Excessive emissions of nitrogen oxides from flue gas have imposed various detrimental impacts on environment,and the development of deNO_(x) catalysts with low-cost and high performance is an urgent requirement.Iron o...Excessive emissions of nitrogen oxides from flue gas have imposed various detrimental impacts on environment,and the development of deNO_(x) catalysts with low-cost and high performance is an urgent requirement.Iron oxide-based material has been explored for promising deNO_(x) catalysts.However,the unsatisfactory low-temperature activity limits their practical applications.In this study,a series of excellent low-temperature denitrification catalysts(Ha-FeO_(x)/yZS)were prepared by acid treatment of zinc slag,and the mass ratios of Fe to impure ions was regulated by adjusting the acid concentrations.Ha-FeO_(x)/yZS showed high denitrification performance(>90%)in the range of 180–300℃,and the optimal NO conversion and N2 selectivity were higher than 95%at 250℃.Among them,the Ha-FeO_(x)/2ZS synthesized with 2 mol/L HNO3 exhibited the widest temperature window(175–350℃).The excellent denitrification performance of Ha-FeO_(x)/yZS was mainly attributed to the strong interaction between Fe and impurity ions to inhibit the growth of crystals,making Ha-FeO_(x)/yZS with amorphous structure,nice fine particles,large specific surface area,more surface acid sites and high chemisorbed oxygen.The in-situ DRIFT experiments confirmed that the SCR reaction on the Ha-FeO_(x)/yZS followed both Langmuir-Hinshelwood(L-H)mechanism and Eley-Rideal(E-R)mechanism.The present work proposed a high value-added method for the preparation of cost-effective catalysts from zinc slag,which showed a promising application prospect in NO_(x) removal by selective catalytic reduction with ammonia.展开更多
To meet increasingly stringent emission standards and lower the brake-specific fuel consumption(BSFC)of marine engines,a collaborative optimization study of exhaust gas recirculation(EGR)and a Miller cycle coupled tur...To meet increasingly stringent emission standards and lower the brake-specific fuel consumption(BSFC)of marine engines,a collaborative optimization study of exhaust gas recirculation(EGR)and a Miller cycle coupled turbocharging system was carried out.In this study,a one-dimensional numerical model of the EGR,Miller cycle,and adjustable two-stage turbocharged engine based on WeiChai 6170 marine diesel engine was established.The particle swarm optimization algorithm was used to achieve multi-input and multi-objective comprehensive optimization,and the effects of EGR-coupled Miller regulation and high-pressure turbine bypass regulation on NO_(x)and BSFC were investigated.The results showed that a medium EGR rate-coupled medium Miller degree was better for the comprehensive optimization of NO_(x)and BSFC.At medium EGR rate and low turbine bypass rates,NO_(x)and BSFC were relatively balanced and acceptable.Finally,an optimal steady-state control strategy under full loads was proposed.With an increase in loads,the optimized turbine bypass rate and Miller degree gradually increased.Compared with the EGRonly system,the optimal system of EGR and Miller cycle coupled turbine bypass reduced NO_(x)by 0.87 g/(kW·h)and BSFC by 17.19 g/(kW·h)at 100%load.Therefore,the EGR and Miller cycle coupled adjustable two-stage turbocharging achieves NO_(x)and BSFC optimization under full loads.展开更多
Due to the boost of CO_(2)/NO_(x)emissions which cause environmental pollution,processes that remove such pollutants from flue gas have attracted increasing attention in recent years.Among these technologies,biologica...Due to the boost of CO_(2)/NO_(x)emissions which cause environmental pollution,processes that remove such pollutants from flue gas have attracted increasing attention in recent years.Among these technologies,biological CO_(2)/NO_(x)emission reduction has received more interest.Microalgae,a kind of photosynthetic microorganism,offer great promise to convert CO_(2)/NO_(x)to biomass with high content of lipid and protein,which can be used as feedstock for various products such as biodiesel,health products,feedstuff and biomaterials.In this paper,biological CO_(2)/NO_(x)removing technologies by microalgae,together with the products(such as biofuel and protein)and their economic viability are discussed.Although commercial applications of microalgae for biodiesel and protein products are hampered by the high production cost of biomass,the use of CO_(2)/NO_(x)from flue gas as carbon and nitrogen sources can reduce the cost of biomass production,which makes these technologies more competent for real-life applications.Moreover,it is projected that the increasing in CO_(2)allowances will lead to further reduction in the cost of biomass production,which especially favors related products with lower values such as biodiesel.Furthermore,by combining various process optimization and integration,biorefinery is proposed and considered as the crucial component for the sustainable and economically feasible bulk applications of microalgae biomass.展开更多
The presented work reports the selective catalytic reduction(SCR)of NO_(x) assisted by dielectric barrier discharge plasma via simulating marine diesel engine exhaust,and the experimental results demonstrate that the ...The presented work reports the selective catalytic reduction(SCR)of NO_(x) assisted by dielectric barrier discharge plasma via simulating marine diesel engine exhaust,and the experimental results demonstrate that the low-temperature activity of NH_(3)-SCR assisted by non-thermal plasma is enhanced significantly,particularly in the presence of a C_(3)H_(6) additive.Simultaneously,CeMnZrO_(x)@TiO_(2) exhibits strong tolerance to SO_(2) poisoning and superior catalytic stability.It is worthwhile to explore a new approach to remove NO_(x) from marine diesel engine exhaust,which is of vital significance for both academic research and practical applications.展开更多
Traditional vanadium-based selective catalytic reduction(SCR)deNO_(x) catalyst can hardly adapt to the gas conditions(much high NO_(2)/NO_(x) ratio at lower temperature)of the start-up and low loading periods for a ga...Traditional vanadium-based selective catalytic reduction(SCR)deNO_(x) catalyst can hardly adapt to the gas conditions(much high NO_(2)/NO_(x) ratio at lower temperature)of the start-up and low loading periods for a gas turbine.Therefore,a W-Ti-CeO_(x) catalyst with NO_(x) storage and reduction(NSR)function was developed in this work for gas turbine exhaust NO_(x) elimination.The experimental results reveal that W-Ti-CeO_(x) catalyst exhibits high NO_(2) adsorption capacity at relatively low temperature while that is quite low for V-W/TiO_(2).The abundant surface Ce^(3+) species can be mainly responsible for its high adsorption ability owing to the reaction between NO_(2) and Ce^(3+) to form nitrate/nitrite species and NO.Meanwhile,the adsorption capacity of W-Ti-CeO_(x) can easily regenerate at medium-high temperature and NH_(3)-SCR reaction.Furthermore,W-Ti-CeO_(x) also shows good NH_(3)-SCR activity,which can fulfill the deNO_(x) process at high temperature.The addition of W and Ti into ceria can enhance the surface acidity and redox ability,thereby increasing the SCR activity.This work proposes a novel storage-reduction strategy for NO_(x) elimination throughout the operation of gas turbines.展开更多
The simultaneous removal of SO_(2),NO_(x)and Hg^(0)from industrial exhaust flue gas has drawn worldwide attention in recent years.A particularly attractive technique is selective catalytic reduction,which effectively ...The simultaneous removal of SO_(2),NO_(x)and Hg^(0)from industrial exhaust flue gas has drawn worldwide attention in recent years.A particularly attractive technique is selective catalytic reduction,which effectively removes SO_(2),NO_(x)and Hg^(0)at low temperatures.This paper first reviews the simultaneous removal of SO_(2),NO_(x)and Hg^(0)by unsupported and supported catalysts.It then describes and compares the research progress of various carriers,eg.,carbon-based materials,metal oxides,silica,molecular sieves,metal-organic frameworks,and pillared interlayered clays,in the simultaneous removal of SO_(2),NO_(x)and Hg^(0).The effects of flue-gas components(such as O_(2),NH3,HCl,H2 O,SO_(2),NO and Hg^(0))on the removal of SO_(2),NOx,and Hg^(0)are discussed comprehensively and systematically.After summarizing the pollutantremoval mechanism,the review discusses future developments in the simultaneous removal of SO_(2),NOx and Hg^(0)by catalysts.展开更多
基金National Natural Science Foundation of China(21676209)Natural Science Basic Research Program of Shaanxi(2022JQ-328)Postdoctoral Research Foundation of the Xi’an University of Architecture and Technology(19603210120).
文摘Excessive emissions of nitrogen oxides from flue gas have imposed various detrimental impacts on environment,and the development of deNO_(x) catalysts with low-cost and high performance is an urgent requirement.Iron oxide-based material has been explored for promising deNO_(x) catalysts.However,the unsatisfactory low-temperature activity limits their practical applications.In this study,a series of excellent low-temperature denitrification catalysts(Ha-FeO_(x)/yZS)were prepared by acid treatment of zinc slag,and the mass ratios of Fe to impure ions was regulated by adjusting the acid concentrations.Ha-FeO_(x)/yZS showed high denitrification performance(>90%)in the range of 180–300℃,and the optimal NO conversion and N2 selectivity were higher than 95%at 250℃.Among them,the Ha-FeO_(x)/2ZS synthesized with 2 mol/L HNO3 exhibited the widest temperature window(175–350℃).The excellent denitrification performance of Ha-FeO_(x)/yZS was mainly attributed to the strong interaction between Fe and impurity ions to inhibit the growth of crystals,making Ha-FeO_(x)/yZS with amorphous structure,nice fine particles,large specific surface area,more surface acid sites and high chemisorbed oxygen.The in-situ DRIFT experiments confirmed that the SCR reaction on the Ha-FeO_(x)/yZS followed both Langmuir-Hinshelwood(L-H)mechanism and Eley-Rideal(E-R)mechanism.The present work proposed a high value-added method for the preparation of cost-effective catalysts from zinc slag,which showed a promising application prospect in NO_(x) removal by selective catalytic reduction with ammonia.
基金Project(K16011)supported by the Marine Low-speed Engine Project-Phase I,China。
文摘To meet increasingly stringent emission standards and lower the brake-specific fuel consumption(BSFC)of marine engines,a collaborative optimization study of exhaust gas recirculation(EGR)and a Miller cycle coupled turbocharging system was carried out.In this study,a one-dimensional numerical model of the EGR,Miller cycle,and adjustable two-stage turbocharged engine based on WeiChai 6170 marine diesel engine was established.The particle swarm optimization algorithm was used to achieve multi-input and multi-objective comprehensive optimization,and the effects of EGR-coupled Miller regulation and high-pressure turbine bypass regulation on NO_(x)and BSFC were investigated.The results showed that a medium EGR rate-coupled medium Miller degree was better for the comprehensive optimization of NO_(x)and BSFC.At medium EGR rate and low turbine bypass rates,NO_(x)and BSFC were relatively balanced and acceptable.Finally,an optimal steady-state control strategy under full loads was proposed.With an increase in loads,the optimized turbine bypass rate and Miller degree gradually increased.Compared with the EGRonly system,the optimal system of EGR and Miller cycle coupled turbine bypass reduced NO_(x)by 0.87 g/(kW·h)and BSFC by 17.19 g/(kW·h)at 100%load.Therefore,the EGR and Miller cycle coupled adjustable two-stage turbocharging achieves NO_(x)and BSFC optimization under full loads.
基金supported by the SINOPEC Technology Development Program(218017)。
文摘Due to the boost of CO_(2)/NO_(x)emissions which cause environmental pollution,processes that remove such pollutants from flue gas have attracted increasing attention in recent years.Among these technologies,biological CO_(2)/NO_(x)emission reduction has received more interest.Microalgae,a kind of photosynthetic microorganism,offer great promise to convert CO_(2)/NO_(x)to biomass with high content of lipid and protein,which can be used as feedstock for various products such as biodiesel,health products,feedstuff and biomaterials.In this paper,biological CO_(2)/NO_(x)removing technologies by microalgae,together with the products(such as biofuel and protein)and their economic viability are discussed.Although commercial applications of microalgae for biodiesel and protein products are hampered by the high production cost of biomass,the use of CO_(2)/NO_(x)from flue gas as carbon and nitrogen sources can reduce the cost of biomass production,which makes these technologies more competent for real-life applications.Moreover,it is projected that the increasing in CO_(2)allowances will lead to further reduction in the cost of biomass production,which especially favors related products with lower values such as biodiesel.Furthermore,by combining various process optimization and integration,biorefinery is proposed and considered as the crucial component for the sustainable and economically feasible bulk applications of microalgae biomass.
基金supported by National Key Research and Development Project of China(No.2019YFC1805503)National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2019A13)+1 种基金the Open Project Program of the State Key Laboratory of Petroleum Pollution Control(No.PPC2019013)Major Science and Technology Projects of Shanxi Province(No.20181102017)。
文摘The presented work reports the selective catalytic reduction(SCR)of NO_(x) assisted by dielectric barrier discharge plasma via simulating marine diesel engine exhaust,and the experimental results demonstrate that the low-temperature activity of NH_(3)-SCR assisted by non-thermal plasma is enhanced significantly,particularly in the presence of a C_(3)H_(6) additive.Simultaneously,CeMnZrO_(x)@TiO_(2) exhibits strong tolerance to SO_(2) poisoning and superior catalytic stability.It is worthwhile to explore a new approach to remove NO_(x) from marine diesel engine exhaust,which is of vital significance for both academic research and practical applications.
基金Project supported by the National Key Research and Development Program of China(2022YFC3701601)the National Natural Science Foundation of China(22276162).
文摘Traditional vanadium-based selective catalytic reduction(SCR)deNO_(x) catalyst can hardly adapt to the gas conditions(much high NO_(2)/NO_(x) ratio at lower temperature)of the start-up and low loading periods for a gas turbine.Therefore,a W-Ti-CeO_(x) catalyst with NO_(x) storage and reduction(NSR)function was developed in this work for gas turbine exhaust NO_(x) elimination.The experimental results reveal that W-Ti-CeO_(x) catalyst exhibits high NO_(2) adsorption capacity at relatively low temperature while that is quite low for V-W/TiO_(2).The abundant surface Ce^(3+) species can be mainly responsible for its high adsorption ability owing to the reaction between NO_(2) and Ce^(3+) to form nitrate/nitrite species and NO.Meanwhile,the adsorption capacity of W-Ti-CeO_(x) can easily regenerate at medium-high temperature and NH_(3)-SCR reaction.Furthermore,W-Ti-CeO_(x) also shows good NH_(3)-SCR activity,which can fulfill the deNO_(x) process at high temperature.The addition of W and Ti into ceria can enhance the surface acidity and redox ability,thereby increasing the SCR activity.This work proposes a novel storage-reduction strategy for NO_(x) elimination throughout the operation of gas turbines.
基金supported by the National Natural Science Foundation of China(Nos.52000093,51968034,41807373 and21667015)National Key R&D Program of China(No.2018YFC0213400)+1 种基金China Postdoctoral Science Foundation(Nos.2020T130271,2019M663911XB)Open Fund of National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2019B03)。
文摘The simultaneous removal of SO_(2),NO_(x)and Hg^(0)from industrial exhaust flue gas has drawn worldwide attention in recent years.A particularly attractive technique is selective catalytic reduction,which effectively removes SO_(2),NO_(x)and Hg^(0)at low temperatures.This paper first reviews the simultaneous removal of SO_(2),NO_(x)and Hg^(0)by unsupported and supported catalysts.It then describes and compares the research progress of various carriers,eg.,carbon-based materials,metal oxides,silica,molecular sieves,metal-organic frameworks,and pillared interlayered clays,in the simultaneous removal of SO_(2),NO_(x)and Hg^(0).The effects of flue-gas components(such as O_(2),NH3,HCl,H2 O,SO_(2),NO and Hg^(0))on the removal of SO_(2),NOx,and Hg^(0)are discussed comprehensively and systematically.After summarizing the pollutantremoval mechanism,the review discusses future developments in the simultaneous removal of SO_(2),NOx and Hg^(0)by catalysts.
