OPTIMIZATION OF A 50 MW BUBBLING FLUIDIZED BED BIOMASS COMBUSTION FURNACE BY MEANS OF COMPUTATIONAL PARTICLE FLUID DYNAMICS

摘要

An efficient utilization of biomass fuels in CHP plants is often limited by the melting behavior of the biomass ash which causes unplanned shutdowns of the plants. If temperatures exceed the ash melting temperature deposits can affect the operation negatively: The deposits are observed mainly in the freeboard of the combustion chamber where the highest temperatures are measured. These layers will grow and also could break off the wall and fall into the bed region. In this work a bubbling fluidized bed combustion chamber with 50 MW biomass input is numerically investigated by means of computational particle fluid dynamics to detect zones where ash melting can occur. For this purpose the CPFD code Barracuda Version 16 is used. Areas where the deposits are formed were detected by simulation runs and compared with fouling observed on the furnace walls in the freeboard of the combustion chamber. In a second step the model is used to find an optimized operational point with a reduced number of areas with critical temperature. Based on the findings in this work the model is suitable for further investigations and optimizations of the reactor.