论文总字数：24784字

摘 要

选择性催化还原(SCR)脱硝技术是烟气脱硝的主要技术，关键点就在于它的氮的脱除效率是比较高的，可以满足生产的要求。整个系统工作效率的高低主要由烟气和氨在反应堆内混合的均匀程度决定的。结合多孔介质模型和组分输运方程数值模拟了华电鹿华发电机厂的SCR系统，并分析了速度场，得到了不同条件下的速度分布。

本文以华电鹿华某机组为研究对象，对现有机组进行脱硝改造。主要对反应机器以及与其连接的烟道内的流场进行相应的数值模拟分析，分析主要选择的模型形式为，分析时选择的工况为锅炉的蒸发量在最大的情况下进行。结果显示，无氨混情况下，合理的选择烟道风速、设计烟道尺寸，通过在烟道内增设导流板，可以有效地控制烟道与反应器内的速度分布。反应器能满足设计要求：首层催化剂表面速度分布相对标准偏差为14.7％，从烟气入口段到烟气出口段的系统压力损失为545Pa。

文中分五种方案详细讨论了vane1处导流板的布置方案。

通过模拟分析的结果可以看出，脱硝装置工作效率高低的关键就在于：第一层催化剂入口处的是否是均匀分布的，文中氨氮比分布标准偏差为22.7％。

关键词：选择性还原催化（SCR）；导流板布置；数值模拟；氨氮比

Abstract

Selective catalytic reduction (SCR) denitrification technology is the main technology of flue gas denitrification, the key point is that its production efficiency is relatively high, can meet the requirements of production.The working efficiency of the whole system is mainly determined by the uniformity of the mixture of flue gas and ammonia in the reactor.The SCR system of huadelu huafa electric machine factory was numerically simulated by combining porous media model and component transport equation, and the velocity field was analyzed, and the velocity distribution under different conditions was obtained.

In this paper, a unit of huadian luhua was taken as the research object, and the existing unit was modified by denitrification, the corresponding numerical simulation analysis is carried out on the flow field in the reaction machine and the flue connected with it. The main model form selected for analysis is as follows. The working condition selected for analysis is the boiler evaporation capacity under the maximum condition.The results show that the velocity distribution in the flue and the reactor can be effectively controlled by adding a guide plate in the flue through reasonable selection of flue velocity and design of flue size in the absence of ammonia mixture.The reactor can meet the design requirements: the surface velocity distribution of the first layer of catalyst has a relative standard deviation of 14.7%, and the system pressure loss from the flue gas inlet section to the flue gas outlet section is 545Pa.

The layout of vane1 baffles is discussed in detail in five schemes.

It can be seen from the results of simulation analysis that the key to the working efficiency of the denitrification unit lies in whether the inlet of the first layer catalyst is uniformly distributed, and the standard deviation of ammonia nitrogen ratio distribution in the paper is 22.7%.

Keywords: selective reduction catalysis (SCR);Baffle arrangement;Numerical simulation;

Ammonia nitrogen than

目 录

摘要 Ⅱ

Abstract Ⅲ

第一章 绪论 1

1.1研究背景和意义 1

1.1.1研究背景 1

1.1.2 SCR脱硝系统的介绍 1

1.2国内外研究现状 1

1.2.1国外研究状况 2

1.2.2国内研究状况 3

1.2.3存在的问题 3

1.3本文主要的研究对象和内容 4

第二章 SCR数值模拟的流场模型和基本算法 6

2.1 CFD软件介绍 6

2.2 SCR流场模拟模型的建立 6

2.3模拟理论 7

2.3.1基本方程 7

2.3.2粘性模型 8

2.3.3组分运输模型 8

2.3.4多孔介质模型 9

第三章 基本方案与步骤 10

3.1基本的步骤 10

3.2流场模拟边界条件的设定 11

3.2.1给定的基本参数 11

3.2.2烟气入口边界条件的计算 12

3.2.3氨空混合气入口边界的计算 13

3.3反应器的设计要求 14

3.4数值模拟的基本假设 14

3.5网格模型的绘制 15

第四章 导流板的布置 18

4.1未布置导流板 18

4.2导流板的布置模拟 22

4.3 SCR系统内导流板的布置详图 29

第五章 流场整体模拟和分析 33

5.1整体模型的分析 33

5.2分析结果 44

第六章 总结与展望 47

6.1全文总结 47

6.2展望 47

参考文献 49

致谢 52

第一章 绪论

1.1 研究背景和意义

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