Numerical simulation of NO_x reduction using low-oxygen combustion and optimization in a TTF precalciner

摘要

This paper describes the use of low-oxygen combustion technology to reduce NO_x emissions in cement production. Numerical simulation was also employed to simulate the pulverized coal combustion, calcium carbonate decomposition and NO_x reduction process in the precalciner of a 5000 t/d clinker cement production line. The simulation gave a temperature at the precalciner outlet of 1260 K, a CO_2 mass fraction of 28%, an O_2 concentration of 1.2% and an NO_x concentration of 523 ppm. The data were in good agreement with the actual measurements. The low-oxygen combustion technology was also optimized by changing the oxygen content in the kiln exhaust gas in order to achieve the best conditions. The results showed that the NO_x concentration at the outlet of the precalciner would be lowest (468ppm) when the oxygen content in the kiln exhaust gas was 3%.