密相提升管内颗粒速度与颗粒浓度分布及发展特性  

Particle Velocity and Solids Holdup Characteristics and the Flow Development in a High Density Circulating Fluidized Bed Riser

作　　者：王成秀[1] 裴华健 苏鑫[1] 金楠 吴贤 蓝兴英[1] 高金森[1] 徐春明[1] WANG Chengxiu;PEI Huajian;SU Xin;JIN Nan;WU Xian;LAN Xingying;GAO Jinsen;XU Chunming(State Key Laboratory of Heavy Oil Processing,China University of Petroleum,Beijing 102249,China;School of Chemical and Chemical Engineering,Yantai University,Yantai 264005,China)

机构地区：[1]中国石油大学(北京)重质油国家重点实验室,北京102249 [2]烟台大学化学化工学院,山东烟台264005

出　　处：《化学反应工程与工艺》2020年第1期8-16,共9页Chemical Reaction Engineering and Technology

基　　金：国家自然科学基金介尺度重大研究计划集成项目(91834302);国家自然科学基金面上项目(21978320)。

摘　　要：为研究高密度提升管气固流动结构分布规律及其发展特性,在自建的18m高循环流化床提升管系统中测定了不同气速和固体循环速率下的颗粒浓度分布。结果表明,在低颗粒循环速率(Gs)下颗粒浓度由底部浓相区单调降低并趋于稳定;在高G_s下颗粒浓度在底部浓相区内先增加后降低,沿提升管向上趋于稳定的发展趋势。径向上颗粒浓度分布呈现"中心低边壁高"的特点且在不同径向区域的发展具有不同步性,中心区域发展快且可以实现充分发展,并逐步向边壁区域延伸。颗粒速度轴向分布特性受表观气速影响较大。表观气速较小时颗粒速度基本呈指数型分布且很快进入恒速区,表观气速较大时颗粒速度轴向分布呈现出"倒C型"。颗粒速度在不同径向区域上发展特性与颗粒浓度基本一致。较低提升管内颗粒进入提升管时可能受气固入口结构影响,沿提升管向上运动时流动结构未得到充分发展又可能会受到提升管出口约束,会呈现多段式流动发展特性。本实验18m高提升管内颗粒流动结构可以得到充分发展,轴向上颗粒浓度分布基本呈现指数型分布。High density circulating fluidized bed riser is a good reactor for maximizing light olefins by catalytic pyrolysis of oils which is an important technology for refining-chemical integration.An 18 m high riser circulating fluidized bed system is built and experiments are carried out under wide operating conditions with solids flux up to 600 kg/(m2·s)for systematical study of gas-solids flow characteristics and its flow development.Axially,solids holdup decreases monotonously from the riser bottom and keeps constant above 3 m of the riser when solids flux is lower.With high solids flux/density operations,solids holdup increases first with decreasing at the riser bottom and then remain nearly constant at the top of the riser.Radially,solids holdup is lower near the center with fast flow development and relatively higher near the wall region with slow flow development.Particle velocity distribution axially is affected by superficial gas velocity.Particle velocity shows exponential type along the riser and develops fast into constant value when superficial gas velocity is smaller than 5 m/s.It shows inverse"C"shape along the riser when superficial gas velocity is higher.Radial development of particle velocity shows the same trend as the development of solids holdup.Flow structure would be affected by both inlet and outlet showing multi-staged flow characteristics when flowing in a small riser without fully development.In such a tall riser with 18 m in height,gas-solids flow shows fully development with an exponential flow structure.

关 键 词：提升管 循环流化床 颗粒浓度 颗粒速度 

分 类 号：TQ021[化学工程]