Polar Oil Research Articles

Catalytic hydrodeoxygenation of pyrolysis oil over nickel-based catalysts under H2/CO2 atmosphere

Renewable feedstocks and bio-refinery concepts are the key to a successful transition to a sustainable chemical industry. One conceivable refinery concept is based on pyrolysis oils from biomass, though these oils are quite difficult to handle. A well investigated approach to upgrade pyrolysis oil and turn it into a valuable products is catalytic hydrodeoxygenation (HDO). However, this process has to be optimized and new ideas are needed to make the hydrodeoxygenation process attractive sustainable and economically competitive. With regard to the many successful applications of gas-expanded liquids in heterogeneous catalysis, the expansion of pyrolysis oil with carbon dioxide was applied in the context of a hydrodeoxygenation reaction. The catalyst used for HDO was Ni/Al2O3 (nickel loading 20 %wt). The influence of CO2 on the viscosity was found to be quite strong at low temperature. At 52 °C and a CO2 pressure of 0.5 MPa the viscosity is reduced by 30 %. With 4.0 MPa of CO2 the viscosity decreases by 60 %. With supercritical CO2 a volume expansion of 5 % was observed. The hydrodeoxygenation showed best results at 340 °C and autogenous pressure. The experiments were started at a total pressure of 8.0 MPa at room temperature (H2 + CO2), with a respective partial pressure of CO2 of 0 MPa, 2.0 MPa or 4.0 MPa. A deoxygenation degree of around 70 % could be reached (dry basis) under each atmosphere. The analysis of the upgraded products by different techniques indicated a slight decrease of hydrogenation with increasing the pressure of CO2. Despite we observed a change in the physical properties when expanding the pyrolysis oil with CO2, no real improvement of the catalytic hydrodeoxygenation reaction (e.g. deoxygenation degree) could be found yet. Possible reasons for the absence of gas-expanded liquid effects could be the polar nature of the used pyrolysis oil and the high temperature. We assume that a viscous and more tar-like, but less polar pyrolysis oil will be more influenced. Gas-expansion with CO2 tends to be less effective with polar liquids due to the unpolar nature of CO2. The only observed effect in our actual system was a decrease of the hydrogenation with decreasing partial pressure of hydrogen.

Effect ofZanthoxylum bungeanumMaxim on the Lipid Oxidation and Fatty Acid Composition of Dry-Cured Fish During Processing

The Chinese traditional dry-cured grass carp fish (Layú) was processed without (A) and with (B, 2%, W/W) Chinese prickly ash, Zanthoxylum Bungeanum Maxim, and the lipid oxidation and fatty acid composition of Layú were investigated. The addition of Chinese prickly ash showed no significant differences (P > 0.05) on the nutritional contents of Layú, but significantly inhibited the increase of ratio of polar oil, the content of free fatty acid, peroxide value and TBA (P < 0.05). It also inhibited the increase of saturated fatty acids in oil, and the decrease of the content of polyunsaturated fatty acid and polyunsaturated fatty acids during processing. Z. Bungeanum Maxim could effectively delay lipid oxidative decomposition. The contents of DHA and EPA were significantly higher (P < 0.05) in Layú B than Layú A. It can be concluded that Z. Bungeanum Maxim can display a protective effect against lipid oxidation during dry-cured fish processing. Practical Application The addition of Chinese prickly ash can significantly inhibit the increase of ratio of polar oil, the content of free fatty acid, peroxide value and TBA (P < 0.05). Z. Bungeanum Maxim can effectively delay lipid oxidative decomposition and improve the quality of Layú.

Incorporation of viscosity scaling group into analysis of MPMS index for laboratory characterization of wettability of reservoir rocks

Wettability is a key parameter affecting petrophysical properties of reservoir rocks. Mirzaei-Paiaman et al. (Energy Fuels 27:7360–7368, 2013) presented an index (referred to as MPMS) for laboratory characterization of wettability of native- or restored-state reservoir rock samples. To use this index two counter-current spontaneous imbibition (COUCSI) experiments are needed, one on the native- or restored-state core sample and another on the strongly water-wet (SWW) reference system. Slope analysis of recovery data in these two systems gives inputs for determination of MPMS index. The two systems must have the same pore structure, initial water saturation, and viscosity ratio. The case of high viscosity reservoir crude needs the reference COUCSI test to be performed using a high viscosity polar compounds-free oil. Such test could be very slow and time consuming. The purpose of this study is to remove the need for limiting condition of the same viscosity ratio between the two systems, so that the reference experiment could be performed using any viscosity ratio independent of viscosity ratio of the native- or restored-state system. Thus, in the case of high viscosity reservoir crude, the reference test can be conducted using a low viscosity oil. Such test is relatively very fast and time efficient. We do this by benefiting the viscosity scaling group (VSG) proposed by Mason et al. (J Pet Sci Eng 72:195–205, 2010). Using experimental data from three sets of mixed-wet systems, we show that applicability of this VSG is not limited to SWW systems only. This VSG is used to relax the need for the limiting condition of the same viscosity ratio between the native- or restored-state and reference systems in the MPMS method. Using two sets of experimental data, we show that acceptable results are observed when comparing the MPMS indices estimated by the proposed technique and the original MPMS method.

Rationalization and Prediction of the Equivalent Alkane Carbon Number (EACN) of Polar Hydrocarbon Oils with COSMO-RS σ-Moments.

The equivalent alkane carbon numbers (EACNs) of 20 polar hydrocarbon oils are determined by the fishtail method. These values supplemented by 43 already reported EACNs of other hydrocarbons are rationalized by using the COSMO-RS σ-moments as descriptors for a QSPR analysis. A reliable model, with only two meaningful physicochemical parameters, namely the surface area (M0(X)) and the overall polarity (M2(X)) of the oil X, is able to predict the EACN values of a large variety of oils including (cyclo)alkanes, (cyclo)alkenes, terpenes, aromatics, alkynes, and chloroalkanes and to rationalize structural effects on EACNs. Furthermore, the dependence of the EACN of homologous oils on the chain length provides some molecular insight into how the different oils penetrate into the interfacial film of surfactants.

Transient Marangoni transport of colloidal particles at the liquid/liquid interface caused by surfactant convective-diffusion under radial flow

HypothesisInterfacial tension gradients at a liquid/liquid interface drive Marangoni flows. When colloidal particles are adsorbed to an interface in systems with spatial and temporal gradients of surfactant concentration, these interfacial flows can be potentially significant contributors to the direction and rate of particle transport. ExperimentsIn this work, we use optical microscopy to measure the interfacial velocities of 5μm diameter polystyrene latex particles adsorbed at an oil/water interface, using olive oil to represent polar oils often encountered in cleaning applications. FindingsOn surfactant adsorption the maximum interfacial velocity scales linearly with bulk surfactant concentration, even for concentrations exceeding the critical micelle concentration (CMC). The maximum interfacial velocity weakly decreases with increasing flow rate, but it varies non-monotonically with the radial distance from the inlet. Upon surfactant desorption into a rinse solution, the maximum velocity increases with increasing concentration of the original surfactant solution, but only up to a plateau near the CMC. These experimental trends are well-described by a convective-diffusion model for surfactant transport to or from the liquid/liquid interface coupled with Langmuir-type adsorption, using a constitutive relation between the interfacial tension gradient and interfacial velocity based on the interfacial tangential stress jump.

Chemical Composition and Potential Environmental Impacts of Water-Soluble Polar Crude Oil Components Inferred from ESI FT-ICR MS.

Polar petroleum components enter marine environments through oil spills and natural seepages each year. Lately, they are receiving increased attention due to their potential toxicity to marine organisms and persistence in the environment. We conducted a laboratory experiment and employed state-of-the-art Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) to characterize the polar petroleum components within two operationally-defined seawater fractions: the water-soluble fraction (WSF), which includes only water-soluble molecules, and the water-accommodated fraction (WAF), which includes WSF and microscopic oil droplets. Our results show that compounds with higher heteroatom (N, S, O) to carbon ratios (NSO:C) than the parent oil were selectively partitioned into seawater in both fractions, reflecting the influence of polarity on aqueous solubility. WAF and WSF were compositionally distinct, with unique distributions of compounds across a range of hydrophobicity. These compositional differences will likely result in disparate impacts on environmental health and organismal toxicity, and thus highlight the need to distinguish between these often-interchangeable terminologies in toxicology studies. We use an empirical model to estimate hydrophobicity character for individual molecules within these complex mixtures and provide an estimate of the potential environmental impacts of different crude oil components.

Conversion of polar and non-polar algae oil lipids to fatty acid methyl esters with solid acid catalysts – A model compound study

Bio-based fuels are becoming more and more important due to the depleting fossil resources. The production of biodiesel from algae oil is challenging compared to terrestrial vegetable oils, as algae oil consists of polar fatty acids, such as phospholipids and glycolipids, as well as non-polar triglycerides and free fatty acids common in vegetable oils. It is shown that a single sulphonated solid acid catalyst can perform the esterification and transesterification reactions of both polar and non-polar lipids. In mild reaction conditions (60–70°C) Nafion NR50 catalyst produces methyl palmitate (FAME) from the palmitic acid derivatives of di-, and tri-glyceride, free fatty acid, and phospholipid with over 80% yields, with the glycolipid derivative giving nearly 40% yields of FAME. These results demonstrate how the polar and non-polar lipid derivatives of algal oil can be utilised as feedstocks for biodiesel production with a single catalyst in one reaction step.

Stability and rheological behaviors of different oil/water emulsions stabilized by natural silk fibroin

Abstract In this study, oil/water emulsions stabilized by natural silk fibroin were prepared, and the effects of silk fibroin concentration ( φ SF ), oil volume fraction ( ϕ o ) and oil type on the stability and rheological behavior investigated. After creaming and reaching a stable state, the residual emulsion fraction increases with an increase in φ SF , ϕ o and oil polarity, while the size of emulsion droplets decreases with an increase in φ SF and oil polarity but a decrease in ϕ o . Due to the colloidal networks formed by the dispersed oil droplets, the emulsions show a predominantly elastic behavior with a frequency independent modulus and low phase angle. However, the droplet networks are not very strong, and a remarkable shear-thinning behavior occurs for all emulsions during steady shear flow. Moreover, stress overshoot also appears for some emulsions with low φ SF and polar oil during transient shear flows, due to the deformation of droplets before the breakage of their associates. The modulus, viscosity and yield stress become larger with the increase of φ SF , ϕ o and oil polarity, which is very beneficial for strengthening the creaming stability of the emulsions.

Study on the Use of the Thermal Dissolution Soluble Fraction from Shenfu Sub-bituminous Coal in Coke-Making Coal Blends

Thermal dissolution (TD) of a Chinese Shenfu sub-bituminous coal (SFSBC) at different conditions was carried out, and the effects of the addition of a thermal dissolution soluble fraction (TDSF) in coke-making coal blends on the properties of coke were evaluated in this study. The results suggested that SFSBC gave the highest thermal dissolution soluble yield (TDSY) of 61.9% in 1-methylnaphthalen (1-MN) at 360 °C. Then, the TDSY decreased to 44.8% when the TD temperature increased to 380 °C because of pyrolysis and condensation reactions of coal taking place at this temperature. Polar solvents gave larger dissolution ability to SFSBC than nonpolar solvents. The properties of TDSFs obtained from different conditions were quite different. At the TD temperature of 320–360 °C, the TDSF in 1-MN at a higher temperature contained more −OH groups with a narrow thermoplastic temperature interval compared to that at a lower temperature. The TDSFs in polar solvents crude methyl naphthalene oil (CMNO) and 1-MN added with 20% methanol at 320 °C contained less amount of −OH groups and more aromatic components, thus giving a wide thermoplastic temperature interval than the TDSF obtained in 1-MN. The 5 wt % TDSF addition in the coke-making coal blends decreased the softening temperature of the coal blends, thus improving the coke quality. Blending the TDSF obtained at a lower temperature or in polar solvents in coke-making coal blends had better effects on improving the quality of coke.

The Impact of Brine Composition and Salinity on the Wettability of Sandstone

Understanding how the brine interact with the sandstone and oil is necessary to establish more knowledge about the low salinity water effect. In this study, a series of core flood studies was carried out to investigate (a) the role of salinity and composition of brine in the retention of polar crude oil components onto Berea sandstone and (b) the mechanism of low salinity water effect.

Graphene oxide (GO) nanosheets as oil-in-water emulsion stabilizers: Influence of oil phase polarity

HypothesisTwo-dimensional nanoparticles such as graphene oxide (GO) can serve as emulsion stabilizers due their ability to adsorb at oil–water (o/w) interfaces with high atom efficiency. The ability for GO to act as a surfactant is hypothesized to be highly dependent on the nature (i.e. polarity) of the oil phase, which has not considered previously. Modelling and experimentsThe stabilization energy associated with adsorption of GO sheets at an o/w interface was modelled as a function of the polarity of the oil phase using surface tension contributions terms and Hansen solubility parameters (HSPs). Oil-in-water (o/w) miniemulsions were prepared via ultrasonication in the presence of GO for a variety of different oil phases, and were studied using dynamic light scattering (DLS). FindingsThe stabilization energy associated with GO adsorption was greater for non-polar oil phases compared to more polar oils. This behaviour is driven by the significant reduction in the oil–water interfacial tension as the polarity of the oil increases, to the point where GO adsorption is no longer thermodynamically favourable. This was verified by DLS measurements experiments, as GO-stabilized emulsion were successfully prepared for hydrophobic and aromatic oil phases (e.g. styrene), but not for polar oil phases such as methyl methacrylate.

Multifunctional TiO2‐Based Particles: The Effect of Fluorination Degree and Liquid Surface Tension on Wetting Behavior

A systematic investigation into the influence of the degree of fluorination on the static and dynamic wetting behavior of TiO2‐based nanobelt (TNB) particles with various liquids is described. The effect of the degree of fluorination and the surface tension of the liquid on the occurrence and stability of liquid marbles, foams or dispersions are studied and the wetting behavior and arrangement of particles at the air–liquid surface are observed. Using contact angle (θ) measurements, the relation between the type of particle‐stabilized material and θ is established. For liquids of relatively high tension like water or formamide which do not wet the fluorinated particles, a powder‐like material (marble) is formed. For polar oils of intermediate tension (35–50 mN m−1), which partially wet the fluorinated particles, stable air‐in‐oil foams can be prepared in which particles form a close‐packed layer enveloping air bubbles. Liquids of relatively low tension, e.g., ethanol or polydimethylsiloxane, wet the particles forming a uniform dispersion and partial sedimentation. By contrast, the as‐prepared hydrophilic TNB particles are rapidly wetted by all the liquids as expected due to their high surface energy. The stable cross‐stacked TNB particles with fluoroalkylsilane (FAS) modification could be a versatile platform in a wide range of applications, especially for fluidic devices (e.g., biofluids, gas sensing, and lab‐on‐a‐chip devices). In a proof‐of‐concept study, the oil–water separation performance of fabrics with chemically stable TNB/FAS coating and the liquid isolation by a TNB/FAS shell for highly sensitive gas sensing or reagent assays are investigated.

Formation, thermodynamic properties, microstructures and antimicrobial activity of mixed cationic/non-ionic surfactant microemulsions with isopropyl myristate as oil

HypothesisModification of the interface by blending of surfactants produces considerable changes in the elastic rigidity of the interface, which in turn affects the physicochemical properties of w/o microemulsions. Hence, it could be possible to tune the thermodynamic properties, microstructures and antimicrobial activity of microemulsions by using ionic/non-ionic mixed surfactants and polar lipophilic oil, which are widely used in biologically relevant systems. ExperimentsThe present report was aimed at precise characterization of mixed cetyltrimethylammonium bromide and polyoxyethylene (23) lauryl ether microemulsions stabilized in 1-pentanol (Pn) and isopropyl myristate at different physicochemical conditions by employing phase studies, the dilution method, conductivity, DLS, FTIR (with HOD probing) and 1H NMR measurements. Further, microbiological activities at different compositions were examined against two bacterial strains Bacillus subtilis and Escherichia coli at 303K. FindingsThe formation of mixed surfactant microemulsions was found to be spontaneous at all compositions, whereas it was endothermic at equimolar composition. FTIR and 1H NMR measurements showed the existence of bulk-like, bound and trapped water molecules in confined environments. Interestingly, composition dependence of both highest and lowest inhibitory effects was observed against the bacterial strains, whereas similar features in spontaneity of microemulsion formation were also evidenced. These results suggested a close relationship between thermodynamic stability and antimicrobial activities. Such studies on polar lipophilic oil derived mixed surfactant microemulsions have not been reported earlier.

Chemometrics-Assisted Effect-Directed Analysis of Crude and Refined Oil Using Comprehensive Two-Dimensional Gas Chromatography–Time-of-Flight Mass Spectrometry

An effect-directed analysis (EDA) of fresh and artificially weathered (evaporated, photooxidized) samples of North Sea crude oil and residual heavy fuel oil is presented. Aliphatic, aromatic, and polar oil fractions were tested for the presence of aryl hydrocarbon receptor (AhR) agonist and androgen receptor (AR) antagonist, demonstrating for the first time the AR antagonist effects in the aromatic and, to a lesser extent, polar fractions. An extension of the typical EDA strategy to include an N-way partial least-squares (N-PLS) model capable of relating the comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS) data set to the bioassay data obtained from normal-phase LC fractions is proposed. The predicted AhR binding effects in the fresh and artificially weathered aromatic oil fractions facilitated the identification of alkyl-substituted three- and four-ring aromatic systems in the active fractions through the weighting of their contributions to the observed effects. A N-PLS chemometric model is demonstrated as a potentially useful strategy for future EDA studies that can streamline the compound identification process and provide additional reduction of samples' complexity. The AhR binding effects of the suspected compounds predicted by N-PLS and identified by GC × GC-TOFMS were confirmed using quantitative structure-activity relationship (QSAR) estimates.

Quadrupole terms in the Maxwell equations: Born energy, partial molar volume, and entropy of ions

A new equation of state relating the macroscopic quadrupole moment density Q to the gradient of the field ∇E in an isotropic fluid is derived: Q = αQ(∇E - U∇·E/3), where the quadrupolarizability αQ is proportional to the squared molecular quadrupole moment. Using this equation of state, a generalized expression for the Born energy of an ion dissolved in quadrupolar solvent is obtained. It turns out that the potential and the energy of a point charge in a quadrupolar medium are finite. From the obtained Born energy, the partial molar volume and the partial molar entropy of a dissolved ion follow. Both are compared to experimental data for a large number of simple ions in aqueous solutions. From the comparison the value of the quadrupolar length LQ is determined, LQ = (αQ/3ɛ)(1/2) = 1-4 Å. Data for ion transfer from aqueous to polar oil solution are analyzed, which allowed for the determination of the quadrupolarizability of nitrobenzene.

Investigation of molecular partitioning between non polar oil droplets and aqueous solution using double potential step chronoamperometry

Double potential step chronoamperometry (DPSC) is demonstrated as a technique for investigating partitioning between a solute in aqueous solution and non-polar oil droplet(s) immobilised at an electrode. Here a species in aqueous solution which does not partition into the oil phase is converted at the electrode surface into another species which either does not or does partition into the oil drop. The first case is investigated experimentally by considering generation of the ionic redox species, FcTMA(2+) from FcTMA(+), while the second case is exemplified by studies of Br2 generation from Br(-). The case of molecular partitioning at the three phase interface has received little attention hitherto. To maintain oil droplet stability a boron-doped diamond electrode is employed functionalised with Pt nanoparticles to impart electrocatalytic activity on the electrode towards Br2 production. An arrangement is utilised where the droplet(s) sit(s) on (but does not cover) the electrode surface. We show both experimentally and through finite element simulation how the charge-time profile for the generation and collection of electroactive species can be used to obtain information on the extent of partitioning and how this is affected by factors such as the number and size of droplets. Finally, we highlight the suitability of this approach for investigating reactions which take place within the droplet.

The wetting of steel, DLC coatings, ceramics and polymers with oils and water: The importance and correlations of surface energy, surface tension, contact angle and spreading

The importance of wetting is becoming increasingly obvious and its control is inevitable in many engineering applications, including tribology and interface nanotechnology. However, the relations between the key parameters affecting surface–liquid wetting behaviour under realistic conditions are not very well understood, especially for typical engineering materials and lubricants (oils), often leading to exceptions and contradictions, which impede their use in engineering models and theories, and so the possible optimisation of the interfaces of engineering systems. In this paper we present the correlations between the contact angle, the spreading, the surface tension and the surface energy of fourteen frequently used engineering materials belonging to four different classes of materials (steel, DLC coatings, ceramics, and polymers) wetted with four different liquids: three oils (a non-polar synthetic oil of two different viscosities and a polar natural-based oil) and water. The results represent systematically and consistently obtained data about the wetting-relevant parameters of the selected materials and lubricants and numerous correlations between them. However, the most striking result suggests that the spreading parameter correlates very linearly with the surface energy for all the materials and liquids studied, in both the adhesion-wetting and spreading-wetting regimes. The experimentally determined spreading vs. surface energy correlation functions that appear generally valid for a broad range of properties of the materials and oils can thus be applied as an engineering tool to tailor and design the required/desired wetting performance and nature of the solid–liquid interfaces. The spreading parameter SP – in contrast to the contact angle – was found to be a reliable and relevant parameter for describing the wetting of oils with selected engineering materials.

Oil droplet interaction with suspended sediment in the seawater column: Influence of physical parameters and chemical dispersants

The interaction of dispersed oil droplets with large diameter suspended particulate materials (SPM) has been little studied. In the current study, particle size, oil characteristics and chemical dispersant significantly influence the adsorption of oil droplets to SPM in seawater. Sediments with a smaller particulate size (clay) approaching that of the oil droplets (2–20μm) adsorbed more oil per gram than sediments with large particle size (sand). Heavier, more polar oils with a high asphaltene content adsorbed more efficiently to SPM than lighter, less polar oils. A decrease in the smaller, more water soluble oil components in the sediment adsorbed oil was observed for all oil types. Addition of chemical dispersant decreased the adsorption of oil droplets to suspended carbonate sand in an exponential-like manner. No change in the relative distribution of compounds adsorbed to the sediment was observed, indicating dispersants do not alter the dissolution of compounds from oil droplets.

Ionic Liquids as Antiwear Additives in Base Oils: Influence of Structure on Miscibility and Antiwear Performance for Steel on Aluminum

The use of ionic liquids as additives to base oil for the lubrication of steel on aluminum was investigated. The miscibility and wear performance of various phosphonium, imidazolium, and pyrrolidinium ionic liquids in a range of polar and nonpolar base oils was determined. The structure and ion pairing of the ionic liquids was found to be important in determining their miscibility in the base oils. In wear tests, some of the miscible base oil/IL blends reduced the aluminum wear depth when compared to that found with the base oil alone. The nonpolar base oil/IL blends were able to withstand higher wear-test loads than the polar base oil/IL blends. At 10 N, as little as 0.01 mol/kg of IL, or 0.7-0.9 wt %, in the nonpolar base oils was enough to drastically reduce the wear depth on the aluminum. XPS analysis of the wear surfaces suggested that the adsorbing of the IL to the surface, where it can form low-shear layers and also react to form tribofilms, is important in reducing friction and wear. The largest reductions in wear at the highest load tested were found for a mineral oil/P6,6,6,14 (i)(C8)2PO2 blend.

Damages on the lubricated surfaces in bearings under the influence of weak electrical currents

A special bearing tester was constructed to investigate the damage behavior on the lubricated surfaces in bearings with the passage of weak electrical currents as low as ∼1 mA. The results showed that when polar glycerine was used as the lubricant, many narrow and deep pits formed on the lubricated surfaces. In contrast, when the experimental conditions under the lubrication of the nonpolar paraffin oil were close to those under the lubrication of polar glycerine oil, damages on the lubricated surfaces were unobvious. Emergence of microbubbles in polar lubricants with the passage of electrical currents was proposed to be responsible for the observed damages on the lubricated surfaces.