In-Situ Suppression of Dioxin Formation in Waste Incinerators by SO2 and NH3/Urea

环境中的二恶英(PCDD-多氯二苯并二恶英)和呋喃(PCDF-多氯二苯并呋喃)问题引起了公众的极大关注。它们与城市固体废物焚烧排放的联系，大大加剧了围绕这项技术是否可被公众接受的辩论的负面影响。这项研究建议是在EPSRC最近资助的两项研究拨款之后制定的，该研究拨款调查了多氯二苯并二恶英/多氯二苯并呋喃在模拟城市垃圾焚烧炉燃烧后区域的条件下的反应。我们的研究涉及对影响多氯二苯并二恶英/多氯二苯并呋喃的形成、反应和破坏的工艺条件的多氯二苯并二恶英/多氯二苯并呋喃同系物和异构体的详细分析。这项工作开发了描述飞灰上多氯二苯并二恶英/多氯二苯并呋喃的形成及其随后解吸到烟道气中的机制。尽管已经对垃圾焚烧炉飞灰和空气污染控制残留物中PCDD/PCDF的形成进行了广泛而深入的调查，但确切的机制仍不清楚。本研究的目的是研究特定的烟气(SO2)和NOx控制气体(NH3/尿素)对飞灰和空气污染控制残留物中PCDD/PCDF形成的影响。这些数据对于了解PCDD/PCDF的形成机理以及SO2和NH3/尿素的抑制作用具有重要意义。通过使用固有的就地气体控制多氯二苯并二恶英/多氯二苯并呋喃，可为消除或减少废物焚烧炉的飞灰和空气污染控制残留物中的多氯二苯并二恶英/多氯二苯并呋喃的形成的阶梯变化控制战略提供关键进展。由于节省了目前用于控制的活性碳的使用，这还将大大降低成本。此外，详细了解二氧化硫和铵化合物对多氯二苯并二恶英/多氯二苯并呋喃形成的抑制作用，可能对以低成本减少燃煤发电厂和金属烧结厂等其他燃烧来源的多氯二苯并二恶英/多氯二苯并呋喃的排放具有更广泛的影响。这是一项雄心勃勃的提议，涉及对有毒物质进行困难的实验，并在极低水平的PCDD/PCDF浓度下进行困难的分析，以从根本上了解SO2和NH3/尿素在PCDD/PCDF形成反应机制中的重要作用。

The issue of dioxins (PCDD- polychlorinated dibenzodioxins) and furans (PCDF- polychlorinated dibenzofurans) in the environment are of considerable public concern. Their association with emissions from municipal solid waste incineration contributing significantly to the negativity of the debate surrounding the public acceptability of the technology. This research proposal has been developed following two recent EPSRC funded research grants investigating the reactions of PCDD/PCDF under conditions simulating the post combustion zone of municipal solid waste incinerators. Our research involves detailed, analyses of PCDD/PCDF congeners and isomers in relation to the process conditions influencing PCDD/PCDF formation, reactions and destruction. The work has developed mechanisms to describe the formation of PCDD/PCDF on flyash and their subsequent desorption into flue gases. Although there has been extensive and intense investigation of PCDD/PCDF formation in waste incinerator flyash and air pollution control residues, the exact mechanisms still remain unclear. The aim of this present research proposal is to investigate the influence of particular flue gases (SO2) and NOx control gases (NH3/urea) on the formation of PCDD/PCDF in flyash and air pollution control residues. This data is important in understanding the formation mechanisms of PCDD/PCDF and the suppressive effect of SO2 and NH3/urea. It could provide a key advance for a step change control strategy for the elimination or reduction of PCDD/PCDF formation in flyash and air pollution control residues from waste incinerators by using inherent, in-situ gases to control PCDD/PCDF. It would also result in a significant cost reduction due to savings in the use of activated carbon, which is currently used for control. In addition, the detailed understanding of the suppressive effect of SO2 and ammonium compounds on PCDD/PCDF formation could have wider implications for reducing PCDD/PCDF emissions from other combustion sources, such as coal-fired power plant and metal sinter plant at low cost. This is an ambitious proposal involving difficult experimentation with toxic materials and difficult analysis at extremely low levels of PCDD/PCDF concentration to fundamentally understand the important role of SO2 and NH3/urea in PCDD/PCDF formation reaction mechanisms.