烧结过程二噁英的生成机理与减排途径

Formation mechanism of dioxins in sintering process and their emission reduction approaches

烧结过程二噁英形成方式以“从头合成”为主，其主要生成区域位于干燥预热带（200～450℃），其同系物中以PCDFs为主，PeCDFs和HxCDFs分布比例较高。烧结过程二噁英的减排方法主要分为源头控制、过程控制和末端治理三种。源头控制和末端治理容易受到原料和成本的制约，而过程控制具有良好的减排效果，尤其是在烧结过程中添加以尿素为代表的含氮抑制剂的减排效果最为明显。该工艺具有成本低、效果好、工艺简单和多种污染物可协同减排等优点，是未来烧结过程二噁英减排及烟气综合治理技术的发展方向。

＂Do novo synthesis＂ is the major formation mechanism of dioxins （PCDD/Fs） in sintering process, they are mainly located in the drying and preheating zone（200 to 450 ℃ ）. The homologues of dioxins are mainly of PCDD/Fs with high distribution ratio of PeCDFs and HxCDFs. There are three ways to reduce emissions of PCDD/Fs,that is, the source controlling, the process controlling and treatment in the end. The process controlling is a well choice for PCDD/Fs reduction, while the others are restricted by raw materials and cost. Adding Nitrogen-containing inhibitors represented by urea in sintering process has the most obvious emission reduction effect particularly in process controlling. The process controlling has such advantages as low cost, good effect, simple technique and synergistic emission reduction of multiple pollutants, and it will become a development tendency of PCDD/Fs reduction in sintering process and comprehensive control technology of flue gas.