Preparation and Catalytic Evaluation of Cobalt-Based Monolithic and Powder Catalysts for Fischer−Tropsch Synthesis

Abstract

Cobalt-based monolithic and powder catalysts for Fischer-Tropsch synthesis were prepared. The aluminasupported catalysts contained cobalt (18.6 ( 0.9 wt %) and rhenium (1.2 ( 0.1 wt %) as active phases. To ensure the comparability of both catalysts, monolithic and powder catalysts were prepared from the same CoRe/γ-Al 2 O 3 active powder. While the monolith was prepared by dip coating, the slurry for the coating procedure was also used for preparation of the powder catalyst. It could be shown that both catalysts have comparable composition, pore structure, Brunauer-Emmett-Teller (BET) surface area, and active metal surface area. Catalytic measurements with suspended powder catalyst in a stirred tank reactor and monolithic catalyst in a fixed-bed reactor in the slug-flow regime were performed during Fischer-Tropsch synthesis. Higher reaction rates at comparable methane selectivities were obtained with the monolithic catalyst. Estimations show that the advantageous mass-transfer characteristics of the monolithic catalyst in the slug-flow regime are responsible for this reaction rate enhancement.

Holdup and Pressure Drop in Micro Packed‐Bed Reactors for Fischer‐Tropsch Synthesis

“…The preparation method for C1 was described in detail by Guettel et al [16]. For C2 and C3, c-alumina particles with diameters of ca.…”

Effect of method of preparation on activity of Pd/Al2O3 monolith catalysts

“…Wedler et al (2009) have reported that the point of zero surface charge (pH pzc ) for purealumina as 7, whereas for Pd/Al 2 O 3 as 8. Guettel et al (2008) studied the zeta potentials of the base materials and catalysts and reported that, for a given pH, the absolute zeta potential of the metal impregnated powder was less then the zeta potential of unimpregnated powders. The decrease in zeta potential leads to agglomeration and gellation of catalytic slurries.…”

“…To increase the structural integrity and stability of the slurry, binders have been used (Arnby et al, 2004;González et al, 2007;Guettel et al, 2008;Sánchez et al, 2009). In the present study, colloidal alumina or dispersible pseudo-boehmite (Disperal P2) was used as the binders.…”

Viscous co‐current downward Taylor flow in a square mini‐channel

“…6,7 Recent measurements during Fischer-Tropsch synthesis showed enhanced reaction rates for a fixed-bed reactor with monolithic catalyst in the Taylor flow regime as compared to a stirred tank reactor with suspended powder catalyst. 8 Furthermore, higher C5-C18 liquid fractions are obtained by conducting the Fischer-Tropsch reaction in a monolith catalyst with straight flow channels rather than a packed-bed of catalyst particles. 9 These results are attributed to the advantageous mass transfer characteristics of the monolith reactor in the Taylor flow regime.…”

“…Squalane is a viscous liquid and as an inert species serves as good solvent for Fischer-Tropsch products. 8,24 In the experiments, the gas and liquid superficial velocities are in the ranges of 0.05-0.2 m/s and 0.017-0.1 m/s, respectively. High-speed video camera images are used to roughly estimate the axial length of a unit cell and the gas holdup within the unit cell.…”