Quantification of Formation Rate of Dioxins from Unburned Carbon Particles and the Suppression of their Formation

本研究旨在通过阐明固体废弃物等有机物氧化（燃烧）过程中二恶英生成反应的机理，提出抑制二恶英排放的原则。通过各种基础研究和实际燃烧过程的研究，二恶英的形成被认为是二恶英形成的主要部分，因此需要详细的二恶英形成机理和在废气冷却过程中冷凝/沉淀的含碳残余物“烟灰“的反应速率。通过使用由以下方法制备的模型碳颗粒，对从具有碳的宏观结构的碳质残余物形成二恶英进行了几系列实验：由各种金属化合物和氯化物组成。此外，还测定了二恶英的生成速度和其他相关反应速度，如碳氧化和氯化有机化合物。利用这些数据， ...更多信息 心理参数对反应速率的影响进行了定量研究。另一方面，通过分析实验前后样品和实际过程中飞灰样品中的微量元素，评价了碳、金属化合物和氯代有机化合物的组成（存在）状态。此外，还发现添加尿素可使废气中二恶英排放量减少莱亚十分之一以上。对通过添加尿素形成的各种有机化合物的详细分析给出了以下事实：具有氨基或氰基的几种烃和含氮的有机化合物，如吡啶。基于所获得的结果，认为这些化合物是通过官能团与活性氮的置换反应以及通过与尿素有关的热反应和氮插入到大碳结构中的插层反应生成的氮化合物形成的，并且验证了它们对二恶英形成的影响。少

This study aims to propose the principle to suppress the dioxin emission, by means of clarifying the mechanisms concerning the formation reaction of dioxins in the oxidation (combustion) process of organic materials like solid wastes. The detailed formation mechanisms of dioxins and the reaction rates from carbonaceous residue"soot"condensed/precipitated in the cooling process of exhaust gas have been demanded because its role to the dioxin formation is regarded as major part through various fundamental researches and the studies on the actual combustion processes.First, several series of experiments were conducted on the formation of dioxin formation from carbonaceous residue having macro structure of carbon by using model carbon particles prepared by composing of various metallic compounds and chlorides. Further, formation rate of dioxins and other relating reaction rates such as carbon oxidation and chlorinated organic compounds were measured. Using these data, the effects of experi … More mental parameters on the reaction rates were attempted to quantitatively understand. On the other hand, composing (existing) states of carbon, metallic compounds and chlorinated organic compounds was evaluated by analyzing trace elements in the samples before and after experiments and fly ash samples from actual process. In addition, it was found that the addition of urea leaded to the reduction of dioxin emission through exhaust gas by lea than one tenth. Detailed analysis on the various organic compounds formed by the addition of urea gives the fact that several hydrocarbons having the amino or cyano groups and organic compounds containing nitrogen Like pyridine. Based on the obtained results, it was considered as that such compounds forms by the displacement reaction of the functional groups with active nitrogen and nitrogen compounds generated through thermal reactions concerning urea and intercalation reaction of nitrogen into macro carbon structure and their effects on the dioxin formation was verified. Less