Abstract: It is one of the developing trends to utilize cement kiln to co-dispose refuse derived fuel (short for RDF). But in the process of actual disposal, there exists the problem of unstable pollutant discharge. Hence, five kinds of RDF treated by a cement plant in Hubei province were taken as the research objects. The high-temperature tubular furnace was used to carry out experiments to study the generation and transformation of NO_x and SO₂ at 500~900 ℃. The experimental results show that in the process of RDF combustion the peak concentration of NO_x is more affected by temperature at low temperatures (500~600 ℃), which increases multiply with temperature; the peak concentration of NO_x is less affected at high temperatures (700~900 ℃). At 900 ℃, the NO_x conversion rate is low and the combustion rate is fast, so it’s the suggested temperature to dispose of RDF. In the combustion process of different RDF, the conversion rate of NO_x shows an “inverted V shape” with the changing of combustion temperature, while the conversion rate of SO₂ shows a “positive V shape” with the change of combustion temperature. The NO_x and SO₂ play a mutual inhibition role in the formation process.

Key words: cement kiln, refuse derived fuel, NO_x, SO₂, generation, transformation