Study Of Iron-based Catalysts For The Synthesis Of Lower Olefins Directly From Coal-derived Syngas

There are growing demands for energy supply with the growth of enconomics. China is a country with the energy structure of "rich in coal, lean in oil, poor in natural gas". The utilizations of coal resources to produce value-added chemicals R&D, such as ethylene and propylene, are of great strategic significance and application prospects. The indirect transformation of coal to lower olefins is one of the optimal route for utilization. In this route, coal is firstly converted into syngas (CO and H2), which is then used as raw materials to produce value-added chemicals such as olefins, C2oxygenates etc. The thesis mainly focuses on the kinetic behaviors of Fe-Mn/SiO2catalysts. By investigating the influence of reaction conditions, such as temperature, pressure and space velocity, on the catalytic performance, the relationships of activity and selectivity with the variance of temperature and partial pressures were rationalized. The reaction orders with respect to H2and CO and appearent activation energies for each product were calculated. With the combination of temperature-programmed reduction (TPD), X-rays differaction (XRD) patterns and the reaction kinetics, we found that the crystallite size became smaller with an increase in Mn contents. That means that the addition of Mn may improve the dispersion and reduction of FeOx, resulting in higher conversion and selectivity to lower olefins. The study will provide important guidance to the scale-up in pilot level.