(450d) Investigation of a New Preparation Method for Cobalt Fischer-Tropsch Catalysts

Mahmood Rahmati*, Saeed Safdari, Calvin Bartholomew, William C. Hecker, Morris D. Argyle

Department of Chemical Engineering, Brigham Young University, Provo, UT 84602

Fischer-Tropsch synthesis (FTS) is a catalytic process for production of a wide range of environmentally friendly liquid fuels from synthesis gas. Supported cobalt is used as a commercial catalyst for FTS. Conventional methods for large scale catalyst preparation are time and energy intensive. Research is continuing to develop and improve new preparation methods for cobalt FT catalysts [1]. Recently, we developed a new, simple one-step catalyst preparation method that was successfully applied to produce unsupported iron FT catalysts [2]. This method has been modified to prepare supported cobalt catalysts. This novel preparation method consumes about 75% less energy and 50% less water compared to the incipient wetness impregnation (IWI) method that is one of the most popular methods for cobalt FT catalyst preparation. The goal of this research was to compare supported cobalt FT catalysts prepared by the IWI method, similar to those used industrially, with the same catalyst prepared by the new technique called solvent deficient impregnation (SDI). The macro and nano-scale structures of the catalysts have been compared with various characterization techniques, including TPO, TPR, XRD, TEM, BET, EOR, and CO and H₂ uptake. Catalytic activity, selectivity, and stability were then investigated using a packed bed reactor operated at industrial FTS conditions (220°C and 20 atm) over 240 hour runs. The kinetic data show that catalysts prepared with the SDI method have the same rate, selectivity, and stability compared to catalysts prepared by IWI. Due to low cost and simplicity, this novel one-step preparation method should be preferred for future catalyst development studies.

1. Munnik, P., P.E. de Jongh, and K.P. de Jong, Recent Developments in the Synthesis of Supported Catalysts. Chemical Reviews, 2015. 115(14): p. 6687-6718.

2. Brunner, K.M., et al., Preparation of an Unsupported Iron Fischer–Tropsch Catalyst by a Simple, Novel, Solvent-Deficient Precipitation (SDP) Method. Energy & Fuels, 2015. 29(3): p. 1972-1977.