FCC沉降器粗旋风分离器的料腿泄气率  

Gas-Leakage Ratio of Rough-Cut Cyclone Dipleg in FCC Disengager

作　　者：刘书贤[1] 孙国刚[1] 付烜[1] 时铭显[1] 

机构地区：[1]中国石油大学重质油国家重点实验室,北京102249

出　　处：《石油学报（石油加工）》2011年第1期62-68,共7页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中国石化重油催化沉降器抑制结焦项目(305013);国家重点基础研究发展规划项目(G2005CB22120103)资助

摘　　要：在粗旋冷态模型实验基础上,采用FLUENT 6.2流体力学计算软件对FCC沉降器粗旋内部的两相流动进行数值模拟,针对稀、密相流动分别采用颗粒随机轨道模型和双流体模型,探讨了气速、气体物性和固相颗粒浓度对FCC沉降器粗旋料腿泄气率的影响规律。结果表明,气速和固相颗粒浓度升高均导致粗旋料腿内外压差增大,料腿泄气率随之增大。随固相颗粒浓度增大,料腿泄气率上升的趋势先急后缓,与其固相颗粒浓度-压降关系相对应,料腿泄气率-固相颗粒浓度曲线和压降-固相颗粒浓度曲线显示的转折点质量浓度均为0.8 kg/m3;固相颗粒浓度对料腿泄气率的影响存在着2种作用机制,即下行颗粒群对气体的夹带作用和颗粒在粗旋内壁形成的不断增厚的灰层对气体实际流通横截面积的缩减作用。气体密度的增大会导致料腿泄气率增大;黏度增加在削弱气流的旋转能量的同时,增加了升气管短路流率,对料腿泄气率的增加具有正反两方面作用。综合操作参数、气体物性和结构尺寸等因素的影响,回归得到FCC沉降器粗旋料腿泄气率表达式。With validation of experimental data,influences of gas velocity,gas physical properties and solid particle concentration on the gas-leakage ratio of the rough-cut cyclone dipleg in FCC disengager were analyzed by simulating the gas-solid two-phase flow in a rough-cut cyclone based on the platform of FLUENT 6.2.Discrete phase model and two-fluid model were used for the simulation of dilute phase and dense phase,respectively.The results revealed that pressure drop between inside and outside of the dipleg increased with the increases of gas velocity and solid particle concentration,causing heavier gas leakage.The gas-leakage ratio increased with the solid particle concentration going from steep to mild,and the turning point was around the solid particle concentration of 0.8 kg/m3,in correspondence with the solid particle concentration-pressure drop relation.The wrapping gas function of downward agglomerated particles and the reduction on the actual cross section for gas flow by the continually growing solid layer onto the cyclone wall were the two intrinsic mechanisms interpreting these phenomena.The gas-leakage ratio increased with gas density being larger,while its growth got affected in opposite senses by gas viscidity： positively got the loss of swirl and negatively got the enhanced short-circuit flow.A numerical expression for the gas-leakage ratio of the rough-cut cyclone dipleg in FCC disengager,involving operation conditions,gas physical characters,as well as geometrical dimensions of rough-cut cyclone was also derived.

关 键 词：粗旋 气速 固相浓度 料腿泄气率 

分 类 号：TQ021.1[化学工程]