Sintering and Coking: Effect of Preparation Methods on the Deactivation of $$\hbox {Co}$$ Co – $$\hbox {Ni/TiO}_{2}$$ Ni/TiO 2 in Fischer–Tropsch Synthesis

Abstract

The main challenge of this work is study effect of preparation methods, co-precipitation and sol–gel, on the deactivation of \(\hbox {Co}\)–\(\hbox {Ni/TiO}_{2}\) catalysts in Fischer–Tropsch synthesis. Revealed that coking and sintering are two main mechanisms which have a significant influence on the deactivation of the catalyst. The catalysts were tested under industrially conditions (\(T=350\,{^{\circ }}\hbox {C}\), \(P=10\,\hbox {bar}\), \(\hbox {H}_{2}/\hbox {CO}=2\) and \(\hbox {GHSV}=7200\,\hbox {h}^{-1})\) and during 300 h on stream. Although CO conversion and product selectivity were similar for both catalysts, the sample prepared by co-precipitation method showed a better catalytic performance. The mechanisms of deactivation were interpreted using TPR, TEM/EDS and XRD techniques. Depicted that coking and sintering are two predominate mechanisms for deactivation of co-precipitation and sol–gel catalysts, respectively.