新型旋风分离器的试验研究与流场分析

文章针对高温高压的条件对传统旋风分离器入口结构进行改进,提出了圆柱形径向插入、端面加导流板结构的新型旋风分离器结构。由冷态模型下对超细滑石粉和FCC催化剂颗粒的分离效率-压降对比试验结果表明,新型旋风分离器入口结构强度性能优良,虽然对超细粉料分离性能略有不足,但对大颗粒粉料的分离性能接近传统直切入口旋风分离器,可以满足要求。并且数值流场模拟结果表明,分离器压降与实验结果相一致。     

循环流化床锅炉用旋风分离器性能的实验研究

结合水煤浆流化-悬浮燃烧的特点,通过全面测定循环流化床锅炉用旋风分离器在不同操作参数下的分离效率,研究了入口气速、入口颗粒浓度、入口颗粒物性等对旋风分离器的压降和分离性能的影响规律。实验结果表明,影响旋风分离器分离性能的主要物性参数是颗粒的中位粒径、密度,在入口颗粒的中位粒径相差较大时分离性能主要受粒径的影响,而当入口颗粒粒径相差较小时密度对分离器分离性能的影响则更为显著。     

基于CFD-DPM的旋风分离器结构设计优化

采用计算流体力学离散颗粒模型(CFD-DPM),结合响应曲面法,通过系列正交实验,对旋风分离器结构进行优化设计;考察旋风分离器的7个结构参数以及参数间的交互作用对其性能的影响。结果表明:对压降和分离效率影响最显著的结构参数为排气管直径,然后分别是入口高度、入口宽度、旋风分离器长度、排气管插入深度;入口尺寸与排气管直径对压降的影响存在很强的交互作用;旋风分离器长度与排气管插入深度、入口宽度与排气管直径、入口宽度与旋风分离器长度及排气管直径与旋风分离器长度对分离效率的影响存在较强的交互作用,其余因素影响不显著;通过对各结构参数的响应面进行优化,获得该旋风分离器在最小压降和最大分离效率时对应的几何结构参数。     

旋风分离器内颗粒藏量的实验测量

根据旋风分离器的气固分离特点,定义用于描述旋风分离器气固分离过程的颗粒藏量参数为操作中旋风分离器有效分离空间内全部颗粒的质量,选用流化催化裂化平衡催化剂粉料,通过实验测量旋风分离器内颗粒藏量与入口速度和入口浓度的关系。结果表明:颗粒藏量随着入口浓度和入口速度的增大而增大;旋风分离器的颗粒藏量主要来源于旋风分离器环形空间顶灰环,其余部分是旋风分离器的器壁表面颗粒层。     

气化残炭细粉的流化和分离特性

以气化残炭细粉为原料,利用搭建的冷态实验装置对气化残炭细粉在提升管中的流化特性和在旋风分离器中的分离特性进行研究。结果表明:提升管表观风速大于0.5 m/s时,气化残炭细粉开始被大量夹带,提升管表观风速大于0.9 m/s时,气化残炭细粉能全部从提升管中输运;旋风分离器的压降随着入口颗粒浓度的增大先减小后趋于定值;实验测量和模型计算得到的旋风分离器分离效率吻合较好,并且旋风分离器的分离效率均大于97.5%,分离效率较大与气化残炭细粉的颗粒团聚和颗粒沉降有关。     

基于PV型旋风分离器的结构优化实验

设计了一种新型旋风分离器。相对于PV型旋风分离器,新型旋风分离器采用弧形导流板分隔进气的入口结构、分流型排气的出口结构、加长型的筒体和锥体的结构,有锥顶过渡段的灰斗结构,并匹配了合理的尺寸。为了验证新型分离器的性能,设计并搭建新型结构和基准PV型旋风分离器的冷模对比实验装置,在入口气速为14. 4～26. 1 m/s、入口含尘质量浓度为0. 01 kg/m~3时,同时测量2种分离器的效率和压降。对比实验结果表明:相对于基准PV型分离器,新型旋风分离器能够减小压降约32. 36%,同时保证新型分离器的效率与基准效率相当。     

高效、低阻分离器入口结构改进及测试分析

为了改进旋风分离器的分级除尘效率和压力损失等性能指标,通过对SLK型高效低阻分离器的分级过程和不同入口形式的旋风分离的颗粒切向速度和沉降速度的分析计算,重点研究SLK型分离器入口形式对旋风分离器内气流速度的影响及其对分级除尘效率和压力损失的影响,通过试制SLK样机并利用粉煤灰进行测试分析,定性验证SLK型分离器高效低阻的性能特点。结果表明:该分离器能获得较高的分离效率,并且压力损失比同型号分离器减小100～400Pa。     

入口顶部二次风对PV型旋风分离器性能的影响

提出一种进气口顶部、分离器顶板之下的新型二次风引入口,通过数值模拟和实验考察该二次风对PV型旋风分离器性能的影响。结果表明:引入该二次风后,分离器内气流切向速度增大,上行轴向速度和径向速度减小;二次风可有效抑制顶灰环产生,减小升气管短路流的粉尘量;引入进气口顶部二次风后,分离器的最大效率增加约2%,压降最大减少16.8%;总处理气量增加、压降减小,显示出明显的高效低阻特征。     

稳涡器提升旋风分离器性能的流场分析

为了提高旋风分离器分离效率,采用实验和CFD模拟相结合的方法,研究稳涡器的轴向位置对旋风分离器气固两相流动特性和分离性能的影响,探讨稳涡器抑制颗粒返混逃逸机制的形成。结果表明:稳涡器的设置降低轴线附近气流的轴向速度,加深气流的滞流程度,抑制颗粒的返混和逃逸,强化返混颗粒的二次分离作用,提高颗粒的分离效率;稳涡器轴向位置较高时,排尘口截面的通流面积小,下行气流阻力大,运行压降大;当稳涡器顶部与排尘口等高时,轴线附近的轴向速度降幅最大,返混逃逸颗粒数量减少25%～50%,分离效率最高。     

用于聚合物颗粒回收的旋风分离器的结构改进

针对某聚丙烯酰胺流化床干燥器旋风分离器排料困难、颗粒回收效率低等问题,指出其原因在于灰斗结构不合理,造成排料口负压过大,导致返料风机难以将分离下的颗粒送回干燥器;提出在灰斗内增加新型内构件,以减小排料口压降的改进措施;通过冷态对比实验,对新型内构件的效果进行检验。结果表明:增设新型内构件后,排料口压降降幅达60%以上,分离效率和压降变化较小;排料口静压大幅提高,返料效果得到显著改善。     

Effect of the inlet angle on the performance of a cyclone separator using CFD-DEM

Hydrodynamic characteristics in a cyclone separator are simulated by means of DEM-CFD. Reynolds stress turbulence model (RSM) is used to capture gas turbulence. By changing the inlet angle, the distributions of pressure drop, tangential and axial velocity of gas phase are obtained within the cyclone. Simulated results indicate that the flow pattern consists of two regions: loss-free vortex region and forced vortex region. The negative inlet angle brings about a larger pressure drop comparing to positive inlet angle. The separation efficiency and trajectory of particles from simulation are obtained. The effects of inlet angle and particle size on separation efficiency are quantified. The separation efficiency is increased with an increase of particle size, while the separation efficiency firstly increases and then declined as inlet angle changes from negative to positive. An agreement between the numerical simulation and experimental results has been achieved in a cyclone separator.     

Gas-solid separation performance and structure optimization in 3D printed guide vane cyclone separator

Low separation efficiency and large pressure drop are two common problems of cyclones. In this paper, a 3D printed guide vane cyclone separator was designed to study the separation efficiency, turbulent kinetic energy, and particle movement of particle group by experiment and simulation. The results shown that the tangential velocity was the major influence of separating. The bottom of the exhaust pipe was the main region of gas–solid separation and pressure drop. The separation efficiency and pressure drop were positively correlated with the inlet velocity and the particle radius of the fluid. The distribution of turbulent kinetic energy that leaded to the pressure drop loss was concentrated on the inlet of the exhaust pipe. The swirl has external and internal two directions. The optimized cyclone has a longer and narrower blade flow path to obtain higher separation efficiency, especially at low inlet velocity.     

The Study of Performance in a Novel Gas–Solid Separator

The three slit-type separator is a new separator which can shorten the residence time of oil & gas and improve the separation efficiency. In this study, a critical validation was carried out to examine the separation performances of the three slit-type separator with different inlet velocity and inlet concentration. According to the experimental results, the separation efficiency and pressure drop of the three slit-type separator increase with the increase of inlet velocity and inlet concentration. Numerical simulation of the gas–solid flow field in the three slit-type separator was carried out by the use of Fluent 15.0 platform. The simulated results coincide with the experimental results. The particles move along the inside wall of the separator in the vaulted space, meanwhile, more gas enters into the exhaust pipe through slots, which can improve the separation efficiency. The study shows that the residence time of oil and gas is less than 0.6 and the separation efficiency is up to 99% in the separator, in addition, the pressure drop could be controlled in 4 kPa below.     

空调用高效旋流油分离器仿真优化与实验

为了提高空调系统中旋流油分离器的分离效率、降低压力损失,本文对其结构参数进行了优化设计,通过流体仿真研究了油分离器内部各参数对分离效率和压力损失的影响,得到最佳的参数尺寸比例,并据此制作了一款新型油分离器,安装在空调系统中进行实验测试。实验结果表明:新型油分离器在回油工况(最低制冷剂流速)下分离效率由95.5%提高到99.0%,名义制冷工况下分离效率由97.3%提高到99.6%;名义制冷工况下压力损失由55.2 k Pa降低至23.1 k Pa;同时获得了油滴颗粒的分布函数。     

Experimental and CFD study on effects of spiral guide vanes on cyclone performance

This paper presents an experimental and numerical study on a tangential inlet cyclone separator with a spiral guide vane which is not often researched. Numerical pressure drop results were in close agreement with the experimental data. The spiral guide vane was also found to considerably influence the velocity distribution, turbulence intensity, pressure drop and collection efficiency in the cyclone. A critical value of spiral guide vane turns appeared below or above which there was a marked increase in collection efficiency, pressure drop, and tangential velocity. Compared to a cyclone with zero spiral guide vane turn, the maximal decrease in collection efficiency in the cyclone with the critical spiral guide vane turns (one turn) was 2% approximately. The maximum-efficiency inlet velocity appeared to exist independent of spiral guide vane turns, as inlet velocity affected the radial distance traveled by the rebounded particles from the inner wall. The analysis of flow field in cyclones indicated that the flow field was improved with the spiral guide vanes employed to some extent. The results presented here may provide a workable reference for the effects of spiral guide vanes on the flow field and corresponding performance in cyclone separators.     

Performance evaluation of industrial large-scale cyclone separator with novel vortex finder

This paper presents an experimental and numerical study on an industrial large-scale tangential-inlet cyclone separator with a novel and easy-to-implement vortex finder. The vortex finder was designed with slots on the side wall to improve cyclone performance. The collection efficiency, pressure drop, and interior flow field were analyzed. The proposed device provides an effective gas flow pathway and a coupled swirl-inertia separation mechanism, which eliminates short circuit flows under the bottom inlet of the slotted vortex finder to reduce the swirling intensity and minimize the flow instability in the separator. The pressure drop was reduced up to 27.9% compared to the conventional separator and the maximal increase in collection efficiency was 5.45%. The results presented here may provide a workable reference regarding the effects of vortex finders on improving flow fields and corresponding performance in industrial large-scale cyclone separators.     

多效旋风分离器压降的实验研究

为了有效提高新型多效旋风分离器对粒径为0.1~3μm颗粒的分离效率,获取该设备的阻力性能,采用实验方法研究该新型多效旋风分离器压降与进口气速的关系,并与Lapple型旋风分离器进行比较。结果表明:进口风速为5~30m/s时,主体直径为0.25m的多效旋风分离器总阻力系数为7.29,其中,一级和二级预分离螺旋管的阻力系数分别为1.04和1.73;主体的阻力系数为4.52。直径为0.25m的Lapple型旋风分离器的阻力系数为7.21。     

Experimental study on the separation performance of a novel gas–liquid separator

A novel two-stage dynamic separator called high-gravity cyclone separator (HGCS) has been designed for gas–liquid separation. It is mainly composed of a cyclone chamber and rotary drum. In this study, its performance, including the separation efficiency and pressure drop, is experimentally investigated, and the effects of the operating conditions and drum parameters are evaluated. For droplets with a mean diameter of 7 μm, the results indicate that the optimal gas inlet velocity and high-gravity factor are 12 m/s and 59.4, respectively, and the separation efficiency reaches 98 %. The effect of liquid concentration is sensitive to the high-gravity factor. At a liquid concentration of 57 g/m³, the maximum efficiency will be 98.75 % when increasing the high-gravity factor to 85.6. Furthermore, a smaller radial height is preferable when the gas inlet velocity is greater than 12 m/s, and a better separation efficiency can be obtained by increasing the drum length to 190 mm. However, when the length is 235 mm, the efficiency will be poor because of the Kelvin–Helmholtz and Rayleigh–Taylor instabilities. Compared with the predominant roles of gas inlet velocity, drum length and radial height in pressure drop, the effects of liquid concentration and high-gravity factor are small.