Cfd analyzes on temperature distribution in pulverized coal boiler

In thermal power plants, pulverized coal boilers generating steam have been established by foreign companies in Turkey. The reasons such as, discrepancies of Turkish lignite's chemical composition, the improper design that doesn't take account coal properties and revisions on the boiler and changing operating conditions cause efficiency and capacity problems, in terms of the desired energy generation in the boilers. Due to the flame cannot be grow out in the desired area of the boiler room causes( leads) efficiency loss in the boilers of 4th and 5th unit of Tuncbilek Thermal Power Plant (TTS). By reason of similar problems, geometrical revisions have been made in these imported boilers, nevertheless the problems have not been solved completely. Therefore, it is obvious that there is need to be done studies aiming at prediction and diagnosis of such problems and determining the behavior of the boiler. For this purpose, numerical modeling studies have been carried out, under actual operating conditions and geometries of one of pulverized coal boilers in TTS by using of ANSYS FLUENT 15.0. In the modeling studies based on actual Geometry and working conditions of boiler indicates that there has been correlation 10% approximately between the results of numerical models and measured temperatures at different heights of boiler and having the same characteristic features verified the numerical modeling results. Some result of this Verified numerical modeling study shows that there might have an effect on flame and pipe ruptures. When velocity distributions in the cross section of the boiler are examined, it is identified that air and fuel that flow the corner burner cannot be fully directed to the center and the coal particles that leads boilers wall may hit to the screen pipes and may cause wear on the pipes so thickness of the pipes decreases. When velocity distributions in the longitudinal section of the boiler are investigated, it is seen (evaluated) that the vortex in Hooper area may cause corrosion and slug. The slug may affect the flow in the boiler and it may cause a chance in the flame area. It is identified that structural factors of boiler are more affective on the flame formation and pipe ruptures than operating conditions of the boiler (coal, air flow rate, particle diameter, etc.). It is seen that the geometry of the existing boiler in the TTS is not designed in optimum style. During this project, in order to solve the mentioned problems above, without changing the main dimensions of the boiler, small economic designs have been done as a result of these some improvements have been observed in the flow of the boiler. But it was concluded that in order to achieve optimum accordance between coal and boiler there need to be done radical changes in the main dimensions of the boiler.