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Abstract This study investigates the influence of oil polarity on interfacial tension (IFT), contact angle, oil recovery, and effluent pH in smart water and Low-salinity water injection. The results indicate that the interaction between the hydration shell of ions and the polar components (PCs) of oil is crucial. Increasing oil polarity enhances the potential for interaction with the hydration shell of ions, leading to reduced IFT, altered wettability, and improved oil recovery; which could be boosted by the contribution of a higher number of anions in the smart water bulk through the enhancement of their interaction with the PCs (especially acidic components) of oil. The study demonstrates that increasing the SO4 2− concentration in seawater increased oil recovery for oils with higher acid component content, as indicated by total acid number values of 0.87, 0.99, and 1.32 mgKOH/g, the tertiary oil recovery factors for these oils were 61.10%, 69.82%, and 87.09%, respectively. The effluent pH results align with the findings of contact angle and oil recovery, confirming the dominant influence of anions on oil recovery. The interaction between the PCs of oil and the hydration shell of ions is thus highlighted as a critical factor in the observed outcomes.

The use of environmentally friendly hydraulic fluids is frequently influenced by the temperature reached in the hydraulic circuit. This paper presents an analysis of the effect of temperature on the lifetime of the hydraulic fluid and the hydraulic pump. The test was carried out by continuous loading with a pressure of 21 MPa and a temperature of 96 °C for 100 h. A pressure valve was used for the continuous loading and the temperature was maintained using a cooler. At intervals of 25 h, the flow characteristics of the hydraulic pump were measured and oil sampling was carried out. Subsequently, a comprehensive chemical and physical analysis was carried out. In the present paper, a comprehensive analysis of the influence of eco-friendly hydraulic fluid on the operation of a gear hydraulic pump has been carried out. The study itself did not show the negative influence of the eco-friendly hydraulic fluid on the operation of the gear hydraulic pump. It can be expected that the results of the study will enable the use of eco-friendly hydraulic fluids in environmentally sensitive areas. [ABSTRACT FROM AUTHOR]

The use of environmentally friendly hydraulic fluids is frequently influenced by the temperature reached in the hydraulic circuit. This paper presents an analysis of the effect of temperature on the lifetime of the hydraulic fluid and the hydraulic pump. The test was carried out by continuous loading with a pressure of 21 MPa and a temperature of 96 °C for 100 h. A pressure valve was used for the continuous loading and the temperature was maintained using a cooler. At intervals of 25 h, the flow characteristics of the hydraulic pump were measured and oil sampling was carried out. Subsequently, a comprehensive chemical and physical analysis was carried out. In the present paper, a comprehensive analysis of the influence of eco-friendly hydraulic fluid on the operation of a gear hydraulic pump has been carried out. The study itself did not show the negative influence of the eco-friendly hydraulic fluid on the operation of the gear hydraulic pump. It can be expected that the results of the study will enable the use of eco-friendly hydraulic fluids in environmentally sensitive areas.

The present study demonstrated the efficiency of ionic liquid in the removal of naphthenic acids from crude oil. The crude oil sample was obtained from Belema oil field in Southern Nigeria while tetramethyl ammonium hydroxide pentahydrate (TMAH) ionic liquid was commercially obtained. Liquid-liquid extraction was carried out and the reaction conditions were modelled and optimized using Box-Behnken design of the response surface methodology. Ionic liquid concentration (w/v%), reaction temperature (°C), and reaction time (mins) were selected as the factors while extraction efficiency (%) was selected as the response. The results of the study showed that the highest extraction efficiency of 96.67 % was achieved under reaction conditions of 3 w/v% ionic liquid concentration, 50 °C reaction temperature, and 45 mins reaction time. Owing to R2, adjusted R2, and predicted R2 values generally > 0.90, the model accurately described the deacidification reaction. Optimization results indicated that removal efficiency can reach over 96 % at 2.82 w/v% ionic liquid concentration, 48 °C reaction temperature, and 45 mins reaction time. The characterization of the original and deacidified oils using GC–MS showed reduced concentration of acidic species in the latter. Also, FT-IR of the ionic liquid showed minimal or no variations in functional groups before and after extraction, highlighting a possibility for regeneration of the ionic liquid. The findings of the study showed the use of ionic liquids as green alternatives in the removal of acidic species from crude oil.

Polyol‐ester lubricants have been used and developed for aviation gas turbine engines for many decades. The newest MIL‐PRF‐23699 lubricant class, called enhanced ester (EE), provides the best combination of thermal stability, load carrying capability, boundary lubrication and compatibility with fluoroelastomer O‐rings. Two candidate EE Class formulations and one high thermal stability class formulation conforming to MIL‐PRF‐23699G were evaluated for oil degradation with up to 3000 h of bearing operation. Lubricant degradation was studied using VIM VAR M50 bearings with M50 and silicon nitride balls under two operating conditions using two bearing test rigs. Oil degradation in terms of oxidation time, total acid number and viscosity was studied as a function of time with varying results for the three lubricants. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess whether electrical parameters (capacitance and conductivity) of fresh engine oils—tested over a wide range of measurement voltage frequencies—can be used for oil quality assessment and its identification, based on physicochemical properties. The study encompassed 41 commercial engine oils with different quality ratings (American Petroleum Institute (API) and European Automobile Manufacturers' Association (ACEA)). As part of the study, the oils were tested for their total base number (TBN) and total acid number (TAN), as well as their electrical parameters, including impedance magnitude, phase shift angle, conductance, susceptance, capacitance and quality factor. Next, the results for all of the samples were examined for correlations between the mean electrical parameters and the test voltage frequency. A statistical analysis (k-means and agglomerative hierarchical clustering) was applied to group oils with similar readings, drawing on the values for all electrical parameters to produce group oils with the highest similarity to each other into clusters. The results show that the electrical-based diagnostics of fresh engine oils can serve as a highly selective method for identifying oil quality, offering much higher resolution than assessments based on the TBN or the TAN. This is further supported by the cluster analysis, with five clusters generated for electrical parameters of the oils, compared to only three generated for TAN- and TBN-based measurements. Out of all the tested electrical parameters, capacitance, impedance magnitude and quality factor were found to be the most promising for diagnostic purposes. The value of electrical parameters of fresh engine oils is mostly dependent on the test voltage frequency (with the exception of capacitance). The correlations identified in the course of the study can be used to select for those frequency ranges that offer the highest diagnostic utility. [ABSTRACT FROM AUTHOR]

The bio-oil produced from the pyrolysis of biomass is highly corrosive due to the high content of organic acids. These organic acids could be removed through an appropriate upgrading process, i.e., esterification using alcohols to form less polar esters. In this study, the bio-oil used as the feedstock in the esterification was produced from the pyrolysis of Sengon wood with a particle size of 297 µm at 600 °C. The esterification was performed at 70 °C in the presence of a trichloro acetic acid (TCA)-modified Indonesian H-zeolite catalyst with various weight ratios of bio-oil-to-methanol and reaction times under a constant stirring rate of 500 rpm. The esterification progress was indicated by the decrease in the total acid number of the bio-oil after esterification. No significant coke formation (< 0.05 wt%) was observed indicating that the suppression of repolymerisation could be achieved. This study showed that the esterification underwent in a fast rate, indicated by the decrease in the total acid number of the bio-oil by 47.85 % only over a 15-min esterification. Compared to the uncatalysed esterification, the TCA/zeolitecatalysed esterification showed a higher decrease in the total acid number of the bio-oil up to 65.83 %, due to the conversion of the carboxylic acids to esters. [ABSTRACT FROM AUTHOR]

The occurrence of naphthenic acids (NAs) in crude oil and its fractional distillation cuts have been widely recognized to be a natural phenomenon. Despite this, they continue to generate wide interest due to the ecological and industrial concerns emanating from their toxicity and corrosion effects. In this study, refined petroleum products were assayed for their physical and chemical properties as well as associated NAs. The NAs were removed using the solvent extraction method and characterized using the gas chromatography–mass spectrometry technique. The total acid number and densities of the gasoline, kerosene, diesel, and lubricating oil samples were 9.37, 5.44, 12.45, and 5.72 mg KOH/g, and 0.63, 0.66, 0.72, and 0.75 g/cm3, respectively. In consonance with other estimated properties, it was observed that lubricating oil was the heaviest of the studied oil samples while gasoline was the lightest. This was attributed to the presence of more aromatic compounds in the lubricating oil sample. Although there were slight variations in the profiles of NAs from sample to sample, they generally contained degree of unsaturation (z), z = 0 to z = − 16 compounds with a high predominance of aliphatic naphthenic acid types. The carbon numbers of the NAs detected in the oil samples ranged from 8 to 15. The estimated carbon preference index (CPI) indicated that the lubricating oil sample may have emanated from biogenic contribution (CPI > > 1) while the other samples likely emanated from petrogenic sources (CPI < 1). The even–odd carbon ratio (E/O) indicated that there is no carbon preference among the studied oil samples. [ABSTRACT FROM AUTHOR]

Characterization of PLGA polymers used in FDA-approved drug products is critical for quality control and qualitative/quantitative (Q1/Q2) evaluation of potential generic formulations. Various techniques have been developed and used to characterize the molecular properties of PLGA polymers, such as molecular weight, molecular composition, and molecular structure. Commonly used techniques include gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), semisolvent methods, and GPC-based intrinsic viscosity measurement. It is noted that the existing analytical methods may not be able to separate and quantify PLGA polymers when used as a mixture in a drug product (e.g., Durysta and Ozurdex). In particular, one assay method still lacking is quantitating the PLGA polymer with acid-end-cap (PLGA-A) in the mixture containing PLGA with ester-end-cap (PLGA-E), especially when the sample quantity is below the submilligram level. The total PLGA quantities available in Durysta and Ozurdex formulations are too small (<1 mg) to use existing assay methods to quantify the PLGA-A content. A new assay method was developed to quantitate PLGA-A in the mixture with PLGA-E. The acid end-cap was modified with pyrene methylamine (a UV dye) to enhance the signal and compared with the total PLGA quantity measured with the refractive index (RI) after a sample was run through a GPC. This GPC-UV/RI approach is based on measuring the total acid number (TAN) of PLGA-A and converting it to the PLGA-A quantity to compare with the total PLGA. Unlike conventional methods of measuring TAN, the GPC-UV/RI methods enables TAN measurements of submilligram PLGA quantities. Application of this method to Ozurdex-similar samples showed the expected acid:ester ratio of PLGAs. This new approach provides another powerful tool for characterizing PLGA polymers in FDA-approved drug products. This is especially significant considering that the PLGAs of commercial products are likely to have molecular properties different from those of the raw PLGAs before going through the manufacturing process.

The study of lube oil is useful in scheduled maintenance activity, determining the oil replacement time for engines, to increase the engine life and ensure the maximum performance. Investigation of engine oil can reduce maintenance cost and promises higher design efficiency. Experiments were carried out on a mono cylinder compression ignition engine fueled with diesel-ethanol blended, which is operated at a constant rated speed of 1500 rpm for 100 hours. The lube oil samples were subjected to wear metal tests, chemical and physical tests. The quantity of wear metal in the engine oil was observed using the atomic absorption spectrometer. The total base number and total acid number were measured by the titration method according to ASTM code ASTM D6654 and ASTM2896, respectively. The viscosity was determined using the Stab Viscometer, SVM3000, by the ASTM D445 method at 40oC temperature. Iron and copper concertation was increased with an increase in usage time. However, TBN decreased, and TAN increased with the usage time. Viscosity and density decrease with the increase in usage time. The lube oil shows that the engine can be operated for an extended time with the same lube oil since all the measured parameters are within the limit.

This scientific data article is related to the research work entitled “Optimization of bio-oil production from microwave co-pyrolysis of food waste and low-density polyethylene with response surface methodology” published in “Journal of Environmental Management” (10.1016/j.jenvman.2021.113345). In this work, collection of Food Waste (FW) and Low-density polyethylene (LDPE) for 7 consecutive days and its characterization was done. Based on the characterization, the composition of simulated FW was fixed for different experimental runs. Valorization of feedstock (FW and LDPE) with increasing temperature with/without the presence of microwave susceptor was analyzed. Statistical significance of LDPE and microwave susceptor addition on bio-oil yield and Total Acid Number (TAN) was verified with single-factor ANOVA. The outcomes of the present dataset will be helpful for the researchers and engineers working in the field of bio-oil generation from microwave co-pyrolysis of mixed waste.

[Display omitted] • Potentiometric method for TAN determination free of chloride salt interference. • Micellar solubilization of acidic compounds of crude oil in O/W nanoemulsions. • The potentiometric method was applied to different types of crude oil samples. • Ca, Mg, and Sr salts in crude oil did not affect TAN determination. The determination of the total acid number (TAN) of crude oils is of great importance in the petroleum refining industry for evaluating the corrosion potentials of oils. The presence of salts CaCl 2 and MgCl 2 at concentrations higher than 100 mg kg−1 in crude oil can interfere with some standard methods used to measure the TAN; thus, CaCl 2 and MgCl 2 salts can hinder the accuracy of TAN determination. In this work, a new method based on the potentiometric titration of O/W nanoemulsions (NMS_TAN) was developed to eliminate the interference of CaCl 2 and MgCl 2 on TAN determination. This method is based on the potentiometric titration of oil-in-water (O/W) nanoemulsions formed via the micellar solubilization of the acidic compounds of crude oil with KOH in propan-2-ol. The O/W nanoemulsion was prepared using ultrasound and a nonionic surfactant (Tween 80). The accuracy of the method was evaluated by recovery tests, and the interferences of the mixture of salts NaCl, CaCl 2 , MgCl 2 , and SrCl 2 in the determination of TAN using NMS_TAN were investigated. NMS_TAN was employed to determine the TAN of 15 oil samples (American Petroleum Institute gravity: 13.2–38.3), and the results were statistically compared with those of standard methods. The accuracy of the NMS_TAN method was not affected by the presence of salts in the crude oil samples. Recoveries from a sample spiked with hexanoic acid ranged from 95.0 % to 100.3 % of the theoretical values. The TAN of crude oil samples with CaCl 2 and MgCl 2 concentrations below 50 mg kg−1 determined using the potentiometric method were comparable to those determined by standard methods. The TAN of crude oil samples with high salt concentrations (>500 mg kg−1) obtained by the standard methods were 77 %–90 % higher than those determined by NMS_TAN. The potentiometric method is fast, simple, and accurate and allows for robust quantifications of the TAN of different crude oil samples without chloride salt interferences. [ABSTRACT FROM AUTHOR]

The study of lube oil is useful in scheduled maintenance activity, determining the oil replacement time for engines, to increase the engine life and ensure the maximum performance. Investigation of engine oil can reduce maintenance cost and promises higher design efficiency. Experiments were carried out on a mono cylinder compression ignition engine fueled with diesel-ethanol blended, which is operated at a constant rated speed of 1500 rpm for 100 hours. The lube oil samples were subjected to wear metal tests, chemical and physical tests. The quantity of wear metal in the engine oil was observed using the atomic absorption spectrometer. The total base number and total acid number were measured by the titration method according to ASTM code ASTM D6654 and ASTM2896, respectively. The viscosity was determined using the Stab Viscometer, SVM3000, by the ASTM D445 method at 40oC temperature. Iron and copper concertation was increased with an increase in usage time. However, TBN decreased, and TAN increased with the usage time. Viscosity and density decrease with the increase in usage time. The lube oil shows that the engine can be operated for an extended time with the same lube oil since all the measured parameters are within the limit. [ABSTRACT FROM AUTHOR]

We present the main reason behind two low-salinity waterflooding (LSW) coreflood tests, that failed to demonstrate promising EOR response. Repeating the coreflood tests using the acid-enriched oil and injecting the low-salinity brine in the secondary and tertiary modes has led us that the total acid number (TAN) and the recovery mode appear to be the key successful factors for LSW in our carbonate system. [ABSTRACT FROM AUTHOR]

Thermal oxidation stability is an important parameter for jet fuel practical application. In this work, in order to evaluate the influence of deoxygenation on fuel stability, samples of typical fuels (JP-10 and RP-3) were subjected to deoxygenation by nitrogen purge and then subjected to accelerated thermal oxidation (180°C, 200°C, and 220°C). The parameters of hydroperoxide number, total acid number, size distribution of insoluble oxidation products, and concentration of remaining antioxidant (butylated hydroxytoluene, MIT) were monitored and analyzed. The results show that deoxygenation and thermal oxidation have very little influence on the fuel physical properties (density, net heating value, and kinematic viscosity). However, deoxygenation significantly reduces hydroperoxide number, total acid number, and remaining BHT concentration in the fuel after accelerated oxidation. Moreover, the deoxygenation treatment also inhibits the formation of soluble macromolecular oxidatively reactive species (SMORS) and insoluble oxidation products such as gums and deposits. [ABSTRACT FROM AUTHOR]

The naphthenic acids (NAs) present in the crude oil can lead to the corrosion problems in oil refinery equipment apart from reduces the performances of the oil. In this study, the method to remove NA were done by means of extraction using sodium thiocyanate in ethanol with the aid of Ni/Ca/Al2O3 and Ni/Ce/Al2O3 catalysts at 27 °C reaction temperature. The catalyst was prepared by incipient wetness impregnation method (IWI) and calcined at three different temperature, 800, 900 and 1000 °C respectively. The efficiency of the extraction was affected by the catalyst calcination temperature. Both catalysts calcined at 800 and 900 °C gave total acid number (TAN) value more than 1 mg KOH/g while by using Ni/Ca(10:90)/Al2O3 and Ni/Ce(10:90)/Al2O3 calcined at 1000 °C the TAN value were reduced to 0.28 and 0.65 mg KOH/g respectively. Brunauer-Emmett Teller (BET) result shows both catalysts have large surface area that provide more reaction cites when calcined at 1000 °C. X-ray Diffraction Spectroscopy (XRD) analysis of Ni/Ca/Al2O3 catalyst revealed that the active site was dominated by the Al2O3 species while CeO2 was the active site for Ni/Ce/Al2O3 catalyst. In conclusion, both catalysts reduced the TAN value of acidic crude oil efficiently. [ABSTRACT FROM AUTHOR]

[Display omitted] • The thermometric method for TAN determination in crude oil does not account for chloride salts as interferents. • The impact of chloride salts on TAN determination was investigated in titration solvents, and the precipitates were characterized. • NaCl in the sample did not affect TAN determination. • The presence of CaCl 2 and MgCl 2 in titration solvent (concentration > 100 mg kg−1) increased the apparent TAN. • Chloride salt addition affected the TAN results of API 31.0 and 16.7 crude oil samples. Crude oils extracted from reservoirs often contain water with corrosion-causing dissolved salts. Therefore, the residual salt content of crude oils supplied to an oil refinery should be as low as possible. The total acid number (TAN) is an indicator of the corrosive activity of crude oil. However, its determination remains an analytical challenge because of the presence of dissolved salts, mineral matter, or chemicals. Herein, we quantified the impact of chloride salts on the measurement of the TAN of titration solvents and crude oil samples using the American Society for Testing and Materials (ASTM) D8045. Water-in-crude oil (W/O) emulsions (2.4 wt% water) were prepared using light and heavy crude oils mixed with saline solutions, and their TAN was evaluated. The precipitates obtained from the titration solvent were characterized. A chloride salt content of 100 mg kg−1 in the titration solvent increased the apparent TAN. Analyses of the precipitates indicated that they comprised Ca(OH) 2 , Mg(OH) 2 , and Sr(OH) 2. The W/O emulsions of samples 1 (API 31.0) and 2 (API 16.7) exhibited an increase in their TAN of up to 89 and 45 wt%, respectively. When using catalytic thermometric titration, CaCl 2 , MgCl 2 , and SrCl 2 with concentrations above 100 mg kg−1 interfere with the determination of TAN. [ABSTRACT FROM AUTHOR]

The aim of this study is to explore the capability of subcritical methanol to reduce the acidity of naphthenic acids and to determine reaction kinetics for large-scale reactor design.The experiments were carried out in a 25 mL autoclave reactor (China) at temperatures of 70-120oC, Methanol Partial Pressures (MPPs) of 0.1-1.5 MPa, and reaction times of 0-60 min. The total acid number content of the samples was analyzed using ASTM D 974 techniques. Experimental results reveal that total acid number reduction of naphthenic acids increased with increasing reaction temperature, MPP, and reaction time. Approximately 74.20% total acid number was reduced at a temperature of 120oC, a MPP of 1 MPa, and a reaction time of 60 min. Experimental data revealed that total acid number removal reaction kinetics followed second-order kinetics with an activation energy of 11.27 kcal/mol. Therefore, subcritical methanol is able to reduce the total acid number of naphthenic acids without the addition of any catalyst.

The presence of naphthenic acids (NAs) in crude oil is the major cause of corrosion in the refineries and its processing equipment. The goal of this study is to reduce the total acid number (TAN) of NAs by treating them with subcritical methanol in the presence of acidic ionic liquid (AIL) catalysts. Experiments were carried out in an autoclave batch reactor and the effect of different reaction parameters was investigated. It was observed that TAN reduction was positively dependent on the temperature and concentration of the AIL whereas excess of methanol has a negative effect. Approximately 90% TAN reduction was achieved under the optimized reaction conditions using [BMIM]HSO4 as catalyst. It was also perceived from the experimental results that the AILs with longer alkyl chain exhibited higher catalytic activity. The activity and stability of AIL showed that they can be promising catalyst to esterify NAs under subcritical methanol.

The presence of an alkali such as sodium hydroxide (NaOH) within a process of enhanced recovery of crude oil having certain acidity allows the formation of surfactants with the ability of enhancing the separation of the crude oil from the reservoir rock where it is adsorbed due to a change of wettability. This work focused on studying the effect of NaOH on the enhanced recovery, in terms of the SARA composition, of two different API gravity crude oils (38.5 and 24.1°) having different total acid number. The results showed the existence of acid components with high and low reactivity to NaOH in the crude oil, where the first group is responsible of the in-situ synthesis of the surfactant. Moreover, it was found that the utilization of the alkali improved the recovery of the SARA fractions for each crude oil, especially for the 24.1°API crude oil for which the recovery resulted twice or three times higher to the evaluated for the 38.5°API crude oil. Additionally, it was found that a minimum of 0.2 wt% of NaOH reduced up to 4 times the value of the interfacial tension between the crude oil and the brine, regardless of the type of crude oil. [ABSTRACT FROM AUTHOR]

Abstract Foam flooding has been applied to improve oil recovery. However, interactions between crude oil and foam destabilize the foam and reduce its efficiency. Many researchers have examined the effects of interactions between crude oil and foam with a focus on the negative effects of these interactions. The goal of this study is to investigate the potential of a new hybrid Enhanced Oil Recovery (EOR) method termed Low Salinity Water Assisted Foam flooding (LSWAF) in sandstone rocks. This method involves the injection of Low Salinity Water (LSW) followed by the alternate injection of a Surfactant Aqueous Solution (SAS) and CO 2 gas. LSW solutions were prepared using different salinities of NaCl, KCl, CaCl 2 , and MgCl 2. Experiments were carried out using two types of crude oil with a different Total Base Number (TBN) and Total Acid Number (TAN), namely crude oil A and B. In terms of changes in wettability, for both crude oils, the experimental results revealed that the test with LSW of 500 ppm KCl outperformed other salinities. For crude oil with a higher TBN, the proposed hybrid technique led to improved performance. The insights presented in this study provide a good reference for further research in this area. Highlights • The ultimate goal of this work is to investigate the potential of a new hybrid EOR method termed Low Salinity Water Assisted Foam flooding (LSWAF). • The presence of polar components in crude oil is one of the fundamental requirements for the performance of LSW injection. • The proposed new mechanism "MIE-RS" for LSW was supported by the concept of cations replacement from rock surfaces and the reactivity series. • For both crude oils A and B, the highest residual oil recovery was achieved by the KCl injection pattern (FW-KCl–Foam), followed by the MgCl2 (FW-MgCl2–Foam) and finally by the FW injection pattern (FW-FW–Foam). [ABSTRACT FROM AUTHOR]

Cyclopentane carboxylic acid (CPCA) is a model compound of Naphthenic acids (NAs). This objective of this paper is to discover total acid number (TAN) reduction kinetics and pathways of the reaction between CAPA and subcritical methanol (SubC-MeOH). The experiments were carried out in an autoclave reactor at temperatures of 180-220°C, a methanol partial pressure (MPP) of 3 MPa, reaction times of 0-30 min and CPCA initial gas phase concentrations of 0.016-0.04 g/mL. TAN content of the samples were analyzed using ASTM D 974 techniques. The reaction products were identified and quantified with the help of GC/MS and GC-FID respectively. Experimental results reveal that TAN removal kinetics followed first order kinetics with an activation energy of 13.97 kcal/mol and a pre-exponential factor of 174.21 s-1. Subcritical methanol is able to reduce TAN of CPCA decomposing CPCA into new compounds such as cyclopentane, formaldehyde, methyl acetate and 3-pentanol.

Passenger safety requires that in commercial airplanes hydraulic actuators be powered by fire-resistant hydraulic fluids. As a downside, such fluids are hygroscopic which means that these tend to accumulate humidity from the environment and that the dissolved humidity tends to produce acidity which can corrode all kinds of metallic components inside a hydraulic system. As such damage in safety-critical subsystems is hard to localize and expensive to repair, sensor technologies are required which allow the state of water contamination and fluid degradation to be routinely checked and necessary maintenance actions to be scheduled in a way that causes minimum flight interruptions. The paper reviews progress that has been made in developing such sensor systems and in commissioning these into practical flight operation. Sensor technologies that proved optimally adapted to this purpose are multi-channel non-dispersive (NDIR) systems working in the mid-infrared range. Additional options concern optical absorption sensors working in the near-infrared and visible ranges as well as fluorescence sensors.

High acid crude oils contain large amount of naphthenic acids which cause serious corrosion problem in petroleum industry. Therefore, the removal of naphthenic acids becomes a great concern and challenge for oil refineries. In this study, the naphthenic acids in high TAN crude oils were removed by esterification with low consumption of methanol using a solid acid catalyst consisting of 12-tungstophosphoric acid (TPA) supported on γ-Al 2 O 3 (TPA/γ-Al 2 O 3 ) in a fixed-bed up-flow reactor. The catalyst was prepared by conventional wet impregnation method, and it possessed 25 wt% TPA with high dispersion, and large pore structure. TPA leaching problem from catalyst support was not observed during the reaction. The effect of various reaction parameters such as temperature and liquid hour space velocity (LHSV), and methanol to the crude oil ratio on TAN reduction were investigated in detail to maximize TAN reduction. The results revealed that the TPA/γ-Al 2 O 3 catalyst effectively removed the naphthenic acids via esterification in high TAN crude oils. The TAN decreased with increase in methanol/oil mass ratio, reaction temperature, but it increased with increase in LHSV. In a long-term experiments (up to 100 h) running at a reaction temperature of 250 °C and LHSV of 3 h −1 using 2 wt% methanol in acidic crude oil, the TANs of acidic crude oil reduced from 2.0 mg KOH/g to a value below 0.5 mg KOH/g which is an acceptable TAN value of crude oil to process in the refineries without material upgrades. [ABSTRACT FROM AUTHOR]

The oxidative stability of three base lubricating oils of different grades light, medium and heavy oils (B1, B2 and B3, respectively) was studied at oxidative times 50, 100 and 150 hours. The quality of base oils under investigation were evaluated on the basis of total acid number, vaporization loss, kinematic viscosity and quantity of sludge formed. Also, the chemical composition of the studied lubricating oils was achieved via capillary gas chromatography. The comparative study of the oxidative performance of the base oils showed that the higher degrees of heavy oil than light one. The increase in the oxidation time led to increases of the evaporation loss and lubricant viscosity. Analysis of a lubricant's oxidation stability therefore contributes to a better understanding of its effectiveness under normal operating conditions and its suitability for formulating automotive lubricants. The aim of this work is the study the Potential life of lubricant oils inside engine motor at different oxidative times in view of their oxidation stability. [ABSTRACT FROM AUTHOR]

The purpose of this work is to introduce a rapid and practical method for quantitatively analyzing total acid number in biodiesel by a reaction headspace gas chromatography. In this method, the carbon dioxide formed by the reaction of acidic species (i.e., fatty acids) in biodiesel and sodium bicarbonate can be measured by GC. The results showed that the complete reaction can be achieved in 25 min at 75 °C. The relative standard deviation of this method in total acid number determination was within 2.93%, the relative differences has been determined by comparing the total acid number obtained from this new analytical technique with the data from the reference technique (i.e., potentiometric titration), which are less than 8.05%. The reaction HS-GC technique is automated, efficient and can be a reliable tool for quantifying the total acid number in biodiesel and related research. [ABSTRACT FROM AUTHOR]

Some benzimidazole derivatives, 2(1-H benzo(d)imidazole-2-y1)thio) N-butyl acetamide Ia, 2(I-H benzo(d)imidazole-2-yl)thio) N-octylacetamid Ib and 2(I-H benzo(d)imidazole-2-yl) thio) N-dodecylactamide Ic were prepared and studied as antioxidants for base stock. The structure of these compounds was elucidated by elemental analysis, IR and 1 H NMR spectroscopy. The inhibition efficiency of the prepared compounds was determined by studying the oxidation stability of the local base oil via the change in total acid number (TAN), viscosity and infrared (IR) spectroscopy. [ABSTRACT FROM AUTHOR]

Refining of high acid crudes (HACs) is seriously limited by extensive corrosion of refinery equipment due to the presence of intrinsic naphthenic acids (NAs). Herein, in the absence of a catalyst or external hydrogen, effective removal of the NAs contained in HACs was achieved using methanol at moderate temperature and moderate pressure. Several process variables, including the temperature, crude concentration, and reaction time are explored to optimize the removal of NAs from HACs. At 250 °C, 6.4 MPa, and 33.3 wt% crude, a very low total acid number (TAN) of 0.08 mg-KOH/g-oil (96.9% reduction efficiency) with a high oil yield (95 wt%) is achieved. During the reduction of the TAN using methanol, some fraction of the resins and asphaltenes in the crude oil crack to form low-molecular-weight aromatic compounds. Compared to deacidification using methanol, pyrolysis (without methanol) results in a much lower TAN reduction efficiency (38.6%). The major deacidification mechanism using methanol is esterification, while that of pyrolysis (without methanol) is decarboxylation. [ABSTRACT FROM AUTHOR]

Subject of this study is the parametric investigation of the effect of biodiesel aging on the formation of deposits inside common rail Fuel Injection Equipment (FIE). The parameters investigated are key fuel properties and their degradation rate, FAME composition as well as FIE component design. Fuel degradation and deposit formation is simulated in a prototype FIE test rig. A market study was initially performed to monitor market diesel fuel quality in Europe. The sensitivity of the FIE to FAME concentration was investigated with market B7 and B20 test fuel. B20 pre-aging and fuel enhancement with anti-oxidant were studied to assess the impact of fuel degradation speed and level relatively to deposit formation. A selection of EU market B7 fuels with different fresh fuel properties and FAME composition, were comparatively evaluated on the rig as regards their impact on injection flow and pump response deterioration together with their tendency to form deposits. Test rig operation with 2 different injector designs was utilized to further investigate deposit sensitivity. Injection flow deterioration and internal deposits were affected by injector design and fuel aging speed and were found to be related to Total Acid Number. A correlation between initial B7 Rancimat IP and FIE failure due to fuel aging was identified. The methodology developed is proposed as reference test for the evaluation of current and future automotive fuels as regards their tendency to form deposits. [ABSTRACT FROM AUTHOR]

Naphthenic acids (NAs) tend to cause operational problems that can lead to the deactivation of catalysts. To overcome the problem, catalytic deacidification was introduced utilizing an ammonia solution in ethylene glycol with the aids of alkaline earth metal catalyst with alumina as a support. The initial total acid number observed for NAs in n-dodecane was 4.21 mg KOH/g. In total, 1,000 mg/L of 0.4% NH3-EG were used as the acid removal agent. Calcium, barium, and magnesium catalysts were tested in this study. The results showed Cu/Ca/Al2O3was found to be the best catalyst that could be used to enhance the reaction. [ABSTRACT FROM PUBLISHER]

In this study, reclaimed waste cooking oil is proposed as an alternative insulating liquid for oilimmersed power transformers. Reclamation is carried out by heating a mixture of waste cooking oil and Fuller's Earth adsorbent and followed by filtration. Propyl gallate antioxidant is then added into the filtered oil. Four oil samples are investigated in this study: (1) new cooking oil (NCO), (2) waste cooking oil (WCO), (3) reclaimed oil (RWCO) and (4) reclaimed oil with propyl gallate antioxidant (RWCOPG). The AC breakdown voltage, moisture content and total acid number is measured for all oil samples according to the ASTM D1816, ASTM D1533 and ASTM D974 standard test method, respectively. The results show that the AC breakdown voltage is highest for the RWCOPG sample (28.08 kV), which is 0.4% higher than the standard requirement of 20 kV. The moisture content for this sample is 180.60 ppm, which is still below the allowable limit of 200 ppm. However, the total acid number is highest for the RWCOPG sample which suggests that it has high acidity. It is indicated that the antioxidant-reclaimed waste cooking oil has potential to be used as an insulating liquid for oil-immersed power transformers, but much work is still needed to reduce the total acid number of this oil. [ABSTRACT FROM AUTHOR]

A robust analytical method is required for the determination of low-molecular weight organic acids, which are potential causes of refinery and internal combustion engine corrosion. The ion chromatographic method developed in this study allows the determination of acetic acid and formic acid in diesel oil mixtures with a motor oil volume fraction of up to 10%. The hydrophobic matrix is automatically removed in-line through a matrix elution step with organic solvent and nonaqueous anion-exchange analyte extraction. Acetic acid and formic acid, as the smallest and most acidic aliphatic naphthenic acids, were determined. Gradient anion-exchange chromatography on high-capacity columns in combination with suppressed conductivity detection allowed their selective and sensitive determination. Typical recovery values were from 82 to 107% for each acid in the matrices evaluated with reproducibility less than 5% for acid fortified samples. [ABSTRACT FROM PUBLISHER]

• Four novel pyrrolidinium-based amino acid ionic liquids (AAILs) were synthesized. • The physicochemical properties of these AAILs were investigated. • AAILs were used as a green chemistry approach for the deacidification of crude oil. • Extremely small amounts of ILs are sufficient to deacidify highly acidic crude oil. • Antimicrobial activity assay was performed to study its effect on aquatic system. Four novel pyrrolidinium-based amino acid ionic liquids were synthesized and characterized. The physicochemical properties of these amino acid ionic liquids (AAILs), such as viscosity, density, thermal stability, and surface tension were investigated. These ionic liquids (ILs) were used as a green chemistry approach for the extraction of naphthenic acid from the model oil. The influence of amino acid anions on the de-acidification process was assessed by attaching prolinate, glycinate, alaninate and serinate. Extraction results show that very small amounts of ILs are sufficient to extract naphthenic acid from a model oil configuration with a high total acid number. The regeneration and reusability of the synthesized ILs have also been analysed in this work. Moreover, the antimicrobial activity assay was performed to ascertain the potential toxicological effect of the synthesized set on the aquatic system. [ABSTRACT FROM AUTHOR]

This article examines the possibility of measuring lift maintenance through analysis of used hydraulic oil. Hydraulic oils have proved to be a reliable indicator for the maintenance performed on elevators. It has also been proved that the end users or the maintenance personnel do not always conform to the instructions of the elevators’ hydraulic machine manufacturer. Furthermore, by examining the proportion of the metals, an estimation of the corrosion and the wear resistance of the joined moving parts can be observed. Additionally, the presence of chlorine and calcium in hydraulic oils demonstrates their function in a highly corrosive environment.

The oxidation resistance of iron-based alloys depends on the formation of thin protective films consisting of reaction products between the alloys and the ambient atmosphere. The high corrosion resistance of Fe-Cr-Mo alloys has been attributed to the rapid formation of a uniform, highly protective passive film. The pipes hardness and resistance to various forms of corrosion are determined by the composition of the oxide layer that plays an important role in determining the lifetime of the pipes themselves. The thermal stability of the oxide layer is influenced by its composition and thickness as well as by the bond to the underlying metal.Determining factors for the high temperature corrosion are generally: temperature, metallurgy, TAN (chloridric and naphthenic acid), local flow conditions, sulphur compounds.