Conversion of syn-gas to lower alkenes over Fe-TiO2-ZnO-K2O catalyst system

Conversion of syn-gas to lower alkenes is studied over a multicomponent cat alyst system, Fe-TiO2-ZnO-K2O, Various reaction variables affecting the con version were studied. At H-2:CO = 1, 2.5 kg/cm(2) pressure, 250 degreesC te mperature and GHSV = 960 h(-1), maximum selectivity of 68% to alkenes was o btained 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 measur ements, TPR and TPD. XRD and ESCA studies reveal the presence of Fe2O3 phas e in the fresh catalyst. This phase is ably promoted by Zn and K. On reacti on with CO + H-2, electron-rich species are formed on catalyst surface, whi ch are the most likely active species. In addition to this, there is an imp rovement in dispersion of the active phase. These factors may contribute to ward better performance of the catalyst in the conversion of syn-gas to low er alkenes. (C) 2001 Elsevier Science B.V. All rights reserved.