Emissions of exhaust gases and particulate matter from a dual fuel marine engine using methanol as fuel with marine gasoil as pilot fuel have been examined for a ferry during operation.The emission factor for nitrogen...Emissions of exhaust gases and particulate matter from a dual fuel marine engine using methanol as fuel with marine gasoil as pilot fuel have been examined for a ferry during operation.The emission factor for nitrogen oxides is lower than what is typically found for marine gasoil but does not reach the tier III limit.The emissions of particulate matter are significantly lower than for fuel oils and similar to what is found for LNG engines.The main part of the particles can be found in the ultrafine range with the peak being at around 18 nm.About 93%of the particles are evaporated and absorbed when using a thermodenuder,and thus a large majority of the particles are volatile.Methanol is a potential future marine fuel that will reduce emissions of air pollutants and can be made as a biofuel to meet emission targets for greenhouse gases.展开更多
Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely r...Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely reported. This paper presents an analysis of more than 20 kinds ofhydrocarbons in the emissions obtained from a spark-ignition Shanghai car running 85# gasoline anda comparison with emission from a Santana test car running M-100 methanol fuel. A set ofenrichment method has also been described. Test results show that at the current stage of methanolengine development the concentration of individual hydrocarbon including some poisonous substancesis lower than those of normal gasoline engine.展开更多
Diesel engine alternative fuels, such as methanol and biodiesel, are beneficial to reduce diesel engine emission. In order to study the influence of methanol and biodiesel on the performance, economy and emission of s...Diesel engine alternative fuels, such as methanol and biodiesel, are beneficial to reduce diesel engine emission. In order to study the influence of methanol and biodiesel on the performance, economy and emission of small agricultural diesel engine, the physical-chemical properties(cetane number, lower heat value(LHV), viscosity, etc.) of methanol and biodiesel were analyzed. The methanol and biodiesel showed good complementary property to some extent. When a large proportion of methanol was added into biodiesel, the cetane number of the methanol/biodiesel blend will be greatly reduced. Since the cetane number of the blend fuel has great influence on the combustion process of diesel engine, after testing for blending ratio of methanol/biodiesel, the blend was prepared with 5%(BM5), 10%(BM10) and 15%(BM15) methanol, respectively. Di-Tert-Butyl Peroxide(DTBP) was chosen as a cetane number improver to be added into methanol/biodiesel blend. 0.25%, 0.50% and 0.75% of DTBP was added into BM15. The bench test was carried out on a 186 FA diesel engine to study the effect of methanol and DTBP on the engine performance and emissions. The results show that, at rated condition, compared with biodiesel, the NO;concentration of BM5, BM10 and BM15 is reduced by 5.02%, 33.85% and 21.24%, and smoke is reduced by 5.56%, 22.22% and 55.56%. However, the engine power is also reduced by 5.77%, 14.23% and 25.41%, and the brake specific energy consumption is increased by 3.31%, 7.78% and 6.37%. The addition of DTBP in methanol/biodiesel could recover the engine power to the level of diesel. DTBP shows good effect on the reduction of the brake specific energy consumption and NO_(x), CO, HC concentration, but a little increase of exhaust smoke.展开更多
In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methan...In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methanol, 88% gasoline-12% ethanol and 88% gasoline-6% methanol-6% ethanol）. Additional tests are carried out with the basic gasoline fuel for comparison analysis and performance assessment. Engine performance is investigated under a variety of engine operating conditions. The results are presented in the domain of engine speed. In particular, the brake power of the engine is shown to be slightly increased. The brake thermal efficiency showed an increase compared with the basic gasoline engine. Similarly, it is shown that brake specific fuel consumption is enhanced compared with basic gasoline engine. The exhaust gas temperature showed a decrease compared with gasoline fuel which is preferable to reduce emissions. The alcohol additives are strongly recommended to enhance performance, increasing the mileage and reducing the emissions.展开更多
Methanol,produced from carbon dioxide,natural gas,and biomass,has drawn increasing attention as a promising green carbon feedstock for biomanufacturing due to its sustainable and energy-rich properties.Nicotinamide ad...Methanol,produced from carbon dioxide,natural gas,and biomass,has drawn increasing attention as a promising green carbon feedstock for biomanufacturing due to its sustainable and energy-rich properties.Nicotinamide adenine dinucleotide(NAD^(+))-dependent methanol dehydrogenase(MDH)catalyzes the oxidation of methanol to formaldehyde via NADH generation,providing a highly active C1 intermediate and reducing power for subsequent biosynthesis.However,the unsatisfactory catalytic efficiency and cofactor bias of MDH significantly impede methanol valorization,especially in nicotinamide adenine dinucleotide phosphate(NADP^(+))-dependent biosynthesis.Herein,we employed synthetic NADH and NADPH auxotrophic Escherichia coli strains as growth-coupled selection platforms for the directed evolution of MDH from Bacillus stearothermophilus DSM 2334.NADH or NADPH generated by MDH-catalyzed methanol oxidation enabled the growth of synthetic cofactor auxotrophs,establishing a positive correlation between the cell growth rate and MDH activity.Using this principle,MDH mutants exhibiting a 20-fold improvement in catalytic efficiency(k_(cat)/K_(m))and a 90-fold cofactor specificity switch from NAD^(+)to NADP+without a decrease in specific enzyme activity,were efficiently screened from random and semi-rationally designed libraries.We envision that these mutants will advance methanol valorization and that the synthetic cofactor auxotrophs will serve as versatile selection platforms for the evolution of NAD(P)^(+)-dependent enzymes.展开更多
In order to address typical problems due to the huge demand of oil for consumption in traditional internal combustion engines,a new more efficient combustion mode is proposed and studied in the framework of Computatio...In order to address typical problems due to the huge demand of oil for consumption in traditional internal combustion engines,a new more efficient combustion mode is proposed and studied in the framework of Computational Fluid Dynamics(CFD).Moreover,a Non-dominated Sorting Genetic Algorithm(NSGA-Ⅱ)is applied to optimize the related parameters,namely,the engine methanol ratio,the fuel injection time,the initial temperature,the Exhaust Gas Re-Circulation(EGR)rate,and the initial pressure.The so-called Conventional Diesel Combustion(CDC),Homogeneous Charge Compression Ignition(HCCI)and the Reactivity Controlled Compression Ignition(RCCI)combustion modes are compared.The results show that RCCI has a higher methanol ratio and an earlier injection timing with moderate EGR rate and higher initial pressure.The initial temperature increases as the methanol ratio increases.In comparison,CDC has the lowest hydrocarbon and CO emissions and the highest combustion efficiency.At different crankshaft rotation angles corresponding to 50%of the combustion amount(CA50),the combustion temperature and boundary layer temperature of HCCI change significantly,while those of RCCI undergo limited variations.At the same CA50,the exergy losses of HCCI and RCCI are lower than that of the CDC.On the basis of these findings,it can be concluded that the methanol/diesel RCCI engine can be used to obtain a clean and efficient combustion process,which should be regarded as a promising combustion mode.展开更多
Heterostructures have emerged as elaborate structures to improve catalytic activity owing to their combined surface and distinct inverse interface.However,fabricating advanced nanocatalysts with facetdependent interfa...Heterostructures have emerged as elaborate structures to improve catalytic activity owing to their combined surface and distinct inverse interface.However,fabricating advanced nanocatalysts with facetdependent interface remains an unexploited and promising area.Herein,we render the controlled growth of Pt nanoparticles(NPs)on Pd nanosheets(NSs)by regulating the reduction kinetics of Pt^(2+)with solvents.Specifically,the fast reduction kinetic makes the Pt NPs uniformly deposited on the Pd NSs(U-Pd@Pt HS),while the slow reduction kinetic leads to the preferential growth of Pt NPs on the edge of the Pd NSs(E-Pd@Pt HS).Density functional theory calculations demonstrate that Pd(111)-Pt interface in U-Pd@Pt HS induces the electron-deficient status of Pd substrates,triggering the d-band center downshift and amplifying the Pd-Pt intermetallic interaction.The synergy between the electronic effect and interfacial effect facilitates the removal of poisonous intermediates on U-Pd@Pt HS.By virtue of the Pd NSs@Pt NPs interface,the heterostructure achieves exceptional methanol oxidation reaction activity as well as improved durability.This study innovatively proposes heterostructure engineering with facetdependent interfacial modulation,offering instructive guidelines for the rational design of versatile heterocatalysts.展开更多
为了对柴油机的经济性和排放参数进行高效、准确的预测,根据4190型船用柴油机实验数据与边界参数,建立AVL-BOOST甲醇/柴油混合燃料柴油机仿真模型;利用模型进行仿真实验,并建立甲醇掺混比、废气再循环(exhaust gas recirculation,EGR)...为了对柴油机的经济性和排放参数进行高效、准确的预测,根据4190型船用柴油机实验数据与边界参数,建立AVL-BOOST甲醇/柴油混合燃料柴油机仿真模型;利用模型进行仿真实验,并建立甲醇掺混比、废气再循环(exhaust gas recirculation,EGR)率、喷油提前角和进气压力4个控制参数对有效油耗率和NO x排放预测数据集;利用该数据集对5种不同核函数的高斯过程回归(Gaussian process regression,GPR)模型进行训练;最后将最优的平方指数高斯过程回归(squared exponential-Gaussian process regression,SE-GPR)模型、AVL-BOOST仿真数据和柴油机实验数据进行对比。结果表明:在数据量为180组时,SE-GPR模型对有效油耗率和NO x排放均取得拟合关联度99%以上,均方根误差(root mean square error,RMSE)分别为1.859,0.3445,平均绝对误差(mean absolute error,MAE)分别为0.954,0.2489;并且,相较于AVL-BOOST仿真实验,SE-GPR模型对实验数据具有更好的拟合性。展开更多
文摘Emissions of exhaust gases and particulate matter from a dual fuel marine engine using methanol as fuel with marine gasoil as pilot fuel have been examined for a ferry during operation.The emission factor for nitrogen oxides is lower than what is typically found for marine gasoil but does not reach the tier III limit.The emissions of particulate matter are significantly lower than for fuel oils and similar to what is found for LNG engines.The main part of the particles can be found in the ultrafine range with the peak being at around 18 nm.About 93%of the particles are evaporated and absorbed when using a thermodenuder,and thus a large majority of the particles are volatile.Methanol is a potential future marine fuel that will reduce emissions of air pollutants and can be made as a biofuel to meet emission targets for greenhouse gases.
文摘Increasing global interest in methanoi fuel has led us to investigate the exhaust emissionsof its engine. Analysis of its inorganic and organic emissions. such as CO. NO_x and hydrocarbons(total HC) have been widely reported. This paper presents an analysis of more than 20 kinds ofhydrocarbons in the emissions obtained from a spark-ignition Shanghai car running 85# gasoline anda comparison with emission from a Santana test car running M-100 methanol fuel. A set ofenrichment method has also been described. Test results show that at the current stage of methanolengine development the concentration of individual hydrocarbon including some poisonous substancesis lower than those of normal gasoline engine.
基金Sponsored by the Open Project of State Key Laboratory of Internal Combustion Engine Combustion,Tianjin University(Grand No.K2020-12)the Project of Natural Science Foundation of Jiangsu Province(Grant No.BK20200910)+1 种基金the Natural Science Research Projects in Jiangsu Higher Education Institutions(Grant No.20KJB470015)the Provincial Engineering Research Center for New Energy Vehicle Intelligent Control and Simulation Test Technology of Sichuan(Grant No.XNYQ2021-003)。
文摘Diesel engine alternative fuels, such as methanol and biodiesel, are beneficial to reduce diesel engine emission. In order to study the influence of methanol and biodiesel on the performance, economy and emission of small agricultural diesel engine, the physical-chemical properties(cetane number, lower heat value(LHV), viscosity, etc.) of methanol and biodiesel were analyzed. The methanol and biodiesel showed good complementary property to some extent. When a large proportion of methanol was added into biodiesel, the cetane number of the methanol/biodiesel blend will be greatly reduced. Since the cetane number of the blend fuel has great influence on the combustion process of diesel engine, after testing for blending ratio of methanol/biodiesel, the blend was prepared with 5%(BM5), 10%(BM10) and 15%(BM15) methanol, respectively. Di-Tert-Butyl Peroxide(DTBP) was chosen as a cetane number improver to be added into methanol/biodiesel blend. 0.25%, 0.50% and 0.75% of DTBP was added into BM15. The bench test was carried out on a 186 FA diesel engine to study the effect of methanol and DTBP on the engine performance and emissions. The results show that, at rated condition, compared with biodiesel, the NO;concentration of BM5, BM10 and BM15 is reduced by 5.02%, 33.85% and 21.24%, and smoke is reduced by 5.56%, 22.22% and 55.56%. However, the engine power is also reduced by 5.77%, 14.23% and 25.41%, and the brake specific energy consumption is increased by 3.31%, 7.78% and 6.37%. The addition of DTBP in methanol/biodiesel could recover the engine power to the level of diesel. DTBP shows good effect on the reduction of the brake specific energy consumption and NO_(x), CO, HC concentration, but a little increase of exhaust smoke.
文摘In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methanol, 88% gasoline-12% ethanol and 88% gasoline-6% methanol-6% ethanol）. Additional tests are carried out with the basic gasoline fuel for comparison analysis and performance assessment. Engine performance is investigated under a variety of engine operating conditions. The results are presented in the domain of engine speed. In particular, the brake power of the engine is shown to be slightly increased. The brake thermal efficiency showed an increase compared with the basic gasoline engine. Similarly, it is shown that brake specific fuel consumption is enhanced compared with basic gasoline engine. The exhaust gas temperature showed a decrease compared with gasoline fuel which is preferable to reduce emissions. The alcohol additives are strongly recommended to enhance performance, increasing the mileage and reducing the emissions.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0110201)the National Key R&D Program of China(2018YFA0901500)+3 种基金the National Natural Science Foundation of China(32070083 and 32222004)the Innovation Fund of Haihe Laboratory of Synthetic Biology(22HHSWSS00017)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2021177)the Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(TSBICIP-KJGG-008).
文摘Methanol,produced from carbon dioxide,natural gas,and biomass,has drawn increasing attention as a promising green carbon feedstock for biomanufacturing due to its sustainable and energy-rich properties.Nicotinamide adenine dinucleotide(NAD^(+))-dependent methanol dehydrogenase(MDH)catalyzes the oxidation of methanol to formaldehyde via NADH generation,providing a highly active C1 intermediate and reducing power for subsequent biosynthesis.However,the unsatisfactory catalytic efficiency and cofactor bias of MDH significantly impede methanol valorization,especially in nicotinamide adenine dinucleotide phosphate(NADP^(+))-dependent biosynthesis.Herein,we employed synthetic NADH and NADPH auxotrophic Escherichia coli strains as growth-coupled selection platforms for the directed evolution of MDH from Bacillus stearothermophilus DSM 2334.NADH or NADPH generated by MDH-catalyzed methanol oxidation enabled the growth of synthetic cofactor auxotrophs,establishing a positive correlation between the cell growth rate and MDH activity.Using this principle,MDH mutants exhibiting a 20-fold improvement in catalytic efficiency(k_(cat)/K_(m))and a 90-fold cofactor specificity switch from NAD^(+)to NADP+without a decrease in specific enzyme activity,were efficiently screened from random and semi-rationally designed libraries.We envision that these mutants will advance methanol valorization and that the synthetic cofactor auxotrophs will serve as versatile selection platforms for the evolution of NAD(P)^(+)-dependent enzymes.
文摘In order to address typical problems due to the huge demand of oil for consumption in traditional internal combustion engines,a new more efficient combustion mode is proposed and studied in the framework of Computational Fluid Dynamics(CFD).Moreover,a Non-dominated Sorting Genetic Algorithm(NSGA-Ⅱ)is applied to optimize the related parameters,namely,the engine methanol ratio,the fuel injection time,the initial temperature,the Exhaust Gas Re-Circulation(EGR)rate,and the initial pressure.The so-called Conventional Diesel Combustion(CDC),Homogeneous Charge Compression Ignition(HCCI)and the Reactivity Controlled Compression Ignition(RCCI)combustion modes are compared.The results show that RCCI has a higher methanol ratio and an earlier injection timing with moderate EGR rate and higher initial pressure.The initial temperature increases as the methanol ratio increases.In comparison,CDC has the lowest hydrocarbon and CO emissions and the highest combustion efficiency.At different crankshaft rotation angles corresponding to 50%of the combustion amount(CA50),the combustion temperature and boundary layer temperature of HCCI change significantly,while those of RCCI undergo limited variations.At the same CA50,the exergy losses of HCCI and RCCI are lower than that of the CDC.On the basis of these findings,it can be concluded that the methanol/diesel RCCI engine can be used to obtain a clean and efficient combustion process,which should be regarded as a promising combustion mode.
基金supported by the National Natural Science Foundation of China(Grant numbers 52274304,52073199)。
文摘Heterostructures have emerged as elaborate structures to improve catalytic activity owing to their combined surface and distinct inverse interface.However,fabricating advanced nanocatalysts with facetdependent interface remains an unexploited and promising area.Herein,we render the controlled growth of Pt nanoparticles(NPs)on Pd nanosheets(NSs)by regulating the reduction kinetics of Pt^(2+)with solvents.Specifically,the fast reduction kinetic makes the Pt NPs uniformly deposited on the Pd NSs(U-Pd@Pt HS),while the slow reduction kinetic leads to the preferential growth of Pt NPs on the edge of the Pd NSs(E-Pd@Pt HS).Density functional theory calculations demonstrate that Pd(111)-Pt interface in U-Pd@Pt HS induces the electron-deficient status of Pd substrates,triggering the d-band center downshift and amplifying the Pd-Pt intermetallic interaction.The synergy between the electronic effect and interfacial effect facilitates the removal of poisonous intermediates on U-Pd@Pt HS.By virtue of the Pd NSs@Pt NPs interface,the heterostructure achieves exceptional methanol oxidation reaction activity as well as improved durability.This study innovatively proposes heterostructure engineering with facetdependent interfacial modulation,offering instructive guidelines for the rational design of versatile heterocatalysts.
文摘为了对柴油机的经济性和排放参数进行高效、准确的预测,根据4190型船用柴油机实验数据与边界参数,建立AVL-BOOST甲醇/柴油混合燃料柴油机仿真模型;利用模型进行仿真实验,并建立甲醇掺混比、废气再循环(exhaust gas recirculation,EGR)率、喷油提前角和进气压力4个控制参数对有效油耗率和NO x排放预测数据集;利用该数据集对5种不同核函数的高斯过程回归(Gaussian process regression,GPR)模型进行训练;最后将最优的平方指数高斯过程回归(squared exponential-Gaussian process regression,SE-GPR)模型、AVL-BOOST仿真数据和柴油机实验数据进行对比。结果表明:在数据量为180组时,SE-GPR模型对有效油耗率和NO x排放均取得拟合关联度99%以上,均方根误差(root mean square error,RMSE)分别为1.859,0.3445,平均绝对误差(mean absolute error,MAE)分别为0.954,0.2489;并且,相较于AVL-BOOST仿真实验,SE-GPR模型对实验数据具有更好的拟合性。
