An integrated and systematic database of sooting tendency with more than 190 kinds of fuels was obtained through a series of experimental investigations. The laser-induced incandescence (LII) method was used to acquir...An integrated and systematic database of sooting tendency with more than 190 kinds of fuels was obtained through a series of experimental investigations. The laser-induced incandescence (LII) method was used to acquire the 2D distribution of soot volume fraction, and an apparatus-independent yield sooting index (YSI) was experimentally obtained. Based on the database, a novel predicting model of YSI values for surrogate fuels was proposed with the application of a machine learning method, named the Bayesian multiple kernel learning (BMKL) model. A high correlation coefficient (0.986) between measured YSIs and predicted values with the BMKL model was obtained, indicating that the BMKL model had a reliable and accurate predictive capacity for YSI values of surrogate fuels. The BMKL model provides an accurate and low-cost approach to assess surrogate performances of diesel, jet fuel, and biodiesel in terms of sooting tendency. Particularly, this model is one of the first attempts to predict the sooting tendencies of surrogate fuels that concurrently contain hydrocarbon and oxygenated components and shows a satisfying matching level. During surrogate formulation, the BMKL model can be used to shrink the surrogate candidate list in terms of sooting tendency and ensure the optimal surrogate has a satisfying matching level of soot behaviors. Due to the high accuracy and resolution of YSI prediction, the BMKL model is also capable of providing distinguishing information of sooting tendency for surrogate design.展开更多
A joint consideration of potential combustion and emission performance in spark-ignition engines is essential for designing gasoline fuel replacements and additives,for which the knowledge of the fuels’characteristic...A joint consideration of potential combustion and emission performance in spark-ignition engines is essential for designing gasoline fuel replacements and additives,for which the knowledge of the fuels’characteristic properties forms the backbone.The aim of this study is to predict sooting tendency of fuel molecules for spark-ignition engine applications in terms of their yield sooting indexes(YSI).In conjunction with our previously developed database for gasoline compounds,which includes the physical and chemical properties,such as octane numbers,laminar burning velocity,and heat of vaporization,for more than 600 species,the identification of fuel replacements and additives can thus be performed jointly with respect to both their potential thermal efficiency benefits and emission formation characteristics in spark-ignition engines.For this purpose,a quantitative structure-property relationship(QSPR)model is developed to predict the YSI of fuel species by using artificial neural network(ANN)techniques with 21 well-selected functional group descriptors as input features.The model is trained and cross-validated with the YSI database reported by Yale University.It is then applied to estimate the YSI values of fuels available in the database for gasoline compounds and to explore the sensitivity of fuel’s sooting tendency on molecular groups.In addition,the correlation of YSI values with other properties available in the gasoline fuel database is examined to gain insights into the dependence of these properties.Finally,a selection of potential gasoline blending components is carried out exemplarily,by taking the fuels’potential benefits in thermal engine efficiency and their soot formation characteristics jointly into account in terms of efficiency merit function and YSI,respectively.展开更多
To improve the catalytic performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3)(LSCF)towards carbon soot,we utilized the impregnation method to incorporate Ag into the prepared LSCF catalyst.We conducted a series of cha...To improve the catalytic performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3)(LSCF)towards carbon soot,we utilized the impregnation method to incorporate Ag into the prepared LSCF catalyst.We conducted a series of characterization tests and evaluated the soot catalytic activity of the composite catalyst by comparing it with the LaCoO_(3) group,LaFeO_(3) group,and catalyst-free group.The results indicate that the Ag-LSCF composite catalyst exhibits the highest soot catalytic activity,with the characteristic temperature values of 376.3,431.1,and 473.9℃at 10%,50%,and 90%carbon soot conversion,respectively.These values are 24.8,20.2,and 23.1℃lower than those of the LSCF group.This also shows that LSCF can improve the catalytic activity of soot after compounding with Ag,and reflects the necessity of using catalysts in soot combustion reaction.XPS characterization and BET test show that Ag-LSCF has more abundant surface-adsorbed oxygen species,larger specific surface area and pore volume than LSCF,which also proves that Ag-LSCF has higher soot catalytic activity.展开更多
The catalytic diesel particulate filter(CDPF)is the most widely used after-treatment device for controlling diesel engine soot emissions.The development of cost-effective catalysts is crucial for diesel engines to com...The catalytic diesel particulate filter(CDPF)is the most widely used after-treatment device for controlling diesel engine soot emissions.The development of cost-effective catalysts is crucial for diesel engines to comply with future ultra-low emission regulations.This paper studies a new type of Ce/La modified Cs-V non-noble metal CDPF catalyst.Three test catalysts(Cs-V,Cs-V-5%Ce,and Cs-V-5%La)were formulated to explore the physical properties,activity,and sulfur resistance through XRD,SEM,XPS,and TPO tests.And TGA tests with different catalyst-to-soot mass ratios were designed to analyze the reaction kinetics.The results show that the soot oxidation process is divided into three stages:slow oxidation,rapid oxidation,and soot burnout.SEM and XRD results show that,compared with Ce doping,La-doped catalysts have less damage to the microstructure of the first active component,Cs_(2)V_(4)O_(11).XPS results show that the introduction of Ce and La is beneficial to the formation of oxygen vacancies and lattice distortion,increasing the proportion of active oxygen species,thereby improving the soot oxidation activity,among which La-doped active oxygen species have the highest proportion(94%).And the Cs-V-5%La catalyst has the best effect on improving the soot conversion of the three stages.The fresh state has the best low-temperature activity index,the lowest characteristic temperature(T_(50) of 374℃)and activation energy(115.01 kJ/mol),and excellent sulfur resistance.The soot conversion and oxidation speed of the three stages decreases,duration lengthens,and activation energy increases by more than 100 kJ/mol as catalyst-to-soot mass ratios decrease.展开更多
For internal combustion engines,engines installed for transport ships,cargo ships,and fishing vessels are mainly diesel engines.The number of engines is increasing due to the development of the maritime and seafood ex...For internal combustion engines,engines installed for transport ships,cargo ships,and fishing vessels are mainly diesel engines.The number of engines is increasing due to the development of the maritime and seafood exploitation sectors.Therefore,the high demand for petroleum fuels increases environmental pollution due to engine emissions.Reducing environmental pollution from the combustion of petroleum fuels has become a concern worldwide,especially for internal combustion engines.The exhaust gases from the engine contain harmful substances such as soot and nitrogen oxides(NO_(x)).Fuels with higher carbon content generate more soot when burned.In contrast,biofuels have low carbon and sulfur content and supply ample oxygen,which helps to reduce soot formation.For these reasons,biofuels are encouraged as alternative fuels to petroleum.Vegetable oil is one of the primary raw materials for biofuel production.This study presents a mixture of diesel and vegetable oil utilized as fuel for fishing vessels’diesel engines.The results of experimental research on a fishing vessel’s 4CHE Yanmar diesel engine when using diesel fuel mixed with coconut oil(B15,15%coconut oil,and 85%diesel)show that increasing B15 fuel injection pressure by about 10–15%compared with diesel fuel injection pressure reduces the engine’s soot emissions and increases power compared to unadjusted.This solution contributes to reducing environmental pollution from engine emissions.展开更多
Herein,we fabricate an embedding structure at the interface between Pt nanoparticles(NPs)and CeO_(2)-{100}nanocubes with surface defect sites(CeO_(2)-SDS)through quenching and gas bubbling-assisted membrane reduction ...Herein,we fabricate an embedding structure at the interface between Pt nanoparticles(NPs)and CeO_(2)-{100}nanocubes with surface defect sites(CeO_(2)-SDS)through quenching and gas bubbling-assisted membrane reduction methods.The in-situ substitution of Pt NPs for atomic-layer Ce lattice significantly increases the amount of reactive oxygen species from 133.68μmol/g to 199.44μmol/g.As a result,the distinctive geometric structure of Pt/CeO_(2)-SDS catalyst substantially improves the catalytic activity and stability for soot oxidation compared with the catalyst with no quenching process,i.e.,its T_(50)and TOF values are 332°C and 2.915 h^(-1),respectively.Combined with the results of experimental investigations and density functional theory calculations,it is unveiled that the unique embedding structure of Pt/CeO_(2)-SDS catalyst can facilitate significantly electron transfer from Pt to the CeO_(2)-{100}support,and induce the formation of interfacial[Ce-O_(x)-Pt_(2)]bond chains,which plays a crucial role in enhancing the key step of soot oxidation through the dual activation of surface lattice oxygen and molecular O_(2).Such a fundamental revelation of the interfacial electronic transmission and corresponding modification strategy contributes a novel opportunity to develop high-efficient and stable noble metal catalysts at the atomic level.展开更多
Limiting environmental pollution from exhaust emissions from internal combustion engines includes many measures,including encouraging biofuel use because biofuel is environmentally friendly and renewable.A mixture of ...Limiting environmental pollution from exhaust emissions from internal combustion engines includes many measures,including encouraging biofuel use because biofuel is environmentally friendly and renewable.A mixture of diesel fuel and vegetable oil is a form of biofuel.However,some properties of the mixed fuel,such as viscosity and density,are higher than those of traditional diesel fuel,affecting the injection and combustion process and reducing power and non-optimal toxic emissions,especially soot emissions.This study uses Kiva-3V software to simulate the combustion process of a diesel-vegetable oil mixture in the combustion chamber of a fishing vessel diesel engine with changes in fuel injection timing.The results show that when increasing the fuel injection timing of a diesel-vegetable oil mixture about 1–2 degrees of crankshaft rotation angle before the top dead center compared to diesel fuel injection timing,the engine power increases,and soot emissions decrease compared to no adjustment.The above simulation research results will help orient the experiments conveniently and reduce costs in the future experimental research process to quantify the fuel system adjustment of fishing vessels’diesel engines when using biofuels,including diesel-vegetable oil mixtures.Thus,the engine’s economic indicators will improve,and emissions that pollute the environment will be limited.展开更多
In the quest to develop high-performance lubrication additives,a novel nanocomposite comprising biodiesel soot modified by silver(Ag/BDS)was synthesized.The tribological behavior of Ag/BDS nanocomposite as an additive...In the quest to develop high-performance lubrication additives,a novel nanocomposite comprising biodiesel soot modified by silver(Ag/BDS)was synthesized.The tribological behavior of Ag/BDS nanocomposite as an additive for liquid paraffin(LP)were systematically investigated using response surface methodology.To elucidate the friction and wear mechanisms associated with the Ag/BDS nanocomposite,various analytical techniques were employed,including scanning electron microscopy with energy-dispersive spectroscopy(SEM/EDS),Raman spectroscopy,and molecular dynamics simulations.The results show that the concentration of Ag/BDS has a significant impact on the tribological properties of LP under different applied loads and sliding speeds.Notably,LP containing 0.25%Ag/BDS shows the most favorable tribological performance and in comparison,to pure LP,the average friction coefficient and average wear volume have been reduced by 42.7%and 21.2%,respectively.The mechanisms underlying the reduction in friction and anti-wear mechanism of Ag/BDS have been attributed to the excellent synergies of Ag and BDS.Specifically,the Ag particles facilitate the incorporation of BDS particles in the formation of uniform boundary lubrication films.展开更多
Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaus...Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaust temperatures below 200℃,particularly under conditions of frequent idling.Herein,we report an effective strategy utilizing non-thermal plasma(NTP)to activate Olatt in Ce_(1–x)Co_(x)O_(2–δ)catalysts,achieving dramatic enhancement of the soot combustion rate at low temperatures.At 200℃ and 4.3 W(discharge power,P_(dis)),NTP-Ce_(0.8)Co_(0.2)O_(2–δ)achieved 96.9%soot conversion(X_(C)),99.0%CO_(2) selectivity(S(CO_(2)))and a maximum energy conversion efficiency(Emax)of 14.7 g kWh^(–1).Compared with previously reported results,NTP-Ce_(0.8)Co_(0.2)O_(2–δ)exhibits the highest S(CO_(2))and Emax values.Remarkably,even without heating,X_(C),Emax,and S(CO_(2))reached 92.1%,6.1 g kWh–1,and 97.5%,respectively,at 6.3 W(P_(dis)).The results of characterization and theoretical calculation demonstrated that Co dopes into the CeO_(2) crystal lattice and forms an asymmetric Ce–O–Co structure,making oxygen“easy come,easy go”,thereby enabling the rapid combustion of soot over NTP-Ce_(0.8)Co_(0.2)O_(2–δ).This study highlights the great potential of NTP for activating Olatt and provides valuable insights into the design of efficient NTP-adapted catalysts for oxidation reactions.展开更多
Oxygenated fuels can reduce harmful emissions without affecting engine performance,meeting the big challenge in the transportation industry,which keeps the environment safe and reduces global warming.This study invest...Oxygenated fuels can reduce harmful emissions without affecting engine performance,meeting the big challenge in the transportation industry,which keeps the environment safe and reduces global warming.This study investigates the impact of biodiesel injection strategies and fuel injection pressures(FIP)on diesel engine exhaust emission characteristics.The engine is fuelled with 20%Jatropha biodiesel(JB)and 80%diesel,named JB20D.The ratios of fuel injection pressures started with injecting the fuel(diesel and JB20D)from 200 bar to 500 bar.The experimental outcomes indicate that the engine performance of brake-specific fuel consumption increased by 21.36%from the burning of JB20D compared with diesel,while brake thermal efficiency improved by 6.54%for low and high FIP compared to the diesel.The high fuel injection pressures slightly decrease the nitrogen oxide(NOX)emissions for both diesel and biodiesel.The emissions of NOX decreased from the combustion of JB20D by 18.7%under high fuel injection pressures compared to diesel.The concentration of soot particulate decreased by 20.4%form JB20D combustion than those combusted from diesel fuel.展开更多
The extensive use of diesel engines has led to significant emissions of pollutants,especially soot particles,which pose serious risks to both the environment and human health.At present,developing catalysts with low–...The extensive use of diesel engines has led to significant emissions of pollutants,especially soot particles,which pose serious risks to both the environment and human health.At present,developing catalysts with low–temperature activity,low cost,and high stability remains the core challenge in eliminating soot from diesel engine exhaust.This paper first reviews the mechanisms of soot catalytic oxidation.Based on these mechanisms,the current design directions for soot catalysts are summarized and discussed.On the one hand,the effects of modification methods such as doping,loading,and solid solution on the performance of manganese-based catalysts are reviewed from the perspective of intrinsic activity.On the other hand,the research progress on manganese-based catalysts with specific morphological structures for soot oxidation is explored.Following the identification of design strategies,the commonly used preparation methods to achieve these designs are also outlined.Finally,the paper highlights the challenges associated with manganese-based catalysts in soot catalysis and discusses future research and development directions.展开更多
Catalytic oxidation of soot is of great importance for emission control on diesel vehicles.In this work,a highly active Cs/Co/Ce-Sn catalyst was investigated for soot oxidation,and it was unexpectedly found that high-...Catalytic oxidation of soot is of great importance for emission control on diesel vehicles.In this work,a highly active Cs/Co/Ce-Sn catalyst was investigated for soot oxidation,and it was unexpectedly found that high-temperature calcination greatly improved the activity of the catalyst.When the calcination temperature was increased from 500℃ to 750℃,T_(50) decreased from 456.9℃ to 389.8℃ in a NO/O_(2)/H_(2)O/N_(2) atmosphere.Characterization results revealed that high-temperature calcination can promote the ability to transfer negative charge density from Cs to other metal cations in Cs/Co/Ce-Sn,which will facilitate the production of more oxygen defects and the generation of more surface-active oxygen species.Surfaceactive oxygen species are beneficial to the oxidation of NO to NO_(2),leading to the high yield of NO_(2) exploitation.Therefore,the Cs/Co/Ce-Sn catalyst calcined at 750℃ demonstrated higher activity than that calcined at 500℃.This work provides a pathway to prepare high efficiency catalysts for the removal of soot and significant insight into the effects of calcination on soot oxidation catalysts.展开更多
Catalyzed gasoline particulate filters(cGPFs)are being developed to enable compliance with the particulate number limits for passenger cars equipped with gasoline direct injection(GDI)engines in China and Europe,It is...Catalyzed gasoline particulate filters(cGPFs)are being developed to enable compliance with the particulate number limits for passenger cars equipped with gasoline direct injection(GDI)engines in China and Europe,It is appealing to build catalysts with ceria—an irreplaceable"reducible"component in three-way converters—to help eliminate the soot particles trapped in cGPFs via O_(2)-assisted combustion.While research aiming at understanding how these recipes function has continued for more than two decades,a universal model elucidating the roles of different"active oxygen"species is yet to be realized.In this perspective,by critically assessing the reported data about gasoline soot catalytic combustion over ceria catalysts,it is suggested that ceria ignites soot through contributing its lattice oxygen,giving rise to a"hot ring"region at the periphery of soot-catalyst interface.During the"re-oxidation"semi-cycles,electrophilic superoxides and/or peroxides(O_(x)^(n-))are produced at the Ce^(3+)and oxygen vacancy sites enriched in this collar-like region,and then work as key reactive phases for soot deep oxidation.Based on this"O_(x)^(n-)assisted"Mars-van Krevelen mechanism,several guidelines for ceria catalyst designing are proposed,ending with a summary about where future opportunities and challenges may lie in developing efficient and practical cGPF catalysts.展开更多
Soot is a flocculent carbon nanoparticle that results the imperfect combustion of fossil fuel,and numerous studies are dedicated to the reduction of soot production to alleviate the associated environmental problems.H...Soot is a flocculent carbon nanoparticle that results the imperfect combustion of fossil fuel,and numerous studies are dedicated to the reduction of soot production to alleviate the associated environmental problems.However,soot as a functional material is also widely used in energy storage and superhydrophobic materials.As a partial oxidation technology,the entrained flow coal gasification process will produce part of the soot.It is important to separate soot from the coal gasification fine slag(CGFS)and understand its structural characteristics for soot utilization.For this purpose,two industrial typical pulverized coal gasification fine slag(PCGFS)and coal-water slurry gasification fine slag(WCGFS)were selected for this study.The results showed that both fine slags were rich in soot,and the dry ash free mass fraction of soot in PCGFS and WCGFS was 6.24%and 2.91%,respectively,and the soot of PCGFS had a hollow carbon nanosphere morphology,while the soot of WCGFS showed a flocculent irregular morphology.The average fringe length,fringe tortuosity,and fringe spacing of the soot were 0.84 nm,1.21,and 0.45 nm,respectively.Compared to the WCGFS,the soot particles of PCGFS have less continuity of molecular bonds within the lattice,the larger the defects within the lattice,the fewer isolated lattice carbon layers there are.This study provides important theoretical support for understanding the structural characteristics and next applications of soot in the entrained flow coal gasification fine slag.展开更多
The spatiotemporal distribution of soot concentration in aero-engine combustor is important for assessing its combustion performance.Here,we report experimental measurements of soot concentration in terms of Soot Volu...The spatiotemporal distribution of soot concentration in aero-engine combustor is important for assessing its combustion performance.Here,we report experimental measurements of soot concentration in terms of Soot Volume Fraction(SVF)and its spatiotemporal distribution in a single-sector dual-swirl aero-engine combustor using Two-Color Laser-Induced Incandescence(2C-LII).It is shown that soot predominantly forms in the symmetrical vortices of the primary combustion zone,exhibiting a V-type distribution with higher concentration in the lower half of the zone than the upper half,with a small amount distributed in the secondary recirculation zone.Soot emissions at the combustor outlet are relatively low under three typical operating conditions by LII experiments,which is aligned with Smoke Number(SN)from gas analysis.The effect of inlet air temperature on SVF distribution and dynamics in the primary combustion zone is studied,which suggests that the SVF level in the primary combustion zone monotonically increases with the temperature.Meanwhile,the SVF distribution becomes more symmetrical as the inlet temperature increases,although the overall SVF level in the lower half of the zone is still higher.We also investigate the influence of the inlet air pressure on the SVF distribution at the combustor outlet.The soot concentration at the combustor outlet increases with inlet pressure,mainly distributed irregularly across both sides and the center.On both sides,the distribution is continuous,while the center exhibits dot-like and linear patterns.Numerical simulations correlated SVF distribution with the flow field in the primary combustion zone,qualitatively explaining the observed SVF distribution behavior.These results under various conditions can provide valuable insights for improving the performance of this specific combustor and designing high-temperature-rise combustors in the future.展开更多
Quantitative measurement of Soot Volume Fraction (SVF) is an essential prerequisite for controlling soot particle emissions from aero-engine combustors. As an in-situ and non-intrusive optical diagnostic technique, La...Quantitative measurement of Soot Volume Fraction (SVF) is an essential prerequisite for controlling soot particle emissions from aero-engine combustors. As an in-situ and non-intrusive optical diagnostic technique, Laser-Induced Incandescence (LII) has been increasingly applied for soot concentration quantification in various combustion environments such as laminar flame, vehicle exhaust, internal combustion chamber as well as aero-engine combustor. In this work, we experimentally measured the spatial and temporal distribution of SVF using two-color LII technique at the outlet of a single-sector dual-swirl aero-engine model combustor. The effect of inlet pressure and air preheat temperature on the SVF distribution was separately investigated within a pressure range of 241–425 kPa and a temperature range of 292–500 K. The results show that soot production increases with the inlet pressure but generally decreases with the air preheat temperature. Qualitative analysis was provided to explain the above results of parametric studies. The LII experiments were also conducted under 3 designed conditions to evaluate soot emission under practical operations. Particularly, weak soot emission was detected at the outlet under the idle condition. Our experimental results provide a valuable benchmark for evaluating soot emission in the exhaust plume of this aero-engine combustor during practical operations.展开更多
The evolution of particle size distribution function(PSDF)of soot in premixed flames of benzene and toluene was studied on a burner stabilized stagnation(BSS)flame platform.The cold gas velocities were changed to hold...The evolution of particle size distribution function(PSDF)of soot in premixed flames of benzene and toluene was studied on a burner stabilized stagnation(BSS)flame platform.The cold gas velocities were changed to hold the maximum flame temperatures of different flames approximately constant.The PSDFs of all the test flames exhibited a bimodal distribution,i.e.,a small-size nucleation mode and a large-size accumulation mode.It was observed that soot nucleation and particle growth in the benzene flame were stronger than those in the toluene flame at short residence times.At longer residence times,the PSDFs of the two flames were similar,and the toluene flame showed a larger particle size distribution range and a higher particle volume fraction than the benzene flame.展开更多
This paper presents the results of an application of a first-order conditional moment closure （CMC） approach coupled with a semi-empirical soot model to investigate the effect of various detailed combustion chemistr...This paper presents the results of an application of a first-order conditional moment closure （CMC） approach coupled with a semi-empirical soot model to investigate the effect of various detailed combustion chemistry schemes on soot formation and destruction in turbulent non-premixed flames. A two-equation soot model repre- senting soot particle nucleation, growth, coagulation and oxidation, was incorporated into the CMC model. The turbulent flow-field of both flames is described using the Favre-averaged fluid-flow equations, applying a stan- dard k-c turbulence model. A number of five reaction kinetic mechanisms having 50 - 100 species and 200 - 1000 elementary reactions called ABF, Miller-Bowman, GRI-Mech3.0, Warnatz, and Qin were employed to study the effect of combustion chemistry schemes on soot predictions. The results showed that of various kinetic schemes being studied, each yields similar accuracy in temperature prediction when compared with experimental data. With respect to soot prediction, the kinetic scheme containing benzene elementary reactions tends to result in a better prediction on soot concentrations in comparison to those contain no benzene elementary reactions. Among five kinetic mechanisms being studied, the Qin combustion scheme mechanism turned to yield the best prediction on both flame temperature and soot levels.展开更多
This paper presents the study of polycyclic aromatic hydrocarbons (PAH) and paramagnetism of soot particles sampled from cool sooting flames of methane and propane in a separately-heated two-sectional reactor under at...This paper presents the study of polycyclic aromatic hydrocarbons (PAH) and paramagnetism of soot particles sampled from cool sooting flames of methane and propane in a separately-heated two-sectional reactor under atmospheric pressure at the reactor temperatures of 670-1170 K. The temperature profiles of the flames were studied. The sampling was carred out with a quarts sampler and the samples were frozen with liquid nitrogen. A number of polyaromatic hydrocarbons such as pyrene. fluoranthene, coronene, anthanthrene, 1,1 2-benzperylene, were identified by spectroscopic methods in the extract of soot. The processes of soot formation at methane- oxygen mixture combustion in the electric field with applied potential changed from 0 to 2,2 kV at different polarity of electrodes have been investigated. It has been stated that at the electrical field application, an increase in soot particle sizes and soot yield occurs; besides, at the application of the field, speeding up the positively charged particles, the interplanar distance decreases. On the basis of investigation of soot particles paramagnetism, it was shown that initially soot particles have high carcinogetic activity and pollute the environment owing to a rapid decrease of the number of these radical centers. The reduction of the radical concentration is connected with radical recombination on soot.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52071216)the Shanghai Rising-Star Program.
文摘An integrated and systematic database of sooting tendency with more than 190 kinds of fuels was obtained through a series of experimental investigations. The laser-induced incandescence (LII) method was used to acquire the 2D distribution of soot volume fraction, and an apparatus-independent yield sooting index (YSI) was experimentally obtained. Based on the database, a novel predicting model of YSI values for surrogate fuels was proposed with the application of a machine learning method, named the Bayesian multiple kernel learning (BMKL) model. A high correlation coefficient (0.986) between measured YSIs and predicted values with the BMKL model was obtained, indicating that the BMKL model had a reliable and accurate predictive capacity for YSI values of surrogate fuels. The BMKL model provides an accurate and low-cost approach to assess surrogate performances of diesel, jet fuel, and biodiesel in terms of sooting tendency. Particularly, this model is one of the first attempts to predict the sooting tendencies of surrogate fuels that concurrently contain hydrocarbon and oxygenated components and shows a satisfying matching level. During surrogate formulation, the BMKL model can be used to shrink the surrogate candidate list in terms of sooting tendency and ensure the optimal surrogate has a satisfying matching level of soot behaviors. Due to the high accuracy and resolution of YSI prediction, the BMKL model is also capable of providing distinguishing information of sooting tendency for surrogate design.
基金supported by the Fundamental Research Funds for the Central Universities。
文摘A joint consideration of potential combustion and emission performance in spark-ignition engines is essential for designing gasoline fuel replacements and additives,for which the knowledge of the fuels’characteristic properties forms the backbone.The aim of this study is to predict sooting tendency of fuel molecules for spark-ignition engine applications in terms of their yield sooting indexes(YSI).In conjunction with our previously developed database for gasoline compounds,which includes the physical and chemical properties,such as octane numbers,laminar burning velocity,and heat of vaporization,for more than 600 species,the identification of fuel replacements and additives can thus be performed jointly with respect to both their potential thermal efficiency benefits and emission formation characteristics in spark-ignition engines.For this purpose,a quantitative structure-property relationship(QSPR)model is developed to predict the YSI of fuel species by using artificial neural network(ANN)techniques with 21 well-selected functional group descriptors as input features.The model is trained and cross-validated with the YSI database reported by Yale University.It is then applied to estimate the YSI values of fuels available in the database for gasoline compounds and to explore the sensitivity of fuel’s sooting tendency on molecular groups.In addition,the correlation of YSI values with other properties available in the gasoline fuel database is examined to gain insights into the dependence of these properties.Finally,a selection of potential gasoline blending components is carried out exemplarily,by taking the fuels’potential benefits in thermal engine efficiency and their soot formation characteristics jointly into account in terms of efficiency merit function and YSI,respectively.
文摘To improve the catalytic performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3)(LSCF)towards carbon soot,we utilized the impregnation method to incorporate Ag into the prepared LSCF catalyst.We conducted a series of characterization tests and evaluated the soot catalytic activity of the composite catalyst by comparing it with the LaCoO_(3) group,LaFeO_(3) group,and catalyst-free group.The results indicate that the Ag-LSCF composite catalyst exhibits the highest soot catalytic activity,with the characteristic temperature values of 376.3,431.1,and 473.9℃at 10%,50%,and 90%carbon soot conversion,respectively.These values are 24.8,20.2,and 23.1℃lower than those of the LSCF group.This also shows that LSCF can improve the catalytic activity of soot after compounding with Ag,and reflects the necessity of using catalysts in soot combustion reaction.XPS characterization and BET test show that Ag-LSCF has more abundant surface-adsorbed oxygen species,larger specific surface area and pore volume than LSCF,which also proves that Ag-LSCF has higher soot catalytic activity.
基金supported by the National Natural Science Foundation of China(No.52206167)the Science and Technology Talents and Platform Program(Academician ExpertWorkstation)(No.202305AF150109)+1 种基金Shanghai Sailing Program(No.21YF1448900)the Introduced and co-builded high-level research and development institutions of Jiangxi Province(No.20212CCH45004).
文摘The catalytic diesel particulate filter(CDPF)is the most widely used after-treatment device for controlling diesel engine soot emissions.The development of cost-effective catalysts is crucial for diesel engines to comply with future ultra-low emission regulations.This paper studies a new type of Ce/La modified Cs-V non-noble metal CDPF catalyst.Three test catalysts(Cs-V,Cs-V-5%Ce,and Cs-V-5%La)were formulated to explore the physical properties,activity,and sulfur resistance through XRD,SEM,XPS,and TPO tests.And TGA tests with different catalyst-to-soot mass ratios were designed to analyze the reaction kinetics.The results show that the soot oxidation process is divided into three stages:slow oxidation,rapid oxidation,and soot burnout.SEM and XRD results show that,compared with Ce doping,La-doped catalysts have less damage to the microstructure of the first active component,Cs_(2)V_(4)O_(11).XPS results show that the introduction of Ce and La is beneficial to the formation of oxygen vacancies and lattice distortion,increasing the proportion of active oxygen species,thereby improving the soot oxidation activity,among which La-doped active oxygen species have the highest proportion(94%).And the Cs-V-5%La catalyst has the best effect on improving the soot conversion of the three stages.The fresh state has the best low-temperature activity index,the lowest characteristic temperature(T_(50) of 374℃)and activation energy(115.01 kJ/mol),and excellent sulfur resistance.The soot conversion and oxidation speed of the three stages decreases,duration lengthens,and activation energy increases by more than 100 kJ/mol as catalyst-to-soot mass ratios decrease.
文摘For internal combustion engines,engines installed for transport ships,cargo ships,and fishing vessels are mainly diesel engines.The number of engines is increasing due to the development of the maritime and seafood exploitation sectors.Therefore,the high demand for petroleum fuels increases environmental pollution due to engine emissions.Reducing environmental pollution from the combustion of petroleum fuels has become a concern worldwide,especially for internal combustion engines.The exhaust gases from the engine contain harmful substances such as soot and nitrogen oxides(NO_(x)).Fuels with higher carbon content generate more soot when burned.In contrast,biofuels have low carbon and sulfur content and supply ample oxygen,which helps to reduce soot formation.For these reasons,biofuels are encouraged as alternative fuels to petroleum.Vegetable oil is one of the primary raw materials for biofuel production.This study presents a mixture of diesel and vegetable oil utilized as fuel for fishing vessels’diesel engines.The results of experimental research on a fishing vessel’s 4CHE Yanmar diesel engine when using diesel fuel mixed with coconut oil(B15,15%coconut oil,and 85%diesel)show that increasing B15 fuel injection pressure by about 10–15%compared with diesel fuel injection pressure reduces the engine’s soot emissions and increases power compared to unadjusted.This solution contributes to reducing environmental pollution from engine emissions.
基金supported by the Beijing Nova Program(No.20220484215)National Key Research and Development Program of China(Nos.2022YFB3504100,2022YFB3506200,2021YFA1500300 and 2022YFA1500146)National Natural Science Foundation of China(Nos.22376217,22208373,22272090 and 22272106)。
文摘Herein,we fabricate an embedding structure at the interface between Pt nanoparticles(NPs)and CeO_(2)-{100}nanocubes with surface defect sites(CeO_(2)-SDS)through quenching and gas bubbling-assisted membrane reduction methods.The in-situ substitution of Pt NPs for atomic-layer Ce lattice significantly increases the amount of reactive oxygen species from 133.68μmol/g to 199.44μmol/g.As a result,the distinctive geometric structure of Pt/CeO_(2)-SDS catalyst substantially improves the catalytic activity and stability for soot oxidation compared with the catalyst with no quenching process,i.e.,its T_(50)and TOF values are 332°C and 2.915 h^(-1),respectively.Combined with the results of experimental investigations and density functional theory calculations,it is unveiled that the unique embedding structure of Pt/CeO_(2)-SDS catalyst can facilitate significantly electron transfer from Pt to the CeO_(2)-{100}support,and induce the formation of interfacial[Ce-O_(x)-Pt_(2)]bond chains,which plays a crucial role in enhancing the key step of soot oxidation through the dual activation of surface lattice oxygen and molecular O_(2).Such a fundamental revelation of the interfacial electronic transmission and corresponding modification strategy contributes a novel opportunity to develop high-efficient and stable noble metal catalysts at the atomic level.
文摘Limiting environmental pollution from exhaust emissions from internal combustion engines includes many measures,including encouraging biofuel use because biofuel is environmentally friendly and renewable.A mixture of diesel fuel and vegetable oil is a form of biofuel.However,some properties of the mixed fuel,such as viscosity and density,are higher than those of traditional diesel fuel,affecting the injection and combustion process and reducing power and non-optimal toxic emissions,especially soot emissions.This study uses Kiva-3V software to simulate the combustion process of a diesel-vegetable oil mixture in the combustion chamber of a fishing vessel diesel engine with changes in fuel injection timing.The results show that when increasing the fuel injection timing of a diesel-vegetable oil mixture about 1–2 degrees of crankshaft rotation angle before the top dead center compared to diesel fuel injection timing,the engine power increases,and soot emissions decrease compared to no adjustment.The above simulation research results will help orient the experiments conveniently and reduce costs in the future experimental research process to quantify the fuel system adjustment of fishing vessels’diesel engines when using biofuels,including diesel-vegetable oil mixtures.Thus,the engine’s economic indicators will improve,and emissions that pollute the environment will be limited.
基金funded by the National Natural Science Foundation of China(52075141)the Open Project of Anhui Province Key Laboratory of Critical Friction Pair for Advanced Equipment(LCFP-2408)+9 种基金Key Research&Development(R&D)Plan of Anhui Province under Grant(2022a05020019)Support Program for Outstanding Young Talents in Anhui Province Colleges and Universities(gxyq2022079)Excellent Research and Innovation Teams Project of Anhui Province's Universities(2022AH010092)Discipline Construction Quality Improvement Project of Chaohu University(kj22fdzy03,XLZ202307,XLZ202301)School-level Scientific Research Project of Chaohu University(XLY-202112)Scientific Research Planning Project of Anhui Provincial(2022AH051726)Anhui Province University Science and Engineering Teachers'Internship Program in Enterprises(2024jsqygz89)Anhui Province College Students'Innovation and Entrepreneurship Training Program(S202410380020)Anhui Province Postdoctoral Research Project(2024A773)Horizontal Research Project of Chaohu University(hxkt20230006).
文摘In the quest to develop high-performance lubrication additives,a novel nanocomposite comprising biodiesel soot modified by silver(Ag/BDS)was synthesized.The tribological behavior of Ag/BDS nanocomposite as an additive for liquid paraffin(LP)were systematically investigated using response surface methodology.To elucidate the friction and wear mechanisms associated with the Ag/BDS nanocomposite,various analytical techniques were employed,including scanning electron microscopy with energy-dispersive spectroscopy(SEM/EDS),Raman spectroscopy,and molecular dynamics simulations.The results show that the concentration of Ag/BDS has a significant impact on the tribological properties of LP under different applied loads and sliding speeds.Notably,LP containing 0.25%Ag/BDS shows the most favorable tribological performance and in comparison,to pure LP,the average friction coefficient and average wear volume have been reduced by 42.7%and 21.2%,respectively.The mechanisms underlying the reduction in friction and anti-wear mechanism of Ag/BDS have been attributed to the excellent synergies of Ag and BDS.Specifically,the Ag particles facilitate the incorporation of BDS particles in the formation of uniform boundary lubrication films.
文摘Effective lattice oxygen(Olatt)activation at low temperatures has long been a challenge in catalytic oxidation reactions.Traditional thermal catalytic soot combustion,even with Pt/Pd catalysts,is inefficient at exhaust temperatures below 200℃,particularly under conditions of frequent idling.Herein,we report an effective strategy utilizing non-thermal plasma(NTP)to activate Olatt in Ce_(1–x)Co_(x)O_(2–δ)catalysts,achieving dramatic enhancement of the soot combustion rate at low temperatures.At 200℃ and 4.3 W(discharge power,P_(dis)),NTP-Ce_(0.8)Co_(0.2)O_(2–δ)achieved 96.9%soot conversion(X_(C)),99.0%CO_(2) selectivity(S(CO_(2)))and a maximum energy conversion efficiency(Emax)of 14.7 g kWh^(–1).Compared with previously reported results,NTP-Ce_(0.8)Co_(0.2)O_(2–δ)exhibits the highest S(CO_(2))and Emax values.Remarkably,even without heating,X_(C),Emax,and S(CO_(2))reached 92.1%,6.1 g kWh–1,and 97.5%,respectively,at 6.3 W(P_(dis)).The results of characterization and theoretical calculation demonstrated that Co dopes into the CeO_(2) crystal lattice and forms an asymmetric Ce–O–Co structure,making oxygen“easy come,easy go”,thereby enabling the rapid combustion of soot over NTP-Ce_(0.8)Co_(0.2)O_(2–δ).This study highlights the great potential of NTP for activating Olatt and provides valuable insights into the design of efficient NTP-adapted catalysts for oxidation reactions.
文摘Oxygenated fuels can reduce harmful emissions without affecting engine performance,meeting the big challenge in the transportation industry,which keeps the environment safe and reduces global warming.This study investigates the impact of biodiesel injection strategies and fuel injection pressures(FIP)on diesel engine exhaust emission characteristics.The engine is fuelled with 20%Jatropha biodiesel(JB)and 80%diesel,named JB20D.The ratios of fuel injection pressures started with injecting the fuel(diesel and JB20D)from 200 bar to 500 bar.The experimental outcomes indicate that the engine performance of brake-specific fuel consumption increased by 21.36%from the burning of JB20D compared with diesel,while brake thermal efficiency improved by 6.54%for low and high FIP compared to the diesel.The high fuel injection pressures slightly decrease the nitrogen oxide(NOX)emissions for both diesel and biodiesel.The emissions of NOX decreased from the combustion of JB20D by 18.7%under high fuel injection pressures compared to diesel.The concentration of soot particulate decreased by 20.4%form JB20D combustion than those combusted from diesel fuel.
基金sponsored by the National Natural Science Foundation of China(Grant 22406050)the Top-Notch Personnel Fund of Henan Agricultural University(Grant 30501029)+2 种基金the Natural Science Foundation of Henan Province(Grant 232300420293)the Science and Technology Project of China Tobacco Shaanxi Industrial Co.,Ltd.(Grant BA000-ZB24010)the Postgraduate Education Reform and Quality Improvement Project of Henan Province(Grant YJS2024JD17).
文摘The extensive use of diesel engines has led to significant emissions of pollutants,especially soot particles,which pose serious risks to both the environment and human health.At present,developing catalysts with low–temperature activity,low cost,and high stability remains the core challenge in eliminating soot from diesel engine exhaust.This paper first reviews the mechanisms of soot catalytic oxidation.Based on these mechanisms,the current design directions for soot catalysts are summarized and discussed.On the one hand,the effects of modification methods such as doping,loading,and solid solution on the performance of manganese-based catalysts are reviewed from the perspective of intrinsic activity.On the other hand,the research progress on manganese-based catalysts with specific morphological structures for soot oxidation is explored.Following the identification of design strategies,the commonly used preparation methods to achieve these designs are also outlined.Finally,the paper highlights the challenges associated with manganese-based catalysts in soot catalysis and discusses future research and development directions.
基金supported by the National Natural Science Foundation of China(Nos.22206183,52225004)the National Key R&D Program of China(No.2022YFC3701804)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23010201)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2022309)。
文摘Catalytic oxidation of soot is of great importance for emission control on diesel vehicles.In this work,a highly active Cs/Co/Ce-Sn catalyst was investigated for soot oxidation,and it was unexpectedly found that high-temperature calcination greatly improved the activity of the catalyst.When the calcination temperature was increased from 500℃ to 750℃,T_(50) decreased from 456.9℃ to 389.8℃ in a NO/O_(2)/H_(2)O/N_(2) atmosphere.Characterization results revealed that high-temperature calcination can promote the ability to transfer negative charge density from Cs to other metal cations in Cs/Co/Ce-Sn,which will facilitate the production of more oxygen defects and the generation of more surface-active oxygen species.Surfaceactive oxygen species are beneficial to the oxidation of NO to NO_(2),leading to the high yield of NO_(2) exploitation.Therefore,the Cs/Co/Ce-Sn catalyst calcined at 750℃ demonstrated higher activity than that calcined at 500℃.This work provides a pathway to prepare high efficiency catalysts for the removal of soot and significant insight into the effects of calcination on soot oxidation catalysts.
基金supported by the National Natural Science Foundation of China(22076176,22276106)the Natural Science Foundation of Shandong Province(ZR2021YQ14)+3 种基金the Innovation Ability Improvement Project for Technology-based Small-and Medium-sized Enterprises of Shandong Province(2022TSGC1345)Jiangsu Province Science and Technology Plan Special Fund(BZ2022053)Key Research and Development Program of Anhui Province(202104g01020006)the Fundamental Research Funds for the Central Universities(202141008)。
文摘Catalyzed gasoline particulate filters(cGPFs)are being developed to enable compliance with the particulate number limits for passenger cars equipped with gasoline direct injection(GDI)engines in China and Europe,It is appealing to build catalysts with ceria—an irreplaceable"reducible"component in three-way converters—to help eliminate the soot particles trapped in cGPFs via O_(2)-assisted combustion.While research aiming at understanding how these recipes function has continued for more than two decades,a universal model elucidating the roles of different"active oxygen"species is yet to be realized.In this perspective,by critically assessing the reported data about gasoline soot catalytic combustion over ceria catalysts,it is suggested that ceria ignites soot through contributing its lattice oxygen,giving rise to a"hot ring"region at the periphery of soot-catalyst interface.During the"re-oxidation"semi-cycles,electrophilic superoxides and/or peroxides(O_(x)^(n-))are produced at the Ce^(3+)and oxygen vacancy sites enriched in this collar-like region,and then work as key reactive phases for soot deep oxidation.Based on this"O_(x)^(n-)assisted"Mars-van Krevelen mechanism,several guidelines for ceria catalyst designing are proposed,ending with a summary about where future opportunities and challenges may lie in developing efficient and practical cGPF catalysts.
基金supported by the National Natural Science Foundation of China(22168032,21968024)the National Key Research and Development Program of China(2023YFC3904302).
文摘Soot is a flocculent carbon nanoparticle that results the imperfect combustion of fossil fuel,and numerous studies are dedicated to the reduction of soot production to alleviate the associated environmental problems.However,soot as a functional material is also widely used in energy storage and superhydrophobic materials.As a partial oxidation technology,the entrained flow coal gasification process will produce part of the soot.It is important to separate soot from the coal gasification fine slag(CGFS)and understand its structural characteristics for soot utilization.For this purpose,two industrial typical pulverized coal gasification fine slag(PCGFS)and coal-water slurry gasification fine slag(WCGFS)were selected for this study.The results showed that both fine slags were rich in soot,and the dry ash free mass fraction of soot in PCGFS and WCGFS was 6.24%and 2.91%,respectively,and the soot of PCGFS had a hollow carbon nanosphere morphology,while the soot of WCGFS showed a flocculent irregular morphology.The average fringe length,fringe tortuosity,and fringe spacing of the soot were 0.84 nm,1.21,and 0.45 nm,respectively.Compared to the WCGFS,the soot particles of PCGFS have less continuity of molecular bonds within the lattice,the larger the defects within the lattice,the fewer isolated lattice carbon layers there are.This study provides important theoretical support for understanding the structural characteristics and next applications of soot in the entrained flow coal gasification fine slag.
基金support of the National Science and Technology Major Project of China(No.J2019-V-0005-0096)the National Key Research and Development Program of China(No.2020YFA0405700).
文摘The spatiotemporal distribution of soot concentration in aero-engine combustor is important for assessing its combustion performance.Here,we report experimental measurements of soot concentration in terms of Soot Volume Fraction(SVF)and its spatiotemporal distribution in a single-sector dual-swirl aero-engine combustor using Two-Color Laser-Induced Incandescence(2C-LII).It is shown that soot predominantly forms in the symmetrical vortices of the primary combustion zone,exhibiting a V-type distribution with higher concentration in the lower half of the zone than the upper half,with a small amount distributed in the secondary recirculation zone.Soot emissions at the combustor outlet are relatively low under three typical operating conditions by LII experiments,which is aligned with Smoke Number(SN)from gas analysis.The effect of inlet air temperature on SVF distribution and dynamics in the primary combustion zone is studied,which suggests that the SVF level in the primary combustion zone monotonically increases with the temperature.Meanwhile,the SVF distribution becomes more symmetrical as the inlet temperature increases,although the overall SVF level in the lower half of the zone is still higher.We also investigate the influence of the inlet air pressure on the SVF distribution at the combustor outlet.The soot concentration at the combustor outlet increases with inlet pressure,mainly distributed irregularly across both sides and the center.On both sides,the distribution is continuous,while the center exhibits dot-like and linear patterns.Numerical simulations correlated SVF distribution with the flow field in the primary combustion zone,qualitatively explaining the observed SVF distribution behavior.These results under various conditions can provide valuable insights for improving the performance of this specific combustor and designing high-temperature-rise combustors in the future.
基金supported by the National Key Research and Development Program of China(No.2020YFA0405700).
文摘Quantitative measurement of Soot Volume Fraction (SVF) is an essential prerequisite for controlling soot particle emissions from aero-engine combustors. As an in-situ and non-intrusive optical diagnostic technique, Laser-Induced Incandescence (LII) has been increasingly applied for soot concentration quantification in various combustion environments such as laminar flame, vehicle exhaust, internal combustion chamber as well as aero-engine combustor. In this work, we experimentally measured the spatial and temporal distribution of SVF using two-color LII technique at the outlet of a single-sector dual-swirl aero-engine model combustor. The effect of inlet pressure and air preheat temperature on the SVF distribution was separately investigated within a pressure range of 241–425 kPa and a temperature range of 292–500 K. The results show that soot production increases with the inlet pressure but generally decreases with the air preheat temperature. Qualitative analysis was provided to explain the above results of parametric studies. The LII experiments were also conducted under 3 designed conditions to evaluate soot emission under practical operations. Particularly, weak soot emission was detected at the outlet under the idle condition. Our experimental results provide a valuable benchmark for evaluating soot emission in the exhaust plume of this aero-engine combustor during practical operations.
基金supported by the National Natural Science Foundation of China(Grant No.51776124).
文摘The evolution of particle size distribution function(PSDF)of soot in premixed flames of benzene and toluene was studied on a burner stabilized stagnation(BSS)flame platform.The cold gas velocities were changed to hold the maximum flame temperatures of different flames approximately constant.The PSDFs of all the test flames exhibited a bimodal distribution,i.e.,a small-size nucleation mode and a large-size accumulation mode.It was observed that soot nucleation and particle growth in the benzene flame were stronger than those in the toluene flame at short residence times.At longer residence times,the PSDFs of the two flames were similar,and the toluene flame showed a larger particle size distribution range and a higher particle volume fraction than the benzene flame.
基金Supported by Ministry of National Education,Republic of Indonesia No.433/SP2H/PP/DP2M/VI/2010
文摘This paper presents the results of an application of a first-order conditional moment closure （CMC） approach coupled with a semi-empirical soot model to investigate the effect of various detailed combustion chemistry schemes on soot formation and destruction in turbulent non-premixed flames. A two-equation soot model repre- senting soot particle nucleation, growth, coagulation and oxidation, was incorporated into the CMC model. The turbulent flow-field of both flames is described using the Favre-averaged fluid-flow equations, applying a stan- dard k-c turbulence model. A number of five reaction kinetic mechanisms having 50 - 100 species and 200 - 1000 elementary reactions called ABF, Miller-Bowman, GRI-Mech3.0, Warnatz, and Qin were employed to study the effect of combustion chemistry schemes on soot predictions. The results showed that of various kinetic schemes being studied, each yields similar accuracy in temperature prediction when compared with experimental data. With respect to soot prediction, the kinetic scheme containing benzene elementary reactions tends to result in a better prediction on soot concentrations in comparison to those contain no benzene elementary reactions. Among five kinetic mechanisms being studied, the Qin combustion scheme mechanism turned to yield the best prediction on both flame temperature and soot levels.
文摘This paper presents the study of polycyclic aromatic hydrocarbons (PAH) and paramagnetism of soot particles sampled from cool sooting flames of methane and propane in a separately-heated two-sectional reactor under atmospheric pressure at the reactor temperatures of 670-1170 K. The temperature profiles of the flames were studied. The sampling was carred out with a quarts sampler and the samples were frozen with liquid nitrogen. A number of polyaromatic hydrocarbons such as pyrene. fluoranthene, coronene, anthanthrene, 1,1 2-benzperylene, were identified by spectroscopic methods in the extract of soot. The processes of soot formation at methane- oxygen mixture combustion in the electric field with applied potential changed from 0 to 2,2 kV at different polarity of electrodes have been investigated. It has been stated that at the electrical field application, an increase in soot particle sizes and soot yield occurs; besides, at the application of the field, speeding up the positively charged particles, the interplanar distance decreases. On the basis of investigation of soot particles paramagnetism, it was shown that initially soot particles have high carcinogetic activity and pollute the environment owing to a rapid decrease of the number of these radical centers. The reduction of the radical concentration is connected with radical recombination on soot.
