| dc.description.abstract | The following master thesis is a work package from a larger project for the design of a novel and commercialize more sustainable process for energy generation. This process is a new hybrid natural gas combined cycle power plant with integrated high temperature CO2 capture with solid sorbents by carbonate looping. The novelty resides in the design of the carbonator and calciner, reactors where the sorption/desorption of CO2 occurs, and the optimization of the heat generated by catalytic combustion in the plant. This design achieves a total energy efficiency of 56% of the power plant, while reducing the size, cost and energy consumption of the CO2 capture process.
This master thesis is focused on the heat required for the CO2 capture which, based on the process design, is provided by the catalytic combustion of natural gas. For this purpose, it was studied the reaction of catalytic combustion of methane over cobalt-based catalysts over alumina pellets promoted by cerium oxide as a suitable catalyst for the process. The work in this master thesis includes the catalyst synthesis, characterization, and activity testing as well as a kinetic study. Different catalysts, varying the load of cobalt and cerium, were prepared by different synthesis methods to compare the differences in the surface properties and activity, including: Pechini method and incipient wetness impregnation. Both methods proved to be efficient and reproducible techniques to prepare the catalysts. The textural properties of the catalyst were characterized by the analysis of the N2 adsorption-desorption, X-ray fluorescence spectroscopy and X-ray diffraction.
Finally, the different catalysts were tested for the combustion of methane in a fixed bed reactor. The reaction products were analysed by gas chromatography and the methane conversion was calculated by integration of peaks of the chromatogram by using nitrogen as internal standard and by the mass balance of the components. The results showed that the cobalt catalyst and the promoted support are active with a minimum ignition temperature of 560ºC at the operation conditions. The results of the ignition curves of Co/Al2O3 showed that the total cobalt loading does not influence the activity. However, when the cobalt is impregnated on the cerium promoted support, an enhanced performance in the catalysis of the methane combustion. Furthermore, the catalytic system of cobalt cerium and alumina proved to be stable without activity loss for 24 hours at the operation conditions with minor changes in their atomic structure. | |
