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This paper addresses recycling of waste engine oils treated using acetic acid. A recycling process was developed which eventually led to comparable results with some of the conventional methods. This gives the recycled oil the potential to be reused in cars’ engines after adding the required additives. The advantage of using the acetic acid is that it does not react or only reacts slightly with base oils. The recycling process takes place at room temperature. It has been shown that base oils and oils’ additives are slightly affected by the acetic acid. Upon adding 0.8 vol% of acetic acid to the used oil, two layers were separated, a transparent dark red colored oil and a black dark sludge at the bottom of the container. The base oils resulting from other recycling methods were compared to the results of this paper. The comparison showed that the recycled oil produced by acetic acid treatment is comparable to those recycled by the other conventional methods.

The genesis of the conducted research was the intention to determine how the rheological properties of engine oil change upon the addition of a coolant. The aim of the study was to assess the effect of coolant addition to engine oil on its dynamic viscosity. The experiments were carried out for six different fresh engine oils and six of the same oils sampled during routine oil replacement after a vehicle mileage of 10,000 km. Two oils were selected from each of the three primary categories: synthetic, semi-synthetic, and mineral oils. Then, mixtures of engine oils with the addition of coolant were prepared at 0, 5, 10, 20, 30, 40 and 50% (v/v), respectively. The study involved measuring the dynamic viscosity of the samples at 1000 s−1, covering temperatures from 0 to 50 °C. The tests were conducted using a measurement setup equipped with a RHEOLABQC rotational rheometer manufactured by Anton Paar GmbH (Ostfildern, Germany). To investigate the temperature dependence of dynamic viscosity, a GRANT thermostatic bath was coupled with the rheometer. The studies demonstrated that dynamic viscosity strongly depends on temperature, as well as on the type and condition of the engine oil. At 0 °C, the dynamic viscosity of fresh oils ranged from approximately 500 to 700 mPa·s, whereas at 50 °C it decreased to approximately 100 mPa·s. The addition of 5% (v/v) coolant to engine oil resulted in only a slight change in dynamic viscosity. In contrast, a substantial decrease in dynamic viscosity was observed when 50% (v/v) coolant was added to the tested engine oils. The results indicate that coolant, which may enter the engine oil in the event of an engine failure, can significantly deteriorate the rheological properties of this lubricant.

Recycled engine oil was produced from used engine oil (15W-40) using a combination of MEK and 1-butanol solvents with an activated carbon adsorbent through the adsorption process. The experimental design matrix was prepared using Box-Behnken design (BBD) package within RSM, and recycled engine oil is optimized by response surface methodology (RSM). By varying solvent-to-oil ratio, the temperature and contact duration optimal conditions were identified as a 5.5:1 MEK and 1-butanol solvent-to-oil ratio, 50 min of contact, 42.5 °C, and constant 1 g of activated carbon adsorbent, yielding (65.20%, 65.20%) numerically and experimentally, respectively. Process factors (solvent-to-oil ratio, the temperature, and contact duration) influencing the yield of recycled engine oil are indicated by both contour and surface plots. The characterization of recycled oil indicates that its physiochemical properties, such as density, viscosity, flash point, pour point, and total base number, met the ASTM standards. GC–MS analysis further identified the presence of natural base oil, additives (polymeric, metallic, and non-metallic), and oxidation compounds, indicating the efficacy of the recycling process in recovering valuable components from the used engine oil. Before and after adsorption, FTIR is used to analysis the effect of optimized engine oil adsorption on the activated carbon adsorbent. The recycling method that has been optimized indicates potential for sustainable resource consumption and conservation, which may help the vehicle industry practice environmental stewardship.

The research problem concerning oils used for lubricating piston combustion engines is still very current and important. The proper selection of oil and its properties have a significant impact on engine reliability and durability, their efficiency, effective operating parameters, fuel consumption, environmental impact, and the proper operation of the turbocharger and exhaust system. The work concerned determining the effect of temperature and operating time on the dynamic viscosity of oils: mineral, semi-synthetic, and synthetic, used in compression-ignition engines (diesel engines). Dynamic viscosity tests were conducted for new oils, after a mileage of seven thousand kilometers, and after a mileage of fifteen thousand kilometers. The range of temperature measurement conditions used was from 0 to 50 °C and the shear transmission rate was 1000 s−1. This range allows the oil to be preserved at low and medium temperatures, which are crucial for engine operation during start-up and short operating cycles. As the conducted studies showed, both temperature and operating time have a very large influence on the dynamic viscosity of oils. It was demonstrated that as the operating time of the oils in the engine increased, their dynamic viscosity decreased, and increasing the viscosity measurement temperature results in smaller absolute changes in it.

Bioenhancement of hydrocarbonoclastic microorganisms with suitable nutrients has a huge impact in achieving positive bioremediation of polluted environments. This study was conducted to assess the bio-enhancing effect of some organic amendments on Streptococcus pyogenes and Enterococcus faecalis co-culture with a view to remediating spent engine oil (SEO) contaminated soil. Top soil (1.5 kg) was autoclaved and thereafter contaminated with SEO at three levels. The contaminated soil was inoculated with bacterial co-culture (150 mL) and subsequently bioenhanced with compost, processed cocoa pod husk (CPH) and cow dung. The factorial experiment was laid out in completely randomized design. Concentrations of total petroleum hydrocarbon (TPH) and selected polycyclic aromatic hydrocarbons (PAH) were estimated on the first day, 5th week and 10th week of incubation. Results obtained show that bacterial co-culture bioenhanced with compost produced the most significant TPH reductions (1318 and 261 mg kg-1) on 10% SEO contaminated soil at the 5th and 10th week respectively (p<0.05). Again, bacterial co-culture bioenhanced with compost produced the most significant PAH reductions (65.9 and 55.8 mg kg-1) on 10% SEO contaminated soil at the 5th and 10th week respectively (p<0.05). The significant bioremediation capabilities exhibited by the bacterial co-culture bioenhanced with organic amendments in this study has made these bioremediation agents potential candidates in remediating soils impacted with petroleum hydrocarbons.

The purpose of this study is to improve the gas–liquid separation performance of an oil tank and to establish a design method to enable gas–liquid separation only in an oil tank. Since it is difficult for conventional oil tanks to completely remove bubbles remaining in the hydraulic oil, it is essential to introduce a technology to actively separate and remove bubbles from the oil. Therefore, the bubble removal performance was improved even under the condition of added lateral acceleration by appropriately generating a swirl flow. First, an acrylic model of an oil tank was used to verify the accuracy by performing numerical analysis using various turbulence models. Then, the parameters of the bubble remover, such as the size of the oil tank, were studied. In addition, the bubble removal performance under the condition of added lateral acceleration was examined.

This paper describes the relative frequency of reports of oil and hydraulic fluid fumes in the ventilation supply air (“fume events”) compared to other types of fumes and smoke reported by U.S. airlines over 10 years. The author reviewed and categorized 12,417 fume/smoke reports submitted to the aviation regulator to comply with the primary maintenance reporting regulation (14 CFR § 121.703) from 2002–2011. The most commonly documented category of onboard fumes/smoke was electrical (37%). Combining the categories of “bleed-sourced”, “oil”, and “hydraulic fluid” created the second most prevalent category (26%). The remaining sources of onboard fumes/smoke are also reported. To put the data in context, the fume event reporting regulations are described, along with examples of ways in which certain events are underreported. These data were reported by U.S. airlines, but aviation regulations are harmonized globally, so the data likely also reflect onboard sources of fumes and smoke reported in other countries with equivalent aviation systems. The data provide insight into the relative frequency of the types of reported fumes and smoke on aircraft, which should drive design, operational, and maintenance actions to mitigate onboard exposure. The data also provide insight into how to improve current fume event reporting rules.

The study investigated the enhancement of soil quality of an oil-polluted ultisol using livestock wastes. Top soil (0 - 10 cm) was obtained as a pooled sample and polluted with spent lubricating oil at 10% w/w. The soil was subsequently amended with sun-dried goat (GT), rabbit (RB), and poultry (PG) dung at 10% w/w on dry weight basis both in singles, double-mixed, and triple-mixed combinations. Twelve weeks after treatment application, results showed that there was a 93.9% decrease (p<0.05) in bacterial colony count in the oil-polluted soil compared to the control. Penicillium notatum and Aspergillus niger as well as Bacillus sp. and Proteus sp. were the prominent fungal and bacterial species identified respectively. The most abundant plant in the soil seed bank was Panicum maximum with 10.4% abundance and this showed possible involvement of the plant in remediation of oil-pollution. The total hydrocarbon content of the oil-polluted soil was 9984.0 mg/kg, compared to 3170.6 mg/kg when amended with RB+GT, implying 76.77% remediation efficiency. Among several trials employed in this study, the combination of rabbit and goat wastes proved to be more effective in reducing the total hydrocarbon content of oil-polluted soil and therefore, is recommended as a potential candidate for application in the bioremediation of such soil.

The deposition efficiency and pressure drop of inertial impactor with variable area has been studied numerically and experimentally. The effect of volumetric flow rate, vertical barrier, oblique barrier and flexible concave plate versus deposition and impaction efficiency and pressure drop is investigated. Numerical simulation is carried out with DPM (discrete phase method) and turbulent model of SST k-ω. To validate the numerical results a special test rig is designed to study the deposition efficiency of engine oil droplets (blow-by) with a diameter of 0.1 to 6 µm. Experimental Tests are done in 8, 12, 16 and 20 L/min. To ensure the accuracy of the experimental results, all the tests are repeated at least three times for each volumetric flow rate. Gravimetric method is implemented to calculate the deposition efficiency. According to the results, the deposition efficiency is obtained between 73 and 94 percent for different mentioned impactors and different volumetric flow rate. The numerical results are confirmed by experimental results. Using the barriers increase the efficiency maximum 6 percent in different volumetric flow rate. The results show that by reducing the distance between the vertical barrier and the outlet of nozzle, the deposition and impaction efficiency are increased. Also, the Concave flexible plate with vertical barrier located at 1 mm from the outlet of nozzle is the most efficient case.

This study examines the influence of engine oil on friction reduction in spark ignition (SI) engines, specifically analyzing the effects of mileage on oil viscosity, contaminants, and overall oil quality when employing gasoline versus compressed natural gas (CNG) as fuels. The maintenance of engine oil quality is essential for optimal performance, necessitating rigorous monitoring of parameters in accordance with manufacturer specifications. Although prior research has investigated CNG as a vehicle fuel, its impact on the performance of aged engine oil remains inadequately addressed. A 4‐cylinder, 1.5 L SI engine, exhibiting 161,000 km of mileage, underwent 100 h of testing on gasoline followed by 100 h on CNG. Oil samples were collected at 20‐h intervals for analysis of both local and foreign contaminants, oil performance metrics (total base number (TBN), total acid number (TAN), key additives (calcium, zinc, phosphorus), and viscosity at 40 and 100°C. Results revealed significant changes in oil properties: Oil viscosity decreased more with gasoline than CNG after 100 h at 40°C, silicon (Si) contaminants rose from 0 to 13 ± 1 ppm with gasoline compared to an increase from 0 to 4 ± 1 ppm with CNG; fuel dilution reached 1.5 ± 0.87% with gasoline, while CNG showed a 0.5% increase. Iron (Fe) content surged from 0 to 21 ± 0.5 ppm with gasoline and 11 ppm with CNG, while aluminum (Al) levels fluctuated minimally. TBN and TAN values demonstrated slight variations, indicating that CNG generally outperformed gasoline, with minimal differences in TBN relative to mileage.