiO2 synthesized via the impregnation method had Fe average particles size of 8.6±1.1 nm, as measured by TEM. It resulted in CO conversion of 54% and C5+ selectivity of 20% at 523K, 1.5H2/CO v/v ratio, and 3L/g-cat.h. Under the same reaction conditions, 6%Fe/SiO2 prepared by precipitation method with Fe average particles size of 12.8±4.2 nm resulted in CO conversion of 45% and C5+ selectivity of 8%. The CO conversion trend correlated to the size of Fe nanoparticles where the results show that catalysts with average particles size less than 9 nm yielded in CO conversion >50% as well as higher selectivity of C5+ and olefins, and lower selectivity for light hydrocarbons (C1-C4) compared of those of larger particles

HYDROGENATION OF CARBON DIOXIDE TO METHANOL OVER SUPPORTED COPPER/ZINC OXIDE-BASED NANOCATALYST

Methanol synthesis via C02 hydrogenation provides alternative route for methanol production and attractive option for C02 utilization. The objective of this work is to synthesize, characterize Cu-ZnO-based nanocatalyst on various supports and study the performance of the nanocatalyst for methanol production via C02 hydrogenation reaction. Supported Cu!ZnO-based nanocatalysts have been formulated using impregnation method. Effects of synthesis parameters such as total metal loading, Cu:Zn ratio, synthesis pH and type of support on the physicochemical properties and catalytic performance in C02 hydrogenation to methanol were investigated. The effects of the alkali promoters such as manganese (Mn), zirconium (Zr), lead (Ph), and niobium (Nb) in form of single, double, and tri-promoters on the physicochemical properties of the catalyst have been investigated

Effects of Promoter’s Composition on the Physicochemical Properties of Cu/ZnO/Al₂O₃-ZrO₂ Catalyst

Cu/ZnO catalysts were synthesized via an impregnation method on an Al2O3-ZrO2 support and modified by the addition of manganese and niobium as promoters. The effect of the selected promoters on the physicochemical properties and performance toward the hydrogenation of CO2 to methanol are presented in this paper. The Mn and Nb promoters improved the reducibility of the catalyst as evidenced by the shifting of the H2-TPR peaks from 315 °C for the un-promoted catalyst to 284 °C for the Mn- and Nb-promoted catalyst. The catalytic performance in a CO2 hydrogenation reaction was evaluated in a fixed-bed reactor system at 22.5 bar and 250 °C for 5 h. Amongst the catalysts investigated, the catalyst with equal ratio of Mn and Nb promoters exhibited the smallest particle size of 6.7 nm and highest amount of medium-strength basic sites (87 µmol/g), which resulted in the highest CO2 conversion (15.9%) and methanol selectivity (68.8%)