内循环流化床颗粒循环速率实验研究
2011-09-28赵文立沙作良王铁峰王金福
赵文立,沙作良,王铁峰,王金福
(1. 天津科技大学海洋科学与工程学院,天津 300457;2. 清华大学化学工程系,北京 100084)
内循环流化床颗粒循环速率实验研究
赵文立1,沙作良1,王铁峰2,王金福2
(1. 天津科技大学海洋科学与工程学院,天津 300457;2. 清华大学化学工程系,北京 100084)
采用热颗粒示踪和信号相关法对气固内循环流化床的颗粒循环速率进行实验研究.考察操作气速、提升管下部孔径和提升管高度对于颗粒循环速率的影响.结果表明:在所考察的实验条件下,颗粒循环速率在 15~70,kg/(m2·s)之间变化.操作气速增大时,颗粒流化程度增强,颗粒循环速率增加;提升管下部开孔数目不变而孔径增加时,颗粒循环阻力减小,颗粒循环速率明显增加;提升管高度由235,mm增加到295,mm时,颗粒循环速率呈现先升后降趋势,在提升管高度为265,mm时存在极大值.
内循环流化床;颗粒循环速率;热颗粒示踪
Abstract:The solid circulation rate was experimentally studied by heat-particle tracing and correlation function method.The effects of superficial gas velocity,diameter of orifices on the riser wall and height of the riser on the solid circulation rate were studied in an internally circulating fluidized bed reactor. The results showed that the circulation rate Gswas in the range of 15 to 70,kg/(m2·s). With an increase in the gas velocity,the fluidization of the particles was enhanced and resulted in an increase in Gs. With a fixed number of orifices,increased orifice diameter decreased the friction of the particle circulation and increased the circulation rate. The solid circulation rate had a maximum with the riser height 265,mm when the riser heath changed in the range of 235,mm to 295,mm.
Keywords:internally circulating fluidized bed;solid circulation rate;heat-particle tracing
随着我国经济发展和城市化进程的加速,能源的需求量剧增.循环流化床作为一种气固接触面积大、反应效率高的工业反应器,被广泛应用于煤的燃烧与气化、固体废物焚化以及石油加工领域[1–3].但是,传统的循环流化床需要较高的提升管以及旋风分离器.为了降低流化床的高度以及昂贵的设备费用,各种内循环流化床反应器[4–5]相继被开发出来.这种反应器由低速的移动床(下降管)与高速的流动床(提升管)构成复合结构.流化床中的颗粒在气体的带动下向上运动,颗粒进入移动床后开始向下运动,形成了大尺度的颗粒循环.除了结构紧凑、造价低廉外,内循环流化床反应器还有许多优点.例如,反应过程中的热损失较低;……
