挡板倾斜角度对热高压分离器内颗粒漂移影响的数值模拟

以煤直接液化工艺过程中热高压分离器(简称"热高分")内的颗粒漂移为研究对象,建立带静态分离挡板的热高分物理模型,并采用VOF(Volume of Fluid)模型和DPM(Discrete Phase Model)模型,数值分析静态分离挡板5种倾斜角度下热高分罐内部速度场、不同液位高度颗粒平均浓度及气相出口煤粉漂移率的分布规律。研究结果表明:静态分离挡板的倾斜角度对速度场的影响明显,在挡板附近区域形成小回流涡旋效应,产生对颗粒随气流夹带提升的抑制作用;颗粒平均浓度在气-液交界面区域最高,随着热高分罐内高度的增加而逐渐降低;与其余倾斜角度相比,α=45°时气相出口的颗粒漂移率达到最小,较未设置分离挡板时,颗粒漂移率降低50%以上。研究有望为热高压分离压力容器的设计和运行优化提供参考。

Numerical simulation on the effect of different baffle tilt angles on particle drifting in high temperature and high pressure separator

To study the pulverized coal drifting in high temperature and high pressure (HTHP) separator in coal liquefaction unit，the physical model of HTHP separator with static separation baffles was established.The volume of fluid (VOF) model and the discrete phase model (DPM) were used in this numerical simulation to analyze the distribution regularities of interior velocity field，the averaged particles concentration in different heights and the pulverized coal drifting ratio in gas phase outlet with five kinds of baffle tilt angles.The results show that the tilt angle of separation baffles has a great influence on the velocity field，the vortex effect occurs near the baffles;the mean particles concentration becomes maximum in the area of gas-liquid interface，then decreases gradually with the increase of height;the pulverized coal drifting ratio in gas phase outlet reaches minimum if the tilt angle is 45°，which can reduce more than 50% compared to no static separation baffles.The research results can provide a valuable reference for optimizing the design and operation in HTHP separator.