Relevance of oxygen carrier properties on the design of a chemical looping combustion unit with gaseous fuels
Alberto Abad, Pilar Gayán, Francisco Garcı́a-Labiano, Luis F. de Diego, M.T. Izquierdo, Teresa Mendiara, Juan Adánez
Abstract
Abstract Chemical looping combustion (CLC) is a novel technology for the combustion of fuels with inherent CO 2 capture. CLC is based on the transference of oxygen from air to fuel by means of an oxygen carrier which is based on a metal oxide. CuO/Al 2 O 3 (14 wt.% CuO) and Fe 2 O 3 /Al 2 O 3 (20 wt.% Fe 2 O 3 ) particles have been used in several CLC units with different results when methane combustion was evaluated. In order to shed light on the main processes affecting methane conversion in CLC, a mathematical model for a dual circulating fluidized bed (DCFB) system was developed to simulate the behavior of CuO/Al 2 O 3 and Fe 2 O 3 /Al 2 O 3 in a CLC unit. The model consists of the coupling of individual fuel and air reactor models to simulate steady state of the CLC unit. Individual models consider both the fluid dynamics of the fluidized beds at the high velocity regime and the corresponding kinetics of oxygen carrier reactions, that is, reduction in the fuel reactor and oxidation in the air reactor. The model was validated using results obtained in a 120 kW th CLC unit with CuO/Al 2 O 3 and Fe 2 O 3 /Al 2 O 3 particles. The validated model was used to simulate the performance of these materials in the 10 MW th CLC unit. Desing parameters of the fuel and air reactors as well as the suitable particle size of the oxygen carriers were determined in order to achieve the complete combustion of natural gas in the CLC unit as a function of the oxygen carrier properties. © 2022 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons Ltd.