(560en) Fischer-Tropsch Synthesis on Natural Zeolite-Supported Fe Catalysts | AIChE

(560en) Fischer-Tropsch Synthesis on Natural Zeolite-Supported Fe Catalysts


Gorimbo, J. - Presenter, Institute for the Development of Energy for African Sustainability
Chikati, R., University of the Witwatersrand
Muleja, A. A., University of South Africa
Nkazi, D., University of the Witwatersrand
Natural zeolites have fascinating properties that makes them attractive as supports in Fischer-Tropsch synthesis (FTS) because of their ubiquitous in nature and relatively low costs. Detailed mineralogical knowledge and profound characterization of natural zeolites are essential for fitting chemical composition to use. Si/Al ratios are very import as well as the other contaminates. In this study natural zeolite called clinoptilolite (a type of zeolite found in South Africa) was used as a catalyst support. This support proved to be effective for low-temperature Fischer–Tropsch synthesis (LTFTS) aiming liquid fuel production, as well as chemical feedstock. Synthesis of this highly active catalyst was by loading of iron on clinoptilolite through the wet impregnation method. The prepared catalyst was then characterized by XRF, BET surface area analyzer, XRD and SEM. The catalyst was then loaded into the reactor and reduced with hydrogen prior to FTS. The effects of its use as support in FTS were investigated in a fixed bed reactor. From the XRF results the molecular ratio SiO2/ Al2O3 of the Clino-support was 5.86. The average crystal size of the particles from both HRTEM and XRD ranged 9.83 -11.649 nm and around 10.10nm for used and fresh catalyst. It was found that the CO consumption rate of 1.02 x 10-4mol/min.gcat of which 7.24 x 10-5 mol/min.gcat was the actual Fischer Tropsch rate with the remaining 2.93 x 10-5 mol/min.gcat consumed by the WGS reaction. The product distribution of the gaseous phase analysed were more olefinic than paraffinic. The product distribution for our experimental condition agreed with a one alpha ASF distribution with an alpha value of 0.86. These findings may permit the development of new effective support materials, which are cost effective for clean fuel production via FTS process.