Optimization of Catalysts for Fischer‐Tropsch Synthesis by Introduction of Transport Pores

Abstract

Diffusional restrictions in the porous network of Fischer‐Tropsch catalysts strongly affect activity and product selectivity. Especially small pores hamper the diffusion of reactants. In order to overcome the diffusion restrictions, the introduction of transport pores into the catalyst and the resulting effect on reaction rate and selectivities were studied. It was shown that transport pores allow for an increase in diffusion length, maintaining high reaction rate and C5+ selectivity. Overall, the productivity can be increased through optimization of the transport pore fraction.

Structuring of Reactors and Catalysts on Multiple Scales: Potential and Limitations for Fischer‐Tropsch Synthesis

“…One option is the introduction of transport pores as proposed by Coppens based on theoretical considerations 39, 40. Recently, Becker 38 applied this approach to wall coated micro reactors for FT synthesis targeting at catalyst layers with hierarchical pore structure in order to intensify the internal mass transfer (Fig. 4).…”

“… (a) Schematic drawing of the simplified model for an FT catalyst layer with transport pores and (b) improvement potential of C 5+ ‐yield by introduction of transport pores (from 38). …”

Numerical optimization of a structured tubular reactor for Fischer–Tropsch synthesis

“…Multiple examples can be found in literature, in which various types of reactors are assessed [11][12][13][14][15][16][17][18][19][20][21][22][23]. However, none of these studies has investigated the Packed CCFS reactor internal.…”

Effects of macropores on reducing internal diffusion limitations in Fischer–Tropsch synthesis using a hierarchical cobalt catalyst

“…Because diffusion is assumed to be the only transport mechanism inside the catalysts, the pore size is the key parameter to optimize in order to reduce diffusion limitations and achieve good FT performance. 12 Therefore, catalysts with macropores are expected to reduce internal diffusion limitations in large pellet catalysts for xed-bed FT reactors. Becker et al 12 reported that the introduction of transport pores with large pore sizes can increase reaction rates, reduce methane selectivity and increase C 5+ selectivity.…”

“…12 Therefore, catalysts with macropores are expected to reduce internal diffusion limitations in large pellet catalysts for xed-bed FT reactors. Becker et al 12 reported that the introduction of transport pores with large pore sizes can increase reaction rates, reduce methane selectivity and increase C 5+ selectivity. However, catalysts with large pore sizes oen have small specic surface areas; this is detrimental to the dispersion of the supported metal, leading to low metal dispersion and low catalytic activity.…”