N<sub>2</sub>O Reduction and NOx Adsorption in Carbonator of Calcium Looping CO<sub>2</sub> Capture Process

Abstract

A dual-fluidized bed solid circulating system that comprised a bubbling bed carbonator and a fast fluidized bed regenerator was operated under a condition of Calcium Looping (CaL) CO2 capture process. Calcined limestone (CaO) was employed as bed material. Gas mixture simulating flue gas from air-blown combustor consisted of CO2, N2O, NO, O2, and N2 was fed to the carbonator. Most part of the fed CO2 was captured by the calcined limestone particles, then the partially carbonated particles were transported to the regenerator, in which thermal decomposition of CaCO3 was carried out in air stream. The carbonator of CaL process was found to be effective for N2O reduction when the sorbent particles had activity to capture CO2. A part of NO in the feed gas was also adsorbed by CaO particles, then the adsorbed NO was transported to the regenerator, and released to the gas phase there, though the net decomposition of NOx was not observed. CaL process was revealed to be a multifunctional process of CO2 capture, N2O decomposition, and removal of a part of NO in the flue gas fed to the carbonator.