Simulation Study on Ash Accumulation in Separator Inlet Flue of 660 MW Circulating Fluidized Bed Boiler under Deep Peak Shaving
Aiming at the problem of serious ash accumulation in the inlet flue of the separator when the circulating fluidized bed(CFB)boiler was running at low load,which affected the normal operation of the boiler,taking a 660 MW circulating fluidized bed boiler as the research object,the distribution char-acteristics of the internal flow field and fly ash deposition characteristics of the boiler at low load were an-alyzed by numerical simulation method,and the influence of inlet velocity and particle size on fly ash deposition was explored.The simulation results show that when the flue gas flows from the furnace to the inlet flue of the separator,a vortex zone will be generated at the bottom of the inlet flue.Fly ash with small particle size is more likely to be deposited in the vortex area,while fly ash with medium and large particle sizes is more likely to be deposited in the back half of the flue.Under the same particle size dis-tribution,the fly ash deposition rate decreases with the increase of inlet velocity,and the deposition rate at 30％load is 16.15 times that at 100％load.When the inlet velocity is greater than 1.95 m/s,the deposition rate is significantly improved.The larger the particle size of fly ash,the greater the deposition rate.When the particle size exceeds 80 μm,the deposition rate increases exponentially.
circulating fluidized bed(CFB)boilerdeep peak shavingflue ash accumulationDDPM model
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