Flow charateristics of a low NOx emission burner

Recent technological changes in the Polish power industry have created opportunities for reducing NOx and CO emissions, but - at the same time - created another operation problem: sulphur corossion of boilers' rear water-wall. This has been the motivation for performing a detailed study of the air flow and pulverized coal transport in low-NOx burners. A measuring stand was built inside a real medium power OP-230 boiler equipped with a low-NOx burner to measure the velocity field at the burner's outlet and to prepare experimental characteristics of the burner. To extend the description, a numerical model of the burner was constructed and numerical calculations were executed by means of the Fluent program. Numerically calculated velocity profiles were compared with the results of measurements. Further investigations of the low NOx burner included the flow of the air-pulverized coal mixture. The measured concentration of the coal dust was compared with numerically predicted distribution of particles. Both the measurements and the calculations have shown a highly non-uniform concentration of particles at the burner outlet. The obtained results have been helpful in formulating recommendations to improve burner geometry.