Poisoning of iron catalyst by COS in syngas for Fischer—Tropsch synthesis

Abstract

As a part of converting coal to liquid fuels, the poisoning of commercial FeCuK catalyst in Fischer-Tropsch (FT) synthesis by carbonyl sulfide in synthesis gas was tested. Reduced coprecipitated FeCuK catalyst was investigated with synthesis gas containing 73.2, 184, 232.4, and 350.8 mg of sulfur as COS per cubic meter at 524 K under 2.31 MPa, with an hourly space velocity of 1854. The catalyst activity decreased rapidly in the first few hours of poisoning process, and finally decreased linearly with amount of sulfur fed to the catalyst until the relative activity was 0.01 to 0.05. The deactivation rates were different with the content of sulfur in synthesis gas. The selectivity to methane and gaseous C₂C₄ hydrocarbons increased when the catalyst was poisoned by COS. The weight content of C⁺₅ in product decreased significantly with increasing sulfur fed to catalyst. The water-gas shift reaction in FT synthesis was also discussed in this work.