Enhanced Fischer-Tropsch synthesis through structured bed configurations and zeolite integration

Abstract

The highly exothermic nature and wide range of products of the Fischer-Tropsch (FT) synthesis motivated the study of the influence of different fixed bed configurations on the conversion stability and selectivity of the system. A cobalt catalyst (Co-Ru/Al2O3) was synthesized as a fixed-bed powder reference and compared with monoliths (230 and 770 cpsi) loaded by the washcoating method. The monolith with the lowest cell density showed the greatest stability among the systems evaluated, with no drop in CO conversion during the 50-hour test. The same powder bed was compared with dual-bed configurations and physical mixing with HZSM-5 zeolite. These experiments showed that by adding HZSM-5 zeolite bed after the FT catalyst one can effectively increase the gasoline range selectivity, without favoring the formation of methane and C2-C4 gases. However, when the same mass of zeolite was physically mixed in a single bed, the formation of the C1-C4 fraction increased from 23 % to 33 %. The strategies employed improved product distribution and reduced the deactivation rate compared to the conventional single bed.