Bed material flow modeling in CFB boiler of Nagan Raya power plant

The Nagan Raya power plant is one of the steam power plants in Indonesia using CFB boilers with a capacity of 100 MWe. During operation there are often problems that occur in boilers that cause shutdown or forced outage. One of them is a tube leak suspected to be eroded by the flow of bed material (sand) in the boiler. Therefore, it is necessary to simulate the flow using Computational Fluid Dynamics (CFD) software to predict the flow of bed material in the boiler. An Eulerian granular multiphase model is used to perform a three dimensional (3D) hydrodynamic simulation, full-loop, time-dependent, on the CFB boiler. In this study the simulated parameters were the diameter of the sand in the form of a mixture of 0.1 mm, 0.2 mm, 0.3 mm and 0.4 mm, with each assumption being 25% by volume. In this simulation also varied the ratio of primary air and secondary air. The simulation results are presented in terms of pressure profile, volume fraction and velocity profile of sand, and sand motion animation. The results show that the flow of sand changes significantly in the airflow distribution and the difference in sand size.