气液并流上行式反应器中分配器压降特性

PRESSURE DROP CHARACTERISTICS OF DISTRIBUTOR IN GAS-LIQUID CONCURRENT UP-FLOW REACTOR

在冷模试验装置中对气液并流上行式反应器中两种气液分配器的压降特性进行研究,考察了气体流量和液体流量对分配器压降的影响,结果表明:采用基准气液分配器和新型气液分配器时,分配器压降都随着气体流量的增大而先减小后增大,随着液体流量的增大而增大;在相同条件下新型气液分配器的压降高于基准分配器。针对两种气液分配器分别建立压降模型,压降计算值包括气液分配器的下部入口压降、中部上升管压降和顶部出口压降三部分,模型计算及验证结果表明:基准气液分配器压降中顶部压降占比最大,下部压降和中部压降占比较小,而中部压降中重力压降占比最大,加速压降可忽略不计;压降的模型计算值与试验值随液相流量变化的趋势基本一致,但是在相同条件下压降的计算值大于试验值,且二者的偏差随着液相流量的增大而逐渐增大,其原因是实际分配器中气液两相的流型会发生变化,导致模型计算值偏差变大。

The pressure drop characteristic of new and reference gas-liquid distributors and the effect of flow rates of gas and liquid on the pressure drop were studied in a cold gas-liquid concurrent up-flow reactor model device.The results showed that for both two type of distributors,the pressure drop increased first and then decreased with the increasing gas flow rate,while increased with liquid flow rate up.However,the pressure drop of new gas-liquid distributor was larger than that of the reference one under the same conditions.The relevant mathematical model was established to predict the pressure drops for two gas-liquid distributors,including bottom part inlet pressure drop,middle part rising tube pressure drop,and top outlet pressure drop.The model calculation and verification results showed that in reference gas-liquid distributor,the top part pressure drop dominated,while in the bottom part and middle part was less,where the gravity pressure drop accounted for the largest proportion in the middle pressure drop,and the acceleration pressure drop could be ignored.The trend of pressure drop calculated by the model was basically the same as that of the experimental value with the liquid flow rate,but the calculated value of pressure drop was larger than the experimental value under the same conditions,and the deviation between them gradually increased with the increase of liquid flow rate.The reason was that the flow pattern of gas-liquid two phases in the actual distributor will change,which leads to the deviation of the calculated value of the model becoming larger.