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The production of fuel and chemicals is expected to be based on renewable energies in the next few years. However, combustion causes CO2 emission. Its reduction is one of the main focuses to regulate greenhouse effect, as expected by the Kyoto protocol. One combustion technology which could reduce CO2 emissions is chemical-looping combustion coupled to a CO2 capture device. This technique involves the use of a bed-material, with a size between 100 and 500 µm, composed of an oxide supported by a porous ceramic. This oxide acts as an oxygen carrier and circulates from a reducing atmosphere reactor, where oxygen reacts with CO to produce CO2, to an oxidising reactor, where combustion occurs. In order to improve the reactivity of this carrier, a fluidized bed reactor is used and involves gas velocity. Attrition resistant granulates are therefore needed because of the high impacts occurring in the reactors. Moreover, large pore network is expected to improve the reactivity of the carrier because of the higher accessibility of the gas. Granulates studied for oxygen carrier supports are frequently based on γ-alumina, which is highly mesoporous. In order to understand the importance of microstructure, three different routes were studied with samples composed of macropores, mesopores and a sample composed of both type of pores. Pore size could be successfully tailored with addition of diatomite, composed of pores in the micrometer range. This thesis aims to describe the tailoring of microstructure with addition of diatomite and at understanding its influence on attrition resistance. To be able to verify the performance of the developed supports, impregnation of copper oxide and looping experiments were performed. |
