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产生的排放物的联系大大促进了围绕公众对该技术的可接受性的辩论的消极性。这项研究提案是在环境和污染研究委员会最近资助的两项研究赠款之后制定的，这两项研究赠款调查了在模拟城市固体废物焚化炉燃烧后区域的条件下多氯二苯并对二恶英/多氯二苯并呋喃的反应。我们的研究包括详细分析与影响多氯二苯并对二恶英/多氯二苯并呋喃形成、反应和销毁的工艺条件有关的多氯二苯并对二恶英/多氯二苯并呋喃同系物和异构体。这项工作建立了一些机制，用以描述多氯二苯并对二恶英/多氯二苯并呋喃在飞灰上的形成过程及其随后在烟道气中的解吸过程。尽管对废物焚烧炉飞灰和空气污染控制残留物中多氯二苯并对二恶英/多氯二苯并呋喃的形成进行了广泛而深入的调查，但确切的机制仍不清楚。本研究建议的目的是调查特定的烟道气（SO2）和氮氧化物控制气体（NH3/尿素）对飞灰和空气污染控制残留物中多氯二苯并对二恶英/多氯二苯并呋喃形成的影响。这些数据对于理解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。它可以为逐步改变控制战略提供一个关键的进展，通过使用固有的原位气体来控制多氯二苯并对二恶英/多氯二苯并呋喃，消除或减少废物焚化炉的飞灰和空气污染控制残留物中多氯二苯并对二恶英/多氯二苯并呋喃的形成。由于节省了目前用于控制的活性炭的使用，这也将导致成本大幅降低。此外，详细了解SO2和铵化合物对多氯二苯并对二恶英/多氯二苯并呋喃形成的抑制作用，对于以低成本减少其他燃烧源（如燃煤发电厂和金属烧结厂）的多氯二苯并对二恶英/多氯二苯并呋喃排放具有更广泛的意义。这是一项雄心勃勃的提议，涉及对有毒材料进行困难的实验和在多氯二苯并对二恶英/多氯二苯并呋喃浓度极低的情况下进行困难的分析，以便从根本上了解二氧化硫和氨/尿素在多氯二苯并对二恶英/多氯二苯并呋喃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.