Progress on agitated apparatus for polymer devolatilization and its CFD simulation

doi:10.16085/j.issn.1000-6613.2016.05.003

Abstract

Abstract: The progress on new types of agitated apparatus for polymer devolatilization was reviewed, while the key issues on the development of new devolatilization devices were analyzed. The characteristics of flow field, mixing, film forming and surface renewal are the key factors to strengthen the mass transfer process. Developing highly efficient and self-cleaning devices for polymer devolatilization is the major prospect in this field. The applications of computational fluid mechanics(CFD) simulations on transfer process in such devices were also discussed. Finite element method combined with mesh superposition technique(MST) and finite volume method combined with dynamic mesh technique have been used to deal with problems such as complex geometric blades and fins, twin-shaft rotating motion, tiny gaps within engaged areas and so on. Gas-liquid interface can be precisely tracked by means of volume of fluid(VOF) multiphase flow model. The film forming and surface renewal characteristics can be investigated, which contributes to learn more about the mass transfer mechanism. CFD numerical simulation offers a new idea for designing highly efficient devices for polymer devolatilization.

Key words: devolatilization, self-cleaning, numerical simulation, mass transfer, agitation

摘要： 综述了聚合物搅拌脱挥设备的开发进展,分析了设备开发过程存在的关键问题。指出卧式脱挥设备中的流动特性、混合特性、成膜特性以及表面更新特性等是强化传质的关键因素,具有自清洁搅拌特性的高效卧式脱挥设备是装备开发与研究的主要方向。阐述了计算流体力学(CFD)在研究高黏流体卧式搅拌设备内传递过程机理中的应用。基于网格重叠技术的有限元方法和基于动网格的有限体积方法可以解决复杂几何结构的桨叶和翅片、双轴的旋转运动以及啮合机构非常小的间隙等难题。借助于CFD中VOF多相流模型可以精确地追踪气液相界面,模拟反应器中的成膜过程和表面更新特性,进而可以深入分析设备中的传质过程,为高效聚合物脱挥设备的优化与设计提供了新的思路。

关键词: 脱挥, 自清洁, 数值模拟, 传质, 搅拌

CLC Number:

TQ315

CHENG Wenkai, WANG Jiajun, GU Xueping, FENG Lianfang. Progress on agitated apparatus for polymer devolatilization and its CFD simulation[J]. Chemical Industry and Engineering Progree, 2016, 35(05): 1283-1288.

成文凯, 王嘉骏, 顾雪萍, 冯连芳. 聚合物搅拌脱挥设备及其CFD模拟研究进展[J]. 化工进展, 2016, 35(05): 1283-1288.

References

[1] 赵玲, 朱中南. 聚酯熔融缩聚增黏过程的工程分析[J]. 聚酯工业, 2004, 17(1): 1-4.
[2] 冯连芳, 曹松峰, 顾雪萍, 等. 高粘搅拌聚合反应装置[J]. 合成橡胶工业, 2001, 24(5): 257-261.
[3] HANIMANN K, STIBAL W. Method and device for producing polyester granules and/or shaped parts with a low acetaldehyde content: US 8470220 [P]. 2013-06-25.
[4] WILHELM F, FINKELDEI F. Batch polycondensation method and a rotating disc reactor therefore: US20030139543 [P]. 2003-07-24.
[5] BHATIA K K. Apparatus and process for a polycondensation reaction: US5677415 [P]. 1997-10-14.
[6] OKAMOTO N, MOTOHIRO S, ITOU Y, et al. Apparatus for continuous stirring and process for continuous polycondensation of polymer resin: US6846103 [P]. 2005-01-25.
[7] FLEURY P, WITTE D. Comparison of devolatilization technologies for viscous polymers[C]// Annual Technical Conference, 2005.
[8] SCHEBESTA K, SCHUCHARDT H, ULLRICH M. Self-cleaning reactor/mixer for highly viscous and cohesive mixing materials: US5876115[P]. 1999-03-02.
[9] SCHUCHARDT H. Mixing apparatus: US5 876115 [P]. 1999-03-02.
[10] STUEVEN U, VAN MIERT L, VAN ESBROECK D, et al. Mixing kneader and process for preparing poly(meth)acrylates using the mixing kneader: US 8070 351[P]. 2011-12-06.
[11] FLEURY P, KUNKEL R. Device for carrying out mechanical, chemical, and/or thermal processes: US2014/0376327[P]. 2014-12-25.
[12] PALMER. Mixing kneader: US6039469[P]. 2000-03-21.
[13] SAFRIT B T, DIENER A E. Kneader technology for the direct devolatilization of temperature sensitive elastomers[C]// Annual Technical Conference, 2008.
[14] 祖荣祺, 祁建声. 聚酯终聚反应器脱挥结构分析[J]. 聚酯工业, 1997(2): 33-39.
[15] 蒋春跃, 戴干策, 徐中先. PET聚酯终缩聚过程的工程分析--卧式双轴脱挥反应器[J]. 聚酯工业, 1999, 12(1): 10-18.
[16] SECK O, MAXISCH T, WARNECKE H, et al. Investigation of the mixing- and devolatilization behavior in a continuous twin-shaft kneader[J]. Macromolecular Symposia, 2010, 289(1): 155-164.
[17] 吴妙奇, 李志鹏, 高正明. 圆盘反应器成膜性能的实验研究[J]. 北京化工大学学报(自然科学版), 2010, 37(5): 10-14.
[18] 栗广奉, 李广赞, 王嘉骏, 等. 卧式双轴自清洁反应器粘性体系停留时间分布[J]. 化学工程, 2005, 33(4): 22-25.
[19] SCHNEIDERBAUER S, PUTTINGER S, PIRKER S, et al. CFD modeling and simulation of industrial scale olefin polymerization fluidized bed reactors[J]. Chemical Engineering Journal, 2015, 264: 99-112.
[20] FATHI ROUDSARI S, EIN-MOZAFFARI F, DHIB R. Use of CFD in modeling MMA solution polymerization in a CSTR[J]. Chemical Engineering Journal, 2013, 219: 429-442.
[21] PATEL H, EIN-MOZAFFARI F, DHIB R. CFD analysis of mixing in thermal polymerization of styrene[J]. Computers & Chemical Engineering, 2010, 34(4): 421-429.
[22] 刘叶凤. 卧式双轴搅拌釜数值模拟与实验研究[D]. 天津: 天津大学, 2013.
[23] 刘荣. 新型卧式搅拌装置特性研究与设计开发[D]. 天津: 天津大学, 2009.
[24] 单纯. 卧式单轴自清洁搅拌釜数值模拟[D]. 天津: 天津大学, 2013.
[25] 杨腾. D-T型卧式双轴搅拌装置的数值模拟[D]. 天津: 天津大学, 2010.
[26] ALSTEENS B, LEGAT V, AVALOSSE T. Parametric study of the mixing efficiency in a kneading block section of a twin-screw extruder[J]. International Polymer Processing, 2004, 19(3): 207-217.
[27] 张先明. 挤出过程停留时间分布的实验研究和数值模拟[D]. 杭州: 浙江大学, 2008.
[28] WEI J, LIANG X L, CHEN D B, et al. Evaluation of the mixing performance for one novel twin screw kneader with particle tracking[J]. Polymer Engineering & Science, 2014, 54(10): 2407-2419.
[29] 王嘉骏, 顾雪萍, 冯连芳, 等. 卧式搅拌槽内流体混合的实验与模拟研究[J]. 中国科技论文在线, 2008(12): 911-914.
[30] KALAGA D V, REDDY R K, JOSHI J B, et al. Liquid phase axial mixing in solid-liquid circulating multistage fluidized bed: CFD modeling and RTD measurements[J]. Chemical Engineering Journal, 2012, 191: 475-490.
[31] ZHANG X M, FENG L F, CHEN W X, et al. Numerical simulation and experimental validation of mixing performance of kneading discs in a twin screw extruder[J]. Polymer Engineering & Science, 2009, 49(9): 1772-1783.
[32] 王良生, 戴干策. 圆盘反应器成膜性和持液量研究[J]. 化学反应工程与工艺, 2000(2): 127-135.
[33] HASAN N, NASER J. Determining the thickness of liquid film in laminar condition on a rotating drum surface using CFD[J]. Chemical Engineering Science, 2009, 64(5): 919-924.
[34] 杨晓宇, 李志鹏, 高正明. 圆盘反应器内流动和成膜性能的数值模拟[J]. 北京化工大学学报(自然科学版), 2010, 37(6): 29-34.
[35] 邓斌, 戴干策. 圆盘反应器流场数值模拟[J]. 化学反应工程与工艺, 2015, 31(3): 254-261.
[36] DANCKWERTS P V. Significance of liquid-film coefficients in gas absorption[J]. Industrial & Engineering Chemistry, 1951, 43(6): 1460-1467.
[37] 邓斌, 戴干策. 圆盘反应器液膜表面更新数值模拟[J]. 化工学报, 2015, 66(4): 1407-1416