A novel integrated rotary reactor for NO reduction by CO and air preheating: Reactor design and heat transfer modelling

Abstract

Abstract An integrated reactor for NOx reduction by CO (iNA reactor) was proposed, integrating a rotary air preheater with a decoupled NOx adsorption-reduction reactor. Three zones were created in this reactor: a flue gas zone, a reducing gas zone, and an air zone. It was expected that NOx reduction efficiency could be enhanced by independently controlled temperature and oxygen content. In this paper, heat transfer was investigated for the proposed iNA reactor to understand the temperature evolution. A heat transfer model was first developed for an air preheater for verification. Energy balance equations were proposed for both the gas and the matrix phase. The modelling results showed that the design can meet the targeted temperatures. The developed heat transfer model was further applied to simulate the temperature profiles in the iNA reactor with three zones. The influences of several design and operating parameters on the heat transfer performance were investigated: flow direction of reducing gas, inlet temperature of flue gas, rotating speed of the reactor, inlet temperature and flow rate of reducing gas, and different zone partitions. It was concluded that a slower rotating speed was preferred to maintain large temperature differences between different zones, which benefited the temperature-dependent NOx adsorption-reduction process. For the reducing gas, downward flow direction, higher temperature and flow rates were preferred. The heat transfer performance was not very sensitive to zone partition ratio, although it may have an important effect on the reaction efficiencies.