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Chemical speciation and anthropogenic sources of ambient volatile organic compounds (VOCs) during summer in Beijing, 2004

LU Sihua, LIU Ying, SHAO Min, HUANG Shan

《环境科学与工程前沿(英文)》 2007年 第1卷 第2期   页码 147-152 doi: 10.1007/s11783-007-0026-0

摘要: Volatile organic compounds (VOCs) were measured at six sites in Beijing in August, 2004. Up to 148 VOC species, including C to C alkanes, C to C alkenes, C to C aromatics, and halogenated hydrocarbons, were quantified. Although the concentrations differed at the sites, the chemical compositions were similar, except for the Tongzhou site where aromatics were significantly high in the air. Based on the source profiles measured from previous studies, the source apportionment of ambient VOCs was preformed by deploying the chemical mass balance (CMB) model. The results show that urban VOCs are predominant from mobile source emissions, which contribute more than 50% of the VOCs (in mass concentrations) to ambient air at most sites. Other important sources are gasoline evaporation, painting, and solvents. The exception is at the Tongzhou site where vehicle exhaust, painting, and solvents have about equal contribution, around 35% of the ambient VOC concentration. As the receptor model is not valid for deriving the sources of reactive species, such as isoprene and 1,3-butadiene, other methodologies need to be further explored.

关键词: Beijing     exception     gasoline evaporation     August     exhaust    

Thin-liquid-film evaporation at contact line

Hao WANG, Zhenai PAN, Zhao CHEN

《能源前沿(英文)》 2009年 第3卷 第2期   页码 141-151 doi: 10.1007/s11708-009-0020-2

摘要: When a liquid wets a solid wall, the extended meniscus near the contact line may be divided into three regions: a nonevaporating region, where the liquid is adsorbed on the wall; a transition region or thin-film region, where effects of long-range molecular forces (disjoining pressure) are felt; and an intrinsic meniscus region, where capillary forces dominate. The thin liquid film, with thickness from nanometers up to micrometers, covering the transition region and part of intrinsic meniscus, is gaining interest due to its high heat transfer rates. In this paper, a review was made of the researches on thin-liquid-film evaporation. The major characteristics of thin film, thin-film modeling based on continuum theory, simulations based on molecular dynamics, and thin-film profile and temperature measurements were summarized.

关键词: meniscus     thin film     contact line     disjoining pressure     evaporation    

Caloric evaporation of the brine in Zangnan Salt Lake

Shiqiang WANG, Yafei GUO, Nan ZHANG, Lingzhong BU, Tianlong DENG, Mianping ZHENG

《化学科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 343-348 doi: 10.1007/s11705-010-1029-0

摘要: Zangnan Salt Lake on the south of the Tibet is a type of carbonate lake with high concentrations of lithium, boron, and potassium and obviously it differs from seawater in its chemical composition. An experimental simulation of the caloric evaporation of the lake’s brine was conducted by first freezing the brine and then performing isothermal evaporation at 288.15 K. The freezing path and the physicochemical properties of the brine were determined. The crystallization sequence was natron, hydrohalite, halite, sylvite, zabuyelite, trona, aphthitalite, thermonatrite, and borax. Rubidium and cesium salts did not crystallized out but concentrated in the mother solution. The physicochemical properties (density, refractive index, conductivity, and pH) of the liquid phase changed as the evaporation progressed. In the beginning of the evaporation processes, the concentration of potassium ions in the liquid phase gradually increased but later it decreased. A peak value of 55.21 g/L was obtained when the evaporation was 88% complete. When the mineral aphthitalite began to crystallize; the concentrations of B O , Li , Rb , and Cs gradually increased as the evaporation progressed. When the evaporation was 98% complete, their concentrations in the mother liquor were 40.77 g/L, 4.838 g/L, 400.17 mg/L and 31.95 mg/L, respectively. This essential fundamental study can provide an important reference for the comprehensive utilization of brines in Zangnan Salt Lake.

关键词: Zangnan Salt Lake     evaporation     crystallization path     freezing    

Conversion of polyethylene to gasoline: Influence of porosity and acidity of zeolites

《能源前沿(英文)》   页码 763-774 doi: 10.1007/s11708-023-0897-1

摘要: Plastic waste is causing serious environmental problems. Developing efficient, cheap and stable catalytic routes to convert plastic waste into valuable products is of great importance for sustainable development, but remains to be a challenging task. Zeolites are cheap and stable, but they are usually not efficient for plastic conversion at a low temperature. Herein a series of microporous and mesoporous zeolites were used to study the influence of porosity and acidity of zeolite on catalytic activity for plastics conversion. It was observed that H-Beta zeolite was an efficient catalyst for cracking high-density polyethylene to gasoline at 240 °C, and the products were almost C4–C12 alkanes. The effect of porosity and acidity on catalytic performance of zeolites was evaluated, which clearly visualized the good performance of H-Beta due to high surface area, large channel system, large amount accessible acidic sites. This study provides very useful information for designing zeolites for efficient conversion of plastics.

关键词: plastics conversion     polyethylene     zeolites     acidity     porosity    

Online gasoline blending with EPA Complex Model for predicting emissions

Stefan JANAQI, Mériam CHÈBRE, Guillaume PITOLLAT

《工程管理前沿(英文)》 2018年 第5卷 第2期   页码 214-226 doi: 10.15302/J-FEM-2017022

摘要: The empirical Complex Model developed by the US Environmental Protection Agency (EPA) is used by refiners to predict the toxic emissions of reformulated gasoline with respect to gasoline properties. The difficulty in implementing this model in the blending process stems from the implicit definition of Complex Model through a series of disjunctions assembled by the EPA in the form of spreadsheets. A major breakthrough in the refinery-based Complex Model implementation occurred in 2008 and 2010 through the use of generalized disjunctive and mixed-integer nonlinear programming (MINLP). Nevertheless, the execution time of these MINLP models remains prohibitively long to control emissions with our online gasoline blender. The first objective of this study is to present a new model that decreases the execution time of our online controller. The second objective is to consider toxic thresholds as hard constraints to be verified and search for blends that verify them. Our approach introduces a new way to write the Complex Model without any binary or integer variables. Sigmoid functions are used herein to approximate step functions until the measurement precision for each blend property is reached. By knowing this level of precision, we are able to propose an extremely good and differentiable approximation of the Complex Model. Next, a differentiable objective function is introduced to penalize emission values higher than the threshold emissions. Our optimization module has been implemented and tested with real data. The execution time never exceeded 1 s, which allows the online regulation of emissions the same way as other traditional properties of blended gasoline.

关键词: emissions     reformulated gasoline     online control     global optimization    

Experimental study of stratified lean burn characteristics on a dual injection gasoline engine

Chun XIA, Tingyu ZHAO, Junhua FANG, Lei ZHU, Zhen HUANG

《能源前沿(英文)》 2022年 第16卷 第6期   页码 900-915 doi: 10.1007/s11708-021-0812-6

摘要: Due to increasingly stringent fuel consumption and emission regulation, improving thermal efficiency and reducing particulate matter emissions are two main issues for next generation gasoline engine. Lean burn mode could greatly reduce pumping loss and decrease the fuel consumption of gasoline engines, although the burning rate is decreased by higher diluted intake air. In this study, dual injection stratified combustion mode is used to accelerate the burning rate of lean burn by increasing the fuel concentration near the spark plug. The effects of engine control parameters such as the excess air coefficient (Lambda), direct injection (DI) ratio, spark interval with DI, and DI timing on combustion, fuel consumption, gaseous emissions, and particulate emissions of a dual injection gasoline engine are studied. It is shown that the lean burn limit can be extended to Lambda= 1.8 with a low compression ratio of 10, while the fuel consumption can be obviously improved at Lambda= 1.4. There exists a spark window for dual injection stratified lean burn mode, in which the spark timing has a weak effect on combustion. With optimization of the control parameters, the brake specific fuel consumption (BSFC) decreases 9.05% more than that of original stoichiometric combustion with DI as 2 bar brake mean effective pressure (BMEP) at a 2000 r/min engine speed. The NOx emissions before three-way catalyst (TWC) are 71.31% lower than that of the original engine while the particle number (PN) is 81.45% lower than the original engine. The dual injection stratified lean burn has a wide range of applications which can effectively reduce fuel consumption and particulate emissions. The BSFC reduction rate is higher than 5% and the PN reduction rate is more than 50% with the speed lower than 2400 r/min and the load lower than 5 bar.

关键词: dual injection     stratified lean burn     gasoline engine     particulate matter emission     combustion analysis    

Study on extraction of thiophene from model gasoline with br?nsted acidic ionic liquids

Xiaomeng WANG, Mingjuan HAN, Hui WAN, Cao YANG, Guofeng GUAN

《化学科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 107-112 doi: 10.1007/s11705-010-0539-0

摘要: Br?nsted acidic ionic liquids (ILs), -methylimidazole hydrogen sulfate ([HMIm]HSO ) and -methylpyrrolidone hydrogen sulfate ([HNMP]HSO ), are synthesized and employed as extractants to extract thiophene from model gasoline (thiophene dissolved in -octane). The effect of extraction temperature, extraction time and volume ratio of ILs to model gasoline on desulfurization rates is investigated. Then, the optimal desulfurization conditions are obtained: the ratio of ILs to model gasoline is 1∶1, extraction temperature is 50°C for [HMIm]HSO and 60°C for [HNMP]HSO , extraction time is 60 min. Meanwhile, the desulfurization rate of [HNMP]HSO for model gasoline is 62.8%, which is higher than that of [HMIm]HSO (55.5%) under optimal conditions. The reason is discussed on the basis of the interaction energy between thiophene and ILs at the B3LYP/6-311++ G(d,p) level. Furthermore, the total desulfurization rate of [HNMP]HSO and [HMIm]HSO reaches 96.4% and 94.4%, respectively, by multistage extraction. Finally, the used ILs can be reused by vacuum drying, and their desulfurization rates are not significantly decreased after recycling 7 times in single-stage desulfurization.

关键词: br?nsted ionic liquids     model gasoline     thiophene     extraction     density functional theory    

of doping and steam treatment on the catalytic activities of nano-scale H-ZSM-5 in the methanol to gasoline

Baodong Song, Yongqiang Li, Gang Cao, Zhenhai Sun, Xu Han

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 564-574 doi: 10.1007/s11705-017-1654-y

摘要: In the transformation of methanol to gasoline (MTG), the selectivity to gasoline and the aromatic content in the produced gasoline are important factors. The catalytic activities of steam-treated and non-steam-treated nano-scale H-ZSM-5 (NHZ5) catalysts impregnated with Ag(I), Zn(II) or P(V) have been investigated in a continuous flow fixed bed reactor. The NH -TPD results showed that after impregnation, the Ag/NHZ5, Zn/NHZ5 and P/NHZ5 catalysts contained comparatively more strong, medium-strong and weak acid sites, respectively. Treatment with steam decreased the number of acid sites in all the catalysts, but the pore volumes in the catalysts were larger which improved carbon deposition resistance resulting in prolonged lifetimes. After 6 h of MTG reaction, the selectivity to gasoline for the steam-treated catalysts, , and were 70.5, 68.4 and 68.7 wt-%, respectively, whereas their respective aromatic contents in the produced gasoline were 61.9, 55.4 and 39.0 wt-%. Thus is the most promising catalyst for MTG applications which can meet the China IV gasoline standard that the amount of aromatics in gasoline should be less than 48 wt-%.

关键词: MTG     nano-scale H-ZSM-5     steam treatment     gasoline     selectivity to gasoline    

有固相析出的多效两段蒸发系统模型与过程模拟

李玲,阮奇

《中国工程科学》 2008年 第10卷 第10期   页码 54-60

摘要:

建立了带有冷凝水闪蒸的有固相析出的多效两段蒸发系统的常规设计数学模型,模型将系统的相平衡关系用回归式表达,使模型可以用计算机编程求解,避免了手工计算结合查相图的烦琐的计算过程;利用矩阵方程具有结构清晰和高度模块化的特点,将系统的物料衡算和热量衡算方程组写成矩阵方程的形式,只要保留或舍弃矩阵方程中的相关块矩阵,模型就能代表没有冷凝水闪蒸或没有固相析出的多效两段蒸发系统常规设计模型;采用迭代法结合矩阵法来求解模型,算例表明,冷凝水闪蒸对多效两段蒸发系统是有效的节能措施,算法收敛速度快、收敛稳定性好。

关键词: 固相析出     多效两段蒸发数学模型     冷凝水闪蒸    

Desulfurization mechanism of FCC gasoline: A review

Liang ZHAO, Yan CHEN, Jinsen GAO, Yu CHEN,

《化学科学与工程前沿(英文)》 2010年 第4卷 第3期   页码 314-321 doi: 10.1007/s11705-009-0271-9

摘要: This paper reviews the most important developments on the desulfurization mechanism of Fluid Catalytic Cracking (FCC) gasoline. First, the origin of sulfur compounds in FCC gasoline and the current developed desulfurization approaches and technologies are briefly introduced, and then the researches on desulfurization mechanism are summarized from experimental and theoretical perspectives. Further researches on the desulfurization mechanism will lay a foundation for optimizing desulfurization sorbents and technologies.

关键词: Catalytic Cracking     foundation     developed desulfurization     desulfurization mechanism     important    

Catalytic oxidative desulfurization of gasoline using phosphotungstic acid supported on MWW zeolite

Hanlu Wang, Idris Jibrin, Xingye Zeng

《化学科学与工程前沿(英文)》 2020年 第14卷 第4期   页码 546-560 doi: 10.1007/s11705-019-1842-z

摘要: Catalysts for the desulfurization of gasoline samples were synthesized via the immobilization of well-dispersed phosphotungstic acid (HPW) on Mobil composition of matter-twenty-two (MWW) zeolite. Characterization results indicated that these catalysts possess a mesoporous structure with the retention of the Keggin structure of immobilized HPW. Relevant reaction parameters influencing sulfur removal were systematically investigated, including HPW loading, catalyst dosage, temperature, initial S-concentration, molar ratio of oxidant to sulfide (O/S), volume ratio of MeCN to model oil (Ext./oil), and sulfide species. The 40 wt-% HPW/MWW catalyst exhibited the highest catalytic activity with 99.6% dibenzothiophene sulfur removal from prepared samples. The 40 wt-% HPW/MWW catalyst was recycled four times and could be easily regenerated. Finally, as an exploratory study, straight-run-gasoline and fluid catalytic cracking gasoline were employed to accurately evaluate the desulfurization performance of 40 wt-% HPW/MWW. Our research provides new insights into the development and application of catalysts for desulfurization of gasoline.

关键词: oxidative desulfurization     phosphotungstic acid     MWW     wet impregnation     adsorption energy    

A novel cryogenic insulation system of hollow glass microspheres and self-evaporation vapor-cooled shield

Jianpeng ZHENG, Liubiao CHEN, Ping WANG, Jingjie ZHANG, Junjie WANG, Yuan ZHOU

《能源前沿(英文)》 2020年 第14卷 第3期   页码 570-577 doi: 10.1007/s11708-019-0642-y

摘要: Liquid hydrogen (LH ) attracts widespread attention because of its highest energy storage density. However, evaporation loss is a serious problem in LH storage due to the low boiling point (20 K). Efficient insulation technology is an important issue in the study of LH storage. Hollow glass microspheres (HGMs) is a potential promising thermal insulation material because of its low apparent thermal conductivity, fast installation (Compared with multi-layer insulation, it can be injected in a short time.), and easy maintenance. A novel cryogenic insulation system consisting of HGMs and a self-evaporating vapor-cooled shield (VCS) is proposed for storage of LH . A thermodynamic model has been established to analyze the coupled heat transfer characteristics of HGMs and VCS in the composite insulation system. The results show that the combination of HGMs and VCS can effectively reduce heat flux into the LH tank. With the increase of VCS number from 1 to 3, the minimum heat flux through HGMs decreases by 57.36%, 65.29%, and 68.21%, respectively. Another significant advantage of HGMs is that their thermal insulation properties are not sensitive to ambient vacuum change. When ambient vacuum rises from 10 Pa to 1 Pa, the heat flux into the LH tank increases by approximately 20%. When the vacuum rises from 10 Pa to 100 Pa, the combination of VCS and HGMs reduces the heat flux into the tank by 58.08%–69.84% compared with pure HGMs.

关键词: liquid hydrogen storage     hollow glass microspheres (HGMs)     self-evaporation vapor-cooled shield (VCS)     thermodynamic optimization    

Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

YAN Pingxiang, MENG Xianghai, GAO Jinsen, XU Chunming, SUI Zhiyu

《化学科学与工程前沿(英文)》 2008年 第2卷 第1期   页码 74-79 doi: 10.1007/s11705-008-0016-1

摘要: The effects of reaction temperature, mass ratio of catalyst to oil, space velocity, and mass ratio of water to oil on the product distribution, the yields of light olefins (light olefins including ethylene, propylene and butylene) and the composition of the fluid catalytic cracking (FCC) gasoline upgraded over the self-made catalyst GL in a confined fluidized bed reactor were investigated. The experimental results showed that FCC gasoline was obviously reformulated under appropriate reaction conditions. The olefins (olefins with C atom number above 4) content of FCC gasoline was markedly reduced, and the aromatics content and octane number were increased. The upgraded gasoline met the new standard of gasoline, and meanwhile, higher yields of light olefins were obtained. Furthermore, higher reaction temperature, higher mass ratio of catalyst to oil, higher mass ratio of water to oil, and lower space velocity were found to be beneficial to FCC gasoline reformulation and light olefins production.

汽油机燃用轻油基燃料的缸内过程参数分析

孙玲玲

《中国工程科学》 2000年 第2卷 第12期   页码 78-83

摘要:

介绍作者开发的一种汽油机用新型燃料,为检验其品质,对发动机缸内过程参数进行了全面测试分析。结果表明:汽油机燃用轻油基混合燃料时无爆震,动力性稍低于燃用汽油,缸内过程参数标准偏差明显低于燃用汽油。这充分说明,所开发的轻油基混合燃料品质优良,适于汽油机使用。

关键词: 轻油     汽油机     缸内过程参数     抗爆性    

Effect of soil crust on evaporation and dew deposition in Mu Us sandy land, China

SUN Yongliang, LI Xiaoyan, XU Heye, YANG Zhipeng, TANG Jia, ZHANG Xiaoying

《环境科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 480-486 doi: 10.1007/s11783-008-0034-8

摘要: The development of soil crust on sandy land may affect the surface hydrological process. This paper investigates the process of evaporation and dew deposition influenced by different soil surface types which were dominated by sand, primitive biotic crust, and advanced biotic crust, respectively, in the south fringe of Mu Us sandy land in Northwest China from July to September of 2006. The experimental results indicate that the advanced biotic crust could increase evaporation and dew deposition compared to the primitive biotic crust and bare sand although the differences between them were not significant. The average evaporation from advanced biotic crust, primitive biotic crust and sand was 6.8, 6.6, and 6.5 mm/d, respectively, and water content is around 16.2 % in the condition of initially identical soil. The average dew amount on advanced biotic crust was 0.116 mm/d with extreme 0.05 and 0.24 mm/d. The average values on primitive biotic crust and sand were 0.105 and 0.101 mm/d, respectively, with extreme 0.04 and 0.21 mm/d for both treatments. Also, the dew deposition on advanced biotic crust seemed stable and might rest for a longer time than that on primitive biotic crust and sand. The results suggest that the advanced biotic crust possibly facilitates evaporation and dew deposition. Therefore, the development of biotic crust may potentially enhance the hydrological circulation in the upper sand layer in sandy land.

标题 作者 时间 类型 操作

Chemical speciation and anthropogenic sources of ambient volatile organic compounds (VOCs) during summer in Beijing, 2004

LU Sihua, LIU Ying, SHAO Min, HUANG Shan

期刊论文

Thin-liquid-film evaporation at contact line

Hao WANG, Zhenai PAN, Zhao CHEN

期刊论文

Caloric evaporation of the brine in Zangnan Salt Lake

Shiqiang WANG, Yafei GUO, Nan ZHANG, Lingzhong BU, Tianlong DENG, Mianping ZHENG

期刊论文

Conversion of polyethylene to gasoline: Influence of porosity and acidity of zeolites

期刊论文

Online gasoline blending with EPA Complex Model for predicting emissions

Stefan JANAQI, Mériam CHÈBRE, Guillaume PITOLLAT

期刊论文

Experimental study of stratified lean burn characteristics on a dual injection gasoline engine

Chun XIA, Tingyu ZHAO, Junhua FANG, Lei ZHU, Zhen HUANG

期刊论文

Study on extraction of thiophene from model gasoline with br?nsted acidic ionic liquids

Xiaomeng WANG, Mingjuan HAN, Hui WAN, Cao YANG, Guofeng GUAN

期刊论文

of doping and steam treatment on the catalytic activities of nano-scale H-ZSM-5 in the methanol to gasoline

Baodong Song, Yongqiang Li, Gang Cao, Zhenhai Sun, Xu Han

期刊论文

有固相析出的多效两段蒸发系统模型与过程模拟

李玲,阮奇

期刊论文

Desulfurization mechanism of FCC gasoline: A review

Liang ZHAO, Yan CHEN, Jinsen GAO, Yu CHEN,

期刊论文

Catalytic oxidative desulfurization of gasoline using phosphotungstic acid supported on MWW zeolite

Hanlu Wang, Idris Jibrin, Xingye Zeng

期刊论文

A novel cryogenic insulation system of hollow glass microspheres and self-evaporation vapor-cooled shield

Jianpeng ZHENG, Liubiao CHEN, Ping WANG, Jingjie ZHANG, Junjie WANG, Yuan ZHOU

期刊论文

Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

YAN Pingxiang, MENG Xianghai, GAO Jinsen, XU Chunming, SUI Zhiyu

期刊论文

汽油机燃用轻油基燃料的缸内过程参数分析

孙玲玲

期刊论文

Effect of soil crust on evaporation and dew deposition in Mu Us sandy land, China

SUN Yongliang, LI Xiaoyan, XU Heye, YANG Zhipeng, TANG Jia, ZHANG Xiaoying

期刊论文