【作者】 章骥；

【导师】 李晓东； 严建华；

【作者基本信息】 浙江大学 ， 热能工程， 2006， 硕士

【摘要】 水是二噁英生成过程中的重要参数。在固定床试验炉上进行了一系列试验，考察了水对二噁英的非催化和催化从头合成的影响。另外采用夹带流反应器对二噁英的从头合成进行试验和模型研究。 固定床的试验表明，水主要通过活化飞灰的活性位置促进二噁英的生成，由于活性位置对催化对象具有选择性，因此水的促进作用并没有改变二噁英同系物的分布，而是加强其分布的趋势。水可以改变某些关键反应如Deacon反应的平衡，减少反应气氛中Cl₂的浓度，但这种影响只有在水分达到18％时才表现出来，这也印证了Cl₂浓度只在极小范围内对二噁英产生影响。水也可以在没有氧气的条件下为二噁英的生成提供氧元素，但这会减弱水对飞灰的活化作用。对于催化剂，水具有一定的抑制作用，但这种抑制与促进作用相比是有限的。 夹带流反应器的从头合成试验结果表明，SO₂不是通过改变其反应途径来抑制二噁英，而是通过改变某些宏观变量来减少二噁英的生成。氯化模型对PCDF的预测比对PCDD的预测好。通过对整体分布的相关性分析，认为该模型在预测PCDF的生成方面具有相当的准确性。同时，该预测也有力的证明了氯化过程在低氯代PCDF的低温生成中占到了相当的地位，但高氯代PCDF的偏差也表明氯化过程在高氯代产物的生成中没有在低氯代产物的生成中的作用明显。氯化模型对PCDD的预测还不够完善，主要原因是PCDD分子对称性的存在突出了位阻效应对取代位置的影响。另外，PCDD的生成有相当一部分是通过缩聚反应，这是氯化模型目前还无法考虑进来的。更多还原

【Abstract】 Water plays an important role in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans （PCDD/Fs）. A series of experiments were conducted on a fixed bed incinerator to investigate the effect of water on non-catalyzed and catalyzed de novo synthesis of PCDD/Fs. Moreover, experimental and modeling study was carried on a Entrained Flow Reactor （EFR） to study the de novo formation of PCDD/Fs.The result on the fixed bed incinerator indicated that water could activate fly ash to promote the formation of PCDD/Fs. Due to the selectivity of catalyst, the promotion of water did not change the pattern of PCDD/F formation but enforced the original pattern. This pathway was proved to be the dominant one. The second potential pathway was to change the equilibrium of certain key reaction such as Deacon reaction to reduce the concentration of chlorine gas in atmosphere. But this effect could only be presented when water content reached 18%. This effect confirmed the view that chlorine concentration was correlated to PCDD/F formation only when chlorine concentration was very low in atmosphere. The third effect of water was to provide oxygen for PCDD/F formation when there was no addition oxygen source in atmosphere. But this will reduce the effect of activating fly ash. The fourth effect of water was to inhibit the catalyst of de novo synthesis such as CuCl₂. However, this inhibition was limited due to the overall promotion of water on PCDD/F formation.De novo formation of PCDDs and PCDFs has been studied in an entrained-flow reactor （EFR） to simulate waste combustion. The role of sulfur dioxide （SQ2） in de novo formation was isolated for investigation. A chlorination model based on conditional probability was employed to evaluate the homologue patterns of PCDDs and PCDFs. The experimental result revealed that the presence of SO₂ did not change the formation pathway although SO₂ had various inhibition effects on dioxin formation. The model evaluation of PCDFs had a good agreement with the experimental data, which could be referred from a high correlation value of 0.95. However, the prediction更多还原