Deactivation behaviors of hybrid Fischer–Tropsch catalysts in the production of middle distillate from synthesis gas in a dual-bed reactor

Abstract

Production of middle distillate (C 10 -C 20 ) from synthesis gas (CO ? H 2 ) through hydrocracking of wax ([C 21? ) was carried out in a dual-bed reactor. Fischer-Tropsch catalyst (Co/TiO 2 ) was used in the first-bed reactor to produce wax from synthesis gas, and a mesoporous Pd-alumina composite catalyst (Pd-Al 2 O 3 ) was used in the second-bed reactor to produce middle distillate through hydrocracking of wax. Both Fischer-Tropsch synthesis function of Co/TiO 2 catalyst and hydrocracking function of Pd-Al 2 O 3 catalyst were deactivated during 100 h-hybrid Fischer-Tropsch synthesis reaction. It was revealed that deactivation behaviors of Co/TiO 2 and Pd-Al 2 O 3 catalysts were governed by different factors. Wax accumulation and Co sintering were responsible for deactivation of Co/TiO 2 catalyst in the Fischer-Tropsch synthesis reaction. Loss of Pd dispersion and Pd surface area of Pd-Al 2 O 3 catalyst was responsible for its decreased catalytic performance in the production of middle distillate through hydrocracking of wax.

Chemical and Thermal Sintering of Supported Metals with Emphasis on Cobalt Catalysts During Fischer–Tropsch Synthesis

“…= D D a r 0.301 ( / ) s 4 (27) According to eq 27, NC diffusivity (D) is a function of atomic diffusivity (D s ) and the ratio of atomic to NC radius (a/r) to the fourth power. However, eq 27 does not consider two critical factors: namely, effects of (i) E adh and (ii) pore size.…”

“…Most of the early work (1970–2000) focused on high-temperature (500–750 °C), thermally induced sintering of supported Ni and noble metals in H 2 , N 2 , or O 2 . − A few sintering studies of Ni during methanation at 250–350 °C were carried out from 1990 to 1995. , Sintering of supported Co catalysts during low temperature FTS at 210–230 °C has received significant attention during the past 10 years. Accordingly, this last topic, sintering of supported Co FT catalysts during reaction − and detailed data supporting a chemical pathway, ,,,,,,− will be emphasized in this review. The review will also put this topic in the broader perspective of principles applicable to either thermal or chemical sintering of supported metals.…”

“…While a significant number of recent papers have addressed deactivation of Co FT catalysts by sintering, − many issues and questions remain unresolved. Areas that require greater development and understanding include (i) sintering kinetics and mechanisms and (ii) effects on sintering rate of catalyst preparation, composition and properties, NC diameter, support properties, and reaction conditions.…”

A compact and high throughput reactor of monolithic‐structured catalyst bed for conversion of syngas to liquid fuels

“…Coke can be produced from either CO decomposition or uncontrolled polymerization reactions. Coking often causes catalyst deactivation 18, 19. The F–T reaction is highly exothermic and can easily run away if the temperature is not effectively controlled.…”