Hydrodynamic-Combustion Behavior Of A 330 MWth Circulating Fluidized Bed Riser Burning Different Lignites
Osman İPEK Barış GÜREL Mehmet KAN
AbstractCirculating Fluidized Bed Boilers (CFBB) provide the most suitable combustion system for efficient and clean burning and gasification of low quality lignite. In this study, the bed material volume fraction, temperature and the pressure distribution in the furnace were investigated by burning four different types of coal in a ÇAN TS furnace geometry underspecified boundary conditions. A CPFD(Computational Particle Fluid Dynamics)method was used for the numerical analyzes in this study. A MP-PIC (Multiphase-Particle in Cell) method was used to solve gas-solid multiphase flows in the numerical analyzes. An EMMS-YANG 2004 drag model, a SIMPLE solution algorithm, a Particle Donor Cell Differencing discretization method and the LES turbulence method were also used in the numerical analyzes. Time steps for the numerical analyzes were taken every 5 s, and the analyzes were performed over 200 seconds. The numerical models were verified by ÇAN TS experimental results. The temperature, pressure, particle velocity and bed material volumetric ratio distributions in the CFBB combustion chamber were compared for four different lignites. The study results showed that the average sand volume ratio in the base of the furnace and in the combustion chamber varied from 0.4 to0.6, but after secondary air combustion was used in the furnace, the volume ratio of sand in the furnace’s combustion chamber changed from 0.07 to 0.10.