THE EFFECT OF SUPPORT PRETREATMENT ON THE PERFORMANCE OF SUPPORTED FE FISCHER- TROPSCH CATALYSTS

摘要

Typical iron FT catalysts are unsupported, precipitated iron promoted with copper, potassium, and silicon oxides. While these unsupported iron catalysts have sometimes displayed high activity and stability [1], nevertheless, they are structurally too weak to be used in slurry bubble-column reactors (SBCRs), the most thermally efficient and economical reactors for FTS [2]. Supported iron catalysts, which have higher attrition resistance, have previously had much lower activity and productivity in comparison to unsupported iron catalysts. To overcome the low activity and attrition resistant problems, we explored the preparation of supported iron catalysts, and in our previous publications have reported the successful preparation of Fe supported on silica-stabilized alumina (AlSi). This catalyst is the most active supported Fe FT catalyst reported to date and more importantly, it is extremely stable as demonstrated by the fact that its activity continues to increase over 700 h on stream [3, 4]. The key factor to this successful development was the silica stabilizer which enabled us to dehydroxylate the support at high temperature to remove acidic sites. In the current study, we investigate the effect of the calcination temperature of the AlSi on the final properties of the catalyst. In addition, our recent developments to optimize the amount of Cu and K promoters will be discussed.