针对催化汽油辅助反应器改质降烯烃技术,在一套提升管与气-固环流床层耦合反应器大型冷模实验装置上,研究了上部环流床层的流体力学特性。结果表明,在环流床层与提升管耦合操作的情况下,床层内颗粒环流存在两种推动力,分别为静压差推动力和颗粒喷射推动力;环隙与导流筒之间的整体平均固含率差随导流筒表观气速增加而增加,随颗粒外循环强度增加而降低;颗粒环流速度随导流筒表观气速和颗粒外循环强度增加而增加。通过对环流床层进行动量衡算,建立了提升管与环流床层耦合流动的数学模型,模型平均相对误差在15.95%以内。
A large scale cold model experimental setup for a coupled reactor mainly composed of lower riser and upper gas-solid loop fluidized bed was established,aiming at the industrial application background of olefin reduction technology with auxiliary reactor for FCC naphtha upgrading.The hydrodynamic behavior in the upper loop fluidized bed was experimentally investigated.The results show that,under the coupling operation of loop fluidized bed and riser,two kinds of circulating driving forces exist in the loop fluidized bed viz.the static pressure difference and the particle jet driving force.The total averaged solid holdup difference between the draft tube and the annulus region increases with increasing superficial gas velocity in the draft tube,but decreases with increasing external particle circulating flux.Particle circulating velocity increases with increasing superficial gas velocity in the draft tube and external particle circulating flux.Furthermore,a flow mathematical model describing the coupling operation of riser and loop fluidized bed was established on the basis of momentum balance principle of loop fluidized bed,and the model average relative errors were within 15.95%.