Experimental investigations on heat transfer from suspension to impact separators in the riser column of a circulating fluidized bed combustor

In the present work experiments are conducted to investigate the effect of operating parameters on heat transfer from bed to Ubeam impact separators located in the top region of the riser column. The effect of suspension density and bed temperature on heat transfer from bed to the impact separators (test sections) are investigated. The experimental unit consists of a circulating fluidized bed riser column, which is 0.23 m×0.23 m in bed cross-section, 6.3 m in height with a return leg and back pass. The U-beam impact separators are located in the top region of the riser column. Furnace oil # 2 is burnt in the unit and the experimental investigations are conducted. Water is circulated through the U-beam impact separators. The presence of the impact separators in the top region of riser column helps in solids separation and also to absorb certain fraction of heat liberated in the furnace. The bed to U-beam impact separator heat transfer coefficient increases with suspension density due to increased particle concentration, which results in higher cluster and particle heat transfer. The heat transfer coefficient increases with bed temperature due to increased convection and radiation.