SCR装置对焦炉煤气燃烧废气中PCDD/Fs、PCBs和PCNs的协同脱除

研究了某大型焦化厂的选择性催化还原(SCR)装置对焦炉煤气燃烧废气中典型非故意产生持久性有机污染物(UPPOPs)的脱除效果,对SCR装置入口和出口废气和SCR装置降尘中二英(PCDD/Fs)、多氯联苯(PCBs)和多氯萘(PCNs)的全部异构体进行了分析.结果表明,SCR装置对总PCDD/Fs的脱除效率最高,为94.6%,对总PCBs和总PCNs的脱除率分别为74.7%和78.4%.SCR装置入口和出口废气中UP-POPs同系物的分布模式明显不同,入口处以高氯取代为主,出口处以低氯取代为主.SCR装置对高氯取代UP-POPs有更好的脱除效果.催化还原和催化氧化降解同时发生是SCR装置脱除废气中UP-POPs的重要机制.

Simultaneous Removal of Polychlorinated Dibenzo-p-dioxins/dibenzofurans, Polychlorinated Biphenyls, and Polychlorinated Naphthalenes From Flues Gases From Coke Gas Burning Using Selective Catalytic Reduction Equipment

The removal efficiencies of typical unintentionally produced persistent organic pollutants (UP-POPs) from flues gases from coke gas burning were obtained using selective catalytic reduction (SCR) equipment installed in a large coking plant. The total congeners of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polychlorinated naphthalenes (PCNs) in the flue gases at the inlet and outlet of the SCR equipment and the dustfall were analyzed. The results show that the removal efficiency of the total PCDD/Fs was the highest (94.6%). The removal efficiencies of total PCBs and total PCNs were 74.7% and 78.4%, respectively. The homologue profile of UP-POPs in the flue gases at the inlet of the SCR equipment notably differed from that at the outlet. Highly chlorinated UP-POPs predominated over the homologue profile of UP-POPs in the inlet flue gas, while low-chlorinated UP-POPs were predominant in the outlet flue gas. The SCR equipment achieved a better removal efficiency with respect to highly chlorinated UP-POPs. Catalytic reduction and catalytic oxidation degradation are both important mechanisms for the removal of UP-POPs from flue gas using SCR equipment.