组合气-固环流床与常规气-固环流床流动特性的比较

COMPARISON OF FLOW CHARACTERISTICS BETWEEN COMPOUND AND CONVENTIONAL GAS-SOLID LOOP FLUIDIZED BEDS

针对石油炼制装备中所涉及的组合气-固环流床和常规气-固环流床,通过大型冷模实验对二者整体流动特性和局部流动特性进行了对比研究。结果表明:在导流筒区表观气速、环隙区表观气速和床层内颗粒静床高度相同的条件下,组合气-固环流床和常规气-固环流床的导流筒区整体平均固含率、环隙区整体平均固含率及两区整体平均固含率差的差别较小,组合气-固环流床内的颗粒环流速度较大。在床层各区域局部流动特性上,在分布器区和导流筒区下部,组合气-固环流床的局部固含率和颗粒速度均较大;在导流筒区中部,二者的局部固含率和颗粒速度均差别较小;在导流筒区上部和气固分离区,组合气-固环流床的局部固含率较小,颗粒速度较大;在环隙区,二者的局部固含率差别较小,而组合气-固环流床的颗粒速度较小。

A cold model experimental device of gas-solid loop fluidized bed in large scale was set up based on the equipments involved in petroleum refining technology,and comparison study of a compound and conventional gas-solid loop fluidized beds in both global and local flow characteristics was carried out.Results show that under the same superficial gas velocities at draft tube and annulus region,and the same static bed height,for the overall flow characteristics,the average solid hold-up at the draft tube and the annulus region,as well as the total average solid hold-up of these two beds were only slightly different,while particles circulation velocity in the compound bed was higher.For the local flow characteristics in various areas,solid hold-up and particles velocity at the distributor region and draft tube bottom of the compound bed were higher.In the middle part of draft tube,the difference of solid hold-up,particles velocity between these two beds was little;in the upper part of draft tube and gas-solid separating region,solid hold-up was lower and the particles velocity was higher for the compound bed.In the annulus region,the difference of solid hold-up between them was little,while the particles velocity was lower in the compound bed.