旋风分离器内细颗粒浓度分布及运动分析

doi:10.11949/0438-1157.20200610

摘要/Abstract

摘要：

旋风分离器对5 μm以下颗粒的分离效率有待提高。通过雷诺应力模型和随机轨道模型研究1 μm颗粒在超高旋风分离器内的浓度分布。结果表明细颗粒在上行流和准自由涡的重叠区聚集，形成浓度高峰。分析不同轴向位置和不同时刻的颗粒径向分布，发现其形成机制有二：一是高度与自然旋风长不匹配导致旋涡尾端扫壁，引起大量颗粒返混，然后在内旋流的分离作用下向外移动；二是下行流向心汇聚对细颗粒的裹挟作用。机制一对颗粒浓峰的贡献更大。大部分浓环颗粒在上行过程中会继续外移，汇入下行流后再次经受外旋流的分离作用，少部分颗粒在上行流或短路流的裹挟下逃逸。抑制颗粒返混是改善颗粒浓环的关键，可通过优化高度或增加内购件的方式实现。

关键词: 旋风分离器, 离心分离, 颗粒, 浓度分布, 运动轨迹, 计算流体力学

Abstract:

The separation efficiency of cyclone separator for fine particles under 5 μm needs to be improved. In this paper, the concentration distribution of 1 μm particles in cyclone was studied by Reynolds stress model and stochastic trajectory model. The results showed that fine particles were gathered in the annular region where the upstream and quasi-free vortex overlap, forming a concentration peak. By analyzing the radial distribution of particles at different axial positions and at different times, it was found that there were two formation mechanisms. Firstly, the mismatch between the height of separation space and the nature vortex length led to the vortex end sweep the particles on the wall, resulting in a strong backmixing of particles. Then, backmixing particles moved outward due to the separation effect of internal swirl. The other mechanism was the convergence effect of downward flow entrained fine particles. Moreover, the former contributed more to the formation of particle concentration peak. Most of the particles in the dense ring would continue to move outward during running up, and then they would be separated by the external swirling flow again after entering the downflow. A few particles escape due to the entrainment of upflow or short-circuit flow. Inhibition of particle backmixing is the key to ameliorate particle dense ring. It can be achieved by optimizing the height or the internals.

Key words: cyclone separator, centrifugation, particle, concentration distribution, motion trajectory, computational fluid dynamics

中图分类号:

TQ 051.8

王斌, 沈聪, 王佳音, 杨景轩, 郝晓刚. 旋风分离器内细颗粒浓度分布及运动分析[J]. 化工学报, 2020, 71(S2): 201-209.

Bin WANG, Cong SHEN, Jiayin WANG, Jingxuan YANG, Xiaogang HAO. Analysis on concentration distribution and trajectory of fine particles in cyclone separator[J]. CIESC Journal, 2020, 71(S2): 201-209.

图/表 6

图1 旋风分离器几何模型

Fig.1 Geometric model of cyclone separator

图2 模拟结果与实验数据对比

Fig.2 Comparison of simulation result and experimental data

图3 气相速度和颗粒浓度沿径向位置分布

Fig.3 Distribution of gas velocity and particle concentration along radial position

图4 锥体段的两相流场

Fig.4 Two-phase flow field of cone segment

图5 不同时刻分离器内的两相流场

Fig.5 Two-phase flow field in the separator at different times

图6 分离空间内细颗粒的运动轨迹

Fig.6 Trajectory of fine particles in the separation space

参考文献 30

1	陈兆辉, 高士秋, 许光文. 煤热解过程分析与工艺调控方法[J]. 化工学报, 2017, 68(10): 3693-3707.
	Chen Z H, Gao S Q, Xu G W. Analysis and control methods of coal pyrolysis process [J]. CIESC Journal, 2017, 68(10): 3693-3707.
2	张生军, 郑化安, 陈静升, 等. 煤热解工艺中挥发分除尘技术的现状分析及建议[J]. 洁净煤技术, 2014, 20(3): 79-83.
	Zhang S J, Zheng H A, Chen J S, et al. Status analysis and improvement measures of volatile dust removal technology in coal pyrolysis process[J]. Clean Coal Technology, 2014, 20(3): 79-83.
3	时铭显, 汪云瑛. PV型旋风分离器尺寸设计的特点[J]. 石油化工设备技术, 1992, 13(4): 14-18.
	Shi M X, Wang Y Y. Features of size design of PV cyclone separator [J]. Petro-Chemical Equipment Technology, 1992, 13(4): 14-18.
4	王伟东, 汪洋, 马强, 等. 页岩灰与催化裂化催化剂细粉旋风分离性能的对比试验研究[J]. 中国粉体技术, 2012, 18(4): 70-76.
	Wang W D, Wang Y, Ma Q, et al. Contrast experiments on cyclone separator performances of shale ash and FCC fine catalysts [J]. China Powder Science and Technology, 2012, 18(4): 70-76.
5	黄雷, 张玉明, 张亮, 等. 页岩灰和FCC催化剂调控油页岩热解产物二次反应特性[J]. 化工学报, 2017, 68(10): 3770-3778.
	Huang L, Zhang Y M, Zhang L, et al. Effects of shale ash and FCC catalyst on adjusting secondary reaction of volatiles in oil shale pyrolysis [J]. CIESC Journal, 2017, 68(10): 3770-3778.
6	孙国刚, 时铭显. 提高旋风分离器捕集细粉效率的技术研究进展[J]. 现代化工, 2008, 28(7): 64-69.
	Sun G G, Shi M X. Progress in improving removal efficiency of gas cyclones for fine particles [J]. Modern Chemical Industry, 2008, 28(7): 64-69.
7	宋健斐, 魏耀东, 时铭显. 旋风分离器内颗粒浓度场的数值模拟[J]. 中国石油大学学报(自然科学版), 2008, 32(1): 90-94.
	Song J F, Wei Y D, Shi M X. Numerical simulation on particle concentration distribution in cyclone separator [J]. Journal of China University of Petroleum (Edition of Natural Science), 2008, 32(1): 90-94.
8	万古军, 孙国刚, 魏耀东, 等. 压力对旋风分离器内颗粒浓度分布影响的模拟[J]. 石油学报(石油加工), 2008, 24(6): 689-696.
	Wan G J, Sun G G, Wei Y D, et al. Simulation of influence of pressure on solids concentration distribution in cyclone separator [J]. Acta Petrolei Sinica (Petroleum Processing Section), 2008, 24(6): 689-696.
9	万古军, 魏耀东, 薛晓虎, 等. 温度对旋风分离器内颗粒浓度分布影响的模拟[J]. 燃烧科学与技术, 2008, 14(6): 562-568.
	Wan G J, Wei Y D, Xue X H, et al. Simulation of influence of temperature on solids concentration distribution in cyclone separator [J]. Journal of Combustion Science and Technology, 2008, 14(6): 562-568.
10	Xue X H, Sun G G, Wan G J, et al. Numerical simulation of particle concentration in a gas cyclone separator [J]. Petroleum Science, 2007, 4(3): 76-83.
11	薛晓虎, 孙国刚, 时铭显. 旋风分离器内颗粒浓度分布特性的数值分析[J]. 机械工程学报, 2007, 43(12): 26-33.
	Xue X H, Sun G G, Shi M X. Numerical simulation on particle concentration distribution in cyclone separator [J]. Journal of Mechanical Engineering, 2007, 43(12): 26-33.
12	Wan G J, Sun G G, Xue X H, et al. Solids concentration simulation of different size particles in a cyclone separator [J]. Powder Technology, 2008, 183(1): 94 -104.
13	吴小林, 黄学东, 时铭显. 旋风分离器的颗粒浓度分布的实验研究[J]. 石油大学学报, 1993, 17(4): 54-59.
	Wu X L, Huang X D, Shi M X. Experimental research on particle concentration distribution in cyclone [J]. Journal of China University of Petroleum, 1993, 17(4): 54-59.
14	吴飞雪, 董守平, 时铭显. 激光粒子成像技术测定旋风分离器内颗粒浓度场的实验研究[J]. 石油大学学报(自然科学版), 2000, 24(26): 72-76.
	Wu F X, Dong S P, Shi M X. Experimental study on particle concentration distribution in a cyclone by particle image technology [J]. Journal of China University of Petroleum (Edition of Natural Science), 2000, 24(26): 72-76.
15	Hoffmann A C, Peng W, Dries H W A, et al. Advantages and risks in increasing cyclone separator length [J]. AIChE Journal, 2001, 47(11): 2452-2460.
16	吴小林, 熊至宜, 姬忠礼, 等. 旋风分离器旋进涡核的数值模拟[J]. 化工学报, 2007, 58(2): 383-390.
	Wu X L, Xiong Z Y, Ji Z L, et al. Numerical simulation of precessing vortex core in cyclone separator [J]. Journal of Chemical Industry and Engineering (China), 2007, 58(2): 383-390.
17	Wasilewskia M, Brar L S. Effect of the inlet duct angle on the performance of cyclone separators [J]. Separation and Purification Technology, 2019, 213(15): 19-33.
18	Zhou F Q, Sun G G, Zhang Y M, et al. Experimental and CFD study on the effects of surface roughness on cyclone performance [J]. Separation and Purification Technology, 2018, 193(20): 175-183.
19	Nassaj O R, Toghraie D, Afrand M. Effects of multi inlet guide channels on the performance of a cyclone separator [J]. Powder Technology, 2019, 356: 353-372.
20	Lim J H, Park S I, Lee H J, et al. Performance evaluation of a tangential cyclone separator with additional inlets on the cone section [J]. Powder Technology, 2020, 359: 118-125.
21	Li Q, Wang Q G, Xu W W, et al. Experimental and computational analysis of a cyclone separator with a novel vortex finder [J]. Powder Technology, 2020, 360: 398-410.
22	Fatahian H, Fatahian E, Nimvari M E. Improving efficiency of conventional and square cyclones using different configurations of the laminarizer [J]. Powder Technology, 2018, 339: 232-243.
23	He M Y, Zhang Y H, Ma L, et al. Study on flow field characteristics in a reverse rotation cyclone with PIV [J]. Chemical Engineering & Processing: Process Intensification, 2018, 126: 100-107.
24	王璐, 张兴芳, 董振洲, 等.旋风分离器入口形式对内流场非稳态特性的影响[J].化工学报, 2018, 69(8): 3488-3501.
	Wang L, Zhang X F, Dong Z Z, et al. Effect of inlet structure on transient properties of gas flow in cyclone separator[J]. CIESC Journal, 2018, 69(8): 3488-3501.
25	黄学东. PV型旋风分离器内颗粒浓度分布的研究 [D]. 北京: 中国石油大学(北京), 1989.
	Huang X D. Study on particle concentration distribution in PV cyclone separator[D]. Beijing: China University of Petroleum, 1989.
26	Peng W, Hoffmann A C, Dries H W A, et al. Experimental study of the vortex end in centrifugal separators: the nature of the vortex end[J]. Chemical Engineering Science, 2005, 60(24): 6919-6928.
27	Yang J X, Dong Z Z, Shen C, et al. Analysis of effect of radial confluence flow on vortex core motion[J]. Powder Technology, 2019, 356: 871-879.
28	付烜, 孙国刚, 刘佳, 等. 旋风分离器短路流的估算问题及其数值计算方法的讨论[J]. 化工学报, 2011, 62(9): 2535-2540.
	Fu X, Sun G G, Liu J, et al. Discuss on estimation difficulties and numerical computation methods for short circuit flow in cyclone separators[J]. CIESC Journal, 2011, 62(9): 2535-2540.
29	Hoffmann A C, Stein L E. Gas Cyclones and Swirl Tubes Principles, Design, and Operation [M]. Berlin, Heidelberg: Springer-Verlag, 2007.
30	沈聪, 董振洲, 王佳音, 等. 稳涡内构件对旋风分离器内流场和性能的影响[J]. 太原理工大学学报, 2020, 51(1): 66-72.
	Shen C, Dong Z Z, Wang J Y, et al. Effect of installation of apex cone on flow field and performance in cyclone separator [J]. Journal of Taiyuan University of Technology, 2020, 51(1): 66-72.

[1]	张思雨, 殷勇高, 贾鹏琦, 叶威. 双U型地埋管群跨季节蓄热特性研究[J]. 化工学报, 2023, 74(S1): 295-301.
[2]	肖明堃, 杨光, 黄永华, 吴静怡. 浸没孔液氧气泡动力学数值研究[J]. 化工学报, 2023, 74(S1): 87-95.
[3]	温凯杰, 郭力, 夏诏杰, 陈建华. 一种耦合CFD与深度学习的气固快速模拟方法[J]. 化工学报, 2023, 74(9): 3775-3785.
[4]	曾如宾, 沈中杰, 梁钦锋, 许建良, 代正华, 刘海峰. 基于分子动力学模拟的Fe₂O₃纳米颗粒烧结机制研究[J]. 化工学报, 2023, 74(8): 3353-3365.
[5]	郑玉圆, 葛志伟, 韩翔宇, 王亮, 陈海生. 中高温钙基材料热化学储热的研究进展与展望[J]. 化工学报, 2023, 74(8): 3171-3192.
[6]	岳林静, 廖艺涵, 薛源, 李雪洁, 李玉星, 刘翠伟. 凹坑缺陷对厚孔板喉部空化流动特性影响研究[J]. 化工学报, 2023, 74(8): 3292-3308.
[7]	汪林正, 陆俞冰, 张睿智, 罗永浩. 基于分子动力学模拟的VOCs热氧化特性分析[J]. 化工学报, 2023, 74(8): 3242-3255.
[8]	邢雷, 苗春雨, 蒋明虎, 赵立新, 李新亚. 井下微型气液旋流分离器优化设计与性能分析[J]. 化工学报, 2023, 74(8): 3394-3406.
[9]	何晓崐, 刘锐, 薛园, 左然. MOCVD生长AlN单晶薄膜的气相和表面化学反应综述[J]. 化工学报, 2023, 74(7): 2800-2813.
[10]	张孟斌, 李锐, 张嘉杰, 马素霞, 张建胜. 基于共面电容原理的煤炭灰渣介电特性实验研究[J]. 化工学报, 2023, 74(7): 3028-3037.
[11]	牛超, 沈胜强, 杨艳, 潘泊年, 李熠桥. 甲烷BOG喷射器流动过程计算与性能分析[J]. 化工学报, 2023, 74(7): 2858-2868.
[12]	高金明, 郭玉娇, 鄂承林, 卢春喜. 一种封闭罩内顺流多旋臂气液分离器的分离特性研究[J]. 化工学报, 2023, 74(7): 2957-2966.
[13]	陈巨辉, 张谦, 舒崚峰, 李丹, 徐鑫, 刘晓刚, 赵晨希, 曹希峰. 基于DEM方法的旋转流化床纳米颗粒流动特性研究[J]. 化工学报, 2023, 74(6): 2374-2381.
[14]	刘道银, 陈柄岐, 张祖扬, 吴琰. 颗粒聚团结构对曳力特性影响的数值模拟[J]. 化工学报, 2023, 74(6): 2351-2362.
[15]	李晨曦, 刘永峰, 张璐, 刘海峰, 宋金瓯, 何旭. O₂/CO₂氛围下正庚烷的燃烧机理研究[J]. 化工学报, 2023, 74(5): 2157-2169.