Effect of Palladium on Iron Fischer?Tropsch Synthesis Catalysts

Abstract

Studies were conducted to investigate the effect of Pd on the Fischer-Tropsch Synthesis (FTS) selectivity, activity and kinetics as well as on the water-gas shift activity of an iron catalyst. Two palladium promoted catalysts (Pd0.002/Fe100 and Pd0.005/ Fe100) were prepared from a base Fe100/Si5.1 (atomic ratio) catalyst. Results of FTS over the two palladium promoted catalysts were compared to those obtained from the K/Fe/Si base catalyst and a Cu/K/Fe/Si catalyst. The results indicate that Pd enhanced the FT activity while the selectivity for CO 2 and CH 4 changed little compared to the results for the base catalyst and the Cu promoted catalyst. Palladium promotion had a negative effect on the C 2 -C 4 olefin to paraffin ratio. Pd promotion led to a higher WGS rate than the other two catalysts at high syngas conversions. A higher WGS rate compared to the FTS rate was obtained only for the Pd promoted catalysts. The FTS rate constant for the Pd promoted catalyst is higher than the base catalyst but lower than for the Cu promoted catalyst.

Effect of Pt Impregnation on a Precipitated Iron-based Fischer–Tropsch Synthesis Catalyst

“…Richter and Baerns [11] examined Rh or Pd promoted Fe-Mn catalysts, and found that Rh and Pd increased FTS activity, decreased the olefin fraction and led to low molecular weight hydrocarbons. Davis [12] obtained the similar results on Pd promoted FeSiO 2 catalysts. Recent work down by Xu and Bartholomew [20] indicated that as Rh and Pd, Pt promoted FTS activity of a SiO 2 -supported iron catalyst, however, it suppresses methane selectivity and enhances C 2 + hydrocarbons selectivity.…”

“…The effects of them on catalytic behavior of ironbased catalysts have been widely studied [7][8][9]. Some other active metals such as group VIII noble metals as promoters for FTS are seldom investigated in iron-based FischerTropsch catalyst system [10][11][12], despite that these metals (Ru, Pd, Re, Pt) are commonly used as promoters for cobalt-based FTS catalysts and have been carefully studied for years. As stated in several literatures, these noble metal promoters facilitate the reduction of cobalt-based FTS catalysts at much lower temperatures, presumably by spillover hydrogen from their surface to cobalt oxide [13][14][15][16][17][18][19].…”

Fischer‐Tropsch Catalysts for the Biomass‐to‐Liquid (BTL)‐Process

“…Iron-based catalysts typically contain copper [112][113][114][115][116][117][118] as a reduction promoter, although ruthenium [84], silver [113,119], palladium [120], and platinum [121] have been used as well. The addition of these metals to the catalyst formulation reduces the reduction temperature, which may result in a higher catalytic activity (see also Fig.…”

“…The price of the metals and the required relative amount of the reduction promoter should be kept in mind to judge the efficiency of these materials. For example, palladium [120] was shown to be effective at levels 100 fold less than copper, but the price of palladium is more than 1000 times the price of copper.…”

Design, Synthesis, and Mechanistic Evaluation of Iron-Based Catalysis for Synthesis Gas Conversion to Fuels and Chemicals

“…Many studies have described the phenomenological effects of promoters on FTS [4][5][6], without specific or rigorous attention to the effects of addition sequence. Therefore, we discuss here the differences in FTS performance between Fe-Zn-K 6 -Cu(Ru) 3 and Fe-ZnCu(Ru) 3 -K 6 from the point view of promoter addition sequence.…”