Oxidation Model And Experimental Study Of Synthetic Lubricant Oil Based On Methylcyclohexane

Since 2010,China’s current manufacturing level has ranked first in the world for 12 consecutive years,and it is currently at an important stage of transformation from a manufacturing power to a manufacturing power.For a long time,the lubrication failure of equipment contacting surfaces and the wear of components caused by mechanical friction have been important causes for the short service life of equipment,low energy utilization efficiency,and serious environmental pollution in the current industry.In order to alleviate this problem,efforts must be made to develop efficient,reliable,green,and clean lubricants.The research on synthetic lubricants has attracted many scholars’ attention.Compared to traditional mineral based lubricants,current synthetic base oils have a more regular molecular morphology,which makes them more suitable for harsh operating conditions.They also have better thermal stability,viscosity temperature property,oxidation resistance,better biodegradability,and low toxicity.Among the various characteristics of lubricating oils,oxidation resistance is one of the basic properties of excellent lubricating oils.At present,synthetic lubricants with cycloalkanes as the main component are widely used,but the research on the oxidation performance of these lubricants is mostly based on the macroscopic state of the oil,lacking in-depth research on oxidation molecular dynamics.In view of the current research situation,a typical monobranched cycloalkane,methylcyclohexane(MCH),was selected as the research object to conduct theoretical and experimental studies on the oxidation of methylcyclohexane at atmospheric pressure and low temperature.In terms of experiments,the low-temperature oxidation experiment in this work was completed in the National Synchrotron Radiation Laboratory of the University of Science and Technology of China.An experimental platform was established using gas chromatography mass spectrometry(GC-MS)as the main analytical instrument.A jet stirred reactor(JSR)was used to simulate the reaction environment of the low-temperature oxidation experiment of MCH,and the oxidation products of MCH in the reactor were sampled and measured.In the low-temperature oxidation experiment at equivalence ratio φ of 0.5,1.0,and 2.0,and reaction temperatures of 500-950 K,39 components including MCH were detected by GC-MS,including isomers of various molecules.The key species include: MCH,propylene,propylene,cis-2-butene,trans-2-butene,1,3-pentadiene,1,4-pentadiene,carbon monoxide,carbon dioxide,acetylene,ethane,benzene,1,3-butadiene,and so on.The mole fraction distribution profiles of these species provide a basis for subsequent model improvement.In terms of model construction,the current work has constructed a new detailed oxidation kinetic model of MCH based on that of Zou,which contains 981 species and 4272 steps of reaction.The current model was validated against and compared with the MCH low-temperature oxidation experimental data.The framework for subsequent reactions to primary free radicals was analyzed and discussed,with emphasis on the generation and consumption routes of important species and the most sensitive reaction types.Finally,in the conclusion and outlook section,the current work of this paper is summarized.And look forward to future research content: including the construction of detailed oxidation mechanisms for more component lubricants,as well as the improvement of oxidation experiments and kinetic models under various conditions.In the future,adding additives or changing the oxidation environment to suppress the reactions that contribute significantly to the oxidation reaction can serve as a research and development strategy to improve the antioxidant properties of lubricating oils.Continuing to improve the MCH oxidation mechanism can help improve the antioxidant properties of naphthenic lubricating oils.