Conversion of syn-gas to lower alkenes over Fe-TiO 2-ZnO-K 2O catalyst system

Abstract

Conversion of syn-gas to lower alkenes is studied over a multicomponent catalyst system, Fe-TiO 2-ZnO-K 2O. Various reaction variables affecting the conversion were studied. At H 2:CO=1, 2.5 kg/cm 2 pressure, 250°C temperature and GHSV=960 h −1, maximum selectivity of 68% to alkenes was obtained at 45% conversion of the feed. The alkenes consist of a mixture of propylene (65%) and ethylene (35%). The catalyst is active even after 200 h of use. The catalyst samples were characterised by BET surface area measurements, TPR and TPD. XRD and ESCA studies reveal the presence of Fe 2O 3 phase in the fresh catalyst. This phase is ably promoted by Zn and K. On reaction with CO+H 2, electron-rich species are formed on catalyst surface, which are the most likely active species. In addition to this, there is an improvement in dispersion of the active phase. These factors may contribute toward better performance of the catalyst in the conversion of syn-gas to lower alkenes.