【作者】 潘丽秋；

【导师】 钟秦； 陈迁乔；

【作者基本信息】 南京理工大学 ， 化工过程机械， 2009， 硕士

【摘要】 结合实验研究和数值计算,针对燃煤烟气脱硝选择性催化还原催化剂的组成和性质进行了分析,设计优化了该技术脱硝所需的关键技术设备,为催化剂设计、流道优化及反应强化提供理论依据。以600MW机组为例,对大型SCR脱硝工程进行设计研究。从催化剂设计和反应装置优化入手,进行烟气脱硝技术开发研究。对工程使用的催化剂进行表征,从组成和物理性质角度分析催化剂的脱硝性能。催化剂具有良好的表面孔隙结构,载体TiO₂为锐钛矿型,活性物质分布较均匀且颗粒比较小,具有稳定的Bronsted酸位。通过活性测试,确定催化剂最佳工作温度在300～420℃之间。建立SCR脱硝反应数学模型,进行蜂窝式催化剂体积、结构的优化设计。基于催化剂脱硝宏观特性实验数据,确定模型关键参数,计算出系统运行所需催化剂体积。在运行参数变化、催化剂活性降低条件下,催化剂用量完全可以满足系统烟气脱硝性能的要求。还通过理论计算,对催化剂内部NO浓度分布进行研究,对催化剂几何特征提出了优化方案,对于工程应用具有一定的理论价值。引入CFD软件FLUENT对SCR反应器及其连接烟道内的流体流动及氨扩散过程进行数值模拟,揭示其内部流动规律。基于流体力学分析结果,对反应装置的结构设计要点进行了研究。反应器顶部采用斜顶结构优于平顶结构,烟道采用弧形拐角可以削弱烟气惯性产生的高低速区现象。对上述布置方案,设置并改进导流叶片的位置、数量与形状,从而在大截面空间范围内有效控制烟气速度均匀分布。还单独研究了NH₃的流动轨迹及迁徙规律,对喷氨格栅进行优化。通过优化几何布置设计出一个达标可靠的系统。更多还原

【Abstract】 Selection of catalysts and simulation of reactor were two key parts of the research of Selective Catalytic Reduction （SCR） technology. It can apply the academic gist to design catalyzer, optimize flue path and strengthen reduction.Based on a 600MW project, some designs for program were propsed, which are compared with actual dates. It is viable for SCR systems to provide domestic theory of accumulation.The cellular catalyst with a better industrial application has a better surface structure, a carrier for anatase TiO₂, some active substances which were distribution of relatively small particles, and Br（?）nsted sites. Optimd activity temperatme of catalysts was between 300℃and 420℃.The design of size of cellular catalyst was calculated with 3D mathematical model. The test data of macroscopie reaction properties of catalyst obtained in the experiment of laboratory-scale was an access to key parameters of model. SCR catalyst volume required was analysised. Performance data and catalyst life of the impact on the size of the catalyst for the system also were considered. The volume of catalyst fully satisfied the system performance requirement. Through theoretical calculations, the geometric characteristics of catalyst were optimized by the distribution of NO within catalyst.Software FLUENT of CFD is a suitable tool to study the fluid flow and diffusion process of ammonia, in order to reveal its internal flow pattern. Based on the results, the structure of the system design was studied. Reactor at the top of bevel face is better than flat-top structure. The use of arc-shaped corner of the flue gas can reduce the high speed phenomenon. On above-mentioned arrangement, set up and improve location, amount and shape of guide device, for section effective control of the speed of uniform distribution of flue gas. Ammonia injection grid （AIG） is other important party of the simulation and optimation, by analysis of NO_x flow field distributions.更多还原