Lubricating Oil Research Articles

Shape selection of alkane hydroisomerization over one-dimensional zeolite supported Pt catalyst: Pt/ZSM-48 versus Pt/ZSM-22

Hydroisomerization of long-chain n-alkanes plays a vital role in petrochemical and coal chemical industries, because it can produce high-quality hydrocarbon fuels and lubricant base oils. ZSM-48 (0.56 × 0.53 nm) and ZSM-22 (0.57 nm × 0.46 nm) are characteristic of one-dimensional 10-member ring zeolites suitable for n-alkanes hydroisomerization reaction. Here, the effect of the structure difference between ZSM-48 and ZSM-22 zeolites on hydroisomerization is titrated by the isobutane and n-dodecane. The product distribution of hydroisomerization of isobutane to n-butane shows the reaction pathway on Pt/ZSM-48 and Pt/ZSM-22, in which the monomolecular hydroisomerization of isobutane is involved within the active sites in zeolite channels, while the polymerization-cracking bimolecular reaction occurs on the pore-mouth of zeolite. Pt/ZSM-48 zeolite, possessing larger channel and aperture size than those of Pt/ZSM-22, is more conducive to the diffusion of butane molecules and bimolecular polymerization. Therefore, the isobutane conversion (14 %) on Pt/ZSM-48 produces less C1+C2 (1.7 wt% vs. 3.4 wt%) and more C3+C5+C8 (19.2 wt% vs. 16.9 wt%). For the hydroisomerization of n-dodecane, the iso-dodecane selectivity of Pt/ZSM-48 (43.3 wt%) is significantly higher than that of Pt/ZSM-22 (12.4 wt%) at the similar n-C12 conversion (40 %). Compare with the isomers of Pt/ZSM-22, the mono-branched isomers with methyl near the middle of the chains and multi-branched isomers are more easily formed on Pt/ZSM-48, which is conducive to the “key-lock” catalysis mechanism. The larger pore size of ZSM-48 is conducive to n-C12 insertion into zeolite pores, methyl migration and isomer diffusion, and its adjacent pores are more compatible with double-branched isomers. In addition, a high selectivity of C4∼C5 alkanes (53.2 wt%) on Pt/ZSM-22 and a high selectivity of C6∼C9 alkanes (44.7 wt%) on Pt/ZSM-48 show obvious difference in cracking product distribution, implying different position of methyl groups in i-C12 isomers on Pt/ZSM-22 and Pt/ZSM-48 samples, respectively. The present comparison between Pt/ZSM-48 and Pt/ZSM-22 benefits the selection and development of one-dimensional zeolitesupported metal catalyst in a wide range of hydro-processing reactions.

Investigation of Surface Integrity of 304 Stainless Steel in Turning Process with Nanofluid Minimum-Quantity Lubrication Using h-BN Nanoparticles

This paper investigates the influence of the concentration and particle size of h-BN nanoparticles in a nanofluid on the surface integrity of 304 austenitic stainless steel during turning, focusing on the cutting force, friction coefficient, cutting temperature, surface roughness, surface residual stress, work hardening capacity, and 3D surface topography. The results show that, compared to dry cutting, the addition of 3 wt.% h-BN nanofluid can reduce the friction coefficient on the rake face by 38.9%, lower the cutting temperature by 43.5%, decrease the surface roughness by 53.8%, decrease the surface residual stress by 61.6%, and reduce the work hardening degree by 27.5%. Two-dimensional profiles and the 3D surface topography display a more balanced peak–valley distribution. Furthermore, by studying the effect of different h-BN particle sizes in nanofluids on the surface integrity of the machined workpiece, it was found that nanoscale particles have a greater tendency to penetrate the tool–chip interface than submicron particles. Moreover, the h-BN particles in the nanofluid play a “rolling effect” and “microsphere” effect, and the sesame oil will also form a lubricating oil film in the knife-chip contact area, thereby reducing the friction coefficient, reducing the cutting force, and improving the machining surface quality.

Effect of nano-graphene lubricating oil on particulate matter of a diesel engine

Nano-graphene lubricating oil with appropriate concentration shows excellent performance in reducing friction and wear under different working conditions of diesel engines, and has been widely concerned. Lubricating oil has a significant impact on particulate matter (PM) emissions. At present, there are few studies on the impact of nano-graphene lubricating oil on the physicochemical properties of PM. In order to comprehensively evaluate the impact of nano-graphene lubricating oil on diesel engines, this paper mainly focused on the effects of lubricating oil nano-graphene additives on the particle size distribution and physicochemical properties of PM. The results show that, compared with pure lubricating oil, the total number of nuclear PM and accumulated PM of nano-graphene lubricating oil is significantly increased. The fractal dimension of PM of nano-graphene lubricating oil increases and its structure becomes more compact. The average fringe separation distance of basic carbon particles decreases, the average fringe length increases. The degree of ordering and graphitization of basic carbon particles are higher. The fringe tortuosity of basic carbon particles decreases, and the fluctuation of carbon layer structure of basic carbon particles decreases. Aliphatic substances in PM are basically unchanged, aromatic components and oxygen functional groups increase. The initial PM oxidation temperature and burnout temperature increase, the maximum oxidation rate temperature and combustion characteristic index decrease, and the activation energy increases, making it more difficult to oxidize. This was mainly caused by the higher graphitization degree of PM of nano-graphene lubricating oil and the increased content of aromatic substances.

The Effect of Lubricity of Calcium Sulfonate on ZnDTP and MoDTC

Reduction of friction and wear by lubrication is necessary to improve the efficiency and prolong the lifespan of industrial machinery. However, several aspects regarding the lubrication effects in additive-combined oil are still unresolved. This study focuses on the effects of combining zinc dialkyldithiophosphate (ZnDTP), molybdenum dithiocarbamate (MoDTC), and Ca sulfonate on the frictional behavior of poly-α-olefin 4 (PAO4) lubricant oils. Ball-on-disk friction tests demonstrated that the exclusive addition of high-base Ca sulfonate solution reduced friction and wear of the lubricating oil. When combined with ZnDTP and MoDTC, the friction coefficients of PAO with high-base and low-base Ca sulfonate are affected by competitive reactions on the sliding surface. Quartz crystal microbalance with dissipation monitoring measurements suggests that high-base Ca sulfonate forms a stronger adsorption film than low-base Ca sulfonate. Atomic force microscope observations confirmed that the addition of low-base Ca sulfonate reduced friction and wear, whereas high-base Ca sulfonate induced competitive reactions with ZnDTP and MoDTC. This study provides valuable insights into the effects of the combination of additives on the lubricity of PAO and their impact on friction and wear characteristics, which are valuable for the design of suitable lubricants for industrial machinery.

Spatial-temporal modeling of oil condition monitoring: A review

Lubricating oil plays a vital role as the information carrier for equipment tribological performance. Therefore, oil condition monitoring (OCM) serves as a crucial technology for assessing and predicting state degradation, providing the first-line defense against functional failure. However, limited by random fluctuation and insufficient knowledge, the modeling of OCM has suffered from uncertainty problems, leading to poor applicability and insufficient generalizability. The existing reviews are less elaborated on the information uncertainty for description, characterization, and treatment, which expresses the essence of modeling constraints. To bridge this gap, the paper provides a comprehensive review of the oil state modeling in terms of uncertainty. The existing methods and metrics are reviewed from the perspective of the spatial oil state assessment (OCA) and temporal remaining useful life (RUL) prediction modeling. Further, the existing methods are analyzed to solve the uncertainty problem, and then the solutions in oil state modeling considering uncertainty are discussed. Finally, targeting the challenges of the monitoring technology, the future trends of OCM are presented.

Recent Patents on Rolling Bearing Lubrication Device

Background: Rolling bearings are the core components of mechanical equipment. Lubrication plays an important role in the operating performance of rolling bearings. The research on rolling bearing lubrication devices is beneficial to making the bearings obtain the characteristics which is suitable for the working conditions and improving the bearing's service life. Compared with the traditional lubrication devices, the new ones provide assistance to various bearings, solving many problems. Objective: To review the latest research on rolling bearing lubrication devices, analyze their solutions to rolling bearing lubrication problems, and discuss their advantages and disadvantages for the reference of scholars and engineers. Methods: The representative patents related to rolling bearing lubrication devices are reviewed according to the lubrication method of bearings, including oil lubrication, grease lubrication and solid lubrication. Oil lubrication includes oil mist lubrication, oil-air lubrication, jet lubrication, under ring lubrication and immersion oil lubrication, etc. Grease lubrication includes external and internal lubrication methods. The working principle and characteristics are explained by analyzing the structure of bearing lubrication devices. Results: By comparing different types of rolling bearing lubrication devices, the main problems of the current lubrication devices are summarized and analyzed. The future development of rolling bearing lubrication devices are prospected. Conclusion: The improvement of rolling bearing lubrication devices is conducive to developing bearing lubrication technology. Advanced mechanical equipments require the rolling bearing lubrication devices to have a simple structure, intelligence, and are easy to be installed.

Improve the thermal properties of oil‐loaded polysulfone microcapsules by optimizing copper layer for self‐lubricating polyamide

AbstractThis work reports polymer/metal double‐shell microcapsules with polysulfone (PSF) and copper as walls for application in self‐lubricating polymer. First, polyalphaolefin 40 (PAO40) was selected as lubricant oil, and PAO@PSF single shell microcapsules were prepared. A critical issue for the formation of copper layer is the sensitization of PSF shell, which can affect not only the adhesion between PSF shell and copper layer, but also the density of copper layer. The sensitization conditions were discussed in detail, and the corresponding effect on the formation of copper layer was evaluated. PAO@PSF/Cu microcapsules obtained under optimal sensitization condition were characterized by scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), x‐ray energy dispersive spectrometer (EDS) and fourier transform infrared spectroscopy (FTIR). A uniform and compact copper layer improved the thermal properties of microcapsules. PSF/Cu microcapsules maintained relatively complete spherical shape when were heated to 300°C, while the PSF microcapsule softened and deformed at 200°C. The self‐lubricating polyamide 6(PA6) composites containing PAO@PSF/Cu microcapsules were fabricated at 230°C, microcapsules maintained complete structure and uniform distributed in the polymer matrix. Coefficient of friction (COF) and wear rate of PA6 composites were tested under different friction conditions. Compared with pure PA6, 15 wt.% PAO@PSF/Cu microcapsules could reduce the COF by 79.5%, and the wear rate was decreased by 98.3% under 300 rpm sliding speed and 50 N friction load.Highlights PSF/Cu double‐shell oil‐loaded microcapsules were designed and prepared. The copper layer effectively improved the thermal properties of microcapsules. The self‐lubricating PA6 composite exhibited excellent tribological properties.

Experimental elucidation of performance of four extracting solvents for reclamation of spent lubricating oil using extraction–flocculation process

Experimental elucidation of performance of four extracting solvents for reclamation of spent lubricating oil using extraction–flocculation process

Modeling of Selected Parameters of Used Lubricating Oil Diluted with Diesel Oil Using the Characteristics of Fresh Lubricating Oil

This article presents the verification of the hypothesis on using certain approximation curves in the evaluation of used lubricating oil. These curves are plotted for fresh lubricating oil to approximate the parameters of lubricating oil diluted with diesel oil. To confirm the hypothesis, an experiment is conducted to determine the flash point, initial boiling point, density at 15 °C, kinematic viscosity at 40 °C and 100 °C, and viscosity index. The analysis covers fresh oil and used SAE 30 grade Marinol CB-30 RG1230 oil taken from the circulating lubrication system of a supercharged, trunk-piston, 4-stroke ZUT Zgoda Sulzer 5 BAH 22 engine that is located in the Marine Power Plant Laboratory of the Maritime University of Szczecin. Undiluted lubricating oils (both fresh and used) and mixtures of lubricating oils with diesel oil are examined for diesel oil concentrations in the mixture equal to 1, 2, 5, 10, 15, and 20% m/m. Orlen Efecta Diesel Biodiesel is used to prepare the mixtures. The functions approximating the parameters for fresh oil are determined and adapted to describe the variation of the same parameters for the used lubricating oil. For each case, the coefficient of determination, the maximum relative error of the model fitting to the experimental results, and the root mean square error (RMSE) are determined. In the experiment, the variation in the parameters of the used lubricating oil remained the same as for fresh oil parameters. Thus, the research hypothesis is confirmed.

Utilization of Jatropha oil as a lubricant

Due to the environmental concern and limited resources of petroleum oil and with the growing concern regarding global warming issues, the research for clean alternative biolubricants sources became a must. Among the most demanded sustainable clean energy sources is the Jatropha oil. The leached Jatropha oil used in this research work has explored the possibility of utilizing Jatropha oil as a lubricant and was analyzed for density, viscosity at (40 C?, 100 C?) viscosity index, and the flashpoint which are necessary tests for base oil. Explore the commercial additives for the improvement of the Jatropha oil as a lubricant and comparison of the improved Jatropha oil lubricant against other commercial lubricant oils. The results show that all these properties are satisfactory and give good agreement. In this study, the Jatropha oil was found to be compatible with the required additives which are specified by API BASE OIL CATEGORIES. The experimental tests for these properties were performed as prescribed ASTM procedures, and the results were tabulated and discussed.

Research on tribological performance of textured thrust bearing using gray relational degree and improved multi-objective water circulation algorithm

To enhance the loading capacity of the oil film, reduce the lubricating oil temperature, and minimize the deformation of the friction pairs, three types of concave textures were proposed. The tribological properties of the thrust bearing underwent multi-objective optimization analysis using the two different methods. By comparing the two methods, it was found that the improved algorithm (MOWCA) demonstrated better optimization performance. Under this algorithm, when the texture shape was triangular, the number of textures was 18n, the size was approximately 0.135 mm, and the spacing between textures was approximately 4.6 mm, the loading capacity of the oil film increased by approximately 26.8%, and the temperature decreased by approximately 0.46%.

Sustainable assessment of low viscous biofuel for compression ignition engine using wear debris analysis – Tribological investigation

Lemon Peel oil is one of the ecologically friendly biofuels has many significant benefits for power generation applications. Lemon peel oil is extracted from left over rinds of lemon peel by applying steam distillation process. In the present work, long term durability study of compression ignition engines has been conducted using 10 % and 20 % low viscous biofuels with diesel. For 256 h long term durability investigation, wear debris, ferrography evaluation of lubricating oil samples and cylinder liner surface roughness analysis are conducted for these fuels operations. The results have revealed that higher metal wear concentrations are observed in the samples of lubricant oil with LPO20 compared with LPO10 and diesel. It is due to more oxidation of fuel and lubricant oil dilution while running the engine. Similarly, wear of the engine cylinder liner surface is also more when the engine is fuelled with LPO20 as compared to LPO10 and diesel. In addition, Ferrography results have shown a higher wear concentration of lubricant samples collected from the LPO20-operated engine compared with other used fuels. Finally, it is concluded that has poor engine life due to its low viscous nature and it could be improved by suitable reformulation for long term application.

Blackening failure of poly-α-olefin impregnated porous polymide due to the splitting of lubrication oil catalyzed by iron

Lubrication failure accompanying with blackening phenomenon significantly reduces the long-running operational reliability of porous polymide (PPI) lubricated with poly-α-olefin (PAO) oil. Here, the effects of lubrication condition and counter-surface chemistry on the blackening failure of PAO impregnated PPI were studied through the comparison of the tribological tests against GCr15 steel ball and Al2O3 ceramic ball with and without PAO oil lubrication. Black products were found to be formed on the PAO impregnated PPI surface slid against steel ball or Al2O3 ball added with iron nano-particles, but be absent under the conditions without iron or PAO oil. Further analysis indicated that the iron-catalyzed splitting of PAO oil into small molecule alkanes and following the formation of black organic matter should be mainly responsible for the blackening phenomenon. Molecular dynamic (MD) simulations demonstrated that the iron facilitated the separation of hydrogen atom and the following broken of C-C bonds in PAO molecules, final resulting in the splitting of PAO oil.

Research on Abrasive Particle Target Detection and Feature Extraction for Marine Lubricating Oil

Research on Abrasive Particle Target Detection and Feature Extraction for Marine Lubricating Oil

Effects of Waste Lubricant Oil on Rheological Properties of Asphalt Binders: Implications for Sustainable Asphalt Mixture Production

Reusing waste lubricant oil as an environmentally-friendly alternative for disposal and transforming it into a value-added product is a promising solution. This study aimed to evaluate the rheological properties of asphalt binder (PG 64-XX) modified with waste hydraulic oil. Two levels of oil content, 3% and 5% by weight of the base binder, were added. Physical and rheological tests, including penetration, softening point, rotational viscosity, and performance grade (PG) tests, were conducted before and after subjecting the samples to the Rolling Thin Film Oven (RTFO), multiple stress creep and recovery (MSCR), linear amplitude sweep (LAS), and master curve procedures. Results showed that the addition of oil decreased the stiffness of the base binder, makingit more susceptible to premature cracking and instability. However, the mixture and compaction temperatures decreased with the oil addition. Overall, considering the investigated oil contents, the asphalt binders modified with waste hydraulic oil did not exhibit satisfactory performance. It is hypothesized that incorporating residual hydraulic oil in recovered asphalt binders may yield more favorable results.

Susceptibility of Poly–Alpha Olefin and Diisooctyl Sebacate Base Oils With Different Polarities to Oleic Acid Surface–Capped Ultra‐Small Cerium Oxide Nanoparticle

ABSTRACTA key issue for nano‐additive to effectively exert tribological function is to ensure its entrance to and adhesion on the frictional contact surfaces. But the adhesion of nano‐additive on the rubbed surfaces under oil lubrication faces the challenge of the competitive adsorption of lubricant base oil thereon. In this study, oleic acid–modified ultra‐small cerium oxide (OA‐CeO2) nanoparticle was synthesised by one‐pot liquid‐phase surface‐modification method in the presence of OA as the surface modifier. The susceptibility of non‐polar poly–alpha olefin 6 (PAO6) and polar diisooctyl sebacate (DIOS) base oils to the as‐prepared OA‐CeO2 nano‐additive was investigated, and the effect of the OA‐CeO2 nano‐additive on the friction‐reducing and anti‐wear abilities of the two kinds of base oils towards a steel–steel sliding contact was investigated with four‐ball friction and wear tester. Furthermore, the tribological mechanism of the adsorption and deposition of the OA‐CeO2 nano‐additive on the surface of friction steel and the competitive adsorption of base oil were discussed. Characterisations by scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy demonstrate that the as‐prepared OA‐CeO2 nanoparticle is of a spherical shape and has an ultra‐small average size of 1.2 nm. As the lubricant additive in PAO6 and DIOS base oils, the OA‐CeO2 nano‐additive exhibits different tribological properties, which is attributed to the difference in the base oils' polarity. Namely, the CeO2 nanoparticle in the non‐polar PAO6 base oil is more easily adsorbed on the rubbed surface of the steel–steel sliding contact, thereby forming the CeO2 deposition film to improve the tribological properties of the base oil. However, the CeO2 nanoparticle added in polar DIOS base oil is difficult to form the CeO2 deposition film, because of the competitive and preferential adsorption of the polar base oil on the rubbed steel surface. Therefore, it is imperative to select the base oils with proper polarity to better exert the friction‐reducing and anti‐wear functions of the OA‐CeO2 nano‐additive.

Preparation and tribological properties of the friction induced Mo-based film

The main idea of this study was to utilize the pressure and heat produced in the friction process to make Mo nanoparticles mixed in lubrication oil into the multi-layered tribo-film. An in-house developed reciprocating wear rig was used for the tribo-film deposition and associated tribological tests. By design of experiment, the optimal deposition parameter was obtained. Results indicate that the multi-layered film consists of a Mo-based concrete structure layer and a carbon-based film. The carbon-based film was produced by the dehydrogenation and carbonization of the lubricating oil catalyzed with Mo nanoparticles. The consumption and deposition of the carbon-based film was dynamically balanced during the wear process, resulting in the outstanding tribological performance.

Study of the corrosion behaviors of M50 steel in brine-contaminated lubricating oil

In the present paper, the wasted oil with the saltwater droplet was prepared to simulate the corrosion behaviors of M50 steel in the salt fog condition. The comprehensive characterization of the local corrosion area on the surface of M50 displays the corrosion behaviors of M50 steel in saltwater-contaminated lubricating oil. The experimental results show that the surface of M50 steel has two types of local corrosion area morphology: pit-like corrosion spots and isolated outer regions, which are found after immersion in saltwater-contaminated lubricating oil. The larger the outer area, the larger the inner area and the probability of occurrence becomes high. The local corrosion areas have an inward depression and an outward protrusion, and the formation mechanisms are galvanic corrosion and uniform corrosion. These finding are helpful to understand the corrosion problems and mechanisms of roller bearings exposed in salt fog contaminated lubricating oil.

Wide temperature range corrosion mechanism of M50 bearing steel in deteriorated oil-water mixture

Bearing corrosion is one of the important causes of engine failures in shipborne aircraft, and solving the problem of bearing corrosion failure is urgent. This article uses chromatography, image analysis, and finite element simulation to study the high-temperature deterioration behavior of Mobil Jet Oil Ⅱ aviation lubricating oil, as well as the corrosion mechanism of M50 bearing steel in oil–water mixture under a wide temperature range. The results indicate that deteriorated lubricating oil without salt water doping does not have corrosiveness. Mobil Jet Oil Ⅱ aviation lubricating oil at 200 °C has obvious deterioration within 48 h, where consumption and decomposition of additives cause acidity changing from pH 8.1 to pH 2 and surface tension decreasing by 11.3 %. The crack corrosion caused by acid and the galvanic corrosion of secondary cementite accelerate the pitting corrosion process. The corrosion enhancement effect of temperature on oil–water mixture shows a parabolic trend. Corrosion can be effectively reduced by lowering the temperature of lubricating oil and quickly removing moisture.

Sensitivity analysis and optimization on oil capture performance of under-race lubrication system for high-speed bearings

Under-race lubrication for high-speed bearings in aero-engines has become more important recently following the ambition of reducing the size and weight of mechanical systems while maintaining or improving power. This paper presents experimental research on the oil capture performance of an under-race lubrication system. The results reveal a strong non-linear relationship between the oil capture performance and design parameters. Jet angle and rotational speed markedly impact the oil capture efficiency, while the orifice diameter is the biggest contributor to determining the captured lubricant oil. With a focus on ensuring a quantitative oil supply to the bearings, the optimized oil capture efficiency is more than 80%, with most of the improvements exceeding 10% compared to the original results.