Mineral Base Oil Research Articles

Electrical dewaxing of the oil raffinate fraction 420-490 оС

Industrial dewaxing of oil raffinates remains the most expensive, complex, low-temperature process in the production of mineral base oils in refining. The development of an alternative, simpler and less energy-intensive method of dewaxing is an urgent task.This article investigates the possibility of dewaxing oil refining in the presence of different classes of depressor additives in a constant inhomogeneous electric field at positive temperatures.A correlation was established between the depressant properties of the additives and their effectiveness in electric field dewaxing.The maximum depressant effect of the additive in the oil raffinate corresponds to the highest indicators of the electrical dewaxing process.The effect of separating oil raffinate in an electric field with ester additives depends on the chemical structure of the dicarboxylic acids used in their synthesis.The nature of the distribution of the additive between the phases has been revealed by changes in the pour point of the resulting dewaxed oil.This article shows the relationship between the magnitude of the electrical charge of paraffin crystals and the time of dewaxing. This is related to the polarisation of the double electric layer of particles in an electric field and their subsequent dipole-dipole interaction.

Role of ZnO/MWCNTs hybrids nanoparticles addition on the tribological behaviour of SN150 paraffinic mineral oil

AbstractNanoparticle incorporation plays an active feature in heat transfer, ultimately enhancing the tribological process under boundary conditions of heat stress. Nanoparticles like zinc oxide (ZnO) and multiwall carbon nanotubes (MWCNT) are well known to significantly affect the cooling and lubrication applications, resulting in improved heat transfer and kinematic viscosity. The present work investigates the tribological performance of ZnO/MWCNTs hybrids as lubricant additive in the paraffinic type of mineral base oil of Group I (SN150) engine oil. The chemical composition of the modified and unmodified oil was examined by an inductively coupled plasma‐optical emission spectrometer (ICP‐OES), energy dispersive x‐ray fluorescence (EDXRF) spectrometer, and Fourier‐transform infrared spectroscopy (FTIR). A ring‐on‐disk tribotester was performed to investigate the tribological behaviour through the linear reciprocating mechanism alloy‐steel contacts. The worn steel alloy surfaces morphology and chemical compositions were examined by scanning electron microscope (SEM), energy‐dispersive x‐ray spectroscopy (EDX), and 3D optical profilometer. Different ZnO/MWCNTs nanomaterial volumetric concentrations were examined in order to determine the most effective performance. According to the tribological results, ZnO/MWCNTs hybrid nanomaterials in the engine oil were found to have significantly higher friction temperature and antiwear capability than the base oil. A volumetric concentration of 3.00 wt% ZnO/MWCNTs nanomaterials to SN150 engine oil imparted excellent wear protection to the steel sample than the pure SN150 base oil. Based on the statistical analysis, the modified oil anti‐wear performance was enhanced by reducing the wear loss by 80.5% and friction temperature by 55.8°C compared with the oil base.

Hydrocarbon biolubricants from hydrotreated renewable and waste derived liquid intermediates

There is a need to support the biofuel sector by utilizing waste materials for its production and utilizing co-products through an integrated approach. Due to bio-oil's diverse composition, its applications for foams and resins syntheses are emerging, but most importantly, as biolubricants, product with increasing global demand. In this study, four hydrocarbon biolubricants (HBL) were produced via a hydrotreatment process. Two samples were produced using hydrothermal liquefaction (HTL) of algae (HAL) and sewage sludge (HSS). Additional samples included animal fat (poultry fat; HPF) and non-edible oil (carinata; HCA). All four samples were evaluated for their tribological properties and compared with the mineral base oil (MBO). These potential biolubricants samples had viscosity indices (VI) ranging from 197 to 254, pour points (PP) from −10 °C to −20 °C, and Noack volatilities between 16% and 23%. The coefficient of friction (COF) for HAL and HSS was lower than MBO, HPF, and HCA, but the wear was higher than HPF. Large amounts of oxygenates and olefins imparted higher VI and lowered PP to HPF. Even though both HSS and HAL demonstrated higher amounts of paraffin, they exhibited lower thermo-oxidative stability, higher PP, and higher volatility than other samples. In the case of HAL and HSS, the aromatics could have played a more prominent role in determining the lubricating properties than the paraffin alone. The HPF had the lowest wear, highest VI, and lower PP but higher COF. The volatility and COF predominantly dependent on the cyclic structures, unsaturation, and heteroatoms. The results indicated that the hydrotreated bio-oil from HTL biocrude and waste precursors could be considered as eco-friendly hydrocarbon biolubricant blend stock.

Dry and MQL Milling of AISI 1045 Steel with Vegetable and Mineral-Based Fluids

The use of mineral-based cutting fluids in machining has the drawback of affecting the environment and industries are under pressures to reduce its use in favor of cleaner productions. In this regard, the vegetal-based cutting fluids can be a superior alternative, provided they improve the technical outcomes. In the milling process, dry cutting is commonly performed, however, the application of cutting fluids using the minimum quantity of lubricant (MQL) method has proven advantageous when compared with dry machining. Furthermore, in the midst of the availability of several cutting fluids in the market, the testing of their individual performance can ascertain their potential and effectiveness for a particular application. This study examined the performances of two vegetable-based and one mineral-based oils applied by the MQL method, followed by their comparison with dry cutting amid end milling of AISI 1045 steel with TiAlN-coated cemented carbide inserts. The cutting temperature, machining forces, power consumption, workpiece surface roughness, tool life, and tool wear mechanisms were chosen as the output parameters. The experiments were conducted using two cutting speeds (150 and 200 m/min) and feed rates (0.07 and 0.14 mm/tooth), and constant axial (1 mm) and radial depths of the cut (25 mm). The temperature was measured using a K-type thermocouple soldered to the part and an infrared camera. The power was monitored with a Fluke 435 energy analyzer, and the machining force components with a Kistler dynamometer. The worn inserts were inspected under a scanning electron microscope (SEM) to analyze the tool wear mechanism. The MQL-assisted application of the cutting fluids notably lowered the cutting temperature and increased the tools’ lives. However, the cutting fluids did not reflect any significant effect on the machining force, power consumption, or surface roughness. Among all the analyzed cutting conditions, the abrasive wear mechanism dominated, damaging the cutting edges, flank, and rake surfaces of the cutting tools. In addition, adhesive and diffusion wear mechanisms were also observed.

A monosurfactant-stabilized dual-responsive and versatile emulsion lubricant

Emulsions consisting of lubricating base oil and water have extensive applications in the fields of metalworking and heavy-duty machinery. Due to the compositional complexity that confines an effective recycling of emulsion constituents and the frequent use of toxic, non-biodegradable mineral base oil, an industrial emulsion lubricant is usually easy to produce severe environmental burdens and health issues. Here we report a dual-responsive and versatile lubricating emulsion solely consisting of water, an eco-friendly ester base oil and a synthetic cationic emulsifier. Taking advantage of the inclusion of azobenzene moiety, [CeCl3Br]- anion and methylimidazole head-group, the surfactant can not only undergo tribochemical reactions to function as a lubricant additive to achieve very low interfacial friction, but also endow the resulting emulsion efficient anticorrosion, antibiosis and both light- and magneto-responsiveness. Based on a reversibly photo-triggered variation in the hydrophobicity of surfactant, an on-demand separation and recycling of emulsion component followed by a nearly one order of magnitude conversion in the friction can be realized. Together with its magneto-controlled migration and adaptivity to high normal loads, we envision that the emulsion lubricant may find potential applications in a broad range of industrial systems requiring lubrication and heat dissipation as well as smart devices needing control over the friction between two contacting surfaces.

Taguchi-Grey Optimization of Tribological Characteristics of Blended SAE 40 Lubricant

A high proportion of lubricants used in automobile engines are mineral-based oil. The depletion of oil reserves and the concerns (non-biodegradable, toxic and environmental issues) of mineral based lubricants prompted the research for a viable alternative. Vegetable oil has been proposed as a potential substitute for the mineral-base lubricants due to its natural and eco-friendly characteristics. In this study, optimization of tribological characteristics of blended SAE 40 produced from SN 500 mineral oil, Shea butter bio-base oil, and viscosity improver was carried out on pin-on-disc tribometer. Taguchi and Taguchi-grey relational method were used to optimize the load and sliding speed to obtain the minimum specific wear rate and coefficient of friction (COF) for the blended SAE 40. The optimum parameters using Taguchi’s and Taguchi-grey relational analysis methods are 8 N load and 5 cm/s sliding speed. At this optimum condition, the minimum specific wear rate of 0.007 mm3 /Nm and minimum coefficient of friction of 0.001 were observed. The developed mathematical model was validated against the experimental results. Deviation of about 5% was obtained in the wear rate model using Taguchi model. Also, the correlation of about 89.77% was observed between the model developed using Taguchi-grey relational model and experimental values. This implies that the two models can be used to predict the tribological properties of blended SAE 40 lubricant.

Lubricated sliding wear of gear material under electrification – A new approach to understanding of the influence of shaft currents in the wear of EV transmissions

Electrification of drivelines of electric vehicles (EVs) can give rise to damaging shaft voltages/currents that can potentially impair the tribological performance of sliding and rolling elements in these driveline systems. In fact, previous research has shown that the existence of shaft voltages/currents in electric machines is indeed highly detrimental for the service life of tribological components of EVs. Such currents/voltages originate from magnetic flux asymmetry, inverter-induced voltage and triboelectrification and may also interfere with the normal sliding condition of other electrically conductive tribological components connected to the electric motors in addition to those that are comprised in the driveline, e.g., gears. In the past, the influence of shaft voltages/currents in gear systems has been explored scarcely. Accordingly, this work aims to investigate specifically the lubricated sliding friction and wear behavior of gear materials under the influence of DC electrification. For this, many tests were conducted on a gear material in a two-electrode-cell-based pin-on-disc tribometer representing the sliding contact of a gear interface. The tests were run under different currents (0, 1.5 and 3 A) and using different lubricants (pure mineral base oil, gear oil and transformer oil). The differences in sliding contact temperature, coefficient of friction (CoF), wear volumes and underlying mechanisms, as well as the chemical changes occurred in the lubricating oils by electrification are analyzed and discussed. Overall, the results confirmed that electrification can indeed have a strong influence on friction and wear of gear materials besides increasing contact temperature and thus accelerating the oxidation at the sliding interfaces for all the lubricants. The increase in wear is most likely due to three-body abrasion caused by increased oxidation and/or oxide-based debris formation under electrification. CoF was found to decrease by electrification, which was ascribed to the formation of a larger wear scar (that reduced contact pressure) and continuous replenishment of an oxide layer affording Lower Friction To Sliding Surfaces.

‘Triangle Ester’ Molecules as Blending Components in Mineral Oil: A Theoretical and Experimental Investigation

The present work explored the use of fatty acid ‘Triangle ester’ molecules (Epoxidized Ester (EE), and Thiirane Ester (TE)) as antifriction and antiwear additives at varying levels for Group I and Group II mineral base oils using the standard ASTMD-4172B four-ball test. Relative to neat base oil, EE blends showed improved antifriction by ~61% and ~42% and antiwear properties by ~32% and ~41% in Group I and Group II base oils, respectively, while the TE blends showed friction reduction by ~65% and ~40% and wear reduction by ~93% and ~50% relative to the same neat base stock. Time evolution of the ‘Triangle ester’ molecules and their blends with mineral oil (modeled as hexadecane) w.r.t. conformational changes, adsorption energy, intermolecular energy, and effect of the applied stress were estimated theoretically using MD simulations. Further, optimized levels of these additives were explored for their effectiveness as a blending component for commercial engine oil (CEO) and could reduce the friction and wear of CEO by ~50% and ~30%, respectively.

Comparative Analysis of the Product Formulated in Group-1 and Group-2 Mineral Base Oil

This research based on the mineral base oil formulated in different additives for Automotive engines. In this experiment, performance of two different groups of mineral base oil are investigated, one of which is Group-1 base oil while the other is Group-II base oil. Different products are prepared for automobile like Motorcycle, CNG Car and Diesel engine with the required additives. Then, the samples were used in the respective vehicles and samples it is observed that the viscosity at 100oC of Group-2 base oil’s products depleted about 4.91%, 5.91% & 9.55% while of Group-1 Base oil’s products are about 16.5%, 10% & 26.08% for Motorcycle, CNG engine car and Diesel engine respectively. Similarly, the flash point of Group-2 base oil’s products decreases less as compare to the products of Group-1 base oil, hence the results of the samples are use shows that the products blended in Group-2 base oil perform better and run longer than the products blended in Group-1 base oil.

A review on transformer condition monitoring with critical investigation of mineral oil and alternate dielectric fluids

Transformers are very critical elements of modern power system network and have evolved in many ways over its long history. Transformers are most significant apparatus in interconnected power systems with consideration of several aspects like reliability, efficiency, economy, wide applications and operation. However mineral oil also called transformer oil is attracting more attention from researchers and transformer industry due to environmental concerns, limited stock, high price of petroleum resources and its disposal issues after getting contaminated. Above issues have motivated researchers to turn their attention to biodegradable and/or renewable insulating oil. Multiple facets, such as environmental requirements, safety and economic considerations, availability of technology and raw material governs the development of new insulating liquid materials. In addition, the increased equipment efficacy and the adoption of more environment friendly alternate dielectric fluids for power system solutions is gaining popularity towards steps to reduce the carbon footprint and achieving net zero cum decarbonisation global policy. This article provides the detailed review of transformer condition monitoring and the critical investigation about environment friendly dielectric fluids. They claim excellent lifecycle of the insulation, better working compatibility and improved performance compared to the traditional mineral oil base fluids in adherence of compliance, standards and graphical abstracts. These alternate dielectric fluids are getting proved as superior transformer fluids. The diverse investigational work carried out is incorporated, providing an overview of research. In addition, the future scopes, challenges and environment friendliness of various fluids are studied and deliberately articulated.

Chemically functionalized graphene oxide with N‐phenyl‐p‐phenylenediamine as efficient tribo‐ and rheological modifier for lubricating oil

AbstractNanoadditive with multifunctional properties holds commercial importance in the lubricant industry. Herein, GO‐N‐PPDA was synthesised as nanoadditive by functionalizing graphene oxide (GO) using N‐phenyl‐p‐phenylenediamine and characterised by Fourier transform infrared spectroscopy, X‐ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy and transmission electron microscopy analysis. The antioxidant behaviour of GO‐N‐PPDA was analysed by 2,2‐diphenyl‐1‐picryl‐hydrazyl‐hydrate. The nanoparticles dispersed mineral base oil (N‐250) in 0.2%, 0.4%, 0.6% (w/v) concentrations were evaluated for tribological, rheological and thermophysical analysis by ASTM methods. The flow behaviour of the nanolubricant shows shear thickening behaviour with an increase in shear rate. In contrast, tribological results indicate a significant reduction in wear scar diameter and coefficient of friction to the base oil. Furthermore, GO‐N‐PPDA shows improved thermophysical properties compared with the mineral base oil. Thus, GO‐N‐PPDA shows multifunctional behaviour in terms of viscosity index, pour point, antioxidant activity, rheology and tribological properties.

Electrification effects on dry and lubricated sliding wear of bearing steel interfaces

In electric vehicles' powertrains, bearings can be susceptible to failure more rapidly than some of the other components mainly because of accelerated fatigue, corrosion and wear. Specifically, due to much severe operating conditions (including high speeds, torques, temperatures) of such vehicles combined with the presence of an electrical environment in which uncontrollable or stray electrical currents discharge through the contact interfaces can further exacerbate the situation and reduce their service lives by triggering much severe adhesive, abrasive and oxidative wear. In this work, we explore the effects of DC current discharges through the contact interfaces of AISI 52100 bearing steel using a novel two-electrode cell-based micro-abrasion tester under electrified dry and boundary lubricated contact conditions. A mineral base oil (as a reference), a gear oil and an automatic transmission fluid (ATF) with different dielectric strengths were tested under unelectrified and DC electrified (1.5 A) conditions. Overall, our test results suggest that passing DC current increases coefficient of friction (CoF) and wear of dry sliding contacts while it slightly reduces CoF but increases wear significantly for lubricated contacts due to accelerated oxidation by electrification. SEM, Raman spectroscopy and non-contact optical profilometry were used for analyzing the physical and chemical nature of worn surfaces and understanding of the specific wear modes and mechanisms.

Characterization of Mineral and Synthetic Base Oils by Gas Chromatography–Mass Spectrometry and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Base oil is a main component of engine oil that enables smooth operation of an internal combustion engine. There are two types of base oils, such as mineral oil and synthetic oil. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography-mass spectrometry (GC-MS) were used to characterize the base oils. One difficulty in analyzing base oils using MS is that the ionization of alkanes can be problematic due to low ionization efficiencies and the predominance of fragmentation. Despite these limitations, the combination of GC-MS and FT-ICR MS data can provide qualitative insights into the composition differences for these various sample types. The distinctive total ion chromatogram obtained by GC-MS of the different base oils allowed the classification of mineral oil from synthetic oil. The additional structural characteristics of paraffinic compounds were also inferred by GC-MS. FT-ICR MS coupled to two different ionization methods, atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI), was tested for the analysis of base oils. It was determined that APPI was suitable for the analysis of aliphatic hydrocarbon compounds, where APPI minimizes the decomposition of hydrocarbon compounds compared to atmospheric pressure chemical ionization. Using APPI FT-ICR MS, the components of the oils were characterized, including not only paraffinic compounds but also cyclic compounds. In addition, the alpha olefin monomer of the synthetic oil was determined, and the homogeneity of the branched compound of the synthetic base oil was confirmed using GC-MS and FT-ICR MS results.

Roles of Eco-Friendly Non-Edible Vegetable Oils in Drilling Inconel 718 through Minimum Quantity Lubrication

Metal cutting fluids (MCFs) have played a principal role as coolants and lubricants in the machining industry. However, the wide use of mineral-based oil MCFs has contributed to an adverse effect on humans and the environment. Thus, to overcome the adverse effects of mineral-based oil MCFs, eco-friendly vegetable oil, which is non-edible oil, has been implemented to overcome the issues related to edible oil such as manufacturing costs and food shortages. This study investigated the performance of three different types of non-edible oil, namely castor, neem, and rice bran oils in drilling Inconel 718 using a coated titanium aluminum nitride (TiAlN) carbide drill towards tool life, tool wear, surface integrity, dimensional accuracy, and chip thickness. The MCFs were implemented under the minimum quantity lubrication (MQL) condition at a 50 mL/h flow rate using different cutting speeds (10, 20 m/min) and a constant feed (0.015 mm/rev). The results showed that castor oil minimizes the rapid growth of tool wear and prolongs the tool life by 50% at 10 m/min as compared to rice bran oil. At 20 m/min, castor oil obtained the lowest values of average surface roughness (1.455 µm) and chip thickness (0.220 mm). It was also found that different cutting speeds did not contribute to any significant trend towards hole diameter and roundness for all MCFs. The outstanding performance of castor oil proved that the oil is a potential alternative as an eco-friendly MCF for a cleaner machining environment. Castor oil was determined to be optimum in terms of tool life, tool wear, surface roughness, and chip thickness.

Investigation of stiffness and damping coefficients in fluid film bearing with bio-oils and mineral-based oil

Rotating machinery utilizes fluid film bearings because of their good load carrying capacity and inherent damping properties. Fluid film bearings offer stiffness and damping parameters to ensure dynamic stability. The damping and stiffness characteristics of oil film significantly change the critical speed and unbalance response of the rotor. The damping and stiffness coefficients (direct, cross-coupled) may lead to system instability, also known as self-excited vibrations. Bio-oils have good tribological and physiochemical properties. They are also environment-friendly and bio-degradable. In this work, bio-oils (rapeseed, palm olein, and soybean) are evaluated in terms of their dynamic characteristics to that of mineral-based SAE40 lubricant for journal-bearing applications. The analytical extraction of damping and stiffness coefficients is performed based on the experimental dynamic viscosity data at different temperatures. In comparison to SAE40, the bio-oils have shown improved responsiveness. Bio-oils showed lower cross-coupled stiffness coefficients than SAE40, the primary source of rotor instability. The main contribution of this study is that it provides damping and stiffness coefficients for various bio-oils at different eccentricity ratios and viscosities for different types of oils. This may be used to characterize the dynamic properties of the fluid film bearing under various operating circumstances. It is concluded that the difference in cross-coupled stiffness favors bio-oils. Whereas, the difference in cross-coupled damping favors SAE40 by around 6%. This discrepancy is decreased to less than 2% for all oil’s final eccentricity ratio values (bio-oils and SAE40).

A green approach in the biological base oil process

Abstract This article presents a green approach in the biological base oil synthesis from catfish fat by-product using the hydrodynamic cavitation technique. The effects of parameters on the yield of reaction were investigated. The application of the cavitation technique has improved the process efficiency significantly. The catfish polyester oil yield reached at high value (94.6%) at the inlet pressure of 60 psi, the molar ratio of acetic anhydride/epoxy of 1.25/1, 85°C, and only 10 min, and also under these reaction conditions, magnetic stirring technique could only give the limited yield of catfish oil polyester of 12%. The results of Fourier transform infrared resonance, 1H nuclear magnetic resonance (NMR), and 13C NMR analyses and characteristic properties of materials and products have demonstrated that the chemical structure of polyester catfish oil was triglyceride chains containing saturated alkyl R chains and branched by methyl ester functional groups and the polyester catfish oil has met the quality standards of SN150 and SN500 mineral base oils. It could be said that the biological base oil process from catfish fat by-products under the assistance of cavitation techniques would develop sustainably.

A novel class of bio-lubricants are synthesized by epoxidation of 10-undecylenic acid-based esters

Mineral-based lubricants are being supplanted by bio-based lubricants because of environmental concerns and the depletion of fossil resources. The derivatives of edible and non-edible oils are considered potential alternatives to existing natural mineral oil base stocks in certain lubricant applications, where immediate intraction with the environment is predicted. A new class of epoxides were synthesized from the undecylenic esters of 2-ethyl hexanol, neopentyl glycol (NPG), and trimethylolpropane (TMP). These unsaturated esters were epoxidized by using meta chloro perbenzoic acid. The synthesized epoxides were characterized by spectral studies (1HNMR, 13CNMR, IR) physio-chemical (density, specific gravity) and lubricant properties (kinematic viscosity, viscosity index, flash point, fire point, cloud point, pour point, copper strip corrosion). TMP epoxide has a high viscosity index, high flash point, and low pour point compared to 2-ethyl hexyl epoxide and NPG epoxide.

Facile synthesis of lipophilic alkylated boron nitride nanosheets as lubricating oil additive to greatly enhance the friction and heat-conducting properties

Boron nitride (BN) is considered as a promising additive in lubricating oil due to its high friction performance and thermal conductivity, but its poor lipophilicity greatly limits its application. Herein, a facile and economic alkylamine-assisted ball milling method has been proposed to produce alkylated BN nanosheets (BNNS). Three different types of alkylamine including the octadecylamine, tetradecylamine, and trioctylamine, are developed as modifiers to probe into the structural effect on friction performance. It reveals that the trioctylamine functionalized BNNS (BNNS-TOA) deliver the best dispersion stability in mineral base oil due to their large steric hindrance. As a result, the mineral base oil with using BNNS-TOA as additive yields a lower friction coefficient (0.152) and smaller wear scar width (4 µm). Moreover, the thermal conductivity for the BNNS-TOA/mineral base oil is 8.83 times higher than that of pure mineral base oil, which effectively promotes the dissipation of friction heat and prolongs the service life of machines. This work opens a new route for the preparation of lipophilic BNNS toward lubrication and friction applications.

Correlation between the Molecular Structure and Viscosity Index of CTL Base Oils Based on Ridge Regression.

In China, coal-to-liquid (CTL) lube base oils with ultrahigh viscosity index (VI) are very popular. Since it consists of chain alkanes only and can be precisely characterized by molecular structures alone, quantitative 13C nuclear magnetic resonance (NMR) data are used to generate the average structural parameters (ASPs) of CTL base oil. In this work, the ASPs and bulk properties of CTL base oils were tested and compared with those of mineral base oils. Based on the test results, the correlation between the unique property of CTL base oil VI and ASPs was analyzed. To eliminate the effect of significant multicollinearity among the input variables, statistical methods such as ordinary least-squares (OLS), stepwise regression, and ridge regression methods were used to build the VI prediction model. The main findings are as follows: according to the 13C NMR spectrum, CTL base oils had a significantly higher content of isomeric chain alkanes (including several branching structures) than mineral base oil, while the content of cycloalkanes was zero; among several branched structures, the one with the largest difference in content is structure S67, which has the highest percentage in the iso-paraffin structures, all above 25.5% in CTL base oils and below 21.39% in mineral oils; according to the distillation curve of the simulated distillation (SimDist) analysis, CTL base oils with similar carbon number distribution showed lower boiling points, narrower distillation ranges, and higher distillation efficiencies than mineral base oil; correlation analysis showed that the average chain length (ACL), normal paraffins (NPs), and structure S67 caused the CTL base oil to exhibit a higher VI; and from 13C NMR data, the ridge regression model was used to obtain regression coefficients consistent with reality, and the expected VI could be well predicted with a correlation coefficient of 0.935.

Experimental and Numerical Investigation of Static and Dynamic Characteristics of Bio-Oils and SAE40 in Fluid Film Journal Bearing.

Mineral-based oils are the market leaders when it comes to their consumption in different types of rotating machines. Recently, a lot of attention has been given to the bio-oils and lubricants due to their better thermophysical, tribological, and environmental characteristics for use in journal bearing and other rotating machines. The superior physical properties of bio-oils have instigated this research in order to evaluate their dynamic characteristics that can cause the harmful dynamic instabilities in rotating machinery. The dynamic characteristics of the fluid film are influenced by temperature, eccentricity ratio, and rotational speed. In this work, the effect of temperature is experimentally measured on the dynamic viscosity of bio-oils and mineral-based oil. The dynamic viscosity measured is then computationally used to estimate the hydrodynamic pressure response of three bio-oils (rapeseed, palm olein, and soybean) and SAE40, a mineral-based oil, to check their performance in the rotor bearing system. It is found that at 40 °C, the hydrodynamic pressure for SAE40 is observed to be 2.53, 2.72, and 3.32 times greater than those of rapeseed, palm olein, and soybean oil, respectively, whereas, at 125 °C, the hydrodynamic pressure for SAE40 is observed to be 8% and 4.3% less than those of rapeseed and palm olein, respectively, but 14% greater than that of soybean oil. Hence, the increasing temperature has less effect on the viscosity and hydrodynamic pressure of bio-oils compared to SAE40. Therefore, for high-temperature applications, the bio-oils can be used with further processing. The superior response of bio-oils is also an indication for better dynamic characteristics.