GTL using efficient cobalt Fischer-Tropsch catalysts

Abstract Sasol has successfully commercialized a range of processes to convert coal and gas into fuels, chemicals and power. These include fused Fe catalyst in circulating and fixed fluidized bed reactors as well as precipitated Fe and Co on alumina catalysts in slurry phase reactors. The company has realized the value of integrating catalyst and reactor knowledge together with operational experience in the development of new technologies. A fundamental understanding of the requirements for catalyst manufacturing and performance has led to the successful development and scale-up of the manufacturing process of the Co on alumina GTL catalyst. A comprehensive but specific range of techniques were used to analyse and characterize the fresh and spent catalyst's structure to develop the fundamentals of its deactivation, as well as the development of a catalyst regeneration process. A detailed model of the catalyst's dynamic performance in the reactor was built and verified through a well-planned series of micro-reactor and pilot plant synthesis gas reaction tests. This model comprises of all the necessary kinetic, hydrodynamic, mass and heat transfer functions to capture the catalyst's functionality in the macro scale reaction environment. The fundamentally based reaction (catalyst and reactor) model was then used as the anchor point to build a fully functional GTL process model. A statistical data management package was interfaced with the process model to enable continuous optimization of the operating facility through tailored sets of key performance indicators. The integrated GTL process model was then used to define catalyst research and process development targets which push the technology beyond the boundaries of the current version. These include increased synthesis gas conversion, higher value product selectivity and regeneration for the catalyst; increased volumetric conversion efficiency and enhanced energy integration for synthesis gas generation. A fundamental understanding of the catalyst forms the corner stone for the advancement of GTL technology.

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