ABSTRACT
The aim of this work is to study the catalytic activity and suppression of carbon deposition in the CO2-Steam reforming of methane (SCR) to develop a high performance catalyst for GTL-FPSO application which is required to high pressure (20 bar) for F-T synthesis. Ni/La-X(6)/Al2O3 (X = Ce, Mg, Zr) catalysts were prepared by the impregnation method. The catalytic reaction was studied in a fixed bed reactor system at high pressure. X-ray diffraction (XRD), BET specific surface area and H2-temperature programmed reduction (TPR) were used to observe the characteristics of the prepared catalysts. The carbon deposition and the carbon amount in the used catalysts were examined by SEM and TGA, respectively. As a result, it was found that the Ni/La-Mg(6)/Al2O3 catalyst showed the highest activity and high carbon resistance. The highest activity in Ni/La-Mg(6)/Al2O3 was attributed to the proper Mg loading. It also had the lowest Ni particle and formed relatively stable MgAl2O4, which have an effect on the catalytic activity.
ABSTRACT
Catalysts were investigated with respect to catalytic activity and coke formation in combined steam and carbon dioxide reforming of methane to develop a highly active and stable catalyst for gas to liquid processes. Ni/La-X/Al2O3 (X = Co, Ce, Mo) catalysts were prepared by an impregnation method. The combined steam and carbon dioxide reforming of methane reaction were studied as a function of high pressure (20 bar) in a fixed bed reactor system. X-ray diffraction, BET surface area, and H2-temperature programmed reduction were used to observe the characteristics of the prepared catalysts. Coke formation of used catalysts was examined by scanning electron microscopy, transmission electron microscopy and the coke amount of used catalysts was measured by thermo gravimetric analysis. Catalysts with smaller particle size had a higher temperature of reduction, which had a positive effect on catalytic activity. The improvement in active site rise and dispersion and the lowest metal crystal size had an effect on catalyst activity. As a result, the Ni/La-Co/Al2O3 catalyst showed the highest activity at a reaction temperature of 800 degrees C and a reaction pressure of 20 bar.
ABSTRACT
Liquid-phase dehydration of glycerol to acrolein over nanosized niobia-supported silicotungstic acid catalysts was performed to investigate the effect of the silicotungstic acid loading on the catalytic performance of the catalysts. The catalysts were prepared by following an impregnation method with different HSiW loadings in the range of 10-50 wt%. The prepared catalysts were characterized by N2 physisorption, XRD, FT-IR, TPD of ammonia, and TGA. Dehydration of glycerol was conducted in an autoclave reactor under the conditions of controlled reaction temperatures under corresponding pressure. Increasing HSiW loading rapidly increased the acidity of HSiW/Nb205 catalyst and rate of glycerol conversion, but acrolein selectivity decreased due to enhanced deactivation of the catalyst by carbon deposit. Consequently, it was confirmed that catalytic activity for the dehydration of glycerol to acrolein was dependant on the acidity of catalyst and can be controlled by HSiW loading.
