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【目的】为解决钒钨钛脱硝催化剂V_2O5-WO3/TiO2(VWTi)在燃煤电厂掺烧污泥烟气中重金属中毒问题，提升污泥掺烧的脱硝效率。【方法】本研究系统评价了Pb、Cr、Hg、Cd、As、Zn这6种典型重金属在烟气中的单一中毒行为，并以毒性最强的Pb为代表，揭示中毒程度对催化剂活性、温度窗口及副产物N_2O选择性的影响规律。采用浸渍-焙烧法制备不同Pb/V摩尔比(0～2.0)的中毒样品，通过比表面积及孔径分析、X射线衍射、X射线光电子能谱、氢气程序升温还原和氨气程序升温脱附等多种表征手段进行了联合分析。【结果】研究表明，从NOx转化率来看，重金属毒性排序为Pb>Zn>As>Hg>Cd>Cr，其中Pb中毒对催化剂的NOx转化率影响较大；Cr虽对NOx转化率影响微弱，却显著增加N_2O排放。性能评价显示，当Pb/V=1.5时，温度从240℃下降至120℃，温度窗口缩窄了120℃，NOx转化率由新鲜样的>90%跌至<50%;Pb/V=2时，高温段几乎完全失活，但N_2O生成量下降40%,N2选择性提高。表征分析结果表明：Pb以PbO形式高度分散于TiO2表面，优先与VOx活性位点反应生成V4+-O-Pb，导致V5+比例由66.1%降至25.1%，化学吸附氧O_α比例由27.3%降至18.6%，同时Brønsted与Lewis酸位点大量丧失，还原峰温向高温偏移50℃以上，这可能导致NOx转化活性急剧降低。【结论】本研究为污泥掺烧中重金属与NOx协同控制提供了量化依据。
Abstract：[Objective] To address the heavy metal poisoning issue of the vanadium-tungsten-titanium denitration catalyst V_2O5-WO3/TiO2(VWTi) in the flue gas from co-combustion of sewage sludge in coal-fired power plants, thereby improving the denitration efficiency during sludge co-combustion. [Methods] This study systematically evaluates the individual poisoning effects of six typical heavy metals—Pb, Cr, Hg, Cd, As, and Zn—present in flue gas on commercial VWTi denitration catalysts. Using Pb, the most toxic among them, as a representative, the influence of poisoning severity on catalyst activity, operating temperature window, and byproduct N_2O selectivity was elucidated. Poisoned samples with varying Pb/V molar ratios(0～2.0) were prepared via impregnation-calcination. Multi-scale characterization techniques, including brunauer-emmett-teller, X-ray diffraction, X-ray photoelectron spectroscopy, hydrogen temperatureprogrammed reduction and ammonia temperature-programmed desorption. [Results] The results indicated that in terms of NOx conversion rate,the toxicity ranking of heavy metals was Pb>Zn>As>Hg>Cd>Cr; among them, Pb poisoning has a significant effect on the NOx conversion rate of the catalyst, although Cr had a minimal impact on NOx conversion, it significantly increased N_2O emissions. Performance assessment demonstrated that at Pb/V=1.5, NOx conversion dropped from >90%(fresh catalyst) to <50%, the active temperature shifts from 240 ℃ to 120 ℃, narrowing by 120 ℃. At Pb/V=2.0, the catalyst was nearly deactivated at high temperatures, yet N_2O generation decreased by 40%, enhancing N2 selectivity. The characterization analysis results showed that Pb is highly dispersed on the TiO2 surface in the form of PbO revealed that PbO species are highly dispersed on the TiO2 surface, preferentially reacting with VOx active sites to form V4+-O-Pb. This reaction reduced the V5+ proportion from 66.1% to 25.1% and decreased chemisorbed oxygen(O_α) proportion from 27.3% to 18.6%, accompanied by a significant loss of both Brønsted and Lewis acid sites,the reduction peak temperature shifting toward higher temperature by more than 50 ℃, this may lead to a sharp decrease in NOx conversion activity. [Conclusion]This study provides quantitative support for the synergistic control of heavy metals and NOx in the co-combustion of sludge.
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基本信息:
DOI：10.19944/j.eptep.1674-8069.2026.03.008
中图分类号:TQ426;X773
引用信息:
[1]李坤鹏,姚展鹏,黄和笑,等.钒钨钛催化剂重金属中毒特性研究[J].电力科技与环保,2026,42(03):422-431.DOI:10.19944/j.eptep.1674-8069.2026.03.008.
基金信息:
国家自然科学基金项目(52470121); 江苏省研究生科研与实践创新计划项目(KYCX24＿1885)
2025-09-04
2025
2025-10-13
2025-10-15
2025
1
2026-06-15
2026-06-15