焦炉烟气中二（口恶）英类物质排放水平研究

二噁英和类二噁英多氯联苯属于《关于持久性有机污染物的斯德哥尔摩公约》规定的非故意产生的持久性有机物,统称为二噁英类物质.焦化生产过程中具备二噁英类物质生成所需的前体物、温度、催化剂等条件,但目前国内外对焦化行业焦炉烟气二噁英类物质排放研究仍属空白,为进一步明确焦化行业排放水平和影响因素,针对性地提出行业减排和控制措施,利用高分辨气相色谱-高分辨质谱法对4个不同规模的典型焦化企业焦炉烟气中二噁英类物质排放情况进行现场采样和实验室分析.结果表明,二噁英类物质毒性当量(以WHO-TEQ计)范围为3.9~30.0 pg·m-3,处于较低水平,检出较多的PCDD/Fs同系物主要是高氯代的.另外,烟气中此类物质的排放量与焦化生产工艺关系密切,捣鼓炼焦、较高的炭化室高度有利于减少二噁英类物质的排放.

Preliminary Investigation on Emission of PCDD/Fs and DL-PCBs Through Flue Gas from Coke Plants in China

According to the Stockholm Convention, polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) are classified into unintentionally produced persistent organic pollutants (UP-POPs), and named dioxins. Coke production as a thermal process contains organic matters, metal and chlorine, is considered to be a potential source of dioxins. Intensive studies on the emission of dioxins from coking industry are still very scarce. In order to estimate the emission properties of dioxins through coke production, isotope dilution HRGC/HRMS technique was used to determine the concentration of dioxins through flue gas during heating of coal. Three results were obtained. First, total toxic equivalents at each stationary emission source were in the range of 3.9-30.0 pg·m^-3 (at WHO-TEQ) for dioxins which was lower than other thermal processes such as municipal solid waste incineration. Second, higher chlorinated PCDD/Fs were the dominant congeners. Third, emissions of dioxins were dependent on coking pattern. Stamping coking and higher coking chamber may lead to lower emission.