The thermal degradation of two synthetic lubricants base oils, poly-a-olefins （PAO） and di-esters （DE）, was investigated under oxidative pyrolysis condition and their properties were characterized in simulated ＂a...The thermal degradation of two synthetic lubricants base oils, poly-a-olefins （PAO） and di-esters （DE）, was investigated under oxidative pyrolysis condition and their properties were characterized in simulated ＂areo-engine＂ by comparing the thermal stability and identifying the products of thermal decomposition as a function of exposure temperature. The characterization of the products were performed by means of Fourier transform infrared spectrometry （FTIR）, gas chromatography/mass spectrometry （GC/MS） and viscosity experiments. The results show that PAO has the lower thermal stability, being degraded at 200℃ different from 300 ℃ for DE. Several by-products are identified during the thermal degradation of two lubricant base oils. The majority of PAO products consist of alkenes and olefins, while more oxygen-contained organic compounds are detected in DE samples based on GC/MS analysis. The related reaction mechanisms are discussed based on the experimental results.展开更多
Nano-silica grease(NSG),an innovative lubricant,is commonly synthesized using base oil thickened with SiO_(2),the choice of appropriate base oil is crucial for obtaining superior performance NSG.Herein,a series of alk...Nano-silica grease(NSG),an innovative lubricant,is commonly synthesized using base oil thickened with SiO_(2),the choice of appropriate base oil is crucial for obtaining superior performance NSG.Herein,a series of alkylnaphthalene(AN)base oils with different side-chain lengths were synthesized through the alkylation reaction between naphthalene andα-olefin.We first reported the synthesis of NSGs based on the AN base oils,and investigated the influence of the synthetic AN base oils on the rheological behaviors and tribological characteristics of the resulted NSGs.The results indicated that the structural strength of the grease increased as the alkyl chain length rose because it reinforced the contact between the alkylnaphthalene base oil and nano-silica thickener.Meanwhile,tribological tests were conducted to examine the effect of various AN base oils on the lubricating performance of the formed NSGs.The tested results showed that increasing the side chain length of the AN could elevate the friction-reducing and anti-wear properties of the NSG.展开更多
This article presents the successful experience in adopting the Isodewaxing technology in the lube oil unit of Shanghai Gaoqiao refinery. In line with the demand of different crude slate for different reaction depth, ...This article presents the successful experience in adopting the Isodewaxing technology in the lube oil unit of Shanghai Gaoqiao refinery. In line with the demand of different crude slate for different reaction depth, and good match between the optimal product quality and the yield, the refinery has make strenuous efforts to optimize the operation and reduce the energy consumption to manufacture high-quality hydrogenated base stocks.展开更多
Solvent extraction is the process of separating aromatics from vacuum distillates for the production oflubricating base oils. In this study, the authors use dimethyl sulfoxide (DMSO) instead of furfural as solvent, in...Solvent extraction is the process of separating aromatics from vacuum distillates for the production oflubricating base oils. In this study, the authors use dimethyl sulfoxide (DMSO) instead of furfural as solvent, in light of itshigher selectivity, to obtain extracts with a high aromatic content for naphthenic lubricating base oils. We systematicallyinvestigated effects of the solvent-to-oil (S/O) ratio and extraction temperature on the yield of the extract, efficiency ofaromatic removal, and composition of the extracts and raffinates. The results showed that the aromatic content of extractsfor naphthenic oils could reach a high value of about 80%. The solvent maintained a high selectivity for aromatics fornaphthenic oils even under a high S/O ratio and a high extraction temperature. Moreover, the efficiency of aromatic removalfor naphthenic lubricating base oils could be enhanced by increasing either the S/O ratio or the extraction temperature,although these measures had limited effects in practice. Following this, we used the non-random two-liquid (NRTL) modelbased on the pseudo-component approach to simulate the liquid-liquid equilibrium of the system of DMSO + naphtheniclubricating base oils, and determined the parameters of binary interaction through regression based on the data on phaseequilibrium. The modeling results showed that the predicted yield, content of the solvent, and composition of the raffinatesand extracts were in good agreement with those obtained in the experiments. This validates the reliability of the model usedto represent the DMSO + naphthenic lubricating base oil system. Both the experimental data and the method of simulationreported here can help optimize the extraction of naphthenic lubricating base oils, and provide a better understanding of thecorresponding process.展开更多
Different kinds of base oils with different viscosity were analyzed in this paper, including eight mineral base oils, alkylnaphthalene and three synthetic PAO oils. The influence of different hydrocarbon molecules on ...Different kinds of base oils with different viscosity were analyzed in this paper, including eight mineral base oils, alkylnaphthalene and three synthetic PAO oils. The influence of different hydrocarbon molecules on physical properties of mineral base oils was investigated, such as density(d), kinematic viscosity(KV), viscosity index(VI), etc. Possible reasons for some inconsistent phenomena in data processing were also theoretically analyzed in detail. The refractive indexes(RI), d and molecular weight(M) decrease linearly with the increase of paraffinic content other than KV, which declines exponentially. There are no clear relationships between physical properties of base oils and naphthenic content while polycyclic alkanes show a strong correlation with M and KV. The influence of aromatics on physical properties of base oils is just the opposite of paraffin's. VI of the base oils with low aromatics content increases linearly as their paraffinic contents rise when their carbon numbers are approximately equal. However, base oils with high aromatics content follow an utterly different rule, in which VI declines dramatically linearly with the increase in polycyclic aromatic content, which is the essential reason why naphthenic base oils all have terrible viscosity-temperature characteristics while paraffinic base oils usually do not.展开更多
In the contemporary pursuit of ensuring long-term lubrication for transmission units operating under harsh conditions,significant challenges remain.Researchers have investigated porous polymer materials as potential s...In the contemporary pursuit of ensuring long-term lubrication for transmission units operating under harsh conditions,significant challenges remain.Researchers have investigated porous polymer materials as potential solutions;however,achieving exceptionally low friction and wear has proven elusive.To address this issue,we developed a novel porous fluorinated polyimide(PPIF-250)characterized by superior mechanical performance,heat resistance,and higher oil content and retention than other porous polyimide(PPI)with comparable pore sizes and porosities.Extensive lubrication testing under varying conditions has demonstrated that PPIF-250 achieves remarkably low friction and wear characteristics,even under high FV(force×velocity)values,representing a significant advancement in this field.Furthermore,our findings indicate that the polarity of base oils plays a crucial role in determining the oil content and retention of PPIF-250.Specifically,the integration of polyethylene glycol 200(PEG200)with a tailored PEG-200 structure results in significantly improved oil content,retention,and long-term lubrication relative to those of other base oils.This improvement is attributed to the formation of high-load capacity boundary films within the PPIF-250 matrix,comprising oxidation processes involving carboxyl functional groups that chelate with iron or its oxides,alongside multilayer adsorption films stabilized by intermolecular hydrogen bonding and van der Waals forces.These insights will be instrumental in the development of more efficient and effective lubrication materials to meet the demands of modern technology.展开更多
Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oi...Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM-III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grinding temperature, and energy ratio coefficient of MQL grinding were compared among the seven vegetable oil types. Results revealed that (1) castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient; (2) palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient; (3) MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil; (4) viscosity significantly influences grinding force and grinding temperature to a greater extent than fatty acid varieties and contents in vegetable oils; (5) although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less viscous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature; (6) saturated fatty acid is a more efficient lubricant than unsaturated fatty acid; and (7) a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force, 87.10 N normal grinding force, 119.6 degrees C grinding temperature, and 42.7% energy ratio coefficient. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.展开更多
The performance of a lubricant largely depends on the additives it involves.However,currently used additives cause severe pollution if they are burned and exhausted.Therefore,it is necessary to develop a new generatio...The performance of a lubricant largely depends on the additives it involves.However,currently used additives cause severe pollution if they are burned and exhausted.Therefore,it is necessary to develop a new generation of green additives.Graphene oxide(GO)consists of only C,H and O and thus is considered to be environmentally friendly.So the tribological properties of the few-layer GO sheet as an additive in hydrocarbon base oil are investigated systematically.It is found that,with the addition of GO sheets,both the coefficient of friction(COF)and wear are decreased and the working temperature range of the lubricant is expanded in the positive direction.Moreover,GO sheets has better performance under higher sliding speed and the optimized concentration of GO sheets is determined to be 0.5wt%.After rubbing,GO is detected on the wear scars through Raman spectroscopy.And it is believed that,during the rubbing,GO sheets adhere to the sliding surfaces,behaving like protective films and preventing the sliding surfaces from contacting with each other directly.This paper proves that the GO sheet is an effective lubricant additive,illuminates the lubrication mechanism,and provides some critical parameters for the practical application of GO sheets in lubrication.展开更多
Nobel metallic Pt/ZSM-22 and Pt/ZSM-23 catalysts were prepared for hydroisomerization of normal dodecane and hydrodewaxing of heavy waxy lube base oil.The hydroisomerization performance of n-dodecane indicated that th...Nobel metallic Pt/ZSM-22 and Pt/ZSM-23 catalysts were prepared for hydroisomerization of normal dodecane and hydrodewaxing of heavy waxy lube base oil.The hydroisomerization performance of n-dodecane indicated that the Pt/ZSM-23 catalyst preferred to crack the C-C bond near the middle of n-dodecane chain,while the Pt/ZSM-22 catalyst was favorable for breaking the carbon chain near the end of n-dodecane.As a result,more than 2%of light products(gas plus naphtha)and3%more of heavy lube base oil with low-pour point and high viscosity index were produced on Pt/ZSM-22 than those on Pt/ZSM-23 while using the heavy waxy vacuum distillate oil as feedstock.展开更多
Low-temperature viscosity of lube oils mixed with paraffinic base oil and naphthenic base oil at different mass ratios has been tested by experiments. The influence of paraffinic base oil on the performance of naphthe...Low-temperature viscosity of lube oils mixed with paraffinic base oil and naphthenic base oil at different mass ratios has been tested by experiments. The influence of paraffinic base oil on the performance of naphthenic base oil was investigated by studying the low-temperature viscosity of tested oils. The viscosity of lube oils increased with an increasing content of high-viscosity paraffinic base oil in the oil mixture. And the low-temperature viscosity was less influenced when the content of paraffinic base oil in the mixture was insignificant. In order to reduce the cost for formulating lubricating oil, a small fraction of paraffinic base oil can be added into naphthenic base oil as far as the property of lubricating oil can meet the specification. According to the study on low-temperature viscosity of the oil mixed with paraffinic base oil and naphthenic base oil, a basic rule was worked out for the preparation of qualified lubricating oils.展开更多
The production of poly-α-olefins(PAOs)has attracted attention due to their excellent viscosity-temperature dependence,wear characteristics,oxidative properties,and high thermal stability.In this study,indene extracte...The production of poly-α-olefins(PAOs)has attracted attention due to their excellent viscosity-temperature dependence,wear characteristics,oxidative properties,and high thermal stability.In this study,indene extracted during coal tar refining was used as a raw material to synthesize a bis(indenyl)zirconium dichloride metallocene catalyst.A PAO with low viscosity and a high viscosity index was produced via the oligomerization of 1-decene in the presence of both the prepared metallocene and a methylaluminoxane(MAO)co-catalyst.Notably,the effects of different synthesis reaction parameters,such as Al:Zr ratio,amount of catalyst,and reaction temperature,on the conversion ratio and product selectivity were investigated in detail.The produced PAO was thoroughly characterized using Fourier-transform infrared,^(13)C,and^(1)H nuclear magnetic resonance spectroscopies;gas chromatography;and viscosity measurements.At 70℃,the metallocene catalyst created more stable active sites.In addition,the alkylation effect of MAO was noticeable.Interestingly,the obtained catalysis results demonstrated that a high conversion ratio of~93%was achieved at a low reaction temperature of 70℃,with a catalyst dosage of 0.0848 mmol and Al:Zr ratio of 8.48mmol:0.0848mmol.Moreover,under these optimal conditions,the kinematic viscosity of PAO was 4.25 mm2/s at 100℃,and the viscosity index was 139,indicating good viscosity-temperature properties.展开更多
A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative ...A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.展开更多
The composition of base oils affects the performance of lubricants made from them.This paper proposes a hybrid model based on gradient-boosted decision tree(GBDT)to analyze the effect of different ratios of KN4010,PAO...The composition of base oils affects the performance of lubricants made from them.This paper proposes a hybrid model based on gradient-boosted decision tree(GBDT)to analyze the effect of different ratios of KN4010,PAO40,and PriEco3000 component in a composite base oil system on the performance of lubricants.The study was conducted under small laboratory sample conditions,and a data expansion method using the Gaussian Copula function was proposed to improve the prediction ability of the hybrid model.The study also compared four optimization algorithms,sticky mushroom algorithm(SMA),genetic algorithm(GA),whale optimization algorithm(WOA),and seagull optimization algorithm(SOA),to predict the kinematic viscosity at 40℃,kinematic viscosity at 100℃,viscosity index,and oxidation induction time performance of the lubricant.The results showed that the Gaussian Copula function data expansion method improved the prediction ability of the hybrid model in the case of small samples.The SOA-GBDT hybrid model had the fastest convergence speed for the samples and the best prediction effect,with determination coefficients(R^(2))for the four indicators of lubricants reaching 0.98,0.99,0.96 and 0.96,respectively.Thus,this model can significantly reduce the model’s prediction error and has good prediction ability.展开更多
In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related pr...In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related properties,and micromorphology.Base oils composed of different proportions of aromatic and saturated hydrocarbons as well as the styrene-butadiene-styrene(SBS)restorer were used to prepare the regenerants.The results showed that the components of the base oil of the regenerant played a crucial role in determining the characteristics and performance of the recycled SBSmodified asphalt.Regenerants containing a high proportion of aromatics dissolved the hard segment in the SBS restorer,thereby delaying the effect of a reduction in the regenerants on the performance of the aged asphalts at a high temperature.Regenerants containing a high proportion of saturates dissolved the soft segment in the SBS restorer to enhance the lowtemperature performance of the recycled asphalts.In addition,the stress sensitivity of the recycled asphalts increased with the fraction of aromatics in the regenerant.As the aromatic content of the base oil components of the regenerants increased and their saturate content decreased,the state of dispersion of the SBS phase in the recycled SBS-modified asphalts improved.The optimal content of aromatics in the base oil of the regenerants should be set in the range of 33%to 47%to ensure the adequate performance of the recycled asphalts and a high efficiency of the SBS restorer.展开更多
The integrity of the oil-gas wellbore is critically depending on the quality of the binding between cement and rock materials.Weak bond between cement and formation may lead to the potential leakage of high-pressure f...The integrity of the oil-gas wellbore is critically depending on the quality of the binding between cement and rock materials.Weak bond between cement and formation may lead to the potential leakage of high-pressure formation fluids through cracks and micro-annulus formed at the interface which results into blowout and groundwater contamination.Failure to properly displace mud prior to cementing can lead to poor bonding at the second interface(SI)of the wellbore.The main purpose of this study is to quantify the impact of oil based-filtercake on the bonding quality at the wellbore Second Interface during the drilling of sandstone reservoir well by using shear bond measurements and material characterization techniques.The results indicated that,the presence of oil based-filtercake at the SI has a detrimental effect on shear bond strength making it as weakest point of adhesion.The tested Blank samples had higher bond strength compared to treated(oil based filtercake)samples.The low bond strength for filtercake system was due to existence of oil based filtercake films which hindered the totally cement hydration process to form a strong bond as the oily film cannot allow the interact with aqueous cement slurry material to complete the hydration process.The FTIR analysis showed that,the lower transmittance(35%)at 1091 cm^(-1) band(SieO)of mud treated samples revealed the low content of chemical binder material(Calcium Silicate Hydrate-CSH)at the interface while the blank samples gave 62% at 1088 cm^(-1) band(SieO)showing the high content of CSH at the interface which led high bond strength.The results show that oil-based filtercake has a significant detrimental effect on shear bond strength of the second interface.展开更多
As an alternative to petroleum-based lubricants, which are harmful to the environment in excessive amounts, a biodegradable multiester derivative(OFANE) was obtained from plant oil through a chemical modification proc...As an alternative to petroleum-based lubricants, which are harmful to the environment in excessive amounts, a biodegradable multiester derivative(OFANE) was obtained from plant oil through a chemical modification process with four steps as follows: hydrolysis, esterification, epoxidation, and ring-opening reaction. The physical and chemical properties of OFANE, such as viscosity, acid value, pour point, evaporation loss, and oxidation induction time were measured. Results showed that OFANE had good low-temperature fluidity, thermal-oxidative stability, and tribological properties. The tribological properties of OFANE with dimeric acid additive were evaluated. The final biodegradation experiment indicated that OFANE had excellent biodegradability. The prepared OFANE showed great potential as substitute for petroleum-based lubricating base oils.展开更多
With the development of coal chemical industry,large amounts of naphthalene and n-butene are produced,and converting them into high value-added products through alkylation has gained particular importance and interest...With the development of coal chemical industry,large amounts of naphthalene and n-butene are produced,and converting them into high value-added products through alkylation has gained particular importance and interest.In this work,liquid coordination complexes(LCCs)were used as acid catalysts for the first time in the naphthalene alkylation reaction under mild conditions to obtain multibutylnaphthalenes with high yield.Various reaction conditions were thoroughly investigated.The LCC consisting of urea and AlCl_(3) showed excellent catalytic performance under optimal reaction conditions,giving 100%conversion of naphthalene and 99.66%selectivity towards multi-butylnaphthalenes.Combining the catalyst properties and catalytic results,a plausible reaction mechanism was proposed.The lubricating properties of the synthesized products were investigated for their potential application as lubricating base oils.The synthesized multi-butylnaphthalenes showed comparable physicochemical properties and tribological performances as the commercial cycloalkyl base oil.展开更多
Lubrication recovery has been observed in tribology research.This refers to the recovery of oil lubrication on a metal after failure or semi-failure by waiting for a period.Past studies attributed this recovery to met...Lubrication recovery has been observed in tribology research.This refers to the recovery of oil lubrication on a metal after failure or semi-failure by waiting for a period.Past studies attributed this recovery to metal oxidation.However,this article presented an alternative mechanism.We proposed that the accumulation of carbon-containing tribofilms from hydrocarbon oils was crucial for lubrication recovery.Changes in surface states,such as increased contact areas,also play a significant role.For studying wear mechanism maps,it is essential to consider both working conditions and surface states.Two new wear mechanism maps based on initial surfaces with or without pregenerated tribofilm were developed.These findings highlight the mechanochemical effects of base oils on lubrication and anti-wear performance.展开更多
Polymerization of mixed alpha-olefins originating from the Fischer-Tropsch synthesis catalyzed by theBu)_3/[Me_2NHPh]^+[B(C_6F_5)_4]^-,was studied.The effects of the Zr/olefin mole ratio,Al/Zr mole ratio,reaction temp...Polymerization of mixed alpha-olefins originating from the Fischer-Tropsch synthesis catalyzed by theBu)_3/[Me_2NHPh]^+[B(C_6F_5)_4]^-,was studied.The effects of the Zr/olefin mole ratio,Al/Zr mole ratio,reaction temperature,and reaction time on the viscosity and molecular weight of the product were investigated.The conversion under optimized conditions reached 97.3%.The product structure was characterized by ^(13)C NMR spectrometry and ~1H NMR spectrometry,and the conversion of olefins with different carbon numbers under different conditions was determined by GC analysis.The polymer obtained under optimized conditions has a high viscosity index of 262 with a narrow molecular weight distribution of 1.95,which is a desired component for lubricating base oil.展开更多
基金Supported by the Fund from the Air Force Armament Department of China for Innovative Research Group(Grant KJ2012283)
文摘The thermal degradation of two synthetic lubricants base oils, poly-a-olefins （PAO） and di-esters （DE）, was investigated under oxidative pyrolysis condition and their properties were characterized in simulated ＂areo-engine＂ by comparing the thermal stability and identifying the products of thermal decomposition as a function of exposure temperature. The characterization of the products were performed by means of Fourier transform infrared spectrometry （FTIR）, gas chromatography/mass spectrometry （GC/MS） and viscosity experiments. The results show that PAO has the lower thermal stability, being degraded at 200℃ different from 300 ℃ for DE. Several by-products are identified during the thermal degradation of two lubricant base oils. The majority of PAO products consist of alkenes and olefins, while more oxygen-contained organic compounds are detected in DE samples based on GC/MS analysis. The related reaction mechanisms are discussed based on the experimental results.
基金financial support by Shanxi Province Basic Research Program Joint Funding Project(Lu'an)(202403011242003)National Natural Science Foundation(U1910202)the Special fund for Science and Technology Innovation Teams of Shanxi Province(201705D131028-9)are gratefully acknowledged。
文摘Nano-silica grease(NSG),an innovative lubricant,is commonly synthesized using base oil thickened with SiO_(2),the choice of appropriate base oil is crucial for obtaining superior performance NSG.Herein,a series of alkylnaphthalene(AN)base oils with different side-chain lengths were synthesized through the alkylation reaction between naphthalene andα-olefin.We first reported the synthesis of NSGs based on the AN base oils,and investigated the influence of the synthetic AN base oils on the rheological behaviors and tribological characteristics of the resulted NSGs.The results indicated that the structural strength of the grease increased as the alkyl chain length rose because it reinforced the contact between the alkylnaphthalene base oil and nano-silica thickener.Meanwhile,tribological tests were conducted to examine the effect of various AN base oils on the lubricating performance of the formed NSGs.The tested results showed that increasing the side chain length of the AN could elevate the friction-reducing and anti-wear properties of the NSG.
文摘This article presents the successful experience in adopting the Isodewaxing technology in the lube oil unit of Shanghai Gaoqiao refinery. In line with the demand of different crude slate for different reaction depth, and good match between the optimal product quality and the yield, the refinery has make strenuous efforts to optimize the operation and reduce the energy consumption to manufacture high-quality hydrogenated base stocks.
基金the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01F37).
文摘Solvent extraction is the process of separating aromatics from vacuum distillates for the production oflubricating base oils. In this study, the authors use dimethyl sulfoxide (DMSO) instead of furfural as solvent, in light of itshigher selectivity, to obtain extracts with a high aromatic content for naphthenic lubricating base oils. We systematicallyinvestigated effects of the solvent-to-oil (S/O) ratio and extraction temperature on the yield of the extract, efficiency ofaromatic removal, and composition of the extracts and raffinates. The results showed that the aromatic content of extractsfor naphthenic oils could reach a high value of about 80%. The solvent maintained a high selectivity for aromatics fornaphthenic oils even under a high S/O ratio and a high extraction temperature. Moreover, the efficiency of aromatic removalfor naphthenic lubricating base oils could be enhanced by increasing either the S/O ratio or the extraction temperature,although these measures had limited effects in practice. Following this, we used the non-random two-liquid (NRTL) modelbased on the pseudo-component approach to simulate the liquid-liquid equilibrium of the system of DMSO + naphtheniclubricating base oils, and determined the parameters of binary interaction through regression based on the data on phaseequilibrium. The modeling results showed that the predicted yield, content of the solvent, and composition of the raffinatesand extracts were in good agreement with those obtained in the experiments. This validates the reliability of the model usedto represent the DMSO + naphthenic lubricating base oil system. Both the experimental data and the method of simulationreported here can help optimize the extraction of naphthenic lubricating base oils, and provide a better understanding of thecorresponding process.
文摘Different kinds of base oils with different viscosity were analyzed in this paper, including eight mineral base oils, alkylnaphthalene and three synthetic PAO oils. The influence of different hydrocarbon molecules on physical properties of mineral base oils was investigated, such as density(d), kinematic viscosity(KV), viscosity index(VI), etc. Possible reasons for some inconsistent phenomena in data processing were also theoretically analyzed in detail. The refractive indexes(RI), d and molecular weight(M) decrease linearly with the increase of paraffinic content other than KV, which declines exponentially. There are no clear relationships between physical properties of base oils and naphthenic content while polycyclic alkanes show a strong correlation with M and KV. The influence of aromatics on physical properties of base oils is just the opposite of paraffin's. VI of the base oils with low aromatics content increases linearly as their paraffinic contents rise when their carbon numbers are approximately equal. However, base oils with high aromatics content follow an utterly different rule, in which VI declines dramatically linearly with the increase in polycyclic aromatic content, which is the essential reason why naphthenic base oils all have terrible viscosity-temperature characteristics while paraffinic base oils usually do not.
基金financially supported by the Natural Science Foundation of Henan Province of China(Grant No.222300420124)the National Natural Science Foundation of China(Grant No.52175199)+1 种基金the Tribology Science Fund of the State Key Laboratory of Tribology in Advanced Equipment at Tsinghua University(Grant No.SKLTKF22B07)the National United Engineering Laboratory for Advanced Bearing Tribology(Grant No.202305)at Henan University of Science and Technology.
文摘In the contemporary pursuit of ensuring long-term lubrication for transmission units operating under harsh conditions,significant challenges remain.Researchers have investigated porous polymer materials as potential solutions;however,achieving exceptionally low friction and wear has proven elusive.To address this issue,we developed a novel porous fluorinated polyimide(PPIF-250)characterized by superior mechanical performance,heat resistance,and higher oil content and retention than other porous polyimide(PPI)with comparable pore sizes and porosities.Extensive lubrication testing under varying conditions has demonstrated that PPIF-250 achieves remarkably low friction and wear characteristics,even under high FV(force×velocity)values,representing a significant advancement in this field.Furthermore,our findings indicate that the polarity of base oils plays a crucial role in determining the oil content and retention of PPIF-250.Specifically,the integration of polyethylene glycol 200(PEG200)with a tailored PEG-200 structure results in significantly improved oil content,retention,and long-term lubrication relative to those of other base oils.This improvement is attributed to the formation of high-load capacity boundary films within the PPIF-250 matrix,comprising oxidation processes involving carboxyl functional groups that chelate with iron or its oxides,alongside multilayer adsorption films stabilized by intermolecular hydrogen bonding and van der Waals forces.These insights will be instrumental in the development of more efficient and effective lubrication materials to meet the demands of modern technology.
基金co-supported by the National Natural Science Foundation of China (Nos. 51175276 and 51575290)the Qingdao Science and Technology Program of Basic Research Projects (No. 14-2-4-18-jch) of Chinathe Huangdao District Application Science and Technology Project (No. 2014-1-55) of China
文摘Vegetable oil can be used as a base oil in minimal quantity of lubrication (MQL). This study compared the performances of MQL grinding by using castor oil, soybean oil, rapeseed oil, corn oil, sunflower oil, peanut oil, and palm oil as base oils. A K-P36 numerical-control precision surface grinder was used to perform plain grinding on a workpiece material with a high-temperature nickel base alloy. A YDM-III 99 three-dimensional dynamometer was used to measure grinding force, and a clip-type thermocouple was used to determine grinding temperature. The grinding force, grinding temperature, and energy ratio coefficient of MQL grinding were compared among the seven vegetable oil types. Results revealed that (1) castor oil-based MQL grinding yields the lowest grinding force but exhibits the highest grinding temperature and energy ratio coefficient; (2) palm oil-based MQL grinding generates the second lowest grinding force but shows the lowest grinding temperature and energy ratio coefficient; (3) MQL grinding based on the five other vegetable oils produces similar grinding forces, grinding temperatures, and energy ratio coefficients, with values ranging between those of castor oil and palm oil; (4) viscosity significantly influences grinding force and grinding temperature to a greater extent than fatty acid varieties and contents in vegetable oils; (5) although more viscous vegetable oil exhibits greater lubrication and significantly lower grinding force than less viscous vegetable oil, high viscosity reduces the heat exchange capability of vegetable oil and thus yields a high grinding temperature; (6) saturated fatty acid is a more efficient lubricant than unsaturated fatty acid; and (7) a short carbon chain transfers heat more effectively than a long carbon chain. Palm oil is the optimum base oil of MQL grinding, and this base oil yields 26.98 N tangential grinding force, 87.10 N normal grinding force, 119.6 degrees C grinding temperature, and 42.7% energy ratio coefficient. (C) 2015 The Authors. Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.
基金Supported by National Natural Science Foundation of China(Grant Nos.51335005,51321092)National Key Basic Research Program of China(973 Program,Grant No.2013CB934200)the Foundation for the Supervisor of Beijing Excellent Doctoral Dissertation(Grant No.20111000305)
文摘The performance of a lubricant largely depends on the additives it involves.However,currently used additives cause severe pollution if they are burned and exhausted.Therefore,it is necessary to develop a new generation of green additives.Graphene oxide(GO)consists of only C,H and O and thus is considered to be environmentally friendly.So the tribological properties of the few-layer GO sheet as an additive in hydrocarbon base oil are investigated systematically.It is found that,with the addition of GO sheets,both the coefficient of friction(COF)and wear are decreased and the working temperature range of the lubricant is expanded in the positive direction.Moreover,GO sheets has better performance under higher sliding speed and the optimized concentration of GO sheets is determined to be 0.5wt%.After rubbing,GO is detected on the wear scars through Raman spectroscopy.And it is believed that,during the rubbing,GO sheets adhere to the sliding surfaces,behaving like protective films and preventing the sliding surfaces from contacting with each other directly.This paper proves that the GO sheet is an effective lubricant additive,illuminates the lubrication mechanism,and provides some critical parameters for the practical application of GO sheets in lubrication.
基金financial supports by National Key R&D Program of China(Grant No.2017YFB0306702)are gratefully acknowledged。
文摘Nobel metallic Pt/ZSM-22 and Pt/ZSM-23 catalysts were prepared for hydroisomerization of normal dodecane and hydrodewaxing of heavy waxy lube base oil.The hydroisomerization performance of n-dodecane indicated that the Pt/ZSM-23 catalyst preferred to crack the C-C bond near the middle of n-dodecane chain,while the Pt/ZSM-22 catalyst was favorable for breaking the carbon chain near the end of n-dodecane.As a result,more than 2%of light products(gas plus naphtha)and3%more of heavy lube base oil with low-pour point and high viscosity index were produced on Pt/ZSM-22 than those on Pt/ZSM-23 while using the heavy waxy vacuum distillate oil as feedstock.
文摘Low-temperature viscosity of lube oils mixed with paraffinic base oil and naphthenic base oil at different mass ratios has been tested by experiments. The influence of paraffinic base oil on the performance of naphthenic base oil was investigated by studying the low-temperature viscosity of tested oils. The viscosity of lube oils increased with an increasing content of high-viscosity paraffinic base oil in the oil mixture. And the low-temperature viscosity was less influenced when the content of paraffinic base oil in the mixture was insignificant. In order to reduce the cost for formulating lubricating oil, a small fraction of paraffinic base oil can be added into naphthenic base oil as far as the property of lubricating oil can meet the specification. According to the study on low-temperature viscosity of the oil mixed with paraffinic base oil and naphthenic base oil, a basic rule was worked out for the preparation of qualified lubricating oils.
基金supported by the Chinese Academy of Sciences Strategic Pilot Science and Technology Special (Class A)(XDA21020000)the National Natural Science Foundation of China (22072175,21673272)support from the Ulam program,awarded by the Polish National Agency for Academic Exchange (NAWA),Poland,under project No.PPN/ULM/2020/1/00006/DEC/1
文摘The production of poly-α-olefins(PAOs)has attracted attention due to their excellent viscosity-temperature dependence,wear characteristics,oxidative properties,and high thermal stability.In this study,indene extracted during coal tar refining was used as a raw material to synthesize a bis(indenyl)zirconium dichloride metallocene catalyst.A PAO with low viscosity and a high viscosity index was produced via the oligomerization of 1-decene in the presence of both the prepared metallocene and a methylaluminoxane(MAO)co-catalyst.Notably,the effects of different synthesis reaction parameters,such as Al:Zr ratio,amount of catalyst,and reaction temperature,on the conversion ratio and product selectivity were investigated in detail.The produced PAO was thoroughly characterized using Fourier-transform infrared,^(13)C,and^(1)H nuclear magnetic resonance spectroscopies;gas chromatography;and viscosity measurements.At 70℃,the metallocene catalyst created more stable active sites.In addition,the alkylation effect of MAO was noticeable.Interestingly,the obtained catalysis results demonstrated that a high conversion ratio of~93%was achieved at a low reaction temperature of 70℃,with a catalyst dosage of 0.0848 mmol and Al:Zr ratio of 8.48mmol:0.0848mmol.Moreover,under these optimal conditions,the kinematic viscosity of PAO was 4.25 mm2/s at 100℃,and the viscosity index was 139,indicating good viscosity-temperature properties.
基金Supported by the National Natural Science Foundation of China(21306088)National Key Technologies R&D Program of China(2015BAD15B07)+1 种基金State Key Laboratory of Chemical Engineering(SKL-Ch E-13A01,Tsinghua University,China)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,China)
文摘A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior,viscosity index,thermostability,oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate.Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions.The order of effectiveness of acid binding agent was N,N-diisopropylethylamine(DIEA) > pyridine > diethylamine > triethylamine,and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied.A maximum yield of 34.54%was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of1:1.25:1,reaction temperature 40℃,reaction time 1.5 h.
基金financial support extended for this academic work by the Beijing Natural Science Foundation(Grant 2232066)the Open Project Foundation of State Key Laboratory of Solid Lubrication(Grant LSL-2212).
文摘The composition of base oils affects the performance of lubricants made from them.This paper proposes a hybrid model based on gradient-boosted decision tree(GBDT)to analyze the effect of different ratios of KN4010,PAO40,and PriEco3000 component in a composite base oil system on the performance of lubricants.The study was conducted under small laboratory sample conditions,and a data expansion method using the Gaussian Copula function was proposed to improve the prediction ability of the hybrid model.The study also compared four optimization algorithms,sticky mushroom algorithm(SMA),genetic algorithm(GA),whale optimization algorithm(WOA),and seagull optimization algorithm(SOA),to predict the kinematic viscosity at 40℃,kinematic viscosity at 100℃,viscosity index,and oxidation induction time performance of the lubricant.The results showed that the Gaussian Copula function data expansion method improved the prediction ability of the hybrid model in the case of small samples.The SOA-GBDT hybrid model had the fastest convergence speed for the samples and the best prediction effect,with determination coefficients(R^(2))for the four indicators of lubricants reaching 0.98,0.99,0.96 and 0.96,respectively.Thus,this model can significantly reduce the model’s prediction error and has good prediction ability.
基金the National Key R&D Program of China(2021YFB2601200)the Science and Technology Project of Department of Communication of Zhejiang Province(2021043).
文摘In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related properties,and micromorphology.Base oils composed of different proportions of aromatic and saturated hydrocarbons as well as the styrene-butadiene-styrene(SBS)restorer were used to prepare the regenerants.The results showed that the components of the base oil of the regenerant played a crucial role in determining the characteristics and performance of the recycled SBSmodified asphalt.Regenerants containing a high proportion of aromatics dissolved the hard segment in the SBS restorer,thereby delaying the effect of a reduction in the regenerants on the performance of the aged asphalts at a high temperature.Regenerants containing a high proportion of saturates dissolved the soft segment in the SBS restorer to enhance the lowtemperature performance of the recycled asphalts.In addition,the stress sensitivity of the recycled asphalts increased with the fraction of aromatics in the regenerant.As the aromatic content of the base oil components of the regenerants increased and their saturate content decreased,the state of dispersion of the SBS phase in the recycled SBS-modified asphalts improved.The optimal content of aromatics in the base oil of the regenerants should be set in the range of 33%to 47%to ensure the adequate performance of the recycled asphalts and a high efficiency of the SBS restorer.
文摘The integrity of the oil-gas wellbore is critically depending on the quality of the binding between cement and rock materials.Weak bond between cement and formation may lead to the potential leakage of high-pressure formation fluids through cracks and micro-annulus formed at the interface which results into blowout and groundwater contamination.Failure to properly displace mud prior to cementing can lead to poor bonding at the second interface(SI)of the wellbore.The main purpose of this study is to quantify the impact of oil based-filtercake on the bonding quality at the wellbore Second Interface during the drilling of sandstone reservoir well by using shear bond measurements and material characterization techniques.The results indicated that,the presence of oil based-filtercake at the SI has a detrimental effect on shear bond strength making it as weakest point of adhesion.The tested Blank samples had higher bond strength compared to treated(oil based filtercake)samples.The low bond strength for filtercake system was due to existence of oil based filtercake films which hindered the totally cement hydration process to form a strong bond as the oily film cannot allow the interact with aqueous cement slurry material to complete the hydration process.The FTIR analysis showed that,the lower transmittance(35%)at 1091 cm^(-1) band(SieO)of mud treated samples revealed the low content of chemical binder material(Calcium Silicate Hydrate-CSH)at the interface while the blank samples gave 62% at 1088 cm^(-1) band(SieO)showing the high content of CSH at the interface which led high bond strength.The results show that oil-based filtercake has a significant detrimental effect on shear bond strength of the second interface.
基金financial support from the Special Project for Scientific and Technological Innovation of Social Undertakings and People’s Livelihood Guarantee of Chongqing Science and Technology Commission.(Project No.cstc2017shms-zdyfX0066)。
文摘As an alternative to petroleum-based lubricants, which are harmful to the environment in excessive amounts, a biodegradable multiester derivative(OFANE) was obtained from plant oil through a chemical modification process with four steps as follows: hydrolysis, esterification, epoxidation, and ring-opening reaction. The physical and chemical properties of OFANE, such as viscosity, acid value, pour point, evaporation loss, and oxidation induction time were measured. Results showed that OFANE had good low-temperature fluidity, thermal-oxidative stability, and tribological properties. The tribological properties of OFANE with dimeric acid additive were evaluated. The final biodegradation experiment indicated that OFANE had excellent biodegradability. The prepared OFANE showed great potential as substitute for petroleum-based lubricating base oils.
基金the National Natural Science Foundation of China(U1910202,21978194 and 21603256)the Natural Science Foundation of Shanxi Province(201801D121055)Program for the Shanxi Young Sanjin Scholar.
文摘With the development of coal chemical industry,large amounts of naphthalene and n-butene are produced,and converting them into high value-added products through alkylation has gained particular importance and interest.In this work,liquid coordination complexes(LCCs)were used as acid catalysts for the first time in the naphthalene alkylation reaction under mild conditions to obtain multibutylnaphthalenes with high yield.Various reaction conditions were thoroughly investigated.The LCC consisting of urea and AlCl_(3) showed excellent catalytic performance under optimal reaction conditions,giving 100%conversion of naphthalene and 99.66%selectivity towards multi-butylnaphthalenes.Combining the catalyst properties and catalytic results,a plausible reaction mechanism was proposed.The lubricating properties of the synthesized products were investigated for their potential application as lubricating base oils.The synthesized multi-butylnaphthalenes showed comparable physicochemical properties and tribological performances as the commercial cycloalkyl base oil.
基金supported by the National Natural Science Foundation of China(Nos.51425502,52175176,and 52205206)the Beijing Municipal Natural Science Foundation of China(No.2202020).
文摘Lubrication recovery has been observed in tribology research.This refers to the recovery of oil lubrication on a metal after failure or semi-failure by waiting for a period.Past studies attributed this recovery to metal oxidation.However,this article presented an alternative mechanism.We proposed that the accumulation of carbon-containing tribofilms from hydrocarbon oils was crucial for lubrication recovery.Changes in surface states,such as increased contact areas,also play a significant role.For studying wear mechanism maps,it is essential to consider both working conditions and surface states.Two new wear mechanism maps based on initial surfaces with or without pregenerated tribofilm were developed.These findings highlight the mechanochemical effects of base oils on lubrication and anti-wear performance.
文摘Polymerization of mixed alpha-olefins originating from the Fischer-Tropsch synthesis catalyzed by theBu)_3/[Me_2NHPh]^+[B(C_6F_5)_4]^-,was studied.The effects of the Zr/olefin mole ratio,Al/Zr mole ratio,reaction temperature,and reaction time on the viscosity and molecular weight of the product were investigated.The conversion under optimized conditions reached 97.3%.The product structure was characterized by ^(13)C NMR spectrometry and ~1H NMR spectrometry,and the conversion of olefins with different carbon numbers under different conditions was determined by GC analysis.The polymer obtained under optimized conditions has a high viscosity index of 262 with a narrow molecular weight distribution of 1.95,which is a desired component for lubricating base oil.
