Fischer–Tropsch Reaction on a Thermally Conductive and Reusable Silicon Carbide Support

Abstract

The Fischer-Tropsch (FT) process, in which synthesis gas (syngas) derived from coal, natural gas, and biomass is converted into synthetic liquid fuels and chemicals, is a strongly exothermic reaction, and thus, a large amount of heat is generated during the reaction that could severely modify the overall selectivity of the process. In this Review, we report the advantages that can be offered by different thermally conductive supports, that is, carbon nanomaterials and silicon carbide, pure or doped with different promoters, for the development of more active and selective FT catalysts. This Review follows a discussion regarding the clear trend in the advantages and drawbacks of these systems in terms of energy efficiency and catalytic performance for this most-demanded catalytic process. It is demonstrated that the use of a support with an appropriate pore size and thermal conductivity is an effective strategy to tune and improve the activity of the catalyst and to improve product selectivity in the FT process. The active phase and the recovery of the support, which also represents a main concern in terms of the large amount of FT catalyst used and the cost of the active cobalt phase, is also discussed within the framework of this Review. It is expected that a thermally conductive support such as β-SiC will not only improve the development of the FT process, but that it will also be part of a new support for different catalytic processes for which high catalytic performance and selectivity are strongly needed.

Gaseous Nitric Acid Activated Graphite Felts as Hierarchical Metal-Free Catalyst for Selective Oxidation of H2S

“…It is expected that such sulfur selectivity is linked with the high thermal conductivity of the graphite felt support which could efficiently disperse the reaction heat through the catalyst matrix to avoid local hot spots formation which is detrimental for the sulfur selectivity. Similar results have also been reported on the medium thermal conductive silicon carbide carrier where the lack of local hot spots leads to a significant improvement of the reaction selectivity for selective oxidation of H 2 S [10] and also in other exothermal reactions such as Fisher-Tropsch synthesis [53,54], dimethyl ether [55,56], and propylene synthesis [57,58]. The relatively high sulfur selectivity observed in the present work could also be attributed to the presence of large voids inside the sample which could favor the rapid evacuation of the sulfur intermediate species before complete oxidation.…”

Carbon Spheres Prepared by Hydrothermal Synthesis—A Support for Bimetallic Iron Cobalt Fischer–Tropsch Catalysts

“…Carbon-based materials provide an alternative model support for FT catalysts because of their unique properties, which include high purity, high mechanical strength,h igh electrical conductivity,h igh thermals tabilitya nd high effective surface area along with aw eak interaction with the active-phase precursor. [22] As ar esulto ft heir relative inertness, carbon materials are ideal to study metal-metal interactions in bimetallic systems because of their weak interaction with the activep hases. Regardless of these distinct advantages,t he study of carbon materials as supports for bimetallic FT catalysts remains limited.…”

Impacts of SiC Carrier and Nickel Precursor of NiLa/support Catalysts for CO2 Selective Hydrogenation to Synthetic Natural Gas (SNG)

“…Silicon carbide (β‐SiC) possesses many advantages such as excellent mechanical strength, superior thermal stability, high heat conductivity and chemical inertness . Previous studies have shown that SiC as a catalyst support has many advantages under high temperature or strongly exothermic non‐oxidation reactions, e. g. CO 2 hydrogenation . In addition, La 2 O 3 has been regarded as an effective additive to improve the dispersion of active species and thus increased the activity and stability of the catalysts …”