Comprehensive diagnosis of PCDD/F emission from three hazardous waste incinerators

Comprehensive diagnosis of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) emissions was systematically conducted on three hazardous waste incinerators (HWIs.) Results indicated that PCDD/F mainly existed in the solid phase before the bag filter. This was especially true for higher chlorinated dioxin and furan congeners (hexa-, hepta- and octa-.) The aged bag filters tended to increase the gas-phase PCDD/F. Emissions also increased due to PCDD/F desorption from circulated scrubbing solution and plastic packing media used in the wet scrubber. The PCDD/F concentrations were elevated during start-up process, reaching up to 5.4 times higher than those measured during the normal operating period. The ratios of PCDFs/PCDDs revealed that the surface-catalyzed de novo synthesis was the dominant pathway of PCDD/F formation. Installation of more efficient fabric filters, intermittent replacement of circulated scrubbing solution will result in reduced PCDD/F emission. Additionally, 2,3,...

本研究针对3台危险废物焚烧炉（Hazardous Waste Incinerators, HWIs）系统开展了多氯二苯并对二噁英与多氯二苯并呋喃（polychlorinated dibenzo-p-dioxin and dibenzofuran, PCDD/F）排放的综合诊断分析。研究结果表明，袋式除尘器（bag filter）前的烟气中，PCDD/F主要以固相形态存在；对于高氯代二噁英与呋喃同系物（六氯代、七氯代、八氯代同系物）而言，该特征尤为突出。老化的袋式除尘器会显著提升气相PCDD/F的占比。此外，湿式洗涤器（wet scrubber）内循环洗涤液与塑料填料表面的PCDD/F脱附作用，同样会导致排放浓度升高。焚烧炉启动阶段的PCDD/F浓度显著升高，最高可达正常运行阶段的5.4倍。PCDFs与PCDDs的浓度比值显示，表面催化从头合成（de novo synthesis）是PCDD/F生成的主导途径。加装更高效的织物过滤器（fabric filters）、定期更换循环洗涤液，可有效降低PCDD/F的排放水平。此外，2,3,...