洗涤冷却室气液两相流的模拟及结构优化  

Simulation of gas-liquid flow and structure optimization in scrubbing-cooling chambers

作　　者：刘洋 郭中山[3] 赵元琪 管小平 杨宁 Yang LIU;Zhongshan GUO;Yuanqi ZHAO;Xiaoping GUAN;Ning YANG(College of Chemical Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;State Key Laboratory of Multiphase Complex Systems,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China;Ningxia Coal Industry Co.,Ltd.,China Energy Group,Yinchuan,Ningxia 750411,China)

机构地区：[1]中国科学院大学化学工程学院,北京100049 [2]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [3]国家能源集团宁夏煤业有限责任公司,宁夏银川750411

出　　处：《过程工程学报》2022年第1期32-40,共9页The Chinese Journal of Process Engineering

基　　金：国家重点研发计划(编号:2017YFB0602500);国家自然科学基金资助项目(编号:21808222,21925805,22061130204)。

摘　　要：洗涤冷却室是激冷式煤气化炉的重要组成部分,对气化室内生成的高温合成气进行降温及洗涤。目前的洗涤冷却室在工业上依然存在诸多问题,如液位及压力波动较大、装置运行不稳定、洗涤效率不够高等,需要对其结构进行优化改进。采用三维欧拉-欧拉模型对三种不同结构的洗涤冷却室进行了CFD模拟。三种洗涤冷却室的结构分别为无内构件、含有支管内构件及新型耦合支管与导流筒内构件。与文献实验数据的对比表明,模型能较准确地预测洗涤冷却室内的气含率分布。支管的加入分流了部分气量,使部分气体能够从鼓泡区域中心上升,促进了气体的径向扩散,有助于维持装置的稳定运行;而导流筒内构件的加入增大了支管气体分流的比例,提升了洗涤冷却室液面下的全局气含率,增强了气液回流,从而进一步强化洗涤效果。The scrubbing-cooling chamber is an important part of a coal gasifier to wash and cool the generated hightemperature syngas.It is composed of a vertical pipe and the liquid bath.However,some technical problems still exist in industrial-scale scrubbers,such as unstable operation,lower washing efficiency,all of which are relevant to gas dispersion in scrubbers.It is of great significance to design a scrubbingcooling chamber with higher washing efficiency.Due to the difficulty of transforming the scrubbers on an industrial-scale,the CFD simulations were used to understand the complex gasliquid flow in different structures of scrubbing-cooling chambers and to provide theoretical guide for industrial design and process scale-up.In this work,a new scrubber which combined of branch pipes and a draft tube on the basis of the general scrubbers was proposed to promote gas dispersion and a three-dimensional Euler-Euler twofluid model was used to simulate the flow behavior in three different scrubber geometry,i.e.,no-internals,branch pipes attached on the vertical pipe,a combination of branch pipes and a draft tube.Gas holdup,liquid flow field and gas distribution were compared among the three different geometries.Comparison between the simulation and the experiments in literature showed that the model can accurately predict the gas holdup distribution.Furthermore,simulations indicated that the added branch pipes diverted a portion of gas to the central region of the chambers,which may otherwise be entrained along the wall of the central pipe.The branch pipes promoted the radial dispersion and was helpful to maintain stable operation.Further installation of a draft tube enhanced the amount of gas transported by the branch pipes,and increased the global gas holdup under the liquid surface of the scrubber.It was found that the combination of the branch pipes and the draft tube can effectively intensify gas-liquid circulation and interfacial contact,and improve the washing efficiency.

关 键 词：洗涤冷却室 气液两相流 计算流体力学 气含率 气量分配 

分 类 号：TQ053.5[化学工程]