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Measuring the Adiabatic Ignition Delay of n-pentane Mixture using Rapid Compression Machine

Journal of Thermal Science 2022年第2期31卷 552-560页

作者： J.A.Piehl O.Samimi-Abianeh Mechanical Engineering Department of Wayne State University DetroitMIUnited States of America

Recent combustion research has focused on low temperature combustion to meet engine emission regulations and to advance the development of low temperature homogenous compression ignition engines.Autoignition studies in this temperature regime are primarily performed by Rapid Compression Machines(RCMs)which are sensitive to the heat transfer characteristics of the experimental device.RCMs are widely used to measure autoignition data such as ignition delay and species concentration.Measured ignition delays from RCMs are typically reported at an adiabatic condition;however,this assumption may produce a systematic error in ignition delay measurement as heat transfer is observed to reduce the pressure and temperature during the autoignition process,e.g.,a longer ignition delay has a greater pressure and temperature drops.RCMs are custom built and have unique design characteristics that affect the heat transfer during the autoignition process.In addition,depending on the diluent composition(e.g.,helium versus nitrogen or argon),different heat transfer characteristics are expected.As a result,autoignition results at similar conditions may vary from facility to facility or depending on the used diluent.The dependency of the measured data on the used facility or diluent may produce uncertainty in the data which impact the development of high-fidelity combustion mechanisms.In this work,a new method is developed and utilized to eliminate heat transfer from the ignition delay data.To evaluate the new method,the autoignition of n-pentane mixtures in the low temperature regime were investigated using an RCM.To vary the heat transfer,the compression ratio of the RCM was changed and the ignition delays were measured at similar pressure and temperature conditions.The tests were performed at an equivalence ratio of approximately one and nitrogen and argon as diluents.By applying the new method,the effect of heat transfer on the ignition delays were eliminated successfully and ignition delays at adiabatic condition were determined.

关键词： heat transfer Rapid Compression Machine(RCM) n-pentane autoignition ignition delay

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Isomerization of n-pentane catalyzed by amide-AlCl3-based ionic liquid analogs with various additives

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Chinese Journal of Chemical Engineering 2020年第1期28卷 152-157页

作者： Pengcheng Hu Jingwei Zheng Wei Jiang Lijuan Zhong Shufeng Zhou College of Chemical Engineering Huaqiao UniversityXiamen 361021China

The isomerization of n-pentane to generate high-quality blending components for clean gasoline was catalyzed by several amide-AlCl3-based ionic liquid(IL) analogs with various amides as donor molecules. The catalytic performance of these IL analogs was evaluated in a magnetic agitated autoclave operated in batch mode.IL analog based n-methylacetamide(nMA)-AlCl3 with the amide/AlCl3 molar ratio of 0.65 showed excellent performance toward n-pentane isomerization because 0.65 nMA-1.0 AlCl3 had a low viscosity and bidentate coordination structure. The influences of reaction time, reaction temperature, and stirring speed on the catalytic performance were also investigated. Optimal reaction conditions comprised the reaction time of 1 h, the reaction temperature of 40 °C, and the stirring speed of 1500 r·min-1. Under optimal condition, the n-C5 conversion,research octane number(ROn) increment, total liquids yield, and isoparaffin yield in isomerized oil were56.80%, 13.51, 89.90 wt%, and 44.32 wt%, respectively. A new mathematical model was constructed to predict the relationships among ROn increment, ROn increment/n-C5 conversion ratio, and n-C5 conversion. The new model indicated that an appropriate conversion per pass of n-C5 did not exceed 50%–55%. Various cycloparaffin additives were used to improve the catalytic performance of 0.65 nMA-1.0 AlCl3. The n-C5 conversion increased from 56.80% to 67.32%. The ROn increment, total liquids yield, and isoparaffin yield reached 17.83, 97.36 wt%,and 63.74 wt%, respectively.

关键词： Isomerization Ionic liquid analogs n-pentane Mathematical model Additives

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A novel scalable synthesis process of PPTA by coupling n-pentane evaporation for polymerization heat removal

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Chinese Chemical Letters 2011年第11期22卷 1379-1382页

作者： Tao Zhang Guo Hua Luo Fei Wei Yan Yan Lu Wei Zhong Qian Xin Lin Tuo Department of Chemical Engineering Tsinghua University Beijing 100084 China

In this study,we compared the effect of n-pentane and ice-water bath on removing the thermal effect in the poly（p-phenylene terephthalamide）（PPTA） polymerization process.The results indicate that the n-pentane can help to transfer the reaction heat faster and better.Adding suitable amount of n-pentanes into the PPTA preparation process not only improve the heat transfer,but also reduce the motor power in the polymerization process.Moreover,the introduction of n-pentane properly does not result in decrease of the inherent viscosity（η_（inh）） of polymer.Instead,it leads to increased viscosity of polymer during the PPTA preparation process.The results indicate that n-pentane can effectively transfer the reaction heat and avoid overheating during the polymerization of PPTA.

关键词： PPTA n-pentane Ice-water bath Reaction heat

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γ-Al2O3Supported SO42&#45/ZrO2Solid Superacid Catalysts for n-pentane Isomerization

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Modern Research in Catalysis 2014年第3期3卷 89-93页

作者： Li Zhao Xiaoshuang Cheng Ye Hu Shuqing Ma Yingjun Wang College of Chemistry & Chemical Engineering Provincial Key Laboratory of Oil & Gas Chemical Technology Northeast Petroleum University Daqing China

A solid superacid catalyst Pt-SO42-/ZrO2-A12O3 for n-pentane isomerization, was prepared by incipient-wetness impregnation. Preparetion conditions, namely, calcination temperature, concentration of sulfuric acid solution used in impregnation and Al2O3 concentration, were varied to investigate the effects on catalytic performance of Pt-SO42-/ZrO2-A12O3. The results showed that the PtSZA catalyst exhibited excellent catalytic performance for n-pentane isomerization. Under optimized preparation conditions of calcination temperature of 650°C, reaction time for 3 h, concentration of sulfuric acid solution for 0.5 mol/L, 30% of Al2O3 concentration and 0.3% of Pt concentration, the n-pentane conversion and isopentane selectivity of Pt-SO42-/ZrO2-A12O3 could reach up to 62.17% and 91.60%, respectively.

关键词： SO42-/ZrO2 n-pentane Isomerization γ-Al2O3 Supported Superacid Catalysts

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Reaction characteristics of maximizing light olefins and decreasing methane in C_(5) hydrocarbons catalytic pyrolysis

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Petroleum Science 2023年第3期20卷 1909-1921页

作者： Mei-Jia Liu Gang Wang Shun-nian Xu Tao-Ran Zheng Zhong-Dong Zhang Sheng-Bao He State Key Laboratory of Heavy Oil Processing China University of PetroleumBejing102249China Petrochemical Research Institute PetroChinaBejing102206China

When converting C_(5) hydrocarbons to light olefins by catalytic pyrolysis,the generation of low value-added methane will affect the atomic utilization efficiency of C_(5) hydrocarbons.To improve the atomic utilization efficiency,different generation pathways of light olefins and methane in the catalytic pyrolysis of C_(5) hydrocarbons were analyzed,and the effects of reaction conditions and zeolite types were inves-tigated.Results showed that light olefins were mainly formed by breaking the C_(2)-C_(3) bond in the middle position,while methane was formed by breaking the C_(1)-C_(2) bond at the end.Meanwhile,it was discovered that the hydrogen transfer reaction could be reduced by about 90%by selecting MTT zeolite with 1D topology and FER zeolite with 2D topology under high weight hourly space velocity(WHSV)and high temperature operations,thus leading to the improvement of the light olefins selectivity for the catalytic pyrolysis of n-pentane and 1-pentene to 55.12% and 74.60%,respectively.Moreover,the fraction ratio of terminal C_(1)-C_(2) bond cleavage was reduced,which would reduce the selectivity of methane to 6.63%and 1.83%.Therefore,zeolite with low hydrogen transfer activity and catalytic pyrolysis process with high WHsV will be conducive to maximize light olefins and to decrease methane.

关键词： n-pentane 1-Pentene Catalytic pyrolysis Light olefins Methane

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Preparation, Characterization and Catalytic Properties of S_2O_8^(2-)/ZrO_2 Supported by Tungsten Carbide

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Chemical Research in Chinese Universities 2004年第1期20卷 68-72页

作者： XUEHua-xin CHEnJian-min DepartmentofEnvironmentalScience＆Engineering FudanUniversityShanghai200433P.R.China

A WC-supported S_2O 2-_8/ZrO_2(PSZ) catalyst was prepared and characterized by means of XRD, BET, FTIR and XPS. The isomerization of n-pentane over the catalyst was investigated as well. The results show that the skeletal isomerization and the crack of n-pentane proceed simultaneously on WC-supported S_2O 2-_8/ZrO_2 catalyst. The addition of tungsten carbide showed a significant enhancement in the activity and stability of the catalyst for n-pentane isomerization. The catalyst showed evidently a better activity than S_2O 2-_8/ZrO_2 supported by Pt and WO_3. The results can be interpreted by the existence of the tungsten oxycarbide compound(WC_xO_y) with carbidic, oxide and acidic sites.

关键词： n-pentane Isomerization S_2O 2-_8/ZrO_2 Tungsten carbide

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