Cold Experiment On Dual Circulating Fluidized Beds

To improve the efficiency of fuel is one of the main direction of research in the next few decades. Circulating fluid bed has various advantages such as burning a wide range of fuels, low emissions, and so on. Dual circulating beds technology can combine pyrolysis, gasification and combustion in a hybrid process according to different compositions of fuel. This is of great value to energy resource of our country.The pressure distribution and solid recirculation rate were investigated in dual circulating fluidized beds. The effects of bed material charge, the fluidization velocities of primary air of the main-bed and the fluidization velocities of secondary air of the attached-bed on the pressure distribution and solid recirculation rate were analyzed respectively.Compared with the fluidization velocity of primary air of the main-bed, that of secondary air of the attached-bed has greater influence on solid recirculation rate. The distribution proportion of solid recirculation rates in the dual beds can be adjusted by controlling the fluidization velocity of secondary air of the attached-bed. Keeping the pressure at the outlet of cyclone stable, the pressures at the other parts of the dual beds increase with the increase in bed material charge, the fluidization velocity of primary air of the main-bed and secondary air of the attached-bed. The lower part of the riser of the attached-bed is the most important part, because the pressure balance of the dual circulating fluidized beds is kept by the height of resident material in the lower part of the riser of the attached-bed, which increases with the increase in the fluidization velocity of primary air of the main-bed, and decreases with the increase in the fluidization velocity of secondary air of the attached-bed.Based on theoretical analysis and experimental results, a pressure balance model of the dual circulating fluidized beds was built.