CO2/H2 methanation technology of strontia based catalyst: physicochemical and optimisation studies by Box-Behnken design

Abstract

Catalytic methanation is a fascinating method in converting the carbon dioxide gas from power plant flue gases into the valuable product of methane gas. It can be of great benefit to the environment and the national economy since the production of methane gas can be used as a fuel to run the turbine for electricity generation in power plant system or to run automobile vehicles. As such, catalytic methanation technology is able to reduce the emission of this greenhouse gas to atmosphere. Strontia based catalyst impregnated with Ru/Mn/Al2O3 was developed in this study. The optimum conditions over 10 g of Ru/Mn/Sr/Al2O3 catalyst were achieved with 65 wt% of based loading and calcined at 1000 °C for 5 h which gave 73.10% carbon dioxide conversion with 43.58% of methane at reaction temperature of 210 °C. The value was closely agreed with the predicted result obtained by Response Surface Methodology (RSM) which achieved 72.41% conversion. The higher carbon dioxide conversion was due to the higher reducibility and basicity of the catalyst surface as well as the higher surface area of 83.27 m2/g. The polycrystalline structure obtained from X-Ray Diffraction analysis showed a mixture of smaller (rod shape < 12 nm) and bigger (square sheet shape ∼130 nm) crystallite particles of alumina (Al2O3), strontia (SrO2), tetrastrontium diruthenate (Sr4(Ru2O9)), manganese (II,III) oxide (Mn3O4) and ruthenium oxide (RuO2). The active sites responsible for the higher carbon dioxide activity were SrO2 and RuO2.