Naphthenic Acids Research Articles

Continuous Extraction of Naphthenic Acid from Low-Grade Oil Using 1,6-Hexanediol in an Ammonia Solution

Continuous Extraction of Naphthenic Acid from Low-Grade Oil Using 1,6-Hexanediol in an Ammonia Solution

Naphthenic Acid Fraction Compounds Reduce the Reproductive Success of Wood Frogs (Rana Sylvatica)

Naphthenic Acid Fraction Compounds Reduce the Reproductive Success of Wood Frogs (Rana Sylvatica)

Naphthenic Acid Dynamic Responses and Degradation Mechanisms of Microbial Communities in Surface Seawater of Jiaozhou Bay

Naphthenic Acid Dynamic Responses and Degradation Mechanisms of Microbial Communities in Surface Seawater of Jiaozhou Bay

Transforming Micropores to Mesopores by Heat Cycling Koh Activated Petcoke for Improved Kinetics of Adsorption of Naphthenic Acids

Transforming Micropores to Mesopores by Heat Cycling Koh Activated Petcoke for Improved Kinetics of Adsorption of Naphthenic Acids

Influence of interfacial responses of Berea Sandstone in low-salinity waterflooding environments

Wetting conditions and fluid–fluid interfacial properties are essential to understanding oil recovery in the context of low-salinity and smart waterflooding. Many have deemed wettability alteration to be the dominant interaction, while some highlight the importance of fluid–fluid interactions. In some rock-fluid systems, benefits from the use of additives can arise to favor hydrocarbon production. Understanding the balance between the fluid–fluid and rock-fluid interactions when utilizing additives is crucial to evaluate benefits in improved efficiency. Ultimately, this understanding will shed light on recovery mechanisms. Regarding oil recovery, previous studies indicate that the injection of a naphthenic acid (NA) blend dissolved in an injection brine improves oil recovery in Berea Sandstone, particularly under low-salinity conditions. Interfacial rheology results for the brine-oil interface correlated well with the recovery response. This observation was speculated to serve as a potential improved recovery mechanism through oil-trapping suppression. However, the said studies did not evaluate potentially concurrent rock wettability alteration during recovery or the initial wetting condition. The purpose of this work is to determine the production behavior in systems with NAs, namely NA-10 (3-Cyclohexanepropinoic acid), NA-14 (Cyclopentane carboxylic acid), NA-18 (Cyclohexane carboxylic acid), and NA-mix (Naphthenic acid mixture), at different initial wetting conditions under spontaneous imbibition. In addition, we tested the NAs ability to alter wettability in Berea Sandstone and determine each “additive’s” capacity to improve recovery. Time-domain nuclear magnetic resonance (TD-NMR), contact angle, and Amott cell tests, i.e. spontaneous imbibition, were used to analyze the influence of the selected naphthenic acids on oil displacement under different initial wetting conditions. Our results indicate that individual naphthenic acids indeed have potential as additives in low-salinity waterflooding for oil-wet systems while negatively impacting recovery in water-wet systems. However, results suggest that the evolution of the interfacial properties and wettability conditions are equally important on the recovery behavior.

Naphthenic Acids: Formation, Role in Emulsion Stability, and Recent Advances in Mass Spectrometry-Based Analytical Methods.

Naphthenic acids (NAs) are compounds naturally present in most petroleum sources comprised of complex mixtures with a highly variable composition depending on their origin. Their occurrence in crude oil can cause severe corrosion problems and catalysts deactivation, decreasing oil quality and consequently impacting its productivity and economic value. NAs structures also allow them to behave as surfactants, causing the formation and stabilization of emulsions. In face of the ongoing challenge of treatment of water-in-oil (W/O) or oil-in-water (O/W) emulsions in the oil and gas industry, it is important to understand how NAs act in emulsified systems and which acids are present in the interface. Considering that, this review describes the properties of NAs, their role in the formation and stability of oil emulsions, and the modern analytical methods used for the qualitative analysis of such acids.

STUDY OF BIOLOGICAL ACTIVITY OF RACEMIC AND OPTICALLY ACTIVE ESTERS OF NAPHTHENIC AND FATTY ACIDS BASED ON UNSATURATED OXYESTERS

Petrochemical products based on petroleum naphthenic acids have special properties. Esters of naphthenic acids possess practically valuable organic compounds. The aim of this work is the development of effective methods for the preparation of aromatic esters based on naphthenic and individual fatty acids which is a very promising direction in the medicine practice. The synthesis of unsaturated racemic and chiral oxyethers was carried out on the basis of the interaction of chloromethylpropargyl (allyl) esters with carbonyl compounds with the participation of metallic zinc. Also, to study the biological activity, racemic and optically active esters were synthesized based on naphthenic acids and unsaturated racemic and chiral oxyesters. As test cultures used: gram-positive (Staphylo-coccus aureus-Staphylococcus aureus), gram-negative (Pseudomonas aeruginosa – Pseu-domonas aeruginosa, Escherichia coli) bacteria, as well as yeast-like fungi of the genus Candida - Candida albicans. Analysis of the biological activity of the synthesized compounds showed that optically active bicyclo [2.2.1] hept-5-ene-2-methylol monoesters have higher antimicrobial and antifungal activity compared to their racemic analogs and drugs used in medicine.

Efficient and sustainable separation of yttrium from heavy rare earth using functionalized ionic liquid [N1888][NDA

The separation of adjacent rare earth (RE) is one of the most difficult separation tasks, especially the separation and purification of yttrium (Y) from heavy rare earth (HREE). In the traditional Y separation process, the organic phase composed of acidic extractants such as naphthenic acid (HA) and neodecanoic acid (NDA) need to be saponified with sodium hydroxide or ammonia in each cycle. The resulting alkali consumption and saponification wastewater have negative impacts on the environment. In this article, a bifunctional ionic liquid [methyltrioctyl ammonium][neodecanoate] ([N1888][NDA]) was synthesized. The extraction capacity, stripping property and recycling stability of [N1888][NDA] were systematically studied. On this basis, the separation process of Y was developed. The separation factors (β) of Ho/Y and Er/Y were 2.64 and 4.32, especially the Lu/Y reached 16.27. A higher separation factor is of significance for the separation of Y from HREEs. The extraction sequence of rare earth elements (REEs) with [N1888][NDA] follows the positive sequence extraction, which is the same as that in neodecanoic acid system. In addition, the separation process of industrial HREE feed liquid containing 0.20 mol L−1 REEs (Y, 88.87 mol.%) was studied. By adjusting the extraction conditions, salting-out reagent such as NaCl did not need to be used in the aqueous phase, which helps to avoid high salt components in RE products. Through the fractional extraction experiment of 11-stage extraction and 4-stage scrubbing, the Y product with a purity of 99.03 mol.% was obtained. The organic phase composed of [N1888][NDA] was stable after being regenerated with NaOH for recycling extraction.

Removal of Excess Alkali from Sodium Naphthenate Solution by Electrodialysis Using Bilayer Membranes for Subsequent Conversion to Naphthenic Acids.

The processing of solutions containing sodium salts of naphthenic acids (sodium naphthenate) is in high demand due to the high value of the latter. Such solutions usually include an excessive amount of alkali and a pH of around 13. Bipolar electrodialysis can convert sodium naphthenates into naphthenic acids; however, until pH 6.5, the naphthenic acids are not released from the solution. The primary process leading to a decrease in pH is the removal of excess alkali that implies that some part of electricity is wasted. In this work, we propose a technique for the surface modification of anion-exchange membranes with sulfonated polyetheretherketone, with the formation of bilayer membranes that are resistant to poisoning by the naphthenate anions. We investigated the electrochemical properties of the obtained membranes and their efficiency in a laboratory electrodialyzer. Modified membranes have better electrical conductivity, a high current efficiency for hydroxyl ions, and a low tendency to poisoning than the commercial membrane MA-41. We propose that the primary current carrier is the hydroxyl ion in both electromembrane systems with the MA-41 and MA-41M membranes. At the same time, for the modified MA-41M membrane, the concentration of hydroxyl ions in the anion-exchanger phase is higher than in the MA-41 membrane, which leads to almost five-fold higher values of the specific permeability coefficient. The MA-41M membranes are resistant to poisoning by naphthenic acids anions during at least six cycles of processing of the sodium naphthenate solution.

Effects of monovalent and divalent cations on the rheology of organic acid laden interfaces

The focus of this work is to investigate the interfacial rheology of a fatty acid, stearic acid (SA), and a commercial mixture of naphthenic acid (CMNA), capable of mimicking the real naphthenic acids (NAs) found in crude oils. We aim to propose an acidic molecular interaction at the water-oil interface under different aqueous phase compositions, by changing its electrolyte content, adding monovalent salts (NaCl and KCl), divalent salts (CaCl2 and BaCl2), and, increasing the pH of the water subphase. The viscoelastic properties are measured using the pendant drop dilation and contraction technique known as drop shape analysis (DSA). Furthermore, we prepare water-in-oil emulsions to correlate interfacial properties with their stability. The experimental results reveal that SAs can form rigid and viscoelastic films upon low sinusoidal deformations and higher cation content. We find that the emulsions containing SAs are more stable in high pH environments, where we observe the presence of birefringence features in SA laden droplets. This outcome evidences the interplay between emulsion stability and mechanical resistance at hydrocarbon-high pH interfaces loaded with SAs.

Impacts of bioreactor operating parameters on removal efficiency, biodegradation rate, molecular distribution, and toxicity of commercial naphthenic acids.

Effects of naphthenic acids (NAs) concentration (50-200mg NA L-1; 35-140mg TOC L-1) and loading rate (1.4-1249mg NA L-1h-1; 1-874mg TOC L-1h-1) on removal efficiency, removal rate, and molecular distribution of NAs, and effluent toxicity were evaluated for biodegradation of commercial NAs mixture in circulating packed bed bioreactors (CPBBs). Increase of NAs concentration and loading rate (shorter residence times) increased the removal rate, while removal efficiency initially declined and then stabilized. The maximum biodegradation rates for 50, 100, 150, and 200mg NA L-1 were 128.0, 321.7, 430.2, and 630.0mg TOC L-1h-1 at loading rates of 218.5, 455.6, 673.5 and 874.0mg TOC L-1h-1, respectively, with removal efficiencies of 58.6, 70.6, 63.9 and 72.1%. Analysis of influent and treated effluents with gas chromatography-mass spectrometry showed that molecular weight and cyclicity (C and Z numbers) affected the biodegradation, with low molecular weight acyclic NAs (C = 6-12) were the most amenable to biodegradation and those with intermediate and high molecular weights (C = 13-22) and moderate cyclicity (Z = -4, -6) were the most recalcitrant. In the biofilm, Proteobacteria and Actinobacteria were the most abundant phyla, and Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were the dominant classes. Toxicity analyses with Artemia salina and Vibrio fischeri (Microtox) showed that high influent concentrations and loading rates (short residence times) led to higher NAs residual concentration and effluent toxicity. To design and operate large-scale CPBBs, intermediate loading rates and residence times that result in high removal efficiency, reasonable removal rates, and low toxicity are recommended.

Reduction Mechanism of Alcohols Contents Caused by Acids During Oil-Paper Insulation Aging

This work investigates which acid can mainly lead to the reduction of alcohols contents in insulating oil during transformer oil-paper insulation aging. In terms of the activation free energy barrier theory, the microscopic mechanisms for the preferential reactions of methanol and ethanol with formic, acetic, naphthenic and stearic acids are analyzed. It is revealed that the decrease in alcohols concentrations in the middle and late stages of transformer oil-paper insulation aging is mainly caused by the reaction between alcohols and naphthenic acid. The results are cross-validated by utilizing the frontier molecular orbital theory and accelerated thermal aging experiments. Additionally, it is observed that methanol is more susceptible to the effect of acids than ethanol in the middle and late stages of aging. The obtained conclusions, in this paper, could provide a theoretical basis for using alcohols in oil as aging indicators to characterize the full-stage aging status of transformer paper insulation.

Aerobic naphthenic acid-degrading bacteria in petroleum-coke improve oil sands process water remediation in biofilters: DNA-stable isotope probing reveals methylotrophy in Schmutzdecke

There is an increasing interest in treatment of oil sands process water (OSPW) via biofiltration with petroleum coke (PC) as a substratum. In fixed bed biofilters (FBBs) with PC, the dominance of anaerobic digestion of dissolved organics results in poor removal of naphthenic acids (NAs) along with a high degree of methanogenesis. In this study, the operation of FBBs was modified to improve OSPW remediation by supporting the filtering bed with aerobic naphthenic acid-degrading bacteria treating aerated OSPW (FBBbioaugmentation). The results were compared with a biofilter operated under controlled conditions (FBBcontrol). To this end, a consortium of three aerobic NAs-degrading bacterial strains was immobilized on PC as a top layer (10 cm). These bacteria were pre-screened for growth on 15 different NAs surrogates as a sole carbon source, and for the presence of catabolic genes coding alkane hydroxylase (CYP153) and alkane monooxygenase (alkB) enzymes. The results illustrated that biofiltration in FBBbioaugmentation removed 32% of classical NAs in 15 days; while in the FBBcontrol, degradation was limited to 19%. The degradation of fluorophore (aromatic) compounds was also improved from 16% to 39% for single ring (OI), 22% to 29% for double ring (OII), and 15% to 23% for three rings (OIII) compounds. DNA-Stable Isotope Probing revealed that potential hydrocarbons degraders such as Pseudomonas (inoculated), Pseudoxanthomonas (indigenous) were present up to 9.0% in the 13C-labelled DNA fraction. Furthermore, a high abundance of methylotrophs was observed in the Schmutzdecke, with Methylobacillus comprising more than two-third of the total community. This study shows that bioaugmentation rapidly improved OSPW remediation. Aeration mostly contributed to methane consumption in the top layer, thus minimizing its release into the environment.

Correlation of type II adsorption isotherms of water contaminants using modified BET equations

The BET equation is commonly used to describe type II sigmoid isotherms of water contaminants. However, there are some type II isotherms that do not agree with the BET equation. In this paper, three modified BET equations (Aguerre–Suarez–Viollaz, Pantuso–Tolaba–Aguerre, and Aranovich–Donohue) are evaluated against published isotherm data of dysprosium, reactive blue 5G, and naphthenic acid. In the cases studied, the three modified BET equations are shown to outperform the original BET equation. The Aranovich–Donohue equation is a promising isotherm model, offering accurate data correlations and statistically significant parameter estimates. In particular, it is very effective in tracing the atypical curve shapes of the reactive blue 5G and naphthenic acid isotherms. Although the Aranovich–Donohue equation has not attracted much attention, it is a practical alternative to the widely used BET equation for correlating adsorption isotherms of water contaminants.

Non-catalytic thermal decomposition of naphthenic acids of petroleum crudes

Non-catalytic thermal decomposition of naphthenic acids of petroleum crudes

Study of kerosene caustic wash process for jet fuel production

Caustic wash is one of many industrial processes that are used to produce jet fuel. In this study, an analysis of the key parameters of the kerosene caustic wash process was conducted to improve the total performance of the treatment process. The investigated parameters are caustic concentration (from 0.03 to 3.0 wt%), caustic volume (from 110% of theoretical to 250%), number of treatment stages (one and two stages), wash water type (demineralized water and alkaline soft water), and wash water volume (10% and 30% of kerosene feed volume). Results revealed that the reaction between sodium hydroxide and naphthenic acids is a diffusion-controlled chemical reaction. The diluted caustic solutions (0.5 wt%) are better than the concentrated ones (3 wt%). Higher excess caustic volume has a slight effect on kerosene acidity. Performing the caustic treatment process in one stage is sufficient, and the two-stage process has no effect on acidity. Washing caustic-treated kerosene with demineralized water (pH=7) has a slight adverse effect on kerosene acidity. Increasing the demineralized water volume results in a slight increase in the acidity of the treated kerosene. Wash water should be slightly alkaline (pH 7.5–8) to prevent the reverse reaction of sodium naphthenates back into naphthenic acid. Increasing wash water volume (more than 10 vol% of kerosene feed) has no noticeable effect on the water content of treated kerosene.

The Use of Surface-Modified Nanocrystalline Cellulose Integrated Membranes to Remove Drugs from Waste Water and as Polymers to Clean Oil Sands Tailings Ponds.

There is an urgent environmental need to remediate waste water. In this study, the use of surface-modified nanocrystalline cellulose (CNC) to remove polluting drugs or chemicals from waste water and oil sands tailing ponds has been investigated. CNC was modified by either surface adsorbing cationic or hydrophobic species or by covalent methods and integrated into membrane water filters. The removal of either diclofenac or estradiol from water was studied. Similar non-covalently modified CNC materials were used to flocculate clays from water or to bind naphthenic acids which are contaminants in tailing ponds. Estradiol bound well to hydrophobically modified CNC membrane filter systems. Similarly, diclofenac (anionic drug) bound well to covalently cationically modified CNC membranes. Non-covalent modified CNC effectively flocculated clay particles in water and bound two naphthenic acid chemicals (negatively charged and hydrophobic). Modified CNC integrated into water filter membranes may remove drugs from waste or drinking water and contaminants from tailing ponds water. Furthermore, the ability of modified CNC to flocculate clays particles and bind naphthenic acids may allow for the addition of modified CNC directly to tailing ponds to remove both contaminants. CNC offers an environmentally friendly, easily transportable and disposable novel material for water remediation purposes.

Efficient naphthenic acid extraction from high acidic oil using novel 1,5-diazabicyclo[4.3.0]non-5-ene based ionic liquids

In this work, the high acidic crude oil deacidification study was performed with novel 1-alkyl-1,5-diazabicyclo[4.3.0]non-5-ene (DBN) based ionic liquids (ILs). Firstly, we took advantage of the systematic COSMO-RS (Conductor-like Screening Model for Real Solvents) calculations to screen the possible ILs with good acid extraction performance from the combinations of 94 cations and 56 anions. Four 1-alkyl-1,5-diazabicyclo[4.3.0]non-5-enium imidazolide ([DBN-R][IM]) ILs with varying alkyl chains were eventually identified and synthesized successfully. Their deacidification performances were tested experimentally and different factors, including the alkyl chain length, ILs/oil mass ratio, temperature, and the initial total acid number (TAN) value of the simulated acidic oil, were also studied in detail. The experimental results showed that [DBN-R][IM] exhibited excellent performances on naphthenic acids (NAs) removal and [DBN-Et][IM] could achieve 93% of NAs removal employing the ILs/oil mass ratio of 0.06 at room temperature for the acidic oil with the TAN value of 3.28 mg KOH/g. COSMO-RS analyses were also used to elucidate the unusual effects of the alkyl chain length and temperature on the NAs extraction performances. Additionally, a two-step deacidification strategy was proposed aiming at realizing more efficient NAs extraction. Finally, density functional theory (DFT) calculations were carried out and the independent gradient model (IGM) analyses were applied to the IL-NAs system to get insight into the deacidification mechanism of the ILs.

Effective degradation of cyclohexanecarboxylic acid by visible LED driven photo-Fenton

This work explores the feasibility of visible LEDs (λ: 400–800 nm) used in photo-Fenton for the degradation of a 50 mg/L cyclohexanecarboxylic acid (CHA) as model naphthenic acid present in process wastewater from the oil sands industry. The influence of initial pH, catalyst concentration and iron oxidation state, H2O2 dose and radiant flux were studied. In all trials, an initial lag phase in both the H2O2 decomposition and TOC evolution was observed. This seems to be related to the generation of a complex between CHA, hydrogen peroxide and iron (CHA-H2O2-Fe). This iron scavenging decreases the H2O2 decomposition rate, leading to a lagged mineralization kinetics. Nonetheless, process intensification using visible radiation (λmax: 460 nm) favors the CHA-H2O2-Fe photoactivation and breakdown when using an H2O2 concentration higher than 33% of the stoichiometric dose for complete CHA mineralization. Under the optimum conditions pH0 3, Φ: 280 W/m2, Fe2+:20 mg/L and H2O2: 144 mg/L, which corresponds to 60% of the stoichiometric amount, 75% of TOC removal was achieved.

Evaluation of mineral oils as matrices for AISI/SAE–1020 steel naphthenic corrosion study

Petrochemical industry has suffered great economic impact due to light crude oil reserves reduction, so refineries have been processing high acidity heavy crude oils. Studies of corrosion caused by naphthenic acids are interfered by presence of other corrosive agents contained in real crude oils, so naphthenic phenomenon must be isolated using synthetic crude oils. For this reason, in present work two high purity mineral oils were used to evaluate their efficiency as synthetic crude oil matrices in AISI/SAE–1020 steel naphthenic corrosion study. Temperature levels evaluated were 200 °C, 250 °C, and 300 °C, while exposure times evaluated were 5, 10 and 15 hours. Surface morphological characterization of AISI/SAE–1020 steel was carried out using scanning electron microscopy and X–ray diffraction. Gravimetric tests showed that AISI/SAE–1020 steel naphthenic corrosion rate increases with temperature and exposure time for one of the synthetic crude oils. However, results obtained for the other synthetic crude oil did not show increasing behaviour due to presence of sulfur traces in the oil, which caused an interference with AISI/SAE–1020 steel naphthenic corrosion study, reducing the reliability of gravimetric results so they cannot be extrapolated to operating conditions in distillation units.