论文总字数：31232字

摘 要

汞由于其挥发性、迁移性、生物累积性、剧毒性，已经成了继粉尘、SO₂、NO_x之后的又一主要污染物，而燃煤电厂排放的汞是人为汞排放的主要部分。燃煤电厂排放的烟气中汞的形态主要有三种：单质汞（Hg⁰）、氧化态二价汞（Hg² ）、颗粒汞（Hg^p）。其中电厂现有的污染物控制装置很容易将Hg² 和颗粒汞脱除，但是Hg⁰由于其较低的水溶性和较高的挥发性，目前很难被控制。有效脱除Hg⁰的一种重要途径是要把它转化为氧化态汞，而卤素类物质可以有效地氧化Hg⁰。但是目前对烟气中添加HBr脱汞的实验研究较少，烟气中各个组分对HBr氧化汞的影响尚不清楚，HBr对的汞均相氧化机理不明确。因此，深入研究HBr氧化Hg⁰的均相氧化机理具有重要意义。

在固定床汞氧化试验台上进行了模拟烟气中HBr对汞的均相氧化研究，讨论了燃煤烟气组分、HBr浓度及温度等因素对模拟燃煤烟气中Hg⁰氧化的影响。

实验结果表明：HBr能在合适温度和浓度下将烟气中的Hg⁰有效的氧化为Hg² 。均相氧化研究中，HBr浓度越高，汞的氧化率越高；温度对HBr氧化汞的影响为正相关，即温度越高，汞的氧化率越高。烟气组分对汞氧化的影响：O₂、NO会氧化部分汞；CO₂、SO₂不具备氧化汞的能力；全组分气体氧化汞的效率在60%以上，原因为NO会和O₂反应生成NO₂，NO₂具有强氧化性，可以有效地氧化汞。烟气组分对HBr氧化汞的影响：O₂、NO会促进HBr氧化汞；CO₂对HBr氧化汞没有影响；SO₂对HBr氧化汞具有强烈的抑制性，因其SO₂具有还原性，与汞竞争；全组分气体促进HBr对汞的氧化，原因是SO₂与O₂发生反应生成SO₃，SO₃不具备还原性。

关键词：模拟烟气；HBr；汞；均相氧化

Abstract

Mercury has become another major pollutant after dust, SO₂, and NO_x due to its volatility, migration, bioaccumulation, and acute toxicity. Mercury emitted from coal-fired power plants is an important part of human mercury emissions. There are mainly three types of mercury in the flue gas emitted from coal-fired power plants: elemental mercury (Hg⁰), oxidized mercury (Hg² ), and particulate mercury (Hg^p). The existing pollutant control device of the power plant can easily remove Hg2 and particulate mercury, but Hg⁰ is difficult to control because of its low water solubility and high volatility. Therefore, an important way to effectively remove Hg⁰ is to convert it to oxidation state mercury, and the halogen species can oxidize Hg⁰ effectively. However, there are few experimental studies on mercury removal by HBr in flue gas. The effects of various components of the flue gas on HBr oxidize mercury are unclear. The homogeneous oxidation mechanism of HBr oxidize mercury are not clear. Therefore, it is of great significance to study deeply the Homogeneous Oxidation Mechanism of HBr oxidizing Hg⁰.

The homogenous oxidation of Hg in the simulated flue gas was studied on a fixed-bed mercury oxidation test bench, the effects of coal smoke components, HBr concentration and temperature on the oxidation of Hg⁰ in coal-fired flue gas are discussed.

The experimental results show that HBr can effectively oxidize Hg⁰ in flue gas to Hg² at a suitable temperature and concentration. In the study of homogeneous oxidation, the higher the HBr concentration, the higher the oxidation rate of mercury; the temperature has a positive correlation with the HBr oxidation of mercury, that is, the higher the temperature, the higher the oxidation rate of mercury. The influence of smoke components on the oxidation of mercury: O₂, NO will oxidize part of the mercury; CO₂, SO₂ do not have the ability to oxidize mercury; the efficiency of all-component gas oxidation of mercury is above 60%, because NO reacts with O₂ to generate NO₂, which is highly oxidizing and can oxidize mercury effectively. Effect of flue gas composition on HBr oxidation of mercury: O₂ and NO promote oxidation of mercury; CO₂ has no effect on HBr oxidation of mercury; SO₂ has strong inhibition on HBr oxidation of mercury, because SO₂ has reduction and competes with mercury; all-component gas promotes HBr oxidation of mercury, due to SO₂ reacts with O₂ to generate SO₃, and SO₃ does not possess reducibility.

Key words: Simulated flue gas; HBr; Mercury; Homogeneous oxidation

目 录

摘要 I

Abstract II

第一章 绪论 1

1.1 课题研究背景及意义 1

1.2 汞的性质及危害 2

1.3 燃煤电厂中排放及控制 4

1.4 HBr对燃煤汞的均相氧化研究 5

1.5 本文的研究内容 7

1.6 本章小结 7

第二章 实验装置及方法 8

2.1 实验装置 8

2.2 测试表征仪器 9

2.3 本章小结 9

第三章 烟气组分对汞的均相氧化实验研究 10

3.1 O₂对汞氧化的影响 10

3.2 NO对汞氧化的影响 11

3.3 CO₂对汞氧化的影响 11

3.4 SO₂对汞氧化的影响 12

3.5 全气体组分对汞氧化的影响 13

3.6 本章小结 14

第四章 烟气组分对HBr氧化汞的实验研究 15

4.1 温度对HBr氧化汞的影响 15

4.2 O₂对HBr氧化汞的影响 15

4.3 NO对HBr氧化汞的影响 16

4.4 CO₂对HBr氧化汞的影响 17

4.5 SO₂对HBr氧化汞的影响 18

4.6 全气体组分对汞氧化的影响 19

4.7 本章小结 22

第五章 总结与展望 23

5.1 全文总结 23

5.2 展望 24

致 谢 25

参考文献 26

作者简介，攻读学士期间的学术活动 30

绪论

课题研究背景及意义

中国是世界上最大的发展中国家，随着国民经济和消费水平的快速提高，能源消耗迅速增长。2010年，能源消费总量已达32．5亿吨标准煤，是1978年的5．7倍^[1] ，全球人能源消费比重如图1-1所示。然而，我国能源储量分布非常不均匀，比较丰富的是煤炭资源，已经探明的储量排名世界第三，而天然气和石油储量相对贫乏，人均储量还不到世界平均水平的8%^[2]。

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