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过程工程学报 ›› 2021, Vol. 21 ›› Issue (9): 1042-1053.DOI: 10.12034/j.issn.1009-606X.220277

• 流动与传递 • 上一篇    下一篇

多旋臂气液旋流分离器内气相流动特性分析

左鹏  姚秀颖 卢春喜
  

  1. 中国石油大学(北京)重质油国家重点实验室，北京 102249

  • 收稿日期:2020-08-24 修回日期:2020-09-29 出版日期:2021-09-28 发布日期:2021-09-28
  • 通讯作者: 卢春喜 lcxing@cup.edu.cn
  • 基金资助:
    燃煤超细微粒的生成与控制机理研究;燃煤超细微粒的生成与控制机理研究;中国石油大学（北京）科研基金项目

Analysis on gas-phase flow characteristics in multi-spiral gas-liquid vortex separator

Peng ZUO,  Xiuying YAO*,  Chunxi LU*   

  1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China

  • Received:2020-08-24 Revised:2020-09-29 Online:2021-09-28 Published:2021-09-28
  • Contact: ChunXi N/ALU lcxing@cup.edu.cn

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摘要： 为考察费托合成过程中用于油气分离的新型多旋臂气液旋流分离器内气相流场分布特性，明晰离心分离效果，采用RSM湍流模型对分离器气相流场进行模拟研究，所得压降与实验数据吻合较好，表明该模型适用于模拟该分离器。根据结构特点和压力分布特性，将分离器划分为四个区：进料管区、旋臂区、环隙区和分离区。结果表明，气体流经旋臂时运动方向改变产生的阻力损失占总阻力损失的60%以上；经旋臂排出后气体分为三股，即沿封闭罩逆时针上行流和下行流，以及沿旋臂与进料管之间区域顺时针上行流；环隙区轴向高度1.472 m，周向位置45°, 135°, 225°, 315°附近形成轴向速度为零的横向旋涡，同时气体在环隙区内径向位置|r/R|=0.972处出现切、轴向速度的最大值，且运动角度均稳定维持在37.43°附近；分离区内上下行流界限清晰(位于|r/R|=0.854)且切向速度符合Rankine涡结构，拟合得到平均准自由涡旋涡指数n=0.697；旋臂附近区靠近外侧壁面处(|r/R|=0.893)和环隙区内|r/R|=0.972处的切向速度均对入口气速的变化较敏感。

关键词: 气液分离, 多旋臂离心分离, 气相流场, 数值模拟

Abstract: In the Fischer-Tropsch synthesis process, light oil with high temperature is cooled to light oil droplets and non-condensing gas. Gas-liquid (or gas-droplet) separation and operation stability are directly related to both the stability and long period running of production process. Due to its structural complexity, fluid short circuit and wax jams, Fischer-Tropsch cycle heat exchanger is difficult to meet the industrial requirements. Hence, a multi-spiral gas-liquid vortex separator with simple structure, low pressure drop and big separation capacity was designed by drawing the super-vortex quick separator from gas-solids system. The CFD method was used to study the gas-phase flow field distribution characteristics in the MSGLVS. According to its structural characteristics and pressure distribution, the separator was divided into feed pipe zone, spiral arm zone, annular zone and separation zone. The simulation results showed that more than 60% of the total resistance loss of gas flow existed in the spiral arm. Discharged from the spiral arm, the gas was separated into three streams. One was upward counterclockwise gas along closure cover, another was corresponding downward gas and the others was upward clockwise gas in the region between spiral arm and feed pipe. Transverse vortices with zero axial velocity increased the pressure drop and liquid entrainment in the annular zone. The maximum tangential and axial gas velocities were kept at |r/R|=0.972 in the annular zone and the rotation angle of upward-flowing gas was always at 37.43° relative to the vertical direction, which demonstrated the good stability of separator. In the separation zone, there was a clear interface between upward and downward axial velocities. The tangential velocity conformed to the distribution of Rankine vortex along the radial direction, which was beneficial to the separation between gas and liquid phases. All tangential and axial velocities at different positions had a good linear relationship with the inlet gas velocity. The tangential velocities at |r/R|=0.893 (in the spiral arm zone) and 0.972 (in the annulus zone ) were most sensitive to inlet gas velocity.

Key words: Gas-liquid separation, centrifugal separation, gas flow field, numerical simulation