Cold Model Experiments And Numerical Simulation Of The Gas-Solids Flow Characteristics On A Selective Fluidized Bed Bottom Ash Coler For A 410t/h CFB Boiler

Nowadays, a selective fluidized bed bottom ash cooler is commonly used in most of the circulating fluidized bed (CFB) boilers with the capacity of 410t/h or more in China for the cooling of bottom ash. Thus it can be seen that the selective fluidized bed bottom ash cooler is complicated not only in configuration but also in operation. The hot bed materials discharged from the furnace flowed from selective chamber to cooling chambers in turn and discharged from the cooler. The fluidizing air flows through the selective chamber and the other cooling chambers synchronously, and then it flows into the furnace at last. So the bottom ash cooler was often jammed or flowed to be empty by fluidizing air during operation. These problems severely affect the economy and the safety of the CFB boilersAccording to the selective fluidized bed bottom ash cooler in a 410t/h CFB boiler, a visual cold experimental apparatus at the ratio of 1:10 was set up. Under the condition of the steadily operating furnace, a series of cold experimental tests on the gas-solids flow characteristics were completed with bed materials of ash floater.The cold experimental tests mainly include:1. The cold fluidizing characteristic of the bottom ash cooler;2. The relationship of the amount of the bed materials and the bed pressure drops in the bottom ash cooler;3. The effect of the velocity of the fluidizing air to the flow of the bed materials in the bottom ash cooler;4. The influence of pulse air of ash inlet pipe to the flowing of bed material from the furnace to the bottom ash cooler;5. The influence of fluidizing air of each chamber to the ash discharged rate of the bottom ash cooler;The results of the cold experimental tests mainly include:â‘ The cold experimental tests indicate that the critical fluidizing velocity occurs at about 0.17m/s when the bed materials was floater .This critical fluidizing velocity was basically equal to the critical fluidizing velocity gained by calculating with experience formula (0.178m/s);â‘¡The cold experimental tests identified that the variation of the amount of the bed materials and the bed pressure drops was accordant;...