Micromixing characteristics of tubular reactor packed with different packings

doi:10.11949/j.issn.0438-1157.20161232

Abstract

Abstract:

The micromixing characteristics of a tubular reactor packed with different packings were investigated by adopting the competitive parallel reaction, namely, the Villermaux-Dushman reaction. Experimental results showed that the tube packed with rhombus mesh frame packing (RMFP) presented better micromixing efficiency, compared to the tube with mini ring or empty tube. It could be found that the segregation index (X_S) decreased as Reynolds number increased while it increased with increasing volumetric flow ratio. Moreover, the micromixing time (t_m) was calculated using an incorporation model based on the experimental data. The minimum t_m value of the tube packed with RMFP (t_m=2.27 ms) was less than that of the tube with mini ring (t_m=2.73 ms) or empty tube (t_m=3.79 ms).

Key words: tubular reactor, packing, micromixing, reaction, reactor, mixing

摘要：

采用碘化物-碘酸盐平行竞争反应为工作体系，以离集指数（X_S）表征微观混合性能，实验考察了Reynolds数Re、物料体积流量比对装填扁环填料和网架填料的管式反应器的微观混合性能的影响及离集指数在管式反应器轴向、径向的分布。结果表明，X_S随着Re的增大而下降，而物料体积流量比的增加会导致X_S增加，相同条件下网架填料的X_S小于扁环填料，离集指数在轴向上呈现先明显降低后基本不变的趋势。在实验研究的基础上，利用团聚模型计算装填网架填料的管式反应器的微观混合时间（t_m）为4.82~2.27 ms。与扁环填料对比，网架填料最小值（2.27 ms）低于扁环填料的最小值（2.73 ms），同时二者均小于空管的最小值（3.79 ms），表明装填填料可以改善管式反应器的微观混合性能，网架填料的微观混合性能略优于扁环填料。

关键词: 管式反应器, 填料, 微观混合, 反应, 反应器, 混合

CLC Number:

TQ051.1

YUAN Pingfang, GUO Kai, ZHANG Xiaobo, LIU Chunjiang. Micromixing characteristics of tubular reactor packed with different packings[J]. CIESC Journal, 2017, 68(2): 653-659.

原平方, 郭凯, 张小波, 刘春江. 装填不同填料的管式反应器的微观混合性能[J]. 化工学报, 2017, 68(2): 653-659.

References 37

[1]	BALDYGA J, POHORECKI R. Turbulent micromixing in chemical reactors-a review[J]. The Chemical Engineering Journal and the Biochemical Engineering Journal, 1995, 58(2):183-195.
[2]	TOLGYESI W S. Relative reactivity of toluene benzene in nitronium tetrafluoro-borate nitration:limitation of the competitive method of rate determination in fast reactions[J]. Canadian Journal of Chemistry, 1965, 43(2):343-355.
[3]	BOURNE J R, KOZICKI F, RYS P. Mixing and fast chemical reaction(Ⅰ):Test reactions to determine segregation[J]. Chemical Engineering Science, 1981, 36(10):1643-1648.
[4]	BOURNE J R. Mixing on the molecular scale[J]. Chemical Engineering Science, 1983, 38(1):5-8.
[5]	PANTELIDES C C, ERICKSON W D, LONGWELL J P, et al. Use of relative reaction rates of CO and H2 as a measure of micro-mixing in combustion systems[J]. Chemical Engineering Science, 1985, 40(3):375-383.
[6]	BAKLDYGA J, PODGORSKA W, POHORECKI R. Mixing-precipitation model with application to double feed semibatch precipitation[J]. Chemical Engineering Science, 1995, 50(8):1281-1300.
[7]	CHEN J, ZHENG C, CHEN G A. Interaction of macro-and micromixing on particle size distribution in reactive precipitation[J]. Chemical Engineering Science, 1996, 51(10):1957-1966.
[8]	BOURNE J R. Mixing and the selectivity of chemical reactions[J]. Organic Process Research & Development, 2003, 7(4):471-508.
[9]	KRUPA K, NUNES M I, SANTOS R J, et al. Characterization of micromixing in T-jet mixers[J]. Chemical Engineering Science, 2014, 111(8):48-55.
[10]	JACOBESN N C, HINRICHSEN O. Micromixing efficiency of a spinning disk reactor[J]. Industrial & Engineering Chemistry Research, 2012, 51(36):11643-11652.
[11]	ZHANG W, YUMEI Y, ZHANG G, et al. Mixing characteristics and bubble behavior in an airlift internal loop reactor with low aspect ratio[J]. Chinese Journal of Chemical Engineering, 2014, 22(6):611-621.
[12]	赵玉潮, 应盈, 陈光文, 等. T形微混合器内的混合特性[J]. 化工学报, 2006, 57(8):1884-1890. ZHAO Y C, YING Y, CHEN G W, et al. Characterization of micro-mixing in T-shaped micromixer[J]. Journal of Chemical Industry and Engineering(China), 2006, 57(8):1884-1890.
[13]	骆培成, 程易, 汪展文, 等. 面激光诱导荧光技术用于快速液液微观混合研究[J]. 化工学报, 2005, 56(12):2288-2293. LUO P C, CHENG Y, WANG Z W, et al. Study of fast liquid-liquid micromixing using PLIF technique[J]. Journal of Chemical Industry and Engineering(China), 2005, 56(12):2288-2293.
[14]	金涌, 邵婷, 赵述芳, 等. 微通道中液滴内部混合过程的μ-LIF可视化和LBM模拟[J]. 化工学报, 2012, 63(2):375-381. JIN Y, SHAO T, ZHAO S F, et al. μ-LIF visualization and LBM simulation of mixing behaviors inside droplets in microchannels[J]. CIESC Journal, 2012, 63(2):375-381.
[15]	王文坦, 张梦雪, 赵述芳, 等. 激光诱导荧光技术在液体混合可视化研究中的应用[J]. 化工学报, 2013, 64(3):771-778. WANG W T, ZHANG M X, ZHAO S F, et al. Application of laser-induced fluorescence technique in visualization of liquid mixing process[J]. CIESC Journal, 2013, 64(3):771-778.
[16]	ASSIRELLI M, BUJALSKI W, EAGLESHAM A, et al. Intensifying micromixing in a semi-batch reactor using a Rushton turbine[J]. Chemical Engineering Science, 2005, 60(8):2333-2339.
[17]	LEGRAND J, BENMALEK N, IMERZOUKENE F, et al. Characterisation and comparison of the micromixing efficiency in torus and batch stirred reactors[J]. Chemical Engineering Journal, 2008, 142(1):78-86.
[18]	ÖNCUL A A, JANIGA G, THEVENIN D. Comparison of various micromixing approaches for computational fluid dynamics simulation of barium sulfate precipitation in tubular reactors[J]. Industrial & Engineering Chemistry Research, 2008, 48(2):999-1007.
[19]	CHENG J Y, FENG X, CHENG D, et al. Retrospect and perspective of micro-mixing studies in stirred tanks[J]. Chinese Journal of Chemical Engineering, 2012, 20(1):178-190.
[20]	HAN Y, WANG J J, GU X P, et al. Numerical simulation on micromixing of viscous fluids in a stirred-tank reactor[J]. Chemical Engineering Science, 2012, 74(22):9-17.
[21]	YANG H J, CHU G W, ZHANG J W, et al. Micromixing efficiency in a rotating packed bed:experiments and simulation[J]. Industrial & Engineering Chemistry Research, 2005, 44(20):7730-7737.
[22]	YANG H J, CHU G W, XIANG Y, et al. Characterization of micromixing efficiency in rotating packed beds by chemical methods[J]. Chemical Engineering Journal, 2006, 121(2):147-152.
[23]	YANG K, CHU G W, SHAO L, et al. Micromixing efficiency of rotating packed bed with premixed liquid distributor[J]. Chemical Engineering Journal, 2009, 153(1):222-226.
[24]	张文洁, 初广文, 罗勇, 等. 泡沫陶瓷填料旋转填充床微观混合性能[J]. 化工学报, 2014, 65(8):2976-2980. ZHANG W J, CHU G W, LUO Y, et al. Micromixing in rotating packed bed with ceramic foam packing[J]. CIESC Journal, 2014, 65(8):2976-2980.
[25]	CHU G W, SONG Y J, ZHANG W J, et al. Micromixing efficiency enhancement in a rotating packed bed reactor with surface-modified nickel foam packing[J]. Industrial & Engineering Chemistry Research, 2015, 54(5):1697-1702.
[26]	梁继国, 陈建峰, 张建文. 旋转填充床内微观混合的数值模拟[J]. 化工学报, 2004, 55(6):882-887. LIANG J G, CHEN J F, ZHANG J W. Numerical simulation of micromixing in rotating packed bed[J]. Journal of Chemical Industry and Engineering(China), 2004, 55(6):882-887.
[27]	邱崑玉, 吕和祥, 陈建峰. 旋转填充床内微观混合化学反应计算数学模型[J]. 化工学报, 2005, 56(7):1218-1224. QIU K Y, LÜ H X, CHEN J F. Mathematical model for calculating micromixing chemical reaction in rotating packed bed[J]. Journal of Chemical Industry and Engineering(China), 2005, 56(7):1218-1224.
[28]	向阳, 陈建峰, 高正明. 旋转填充床中微观混合模型与实验验证[J]. 化工学报, 2008, 59(8):2021-2026. XIANG Y, CHEN J F, GAO Z M. Modelling and experimental validation of micromixing in rotating packed bed[J]. Journal of Chemical Industry and Engineering(China), 2008, 59(8):2021-2026.
[29]	YANG W, WANG Y, CHEN J, et al. Computational fluid dynamic simulation of fluid flow in a rotating packed bed[J]. Chemical Engineering Journal, 2010, 156(3):582-587.
[30]	张建文, 李亚超, 陈建峰. 旋转床内微观混合与反应过程的特性[J]. 化工学报, 2011, 62(10):2726-2732. ZHANG J W, LI Y C, CHEN J F. Characteristics of micromixing and reaction in a rotating bed[J]. CIESC Journal, 2011, 62(10):2726-2732.
[31]	MEYER T, DAVID R, RENKEN A, et al. Micromixing in a static mixer and an empty tube by a chemical method[J]. Chemical Engineering Science, 1988, 43(8):1955-1960.
[32]	BOURNE J R, TOVSTIGA G. Micromixing and fast chemical reactions in a turbulent tubular reactor[J]. Chemical Engineering Research & Design, 1988, 66(1):26-32.
[33]	FOURNIER M C, FALK L, VILLERMAUX J. A new parallel competing reaction system for assessing micromixing efficiency experimental approach[J]. Chemical Engineering Science, 1996, 51(22):5053-5064.
[34]	GUICHARDON P, FALK L. Characterisation of micromixing efficiency by the iodide-iodate reaction system(Ⅰ):Experimental procedure[J]. Chemical Engineering Science, 2000, 55(19):4233-4243.
[35]	GUICHARDON P, FALK L, VILLERMAUX J. Characterisation of micromixing efficiency by the iodide-iodate reaction system(Ⅱ):Kinetic study[J]. Chemical Engineering Science, 2000, 55(19):4245-4253.
[36]	FOURNIER M C, FALK L, VILLERMAUX J. A new parallel competing reaction system for assessing micromixing efficiency determination of micromixing time by a simple mixing model[J]. Chemical Engineering Science, 1996, 51(23):5187-5192.
[37]	杨海健, 张建文, 苗健瑞, 等. 管式填料床反应器内的湍流微观混合研究[J]. 高校化学工程学报, 2006, 20(3):390-394. YANG H J, ZHANG J W, MIAO J R, et al. Study on turbulent micromixing in a tubular packed bed reactor[J]. Journal of Chemical Engineering of Chinese Universities, 2006, 20(3):390-394.