【摘要】 对于布置有流动密封阀的循环流化床反应器,其系统压力满足自平衡的特性,固体颗粒循环流率Gs和循环回路的压力平衡具有直接的联系。该文在冷态循环流化床实验台上研究了循环流率对系统各部件压降的影响:在流化风速一定时,随着流动密封阀回料风量升高,回料阀流动阻力下降,循环流率升高;提升管内床压降较高时,炉膛内物料体积份额增大。当Gs超过一定值时,提升管内进入"S"型分布的快速流态化,顶部达到饱和携带状态;分离器压降随着颗粒携带浓度Cs的增加先降低后升高,其转捩点约为3.2kg/m3;立管内负压差移动床的流动状态可以通过改变孔隙率和压差梯度,利用较低的料封实现较高的压头,自动吸收其他部件的压降波动,维持系统平衡。更多还原

【Abstract】 The circulating fluidized bed(CFB) with loopseal has ability to maintain pressure balance of the loop,and solids circulating rate,Gs,has directly relationship with pressure balance.In order to study solids circulating rate’s effect on the pressure loop of the CFB,experiments were conducted in a cold CFB test rig.With higher aeration rate in the loopseal,the pressure drop of loopseal decreases and lower pressure drop leads to higher Gs.Correspondingly,the pressure drop in the riser becomes higher,which means high solids concentration in the riser.When Gs exceeds a certain value Gs,flow pattern in the riser belongs to the fast bed fluidization featured with S shape solids distribution,the top region of riser reaches saturated carrying rate of given gas velocity.Pressure drop of the cyclone firstly decreases with solid concentration,and then increases with higher concentration,the transition point is about Cs = 3.2 kg/m3.The pressure gradient and voidage in the move-bed standpipe changes correspondingly with the pressure balance in the CFB loop,it can provide high pressure head with lower sealing height.Standpipe has the function of absorb the pressure drop of other parts and maintain the pressure balance of the CFB loop.更多还原