新型串行流化床流体动力学研究

Study on Hydrodynamics Characteristic of a Novel Interconnected Fluidized Bed

提出了一种用于固体燃料化学链燃烧的新型串行流化床,将燃料反应器设计为不同流型的两段,即快速的混合反应段和低速的未反应碳分离段。混合反应段的射流进料强化了物料的混合,可以实现颗粒性质差异大的载氧体-固体燃料间的充分混合反应;未反应碳分离段代替了碳捕获器的作用,降低了反应装置的复杂性。采用石英砂代替载氧体作为床料,空气作为流化气体,在自行搭建的冷模装置上对提出的新型串行流化床的流体动力学进行了研究。研究表明:冷态系统连续运行平稳,快速混合反应段的一级燃料反应器的固含率εs>0.15,属于高密度流化状态,较高的颗粒浓度强化了载氧体-固体燃料间的反应。另外,颗粒浓度随着表观气速增加而降低,固体循环率随着表观气速的增加而增大。

This paper proposes a novel interconnected fluidized bed for chemical looping com-bustion of solid fuels.The fuel reactor is designed into two stages with different flow pat-terns,namely a fast mixed reaction stage and a low-speed unreacted carbon separation stage.The jet feed in the mixing reaction section strengthens the mixing of materials,and can a-chieve a thorough mixing reaction between oxygen carriers with large particle properties and solid fuels;the unreacted carbon separation section replaces the role of the carbon stripper and reduces the reaction device complexity.Using quartz sand as the bed material and air as the fluidizing gas,the hydrodynamics characteristics of the proposed novel fluidized bed was studied on the self-built cold model device.Research shows that the cold model operates con-tinuously and smoothly.The solid content of the first-stage fuel reactor in the fast mixing re-action sectionε_(s)>0.15,which belongs to a high-density fluidized state,and the higher parti-cle concentration strengthens the reaction between oxygen carrier and solid fuel.In addition,the particle concentration decreases with the increase of the superficial gas velocity,the solid circulation rate increases with the increase of the superficial gas velocity.