Effect of Active Component Contents to Catalytic Performance on Fe-Cu-K/ZSM5 Fischer-Tropsch Catalyst

Abstract

Fischer-Tropsch Synthesis (FTS) on Fe-Cu-K/ ZSM5 catalysts prepared by varying the amount of active components for a given amount of ZSM5 has been investigated to elucidate the effects of iron concentration. The catalysts were prepared by conventional wet impregnation method using ZSM5 and subsequently calcined at 500°C for 5 h. The different catalytic performance is verified by the variation of microporosity such as surface area and pore size distribution of Fe-Cu-K/ZSM5, acidity, reducibility of active phases and the presence of various crystalline phases like a-Fe 2 O 3 , metallic iron and iron carbide. The characterization results are analyzed along with catalytic performance to arrive at optimum amount of active components and to obtain maximum selectivity of FTS products with high conversion of CO during FTS reaction.

Effects of Reaction Variables on Fischer–Tropsch Synthesis with Co-Precipitated K/FeCuAlO x Catalysts

“…CO conversions and product distributions achieved with the catalysts that were reduced at temperatures between 150 and 450°C are shown in Table 1 and (Table 1) were mainly attributable to the presence of unreduced iron oxides [8,14]. A high rate of CO 2 formation and the highest CO conversion were observed with the K/FeCuAlO x (400) catalyst.…”

ZSM-5 Supported Cobalt Catalyst for the Direct Production of Gasoline Range Hydrocarbons by Fischer–Tropsch Synthesis

“…3 and two or three-stage desorption of NH 3 is observed. The desorption peak observed at above 700°C is attributed to the possible water desorption [18,19] which is derived from the framework of ZSM-5 or NH 3 decomposition, whereas the peak at 100-350°C (first peak) to weak acid sites or physically adsorbed ammonia and the peak at 350-550°C (second peak) to strong acidic sites [20]. Table 2 gives the number of acid sites expressed as mmol NH 3 /g of catalyst with respect to only weak and strong acidic sites.…”

Catalytic Performance for Hydrocarbon Production from Syngas on the Promoted Co-Based Hybrid Catalysts; Influence of Pt Contents

“…On the other hand, Co-Al2O3/ZSM-5 and CoAl2O3-Pt(0.05)/ZSM-5 showed one peak only at the low temperature around 422 and 321 o C. TPR peaks of Co-Al2O3-Pt(0.5)/ZSM-5 catalyst appearing at around 204 and 292 o C could be assigned to the easily reducible cobalt crystallites to metallic state at lower temperatures. The larger surface area and smaller crystallite size of cobalt species are found to be the characteristics of Co-Al2O3-Pt(0.5)/ZSM-5 catalyst, and the crystallite size of cobalt oxide and Tmax decreased with increases in Pt content from 321 to 298 o C. As shown in Figure 2, the CoAl2O3/ZSM-5 generates a strong cobalt-ZSM-5 interaction (relatively higher reduction temperature at around 422 o C) on acidic sites of ZSM-5 [18]. The temperature shift to lower values on Co-Al2O3-Pt(0.5)/ZSM-5 catalysts decreased with increasing Pt content.…”

“…The large pores on FTS catalysts have been suggested to be linked to less coke or wax deposition [22]. The high content of weak acidic sites is also responsible for high yields to C5-C9 hydrocarbons, due to the possible catalytic cracking of higher molecular-weight olefins on acidic sites of zeolites [18,19]. As reported in our previous work, the physically-mixed ironbased FTS catalyst with ZSM-5 showed a high selectivity to byproducts and a low selectivity to olefinic hydrocarbons [22].…”