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中文题名:

 Urea-SCR催化器热失活特性数值仿真    

姓名:

 李敏    

学号:

 1049721202216    

保密级别:

 公开    

论文语种:

 chi    

学科代码:

 080703    

学科名称:

 动力机械及工程    

学生类型:

 硕士    

学位:

 工学硕士    

学校:

 武汉理工大学    

院系:

 汽车工程学院    

专业:

 动力机械及工程    

研究方向:

 发动机排放控制技术    

第一导师姓名:

 颜伏伍    

第一导师院系:

 武汉理工大学    

第二导师姓名:

 胡杰    

完成日期:

 2015-05-19    

答辩日期:

 2015-05-19    

中文关键词:

 SCR催化器 ; 相对活性 ; 热失活 ; 数值仿真 ; 性能变化规律    

中文摘要:

随着我国排放法规日趋严格,NOx排放限值不断降低。柴油机仅依靠机内净化技术已不能满足NOx排放要求,因此有必要采取机外控制措施。SCR技术是控制柴油机NOx排放的有效手段。法规要求SCR催化器的耐久性里程不得少于16万公里。针对法规要求,本文对SCR催化器的热失活特性展开数值研究。

基于反应动力学基本理论,结合NH3-SCR反应机理、反应速率模型、传热传质模型和储放氨模型,建立了SCR催化器单孔道反应动力学模型。采用Fluent耦合Chemkin的技术路线,对孔道内的多相催化反应过程进行模拟,得到NO浓度场和温度场的分布规律,并进行SCR催化器性能台架试验,试验结果表明转化效率的仿真值与试验值一致性较好,验证了单孔道反应动力学模型。

分析SCR催化器的老化形式,并从催化剂颗粒直径和反应速率变化的角度对催化剂热失活特性进行研究。基于反应动力学模型,考虑SCR催化剂相对活性的降低,建立SCR催化器热失活动力学模型。

根据快速老化循环,采用单孔道模型进行催化器热失活过程的数值模拟,得出催化器热失活前后孔道内的NO浓度场以及温度场的分布规律,得出不同热失活阶段后催化剂相对活性、NO转化效率以及催化器起燃特性的变化规律。为了研究催化剂相对活性沿载体径向的变化情况,建立SCR催化器二维流动模型,模拟载体入口处的温度变化,并以载体不同径向处的温度为单孔道的初始条件计算催化剂的平均粒径和相对活性变化。最后利用Matlab软件计算出不同热失活阶段后催化剂平均颗粒直径沿载体轴向截面的分布情况,得出载体的中心和前端热失活最为严重。

通过研究SCR催化剂老化机理,本文建立了SCR催化器老化的数值仿真方法,得出催化剂相对活性、NO转化效率、起燃特性以及颗粒平均直径等老化特性参数的变化规律。

参考文献:

[1]Navigant Research. Transportation Forecast: Light Duty Vehicles 2014-2035[OL]. 2014, http://www.navigantresearch.com/research/transportation-forecast-light-duty-vehicles.

[2]赵文仲,雷淋森,宁科亮. 轿车柴油化市场前景分析[J]. 汽车工程师,2013,11:13-15.

[3]Cummins Inc. 世界机动设备排放综述[OL]. http://www.cummins.com.cn/SiteContent/zh/ HTML/products/ebu/construction/events.shtml.

[4]袁方恩. 2.0TCI高速直喷柴油机混合气形成及燃烧过程控制[D]. 长春:吉林大学动力机械及工程系,2013.

[5]宋国富,张艳. 柴油机后处理技术的发展现状及趋势[J]. 内燃机,2013,05:4-8.

[6]张纪元. 重型柴油机SCR系统应用技术研究[D]. 济南:山东大学动力工程及工程热物理系,2013.

[7]国家环境保护部. GB18352.5-2013轻型汽车污染物排放限值及测量方法(中国第五阶段)[S]. 北京:中国环境科学出版社,2013-09-17.

[8]Youngjin Cho, JaeAu Ha, Taewoo Lee, et al. Deactivation of Urea SCR Catalyst for Heavy Duty Diesel Engine[J]. SAE Technical Paper: 2012-01-1956.

[9]殷勇,项旭昇,阳松林. 重型柴油机达国IV SCR试验研究[J]. 汽车科技,2009,02:61-65.

[10]黄君. 车用催化转化器台架快速老化规范研究[D]. 武汉:武汉理工大学动力机械及工程系,2010.

[11]国家环境保护部. HJ451-2008柴油机排气后处理装置技术要求[S]. 北京:中国环境科学出版社,2008-12-10.

[12]Chen J P, Buzanowski M A, Yang R T. Deactivation of the Vanadia Catalyst in the Selective Catalytic Reduction Process[J]. Journal of the Air and Waste Management Association, 1990, 40(10): 1403-1409.

[13]Khodayari Raziyeh, Odenbrand C U. Selective Catalytic Reduction of NOx: A Mathematical Model for Poison Accumulation and Conversion Performance[J]. Chemical Engineering Science, 1999, 54: 1775-1785.

[14]G F Froment. Modeling of Catalyst Deactivation[J]. Applied Catalysis A: General, 2001, 212: 117-128.

[15]Nova I, Dall’Acqua L, Lietti L, et al. Study of Thermal Deactivation of a De-NOx Commercial Catalyst[J]. Applied Catalysis B: Environmental, 2001, 35: 31-42.

[16]Kr?cher O, Elsener M. Chemical Deactivation of V2O5/WO3–TiO2 SCR Catalysts by Additives and Impurities from Fuels, Lubrication Oils, and Urea Solution[J]. Applied Catalysis B: Environmental, 2008, 77: 215–227.

[17]Nicosia D, Czekaj I, Kr?cher O. Chemical Deactivation of V2O5/WO3–TiO2 SCR Catalysts by Additives and Impurities From Fuels, Lubrication Oils and Urea Solution Part II. Characterization Study of the Effect of Alkali and Alkaline Earth Metals[J]. Applied Catalysis B: Environmental, 2008, 77: 228-236.

[18]Bartley G J, Chadwell C J, Kostek T M, et al. SCR Deactivation Kinetics for Model-Based Control and Accelerated Aging Applications[J]. SAE Technical Paper: 2012-01-1077.

[19]Kim J Y, Cavataio G, Patterson J E, et al. Laboratory Studies and Mathematical Modeling of Urea SCR Catalyst Performance[J]. SAE Technical Paper: 2007-01-1573.

[20]胡杰,颜伏伍,苗益坚,等. 柴油机Urea-SCR系统控制模型[J]. 内燃机学报,2013,02:148-153.

[21]梁红亮,郭宾彬. SCR催化剂的研究应用状况和发展方向[J]. 科技情报开发与经济,2008,14:120-121.

[22]PioForzatti. Present Status and Perspectives in De-NOx SCR Catalysis[J]. Applied Catalysis A: General, 2001, 222: 221-236.

[23]于千. 国内外SCR催化剂应用概述[J]. 应用化工,2010,06:921-924.

[24]许越. 化学反应动力学[M]. 北京:化学工业出版社,2004:1-2.

[25]北京师范大学,华中师范大学,南京师范大学无机化学教研室. 无机化学[M]. 北京:高等教育出版社,2002:264-265.

[26]韩德刚,高盘良. 化学动力学基础[M]. 北京:北京大学出版社,1998:4-5.

[27]Church M L. Catalyst Formulations 1960 to Present[J]. SAE Technical Paper: 1989, 98(5): 456-463.

[28]李承烈. 催化剂失活[M]. 北京:化学工业出版社,1989:2-3.

[29]赵学庄. 化学反应动力学原理[M]. 北京:高等教育出版社,1984:128-129.

[30]化学动力学[OL]. 维基百科, http://zh.wikipedia.org/zh/化学动力学.

[31]郭华. 基于详细反应机理的三效催化器快速老化特性数值研究[D]. 长沙:湖南大学动力机械及工程系,2011.

[32]马建泰,李茸. 反应动力学与机理[M]. 兰州:兰州大学出版社,2008:13-15.

[33]Carberry J J. Chemical and Catalytic Reaction Engineering[M]. New York: McGraw-Hill Book Company, 1976: 382-388.

[34]N?rskov J K. Electronic Factors in Catalysis[J]. Progress of Surface Science, 1991, 38: 103-144.

[35]Dumesic J A, Trevino A A, Miligan B A, et al. A kinetic Modeling Approach to Formulation of a Catalyst Design Advisory Program[J]. Industrial & Engineering Chemistry Research, 1987, 26: 1399-1407.

[36]Rudd D F, Dumesic J A. Catalyst Synthesis by Analogy[J]. Catalysis Today, 1991, 10: 147一165.

[37]化学动力学[OL]. 百度百科, http://baike.baidu.com/view/3898.htm.

[38]钟秦. 火电厂烟气脱硝技术及工程应用[M]. 北京:化学工业出版社,2007:18-19.

[39]Koebel M, Elsener M. Selective Catalytic Reduction of NO over Commercial DeNOx Catalysts: Experimental Determination of Kinetic and Thermodynamic Parameters[J]. Chemical Engineering Science, 1998, 53(4): 657-669.

[40]Lietti L, Forzatti P. Temperature Programmed Desorption/Reaction of Ammonia over De-NOx Catalysts[J]. Journal of Catalysis. 1994, 147(1): 241-249.

[41]Kapteijn F, Singoredjo L, Vandriel M. Alumina Supported Manganese Oxide Catalysts: II. Surface Characterization and Adsorption of Ammonia and Nitric Oxide[J]. Journal of Catalysis. 1994, 150: 105-116.

[42]Guido Busca, Luca Lietti, Gianguido Ramis. Chemical and Mechanistic Aspects of the Selective Catalytic Reduction for NOx by Ammonia over oxide catalysts[J]. Applied Catalysis B: Environmental, 1998, 18:1-36.

[43]Inomata M, Miyamoto A, Murakami Y. Mechanism of the Reaction of NO and NH3 on Vanadium Oxide Catalyst in the Presence of Oxygen under Dilute Gas Condition[J]. Journal of Catalysis, 1980, 62: 140-148.

[44]Miyamoto A, Kobayashi K, Inomata M, Murakami Y. Nitrogen-15 Tracer Investigation of the Mechanism of the Reaction of NO with NH3 on Vanadium Oxide Catalysts[J]. The Journal of Physical Chemistry, 1982, 86: 2945-2950.

[45]Nova I, Ciardelli C, Tronconi E, et al. NH3-SCR of NO over a V-based Catalyst: Low-T Redox Kinetics with NH3 Inhibition[J]. AIChE Journal, 2006, 52(9): 3222-3233.

[46]André Bakker. Modeling Chemical Reactions with CFD[OL]. http://www.bakker.org/ dartmouth06/engs199/10-react.pdf.

[47]Wendland D W, Kreucher J E, Anderson E. Reducing Catalytic converter Pressure Loss with Enhanced Inlet-Header Diffusion[J]. SAE Technical Paper, 952398.

[48]Hennecke D K. Heat Transfer by Hagen-Poiseuille Flow in the Thermal Development Region with Axial Conduction[J]. Warme-und Stoffubenragung, 1968, 1: 77.

[49]文志永. 柴油机排气净化消声器总体性能研究[D]. 哈尔滨:哈尔滨工程大学环境工程系,2008.

[50]Nova I, Tronconi E. Urea-SCR Technology for deNOx After Treatment of Diesel Exhausts[M]. Italy: Springer Science & Business Media, 2014: 388-389.

[51]温正. Fluent流体计算应用教程[M]. 北京:清华大学出版社,2013:3-4.

[52]Cavataio G, Girard J, Patterson J E. Laboratory Testing of Urea-SCR Formulations to Meet Tier 2 Bin 5 Emissions[J]. SAE Technical Paper: 2007-01-1575.

[53]Maunula T, Kinnunen T. Design and Durability of Vanadium-SCR Catalyst Systems in Mobile Off-Road Applications[J]. SAE Technical Paper: 2011-01-1316.

[54]Gieshoff J, Sch?fer-Sindlinger A, Spurk P C. Improved SCR Systems for Heavy Duty Applications[J]. SAE Technical Paper: 2000-01-0189.

[55]Walker A P, Blakeman P G, Ilkenhans T. The Development and In-Field Demonstration of Highly Durable SCR Catalyst Systems[J]. SAE Technical Paper: 2004-01-1289.

[56]Gibson J, Groene O. Selective Catalytic Reduction on Marine Diesel Engines[J]. Automotive Engineering, 1991: 18–22.

[57]Chen J P, Buzanowski M A, Yang R T. Deactivation of the Vanadia Catalyst in the Selective Catalytic Reduction Process[J]. Journal of the Air & Waste Management Association. 40: 1403–1409.

[58]Kijlstra W S, Komen N J, Andreini A, et al. Promotion and Deactivation of V2O5/TiO2 SCR Catalysts by SO2 at Low Temperature[J]. Studies in Surface Science and Catalysis, 1996, 101: 951–960.

[59]Blakeman P, Arnby K, Marsh P, et al. Optimization of an SCR Catalyst System to Meet EUIV Heavy Duty Diesel Legislation[J]. SAE Technical Paper: 2008-01-1542.

[60]Cavataio G, Jen H, Dobson D, et al. Laboratory Study to Determine Impact of Na and K Exposure on the Durability of DOC and SCR Catalyst Formulations[J]. SAE Technical Paper: 2009-01-2823.

[61]Tsinoglou D, Koltsakis G. Modeling of the Selective Catalytic NOx Reduction in Diesel Exhaust Including Ammonia Storage[J]. Journal of Automobile Engineering, 2007, 221: 117-133.

中图分类号:

 U464.134    

馆藏号:

 U464.134/2216/2015    

备注:

 403-西院分馆博硕论文库;203-余家头分馆博硕论文库    

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