Numerical Study Effect Using Low Rank Coal on Flow Characteristics, Combustion, and Furnace Exit Gas Temperature on Tangentially Fired Pulverized Coal Boiler 350 MWe

Low rank coal combustion of a tangential firing type boiler is influenced by time, temperature, and turbulence as well as the oxygen sufficiency of combustion air. The mass flow rate ratio of primary air to the pulverized coal will affect the stream velocity of flue gas–solid particles that enter the furnace, so that it has an impact on flow turbulence and primary air-pulverized coal temperature. The flue gas exit temperature, which is too high, is avoided so that the combustion does not occur and exceed the highest limit of the furnace path so that the formation of slagging in the convection area can be avoided. This study analyzed several factors that have a significant effect on combustion using the CFD software simulation software with some boundaries which are set as follows: The flow is assumed to be steady and turbulent. The object of study is the Tanjung Awar-Awar’s boiler with a capacity of 350 MWe with tangentially fired pulverized coal type, boiler operating conditions are the maximum continuous rate, the operating data used is the performance test data, coal uses low rank coal, and coal properties testing has been carried out in the laboratory. The study showed that in the increase of ratio of the primary air to the pulverized coal mass flow rate (PA/PC), the combustion temperature and the average velocity at the burner elevation increased. The lowest average furnace exit gas temperature was obtained at the PA/PC ratio: 2.0 of 1379 °C.