Effect of biomass-derived synthesis gas impurity elements on cobalt Fischer–Tropsch catalyst performance including in situ sulphur and nitrogen addition

• Published in: Journal of catalysis Vol. 279; no. 1; pp. 163 - 173
• Main Authors: Borg, Øyvind, Hammer, Nina, Enger, Bjørn Christian, Myrstad, Rune, Lindvåg, Odd Asbjørn, Eri, Sigrid, Skagseth, Torild Hulsund, Rytter, Erling
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01.04.2011; Elsevier; Elsevier BV
• Subjects: Alkali metals; Alkaline earth metals; Biomass; Biomass-to-liquids; Catalysis; Catalysts; Chemical synthesis; Chemistry; Chlorine; Cobalt; Exact sciences and technology; Fischer–Tropsch synthesis; General and physical chemistry; Impurity; Reaction rate; Selectivity; Sulphur; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Alkaline earth metals; Impurity; Chlorine; Alkali metals; Biomass-to-liquids; Selectivity; Reaction rate; Cobalt; Sulphur; Fischer–Tropsch synthesis; In situ; Hydrogen sulfides; Biomass; Electronegativity; Alkaline earth metal; Synthesis gas; Surface activity; Composition; Catalytic reaction; Fischer Tropsch synthesis; Transition metal; Alkali metal; Nitrogen; Ammonia; Heterogeneous catalysis; Impregnation; Liquid; Fischer-Tropsch synthesis; Fischer Tropsch catalyst; Frequency; Surface area
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2011.01.015

The effect of typical biomass-derived synthesis gas impurities on the cobalt Fischer–Tropsch (FT) performance was investigated at industrially relevant conditions. Significant variations in turnover frequency and product selectivity were observed. Effect of biomass-derived synthesis gas impurity… [Display omitted] ► The effect of biomass imposed impurities on FT catalysis has been established. ► The measured turnover frequency (TOF) correlates with electronegativity. ► No poisonous effect of chlorine was found, rather an enhanced TOF. ► Sulphur deactivates the catalysts stoichiometrically. ► Sulphur does not affect the primary Fischer–Tropsch product distribution. The effect of 10 typical biomass-derived synthesis gas impurities on cobalt Fischer–Tropsch catalyst performance was investigated at industrially relevant conditions. Impurities (0–1000ppmw) were introduced ex situ by incipient wetness impregnation to give 23 different compositions. The presence of alkali (Na, K) and alkaline earth elements (Ca, Mg) did not affect the ex situ-measured cobalt surface area but decreased the in situ activity, thereby decreasing the apparent turnover frequency. The C5+ selectivity increased and decreased upon addition of alkali and alkaline earth metals, respectively. Mn, Fe, and P had minor effects on catalyst performance. The presence of Cl decreased cobalt surface without affecting activity, thus increasing the turnover frequency. The changes in turnover frequency correlated with element electronegativity. In situ addition of H2S and (CH3)2S (2.5–10ppm) decreased activity at all concentrations. However, product selectivity was not affected. Addition of NH3 (4ppm) did not change catalytic performance.