Experimental Study on Pressurized Oxyfuel Combustion of Coal
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Determination of kinetic parameters for oxidation and reduction processes in chemical-looping combustion with oxygen uncoupling of pulverized coal using the thermogravimetric methods *Robert Lewtak1, Agnieszka Celinska1, Anita Skulimowska2, Asuncion Aranda2 1Department of Thermal Processes, Institute of Power Engineering, Augustowka 36, 02-981 Warsaw, Poland 2Department of Environmental Technology, Institute for Energy Technology, Instituttveien 18, NO-2007 Kjeller, Norway
Abstract for poster presentation: Chemical Looping Combustion (CLC) of pulverized coal is an interesting method to use fossil fuels for energy generation. Two main processes create the foundation of the CLC process of solid fuels. The first one is the oxidation process of the solid oxygen carriers (OC) taking place in the air reactor where the OCs take in oxygen from air. The other process oc- curring in the fuel reactor is composed of the fuel oxidation by oxygen just released from the
OC reduced. The highly concentrated CO2 and H2O stream that is the combustion product from the fuel reactor can be easily purified, compressed, and sent to storage or for beneficial use. The main effort of the current research is to determine the values of kinetic paramet- ers of the selected mathematical models describing the oxidation and reduction of the OCs in conditions of Chemical Looping with Oxygen Uncoupling (CLOU). The kinetic models take into account the standard Arrhenius temperature-dependent term, the OC conversion func- tion, the reaction order and the equilibrium oxygen concentration. As a first step, thermogravimetric analyses (TGA) have been carried out in a range of temperatures from 800 to 925 °C for a novel Cu-based OC material displaying high oxygen uptake/release capacity and high resistance to attrition. Oxidation of the OC has been carried out in air while reduction under inert atmosphere of argon. The diameter of the OCs ranged between 100 μm and 200 μm. Subsequently, the experimental data have been analysed to determine the values of kinetic parameters. The differences, found in the static and dynamic TGA and different mod- el approach have been identified and discussed.
Keywords: chemical-looping combustion of pulverized coal, TGA, kinetic parameters.
Acknowledgement: This scientific work was supported by the EEA and Norway Grants oper- ated by the National Centre for Research and Development in Warsaw within the confines of Polish-Norwegian Research Programme NewLoop Innovative Idea for Combustion of Solid Fuels via Chemical Looping Technology. Agreement no. POL-NOR/235083/104/2014. The support is gratefully acknowledged.
* Corresponding author: e-mail: [email protected], Tel: +48 797905129