Novel catalyst structures with enhanced heat transfer characteristics

• Published in: Journal of catalysis Vol. 281; no. 2; pp. 254 - 262
• Main Authors: Sheng, Min, Yang, Hongyun, Cahela, Donald R., Tatarchuk, Bruce J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 25.07.2011; Elsevier; Elsevier BV
• Subjects: Catalysis; Catalysts; Chemical synthesis; Chemistry; Colloidal state and disperse state; Effective thermal conductivity; Emulsions. Microemulsions. Foams; Exact sciences and technology; Fischer–Tropsch synthesis; General and physical chemistry; Heat transfer; Highly exothermic or highly endothermic reaction; Metals; Microfibrous entrapped catalyst; Packed bed; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Effective thermal conductivity; Packed bed; Highly exothermic or highly endothermic reaction; Microfibrous entrapped catalyst; Heat transfer; Fischer–Tropsch synthesis; Binary compound; Selectivity; Particle; Packing; Efficiency; Thermal conductivity; Copper; Reactor; Structure; Temperature distribution; Fischer Tropsch synthesis; Transition metal; Heat transfer coefficient; Heterogeneous catalysis; Liquid; Fischer-Tropsch synthesis; Foam; Transport; Alumina; Catalyst
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2011.05.006

Microfibrous entrapped catalyst (MFEC) was addressed to improve the intra-bed heat transfer for highly exothermic and endothermic reactions, as proved in Fischer–Tropsch synthesis. The thermal conductivity of Cu MFEC is 56-fold of that of traditional alumina-packed bed, while the inside wall heat transfer coefficient is 10 times higher. [Display omitted] ► A novel enhanced heat transfer catalyst structure was found for highly exothermic/endothermic reactions. ► Compared to monolith structure, MFEC structure is compatible with pre-manufactured catalyst. ► The thermal conductivity of Cu MFEC is 56-fold of that of traditional alumina-packed bed. ► The inside wall heat transfer coefficient of Cu MFEC is 10 times of that of alumina-packed bed. ► Cu MFEC was proved to increase the thermal stability and product selectivity in FTS process. Highly exothermic and highly endothermic reactions require catalyst beds with good heat transfer characteristics. A novel catalyst structure, microfibrous entrapped catalyst (MFEC) structure, made of high thermal conductive metals can significantly improve heat transfer efficiency, compared with traditional packed beds (PB). First, the thermal parameters of metal MFEC were determined experimentally. In a stagnant gas, the radial effective thermal conductivity of Cu MFEC was 56-fold of that of alumina PB, while the inside wall heat transfer coefficient was 10 times of that of alumina PB. Compared to PB, even those made of pure copper particles, conductive metal MFEC also provides much more effective thermal conductivity and higher inside wall heat transfer coefficient in a flowing gas testing. In addition, an application of Cu MFEC in Fischer–Tropsch synthesis (FTS) demonstrated an improvement in temperature distribution inside the catalyst bed and an increase in product selectivity. Furthermore, unlike monolith catalyst structures and metallic foams, the MFEC structure is compatible with pre-manufactured catalyst particles, very flexible and ease to be corrugated. Contrast to corrugated packing with a poor conductive contribution to heat transport, MFEC with a good self-dependent thermal conductivity does not require the recycle of gas or liquid to increase the convective term of heat transfer. Therefore, the conductive metal MFEC structures serve as a great catalyst structure to enhance the intra-bed heat transfer for highly exothermic or highly endothermic reactions, reducing temperature excursions in the reactors.