Elucidation of the NOx generation in waste incineration processes

Abstract

An incineration process is the most dominant method of the waste disposal in Japan. A stoker furnace is widely used for the waste incineration. Recently, in the stoker furnace, low air ratio and high temperature incineration have been applied increasingly. However, they result in the increase in the amount of air pollutant NOx and greenhouse gas N₂O generated due to flame instability. In this research, in order to clarify the NOx generation mechanisms in the waste incineration, RDF burning experiments were carried out, investigating the combustion behaviors and exhaust gas compositions. Mass reduction of RDF proceeded faster with higher temperature. NOx concentration in exhaust gas was found to decrease with increase in temperature. It might result from the strong reduction atmosphere generated around RDF fuel. In addition, RDF burning simulation was carried out, using elemental reaction kinetics. It was found that most of HCN and NH₃ at high temperature was converted to NO, N₂O and N₂.