卧式反应器特性与数值模拟
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摘要
目前对于反应器的设计还强烈地依赖经验和实验，缺少理论的指导，这种方法不但耗费巨额的资金和大量的人力物力，而且设计周期很长。而近年来发展起来的计算流体力学(CFD，Computational Fluid Dynamics)是一种用于分析流体流动性质的计算技术。CFD与工程技术的结合不仅可以节省大量的人力物力，提高实验效率，而且还可以得到在实验中无法得到的局部详细信息，所以CFD在化工设计和优化中的作用越来越得到人们的重视。本文中对卧式单、双轴格子桨进行了实验研究，并对卧式单轴格子桨特性进行了CFD数值模拟。
以水、糖浆和CMC作为实验介质对卧式单、双轴格子桨的搅拌功率、混合时间和停留时间分布(RTD)等特性进行了研究。功率特性方面：具体研究了搅拌功率随旋转方向、转速、物料粘度、桨间距和相邻桨叶夹角等因素变化的规律；混合时间特性方面：用碘和硫代硫酸钠褪色法考查了转速以及碘和硫代硫酸钠加入量当量比等因素对停留时间分布的影响，发现：两者的当量比对所测得的混合时间影响很大，为了能够使实验数据能够接近于真正的混合时间，必须尽量控制碘和硫代硫酸钠的当量比接近为1：1(Na2S2O3稍微过量)；在停留时间分布特性方面，研究了转速、物料粘度、桨间距和相邻桨叶夹角等因素对当量釜数的影响。同时为了与模拟结果进行宏观对比，还对混合时间以及停留时间分布的示踪剂扩散情况进行了拍照。
数值模拟方面：采用专业流体力学软件对卧式单轴格子桨的流场、混合时间与停留时间分布等特性进行了模拟与研究。对于流场的研究是采用了较简单的稳态计算方法，在与两组互相垂直的桨叶平面互成45度的平面上，通过分析径向、周向和轴向三个方向的速度分布，给出了此平面上径向、周向和轴向速度极值的出现规律；对于混合时间和停留时间分布的模拟采用了先计算稳态流场，然后在此稳态流场的基础上计算示踪剂扩散情况的两步法，两者的模拟结果与实验数据都吻合的较好。对于混合时间的模拟，可以看出实验数据都小于模拟数据，且转速越高，实验数据与模拟结果相差越大，这是由于在实验中，达到视觉上完全混合的时候，转速越高，硫代硫酸钠轴向梯度越大所导致的。
At presents the designing of reactors are depended on experience and experiment, and are lacking in support of theories. Computational Fluid Dynamics (CFD) is used to analyze the flow characters of fluid, which can not only save a lot of resource, but also get some important local data that cannot be gathered in experiment. Now CFD is regarded more and more in the designing and optimization in chemical engineering fields. In this paper single-axial and twin-axial lattice-blade's characters were studied, and the single-axial lattice-blade's characters were simulated.
In this study, water, syrup and CMC was adopted as the experimental fluid, and the researches were focused on the three characters of the reactor: power consumption, mixing time and the resident-time distribution (RTD). First, the relations were studied between the power consumption and the rotation direction, the rotating speed, the viscosity of the system, the distance between two adjacent blades, and the angle between two adjacent blades. Second, by depigmentation method of '2 and Na2SO3, the relations were studied between the mixing time and the rotating speed and the stoichiometric proportion of '2 and Na2S2O3. As the result, we found that the mixing time was deeply effected by the proportion of '2 and Na2 5203, and the proportion must approach 1:1 (Na2S203 is excessive appreciably) in order to make the result approach to the actual mixing time. Third, the resident-time distributions were tested, and the relations were studied between the equivalent CSTRs and the rotating speed, the viscosity of the system, the distance between two adjacent blades, the angle between two adjacent blades. Moreover, in order to compare with the simulation's results, the diffusion of the characters of mixing time and RID have been recorded by digital camera.
About the simulation of the single-axial lattice-blade reactor, the characters of velocity field, mixing time and RTD have been simulated. In the simulation of the steady velocity field, the rule of velocity extremum was put forward. About the simulation of the mixing time and the RID characters, the two-step method was adopted. The steady velocity field was simulated firstly, then diffusion characters were simulated based on the steady velocity field. As the result of the simulation of the mixing time, we found that the experimental data always be less than the simulation data, and the more high the rotating speed was, the more big the differentiate between the experimental data and the simulation data.
以水、糖浆和CMC作为实验介质对卧式单、双轴格子桨的搅拌功率、混合时间和停留时间分布(RTD)等特性进行了研究。功率特性方面：具体研究了搅拌功率随旋转方向、转速、物料粘度、桨间距和相邻桨叶夹角等因素变化的规律；混合时间特性方面：用碘和硫代硫酸钠褪色法考查了转速以及碘和硫代硫酸钠加入量当量比等因素对停留时间分布的影响，发现：两者的当量比对所测得的混合时间影响很大，为了能够使实验数据能够接近于真正的混合时间，必须尽量控制碘和硫代硫酸钠的当量比接近为1：1(Na2S2O3稍微过量)；在停留时间分布特性方面，研究了转速、物料粘度、桨间距和相邻桨叶夹角等因素对当量釜数的影响。同时为了与模拟结果进行宏观对比，还对混合时间以及停留时间分布的示踪剂扩散情况进行了拍照。
数值模拟方面：采用专业流体力学软件对卧式单轴格子桨的流场、混合时间与停留时间分布等特性进行了模拟与研究。对于流场的研究是采用了较简单的稳态计算方法，在与两组互相垂直的桨叶平面互成45度的平面上，通过分析径向、周向和轴向三个方向的速度分布，给出了此平面上径向、周向和轴向速度极值的出现规律；对于混合时间和停留时间分布的模拟采用了先计算稳态流场，然后在此稳态流场的基础上计算示踪剂扩散情况的两步法，两者的模拟结果与实验数据都吻合的较好。对于混合时间的模拟，可以看出实验数据都小于模拟数据，且转速越高，实验数据与模拟结果相差越大，这是由于在实验中，达到视觉上完全混合的时候，转速越高，硫代硫酸钠轴向梯度越大所导致的。
At presents the designing of reactors are depended on experience and experiment, and are lacking in support of theories. Computational Fluid Dynamics (CFD) is used to analyze the flow characters of fluid, which can not only save a lot of resource, but also get some important local data that cannot be gathered in experiment. Now CFD is regarded more and more in the designing and optimization in chemical engineering fields. In this paper single-axial and twin-axial lattice-blade's characters were studied, and the single-axial lattice-blade's characters were simulated.
In this study, water, syrup and CMC was adopted as the experimental fluid, and the researches were focused on the three characters of the reactor: power consumption, mixing time and the resident-time distribution (RTD). First, the relations were studied between the power consumption and the rotation direction, the rotating speed, the viscosity of the system, the distance between two adjacent blades, and the angle between two adjacent blades. Second, by depigmentation method of '2 and Na2SO3, the relations were studied between the mixing time and the rotating speed and the stoichiometric proportion of '2 and Na2S2O3. As the result, we found that the mixing time was deeply effected by the proportion of '2 and Na2 5203, and the proportion must approach 1:1 (Na2S203 is excessive appreciably) in order to make the result approach to the actual mixing time. Third, the resident-time distributions were tested, and the relations were studied between the equivalent CSTRs and the rotating speed, the viscosity of the system, the distance between two adjacent blades, the angle between two adjacent blades. Moreover, in order to compare with the simulation's results, the diffusion of the characters of mixing time and RID have been recorded by digital camera.
About the simulation of the single-axial lattice-blade reactor, the characters of velocity field, mixing time and RTD have been simulated. In the simulation of the steady velocity field, the rule of velocity extremum was put forward. About the simulation of the mixing time and the RID characters, the two-step method was adopted. The steady velocity field was simulated firstly, then diffusion characters were simulated based on the steady velocity field. As the result of the simulation of the mixing time, we found that the experimental data always be less than the simulation data, and the more high the rotating speed was, the more big the differentiate between the experimental data and the simulation data.
引文
[1] 王凯、冯连芳，《混合设备设计》，机械工业出版社，2000年
[2] 黄志恭，“聚酯生产技术剖析”，合成纤维工业，1992，15(2)：58～62
[3] 发明专利说明书，“卧式双轴搅拌机”，1995，6，7，CN：1028723C，西见晴行等人
[4] Zbioinski I. Chem Eng J, 1995, 58: 123-133
[5] 潘勤敏，《聚合工程中的质量传递》，浙江大学出版社，1998年
[6] 王凯、孙建中，《工业聚合反应装置》，中国石化出版社，1997年
[7] 丸子盛久等，《化学工业论文集》，1990，16(4)：673～679
[8] 王凯，《非牛顿流体的流动、混合和传热》，1988
[9] 永田进治，《混合原理及应用》，1975
[10] Metzner A.B. and Otto R.E., AICHIE Journal, 1957,3(1), 3
[11] Calderbank P.H. & M.B.Moo-Young, Trans. Inst. Chem. Eng., 1961,39,337
[12] Bourne J.R. and Butler H., Trans. Instn. Chem. Engrs., 1969,47,263
[13] Chavan V.V. and Ulbrecht J., Ind. Eng. Chem. Process Des. Develop., 1973,12(4),472
[14] 娓本彦久寿、岛田隆文、德男雅宽，三菱重工技报，1975，10(3)，108
[15] 藤本胜政，“高粘流体混合”，学位论文，1972
[16] 陈忠辉，浙江大学硕士学位论文，1999
[17] M. Maruko and S. Kusumoto, Int. Chem. Eng., 1992, 32(4), 759
[18] 赵轶，“间规聚苯乙烯聚合反应器研究”，浙江大学硕士学位论文，1999年
[19] 岛田隆文等，三菱重工技报，1993，30(1)，61
[20] 董记月，浙江大学硕士学位论文，1997
[21] Danckwertz P.V., Appl. Sci. Res., 1952, 3,279
[22] K(?)ppel M., Int. Chem. Eng., 1979, 19(2), 196
[23] Y. Murakami et al., J. Chem. Eng. Jap., 1972, 5(3), 297
[24] 史子谨，《聚合反应工程基础》，1991，化学工业出版社
[25] Schmalzriedt S, Reuss M. In: Proceeding of 9tn Europe Conference on Mixing. Paris, 1997, 171-178
[26] Jaworski Z, Bujalski W, Otomo N, Nienow A W. Trans IchemE,2000,78A:327-333
[27] Moin P, Kim J. J Fluid Mech, 118(1982): 341
[28] 马青山，“搅拌槽内三维流场数值模拟”，北京化工大学博士后出站报告，2001
[29] 陶文铨．数值传热学．西安：西安交通大学出版社，1988
[30] Mavriplis D J. Mesh generation and adaptivity for complex geometries and flows. In: Peyret R. Ed. Handbook of computational fluid mechanics. London: Academic Press, 1996
[31] Thompson J F. A reflection of grid generation in the 90′s: trends, needs and influences. Mississipi State University, Mississipi State, 1996
[32] Patankar S V, Spalding D B. Int J Heat Mass Transfer. 1972, 15:1787
[33] 帕坦卡S V. 传热与流体流动的数值计算．张政译．北京：科学出版社，
1989
[34] Freitas C J. J Fluids Eng. 117(1995) , 208-218
[35] 朱自强等，《应用计算流体力学》，北江航空航天大学出版社, 1998
[36] Xu B H., YuAB. Chem. Eng. Sci., 1997, 52(16) : 2785-2805
[37] YANG Y L., etal. Chem. Eng. Comm, 1998, 170:133-157
[38] Harvey P S, Greaves M. Trans Inst Chem Eng, 1982, 60:201-210
[39] Bakker A, Fansano J B, Leng D E, Chem Eng, 1994, Jan: 94-100
[40] Ljungqvist M, Rasmuson A. Chem Eng Commun, 1998, 165:123-150
[41] Bode J. Computers Chem Eng, 1994, 18:S247-S251
[42] Durst F. Chem Eng Res Des. 1997, 75(A8) : 729-739
[43] Armenante P M, etal. Chem Eng Sci, 1997, 52(20) :3483-3492
[44] Naude I, etal. Can J Chem Eng, 1998, 76(6) : 631-640
[45] Jaworski Z, etal. Can J Chem Eng, 1996, 74(1) : 3-15
[46] Armente P E, Chou C C. AICHE Symp Ser 1994, 90: 33-43
[47] Armente P E, Chou C C. AICHE J, 1996, 42: 42-54
[48] Larmberto D J, Alvarez M M, Muzzio F J. Chem Eng Sci, 1999, 54(7) : 919-942
[49] Rieger R. Computers Chem Eng, 1994, 18: S229-S233
[50] 万银坤.清华大学博士论文. 1998
[51] Hodson J, etal. Chem Eng Symp Ser, 1997, 142: 999-1007
[52] Tierney M, Nast A, Quarini G, Sep Purif Technol, 1998, 13(2) : 97-107
[53] Crocker D S, Fuller E J, Smith C E, J Eng Gas Turbines Power, 1997, 119(3) : 527-534
[54] Harris C K, etal. Chem Eng Sci. 1996, 51(10) : 1569-1594
[55] Kuipers JAM, etal. Advances Chem Eng. 1998, 24: 227-328
[56] Meier A, etal. Chem Eng Sci, 1996, 51(11) : 3181-3186
[57] Holgern A, Anderson B. Chem Eng Sci., 1998, 53(13) : 2285-2298
[58] Read N K., etal. AICHE J, 1997,43(1) : 104-117
[2] 黄志恭，“聚酯生产技术剖析”，合成纤维工业，1992，15(2)：58～62
[3] 发明专利说明书，“卧式双轴搅拌机”，1995，6，7，CN：1028723C，西见晴行等人
[4] Zbioinski I. Chem Eng J, 1995, 58: 123-133
[5] 潘勤敏，《聚合工程中的质量传递》，浙江大学出版社，1998年
[6] 王凯、孙建中，《工业聚合反应装置》，中国石化出版社，1997年
[7] 丸子盛久等，《化学工业论文集》，1990，16(4)：673～679
[8] 王凯，《非牛顿流体的流动、混合和传热》，1988
[9] 永田进治，《混合原理及应用》，1975
[10] Metzner A.B. and Otto R.E., AICHIE Journal, 1957,3(1), 3
[11] Calderbank P.H. & M.B.Moo-Young, Trans. Inst. Chem. Eng., 1961,39,337
[12] Bourne J.R. and Butler H., Trans. Instn. Chem. Engrs., 1969,47,263
[13] Chavan V.V. and Ulbrecht J., Ind. Eng. Chem. Process Des. Develop., 1973,12(4),472
[14] 娓本彦久寿、岛田隆文、德男雅宽，三菱重工技报，1975，10(3)，108
[15] 藤本胜政，“高粘流体混合”，学位论文，1972
[16] 陈忠辉，浙江大学硕士学位论文，1999
[17] M. Maruko and S. Kusumoto, Int. Chem. Eng., 1992, 32(4), 759
[18] 赵轶，“间规聚苯乙烯聚合反应器研究”，浙江大学硕士学位论文，1999年
[19] 岛田隆文等，三菱重工技报，1993，30(1)，61
[20] 董记月，浙江大学硕士学位论文，1997
[21] Danckwertz P.V., Appl. Sci. Res., 1952, 3,279
[22] K(?)ppel M., Int. Chem. Eng., 1979, 19(2), 196
[23] Y. Murakami et al., J. Chem. Eng. Jap., 1972, 5(3), 297
[24] 史子谨，《聚合反应工程基础》，1991，化学工业出版社
[25] Schmalzriedt S, Reuss M. In: Proceeding of 9tn Europe Conference on Mixing. Paris, 1997, 171-178
[26] Jaworski Z, Bujalski W, Otomo N, Nienow A W. Trans IchemE,2000,78A:327-333
[27] Moin P, Kim J. J Fluid Mech, 118(1982): 341
[28] 马青山，“搅拌槽内三维流场数值模拟”，北京化工大学博士后出站报告，2001
[29] 陶文铨．数值传热学．西安：西安交通大学出版社，1988
[30] Mavriplis D J. Mesh generation and adaptivity for complex geometries and flows. In: Peyret R. Ed. Handbook of computational fluid mechanics. London: Academic Press, 1996
[31] Thompson J F. A reflection of grid generation in the 90′s: trends, needs and influences. Mississipi State University, Mississipi State, 1996
[32] Patankar S V, Spalding D B. Int J Heat Mass Transfer. 1972, 15:1787
[33] 帕坦卡S V. 传热与流体流动的数值计算．张政译．北京：科学出版社，
1989
[34] Freitas C J. J Fluids Eng. 117(1995) , 208-218
[35] 朱自强等，《应用计算流体力学》，北江航空航天大学出版社, 1998
[36] Xu B H., YuAB. Chem. Eng. Sci., 1997, 52(16) : 2785-2805
[37] YANG Y L., etal. Chem. Eng. Comm, 1998, 170:133-157
[38] Harvey P S, Greaves M. Trans Inst Chem Eng, 1982, 60:201-210
[39] Bakker A, Fansano J B, Leng D E, Chem Eng, 1994, Jan: 94-100
[40] Ljungqvist M, Rasmuson A. Chem Eng Commun, 1998, 165:123-150
[41] Bode J. Computers Chem Eng, 1994, 18:S247-S251
[42] Durst F. Chem Eng Res Des. 1997, 75(A8) : 729-739
[43] Armenante P M, etal. Chem Eng Sci, 1997, 52(20) :3483-3492
[44] Naude I, etal. Can J Chem Eng, 1998, 76(6) : 631-640
[45] Jaworski Z, etal. Can J Chem Eng, 1996, 74(1) : 3-15
[46] Armente P E, Chou C C. AICHE Symp Ser 1994, 90: 33-43
[47] Armente P E, Chou C C. AICHE J, 1996, 42: 42-54
[48] Larmberto D J, Alvarez M M, Muzzio F J. Chem Eng Sci, 1999, 54(7) : 919-942
[49] Rieger R. Computers Chem Eng, 1994, 18: S229-S233
[50] 万银坤.清华大学博士论文. 1998
[51] Hodson J, etal. Chem Eng Symp Ser, 1997, 142: 999-1007
[52] Tierney M, Nast A, Quarini G, Sep Purif Technol, 1998, 13(2) : 97-107
[53] Crocker D S, Fuller E J, Smith C E, J Eng Gas Turbines Power, 1997, 119(3) : 527-534
[54] Harris C K, etal. Chem Eng Sci. 1996, 51(10) : 1569-1594
[55] Kuipers JAM, etal. Advances Chem Eng. 1998, 24: 227-328
[56] Meier A, etal. Chem Eng Sci, 1996, 51(11) : 3181-3186
[57] Holgern A, Anderson B. Chem Eng Sci., 1998, 53(13) : 2285-2298
[58] Read N K., etal. AICHE J, 1997,43(1) : 104-117