Investigating catalytic performance of Ag/Ce promoted Fe/ Al 2 O 3 catalyst in the CO hydrogenation process: Selectivity modeling and optimization using response surface methodology

Abstract

The present work has focused on the modeling and selectivity of a mesoporous alumina-supported Fe-Ag-Ce, a new CO hydrogenation catalyst, in a fixed-bed microreactor, at different operating conditions as follows: temperature (260°C-340°C), total pressure (2-11 bar), syngas ratio (1-3), and GHSV (1800-3600 hours−1). The effects of operating conditions and their influence on the CO conversion, C5+ selectivity, and light olefins selectivity (light olefinity) were studied using response surface methodology. The products' selectivity was primarily controlled via the reaction conditions. The responses in this catalytic system were described adequately by modified mathematical models. The simultaneous effects of cerium and silver promoters increased the ratio of olefin to paraffin over the iron catalyst in the Fischer-Tropsch synthesis. Model graphs indicated that maximum amounts of light olefins obtained at T = 323°C, P = 10.36 bar, H2/CO = 1.5, and GHSV = 3219 hours−1. Catalysts' characterization was administered via X-ray diffraction, temperature-programmed reduction, and the measurements of N2 adsorption such as BET and BJH methods. Highlights Response surface models were developed for product selectivity of Fischer-Tropsch. Addison of promoter improved both CO conversion and reaction selectivity. The simultaneous effects of using cerium and silver increased the amount of olefin. Optimization is used to find the maximum of the desirable products.