Numerical investigation of a 1MW full-loop chemical looping combustion unit with dual CFB reactors

Abstract

Chemical looping combustion (CLC) is a novel carbon capture technology with inherent advantage of CO2 separation and less energy penalty. The oxygen carrier circulates between the reactors realizing the transportation of oxygen and heat and preventing the mixing of air with flue gas. Currently, it lacks researches on the industrial scale system which operates autothermal. In this work, three-dimensional simulations of 1MW chemical looping combustion unit with gaseous fuel are presented in the frame of Eulerian approach. The configuration with dual circulating fluidized bed reactors is built according to the experimental construction, including air reactor, fuel reactor, loop seals, cyclones and L-valve. The time-averaged and local pressure, temperature and gaseous products are predicted numerically and compared with experimental measurements. Simulation results show that the reduction level changes by 0.08 between reactors corresponding to the oxygen transfer. Due to the exothermic process in air reactor, the difference of outlet temperature between air reactor and fuel reactor is 63 °C. Moreover, the higher operating temperature and solid inventory are beneficial for raising the performance of system. Results turn out that the numerical models developed in this work can be used for investigating detailed characteristic or scale-up of CLC system with high accuracy, high efficiency and low cost.