喷射环流三相流化床反应器轴向液速分布的研究

在喷射环流三相流化床反应器中，应用本文所开发的内热式热膜流体速率探头，获得了带有沉降分离区的夹套式环流反应器在不同压力、气量、流量条件下，不同轴向位置的液体速率分布规律。对于本文所述这类反应器，喷射区流体运动速率最大；自喷口向上，速率先是随距离的增大易急骤下降，然后逐渐向一渐近点逼近；当进入环隙转折口处时，由于气体的逸出及流道的变化液速急骤下降；凝固相进入环隙时，液速随距离的变化也存在渐近点。当采用变径结构时，流道面积突变处的液速变化率仅次于喷射入口区。在环流反应器中，液速主要取决于喷射动能及气提推动力，受液体进料量及压力的影响较小。

STUDY ON THE LIQUID VELOCITY DISTRIBUTION ALONG THE AXIS OF A JET LOOP THREE-PHASE FLUIDIZED BED REACTOR

In a jet loop three-phase fluidized bed reacter with a settling region,the liquid velocity distribution along the axis was measured under different press- ure,gas and liquid superficial velocities by means of a heat-film probe devel- oped by the authors.For such reactor,the liquid velocity at the jet region is the highest.From the jet upwards,at first it decreases rapidly with the in- crease of distance and then approaches to an asymptotic value.When the liquid reaches the turning point of the annular space,the liquid velocity decreases rapidly again as a result of the escape of gas and the alteration of the flow path.There also exists an asymptotic value of liquid velocity in the an- nular space.When a reactor of varying diameter was adopted,the rate of liquid velocity change at the location,where the cross sectional area of the flow path mutates,is just next to that at the jet inlet region.In such loop re- actors,the liqufd velocity is dependent mainly on the kinetic energy of jet and the air-lift driving force,while less dependent on the feed rate and pressure.