Vanadium-titanium-based catalysts are the most widely used industrial materials for NO_x removal from coal-fired power plants. Owing to their relatively poor low-temperature deNO_x activity, low thermal stability, ins...Vanadium-titanium-based catalysts are the most widely used industrial materials for NO_x removal from coal-fired power plants. Owing to their relatively poor low-temperature deNO_x activity, low thermal stability, insufficient Hg^0 oxidation activity, SO_2 oxidation, ammonia slip, and other disadvantages,modifications to traditional vanadium-titanium-based selective catalytic reduction（SCR）catalysts have been attempted by many researchers to promote their relevant performance. This article reviewed the research progress of modified vanadium-titanium-based SCR catalysts from seven aspects, namely,（1） improving low-temperature deNO_x efficiency,（2） enhancing thermal stability,（3） improving Hg^0 oxidation efficiency,（4） oxidizing slip ammonia,（5） reducing SO_2 oxidation,（6） increasing alkali resistance, and（7） others. Their catalytic performance and the influence mechanisms have been discussed in detail. These catalysts were also divided into different categories according to their modified components such as noble metals（e.g., silver, ruthenium）, transition metals（e.g., manganese, iron, copper, zirconium, etc.）, rare earth metals（e.g., cerium, praseodymium）,and other metal chlorides（e.g., calcium chloride, copper chloride） and non-metals（fluorine,sulfur, silicon, nitrogen, etc.）. The advantages and disadvantages of these catalysts were summarized.Based on previous studies and the author＇s point of view, doping the appropriate modified components is beneficial to further improve the overall performance of vanadium-titanium-based SCR catalysts. This has enormous development potential and is a promising way to realize the control of multiple pollutants on the basis of the existing flue gas treatment system.展开更多
In this paper,narrow-pulse power discharge is used to study the synergistic control of mercury and dioxins,in which 1,2,4-trichlorobenzene(TCB)was used as a dioxin analog,by using a selfdesigned experimental system.Th...In this paper,narrow-pulse power discharge is used to study the synergistic control of mercury and dioxins,in which 1,2,4-trichlorobenzene(TCB)was used as a dioxin analog,by using a selfdesigned experimental system.The competitive effects of NO,SO2 and HC1 on the TCB removal by non-thermal plasma are discussed.The influence of acid gas on TCB degradation is reflected in the competitive effect.NO has the greatest influence on TCB degradation efficiency.The oxidation efficiency of Hg°decreased by about 10%in all three acidic gas atmospheres,and the effect of each gas component on Hg()oxidation is complex.In the flue gas atmosphere of'acid gas+Hg°+TCB',the mechanism of the synergistic control of Hg°and TCB by the nonthermal plasma is different,which has competition and promotion relationship between each other.The contribution of various flue gas components to the results was complicated,but the overall experimental results show that the synergistic control effect of the system can continue to improve.According to the generated product backstepping,-OH plays an important role in the synergistic control of the degradation of Hg°and TCB.Through this study,we hope to provide basic research data for the collaborative control of flue gas in the incineration industry.展开更多
基金supported by the Science and Technology Plan Project of Hebei Province of China(16273703D)the Fundamental Research Funds for the Central Universities(2015ZD24,2017XS123)~~
文摘Vanadium-titanium-based catalysts are the most widely used industrial materials for NO_x removal from coal-fired power plants. Owing to their relatively poor low-temperature deNO_x activity, low thermal stability, insufficient Hg^0 oxidation activity, SO_2 oxidation, ammonia slip, and other disadvantages,modifications to traditional vanadium-titanium-based selective catalytic reduction（SCR）catalysts have been attempted by many researchers to promote their relevant performance. This article reviewed the research progress of modified vanadium-titanium-based SCR catalysts from seven aspects, namely,（1） improving low-temperature deNO_x efficiency,（2） enhancing thermal stability,（3） improving Hg^0 oxidation efficiency,（4） oxidizing slip ammonia,（5） reducing SO_2 oxidation,（6） increasing alkali resistance, and（7） others. Their catalytic performance and the influence mechanisms have been discussed in detail. These catalysts were also divided into different categories according to their modified components such as noble metals（e.g., silver, ruthenium）, transition metals（e.g., manganese, iron, copper, zirconium, etc.）, rare earth metals（e.g., cerium, praseodymium）,and other metal chlorides（e.g., calcium chloride, copper chloride） and non-metals（fluorine,sulfur, silicon, nitrogen, etc.）. The advantages and disadvantages of these catalysts were summarized.Based on previous studies and the author＇s point of view, doping the appropriate modified components is beneficial to further improve the overall performance of vanadium-titanium-based SCR catalysts. This has enormous development potential and is a promising way to realize the control of multiple pollutants on the basis of the existing flue gas treatment system.
文摘In this paper,narrow-pulse power discharge is used to study the synergistic control of mercury and dioxins,in which 1,2,4-trichlorobenzene(TCB)was used as a dioxin analog,by using a selfdesigned experimental system.The competitive effects of NO,SO2 and HC1 on the TCB removal by non-thermal plasma are discussed.The influence of acid gas on TCB degradation is reflected in the competitive effect.NO has the greatest influence on TCB degradation efficiency.The oxidation efficiency of Hg°decreased by about 10%in all three acidic gas atmospheres,and the effect of each gas component on Hg()oxidation is complex.In the flue gas atmosphere of'acid gas+Hg°+TCB',the mechanism of the synergistic control of Hg°and TCB by the nonthermal plasma is different,which has competition and promotion relationship between each other.The contribution of various flue gas components to the results was complicated,but the overall experimental results show that the synergistic control effect of the system can continue to improve.According to the generated product backstepping,-OH plays an important role in the synergistic control of the degradation of Hg°and TCB.Through this study,we hope to provide basic research data for the collaborative control of flue gas in the incineration industry.
