Zeolite-supported cobalt catalysts for the conversion of synthesis gas to hydrocarbon products

Abstract

Three differently prepared cobalt/ZSM-5 catalysts were Investigated with respect to physical and chemical properties and to activity and selectivity for conversion of synthesis gas. The catalyst preparations consisted of the following:(1) direct decomposition of C5H5Co(CO)2 on ZSM-5, (2) Impregnation of ZSM-5 with an aqueous solution of cobalt nitrate, and (3) physical admixture of precipitated cobalt oxide with ZSM-5. At about 3 wt % cobalt loading, the first catalyst showed higher dispersion, higher (H2 + CO) conversion, and about 10 times higher yield of gasoline-range hydrocarbons (g/h) than the catalyst prepared by the other two methods. Some H2 and CO chemisorption studies and magnetization measurements were conducted to measure the average particle diameter. Infrared studies of chemisorbed pyridine on these samples indicate that ion exchange of Co2+ for acidic protons occurs in organometallic-impregnated and aqueous solution-impregnated catalysts.

The addition of HZSM-5 to the Fischer–Tropsch process for improved gasoline production

“…The range of FT catalysts include those based on iron [6][7][8][9], iron/manganese [10,11], cobalt [12,13], cobalt/manganese [14,15] and even iron/cobalt [16]. The use of different zeolites (mordenite, erionite, ZSM-11, ZSM-12, L, omega and beta) in combination with a Fischer-Tropsch catalyst has been investigated [17], while other researchers tested HZSM-5 [6,16], gallium-substituted HZSM-5 [14,15] and HY [10].…”

Direct conversion of synthesis gas to aromatic hydrocarbons: Variation of product distribution with time‐on‐stream

“…This decline in conversion is essentially due to the slow deactivation of the FT catalyst caused by the carbonaceous surface layer that forms from the dissociation of CO on the catalyst surface and grows with time-on-stream (Shamsi et al, 1984). The CO conversion drops from 5 1 % after 1 h to 24% after 50 h of operation.…”

“…Une comparaison des resultats pour le temps d'utilisation obtenus en employant le catalyseur I T seul ou melangt avec la zeolite HZSM-5 semble indiquer que les reactions kgissant la distribution globale des produits sont plus lentes sur HZSM-5 que sur le catalyscur I T . Thus, the synthesis gas can be directly converted to gasoline range product by combining FT synthesis function with a shape-selective acid function (Chang et al, 1979;Caesar et al, 1979;Haag and Huang, 1981;Bruce et al, 1984;Shamsi et al, 1984). On prCsente aussi I'analyse du coke sur les catalyscurs dtsactives.…”

“…Most conventional Fischer-Tropsch ( l T ) catalysts produce a wide spectrum of hydrocarbon products (Anderson, 1956), however, if combined with a shape selective catalyst, a more selective hydrocarbon product can be produced. Thus, the synthesis gas can be directly converted to gasoline range product by combining FT synthesis function with a shape-selective acid function (Chang et al, 1979;Caesar et al, 1979;Haag and Huang, 1981;Bruce et al, 1984;Shamsi et al, 1984).…”

Hydrogenation of carbon dioxide by hybrid catalysts, direct synthesis of aromatics from carbon dioxide and hydrogen

“…Carbon monoxide is first hydrogenated on the hydrogenation catalyst and then the products are further converted on the zeolite to form aromatics. With the combination of a medium pore HZSM-5 zeolite and various kinds of Fischer Tropsch (Caesar et al, 1979;Shamsi et al, 1984;Bruce et al, 1984;Varma et al, 1985Varma et al, , 1986Varma et al, , 1987 or methanol synthesis catalysts (Chang et al, 1979;Thomson and Wolf, 1988), aromatics can be directly synthesized from carbon monoxide and hydrogen with the selectivity as high as 90% (Chang et al, 1979). For carbon dioxide, Fujimoto and Shikada (1987) has combined a copper-zinc methanol *To whom correspondence should be addressed.…”