Modified polysaccharides for use in enhanced oil recovery applications

Aqueous solutions of a charged hydrophobically modified hydroxyethylcellulose (HM-HEC(−)) exhibit high viscosities even at low polymer concentrations (0.2 wt%), which is an interesting feature in connection with enhanced oil recovery. This polymer was synthesized for this work. Effects of temperature and addition of sodium dodecyl sulfate (SDS) or hydroxypropyl-β-cyclodextrin (HP-β-CD) on the viscosity properties of a semidilute solution of HM-HEC(−) are examined. The results for the HM-HEC(−)/SDS system disclose strong interactions between HM-HEC(−) and SDS at low level of SDS addition, and this leads to a significant viscosification of the polymer-surfactant mixture. At higher surfactant concentrations the association complexes are disrupted. A strong temperature effect of the viscosity is observed at moderate levels of SDS addition, with lower values of the viscosity at elevated temperatures because of enhanced polymer chain mobility that breaks up the associations. Addition of HP-β-CD monomers to the HM-HEC(−) solution generates decoupling of associations via inclusion complex formation with the polymer hydrophobic tails and the viscosity decreases. By using temperature and addition of these co-solutes, it is demonstrated that the viscosity of the polymer solution can be tuned over a large range of viscosity values.     

Scrap Tires Pyrolysis: Product Yields,Properties and Chemical Compositions of Pyrolytic Oil

This investigation involves an experimental study on the pyrolysis of scrap tires under different operating conditions such as feedstock size and pyrolysis temperature by highlighting the properties of the whole liquid products generated during each thermal degradation process. The complete conversion temperature for the pyrolysis of used tires was close to 500?550°C. The characteristics of liquid fraction were determined by elemental analysis, chromatographic and spectroscopic techniques and distillation data. All the obtained atomic ratios are around 1,4 which is significant that such pyrolytic liquids are a mixture of aliphatic and aromatic compounds derived from polymeric materials. Analysis of the pyrolytic oil (pyro-oil) by chromatographic analysis showed that it was a complex mixture of organic compounds C₅?C₂₆, aromatics and a large proportion of light hydrocarbons that can be used as liquid fuels. Furthermore, the comparison distillation data indicates that more than 40% of such pyrolytic oil fraction with the boiling point range between 180?360°C is specified for diesel. It is noted that the viscosity decreases obviously from 4.87 to 1.79 with the increase in temperature.     

Experimental study on high-pressure rheology of water/crude oil emulsion in the presence of methane

The crude oil is in most cases accompanied with water and natural gas. For this reason, it is important to understand the rheology of the oil emulsion. There are already many works relating to rheology of the oil/water emulsion. However, studies on high-pressure rheology of water/crude oil emulsion in the presence of CH₄ are rare. In this work, light crude oil with characteristics of high wax content, which is typical in Northwest China, was studied. The rheology of water/crude oil emulsion in the presence of CH₄ under various conditions were fully studied. The results show that the crude oil emulsion showed obvious characteristics of non-Newtonian fluid at a lower temperature. Before water fraction reached a certain limit, the viscosity increases with the increase of water fraction, when water fraction reaches and exceeds the limit the emulsion viscosity drops with the increase of water fraction. The shear stress–shear rate curves become similar as the increase of temperature, indicating the decreasing effect of temperature on the relation between shear stress and shear rate. When the pressure reaches 8 MPa, the shear stress measured with CH₄ in the system surpasses that measured without CH₄. At higher pressure, CH₄ shows obvious influence on the rheology.     

离子液体对稠油的改质降黏作用影响因素研究

合成了烷基咪唑型离子液体\[BMIM\]\[AlCl₄\],研究了稠油含硫量、含水量、过渡金属盐、温度等对离子液体进行稠油改质降黏作用的影响。实验结果表明,稠油含一定硫量是进行稠油改质降黏的必要条件。用\[BMIM\]\[AlCl₄\]离子液体对稠油进行有效的改质降黏时,稠油含水量应小于10%。环烷酸镍(NiNaph）与离子液体复配使用对稠油改质降黏具有增效作用。用质量分数为5%的\[BMIM\]\[AlCl₄\]离子液体在一定条件下处理新疆稠油,可使稠油降黏率达到60%,沥青质降低78%。用\[BMIM\]\[AlCl₄\] 离子液体对新疆稠油进行改质降黏的最佳温度为65℃~85℃。     

Analysis for the Reaction of Hydroxyethyl Methacrylate/Benzoyl Peroxide/Polymethacrylate Through DSC and Viscosity Changing and Their Resultants as Oil Absorbent

Polymethacrylate was firstly synthesized via suspension polymerization of the monomers including butyl methacrylate (BMA) and hydroxyethyl methacrylate (HEMA) using benzoyl peroxide (BPO) as initiator. Then a mixture was prepared by mixing the synthesized polymethacrylate with the solution of HEMA and BPO and preserved in a sealed container for 24 h. Thereafter, we employed a differential scanning calorimeter (DSC) to monitor the reaction process of HEMA involved in the mixture at a constant heating rate. The viscosity changing with time for the above mixture was also measured by a rotating viscometer at 85°C with N, N-dimethylformamide (DMF) as diluting agent. Finally, the results of DSC test and viscosity test were analyzed for revealing the reaction mechanism of HEMA involved in the above mixture. Based on this analysis, we chose suitable technology parameters for the above-prepared mixture's reactive extrusion. During the reactive extrusion, the polymerization of HEMA was initiated and the generated PHEMA built an interpenetrating polymer network with the synthesized polymethacrylate by H-bonds to make the extruded resultant applicable for oil absorbent. Then the oil-absorptive capacity of the extruded resultant was characterized through oil absorbency, remaining ratio, and gel fraction, and its internal morphology was observed by polarizing microscope and field emission scanning electron microscopy.     

Production and Characterization of Biodiesel from Tung Oil

The feasibility of biodiesel production from tung oil was investigated. The esterification reaction of the free fatty acids of tung oil was performed using Amberlyst-15. Optimal molar ratio of methanol to oil was determined to be 7.5:1, and Amberlyst-15 was 20.8wt% of oil by response surface methodology. Under these reaction conditions, the acid value of tung oil was reduced to 0.72mg KOH/g. In the range of the molar equivalents of methanol to oil under 5, the esterification was strongly affected by the amount of methanol but not the catalyst. When the molar ratio of methanol to oil was 4.1:1 and Amberlyst-15 was 29.8wt% of the oil, the acid value decreased to 0.85mg KOH/g. After the transesterification reaction of pretreated tung oil, the purity of tung biodiesel was 90.2wt%. The high viscosity of crude tung oil decreased to 9.8mm²/s at 40 °C. Because of the presence of eleostearic acid, which is a main component of tung oil, the oxidation stability as determined by the Rancimat method was very low, 0.5h, but the cold filter plugging point, −11 °C, was good. The distillation process did not improve the fatty acid methyl ester content and the viscosity.     

Proposing a nano-approach to modify viscosity behavior of SAE 5W50 as light road vehicles lubricant

In this paper, viscosity of MWCNT (%50)–TiO₂ (%50)/5W50 is investigated in temperature range of 5–55 °C, solid volume fractions of 0.05%, 0.1%, 0.25%, 0.5%, 0.75% and 1%, and shear rate range of 666.5–10,664 (s^?1). Experimental results showed non-Newtonian behavior of enriched nano-engine oil. Nano-engine oil viscosity reduction (compared to 5W50 base oil) in some specific temperatures and solid volume fractions is one of the unique and interesting results of this research. Maximum viscosity reduction (??11%) occurred in 15 °C and solid volume fraction of 0.05%, and maximum viscosity enhancement (+?17%) was observed in 25 °C and solid volume fraction of 1%. The main goal of present study is to control viscosity increase of nanofluid after adding nanoparticles to the oil. Modeling and prediction of results were achieved via RSM and ANN methods.

     

Different viscosity grade sodium alginate and modified sodium alginate membranes in pervaporation separation of water + acetic acid and water + isopropanol mixtures

Different viscosity grade sodium alginate (NaAlg) membranes and modified sodium alginate membranes prepared by solution casting method and crosslinked with glutaraldehyde in methanol:water (75:25) mixture were used in pervaporation (PV) separation of water+acetic acid (HAc) and water+isopropanol mixtures at 30 °C for feed mixtures containing 10–50 mass% of water. Equilibrium swelling experiments were performed at 30 °C in order to study the stability of membrane in the fluid environment. Membranes prepared from low viscosity grade sodium alginate showed the highest separation selectivity of 15.7 for 10 mass% of water in the feed mixture, whereas membranes prepared with high viscosity grade sodium alginate exhibited a selectivity of 14.4 with a slightly higher flux than that observed for the low viscosity grade sodium alginate membrane. In an effort to increase the PV performance, low viscosity grade sodium alginate was modified by adding 10 mass% of polyethylene glycol (PEG) with varying amounts of poly(vinyl alcohol) (PVA) from 5 to 20 mass%. The modified membranes containing 10 mass% PEG and 5 mass% PVA showed an increase in selectivity up to 40.3 with almost no change in flux. By increasing the amount of PVA from 10 to 20 mass% and keeping 10 mass% of PEG, separation selectivity decreased systematically, but flux increased with increasing PVA content. The modified sodium alginate membrane with 5% PVA was further studied for the PV separation of water+isopropanol mixture for which highest selectivity of 3591 was observed. Temperature effect on pervaporation separation was studied for all the membranes; with increasing temperature, flux increased while selectivity decreased. Calculated Arrhenius parameters for permeation and diffusion processes varied depending upon the nature of the membrane.     

Stereoregulation in the polymerization of methyl α-ethylacrylate by n-BuLi in toluene

The polymerization of methyl α-ethylacrylate was carried out in toluene by n-BuLi at various temperatures. The yield of the polymer decreased with increase in the polymerization temperature and at 30°C and above no polymer was obtained, indicating that the ceiling temperature of this monomer lay between 0 and 30°C. The isotacticity increased with an increase in the polymerization temperature and at 0°C a highly isotactic polymer was obtained. The fractionation of the polymer obtained at ?78°C showed that the polymer was a mixture of isotactic and syndiotactic ones. Upon the addition of a small amount of methanol or water in the polymerization mixture the isotacticity of the polymer increased while the yield decreased. Syndiotactic polymer was obtained in the polymerization by n-BuLi in tetrahydrofuran as well as by diisobutyl aluminum diphenylamide in toluene.     

Influence of thermal degradation in the physicochemical properties of fish oil

Physicochemical and thermal analyses were undertaken to evaluate the influence of the temperature on the oxidation of sea fish oil once its polyunsaturated fatty acids deteriorate rapidly. Fish oil displayed four decomposition steps in synthetic air atmosphere and only one step in nitrogen atmosphere. The first step started at 189 and 222 °C for oxidizing and inert atmospheres, respectively. An OIT value of 53 min was measured at 100 °C. After the degradation process the peroxide index and the iodine index reduced from 35.38 to 9.85 meq × 1000 g^?1 and from 139.79 to 120.19 gI₂ × 100 g^?1, respectively. An increase of the free fatty acids amount from 0.07 to 0.17% was observed while viscosity increased from 57.2 to 58.0 cP. Absorption at 272 nm also increased. The thermogravimetric and spectroscopic techniques are reproducible and versatile being an option for characterization of edible oil oxidation.     

Viscosity reduction of citric-Fe(III) in catalytic aquathermolysis of heavy oil at low temperature

A Fe(III) coordination complex was synthesized, characterized, and then used in aquathermolysis of heavy oil as catalyst at relatively low temperature, 180°C. The effects of water amount, catalyst concentration on aquat hermolysis were investigated in this work. The crude oil before and after aquathermolysis was fully characterized, and the mechanism of viscosity reduction was discussed in detail. The results show that heavy oil can undergo aquathermolysis in the present of water and citric-F e(III) complex at low temperature. Besides, the catalytic aquathermolysis could not only decrease the viscosity of heavy oil, but also remove some heteroatoms, finally make the flow properties better and the quality upgraded.     

Combination of RSM and NSGA-II algorithm for optimization and prediction of thermal conductivity and viscosity of bioglycol/water mixture containing SiO2 nanoparticles

The fluids containing nanoparticles have enhanced thermo-physical characteristics in comparison with conventional fluids without nanoparticles. Thermal conductivity and viscosity are thermo-physical properties that strongly determine heat transfer and momentum. In this study, the response surface method was firstly used to derive an equation for the thermal conductivity and another one for the viscosity of bioglycol/water mixture (20:80) containing silicon dioxide nanoparticles as a function of temperature as well as the volume fraction of silicon dioxide. Then, NSGA-II algorithm was used for the optimization and maximizing thermal conductivity and minimizing the nanofluid viscosity. Different fronts were implemented and 20th iteration number was selected as Pareto front. The highest thermal conductivity (0.576 W/m.K) and the lowest viscosity (0.61 mPa.s) were obtained at temperature on volume concentration of (80 °C and 2%) and (80 °C without nanoparticle) respectively. It was concluded that the optimum thermal conductivity and viscosity of nanofluid could be obtained at maximum temperature (80 °C) or a temperature close to this temperature. An increase in the volume fraction of silicon dioxide led to the enhancement of thermal conductivity but the solution viscosity was also increased. Therefore, the optimum point should be selected based on the system requirement.     

Lidocaine hydrochloride preparations with ionic and non-ionic polymers assessed at standard and increased skin surface temperatures

In this study, the release of lidocaine hydrochloride was assessed considering the use of both the ionic and the non-ionic polymeric carrier at temperatures of 22°C, 32°C, and 42°C; temperature of 32°C was chosen as the reference surface body temperature. The obtained release rates and respective amounts of lidocaine hydrochloride loaded both to methylcellulose beads and polyacrylic acid beads were compared with respective viscosity, pH and conductivity of the studied systems. The release of lidocaine hydrochloride from the methylcellulose system is influenced by temperature; with the increase of temperature the release rate decreases whereas the viscosity increases. In the polyacrylic acid system, release rates are lower, however, in the first stage they are slightly increasing with the increase of temperature. The final amount of released drug after 24 h increases with the temperature of the release process environment, and it is higher in case of a methylcellulose system. The maximum differences between the released amounts for methylcellulose were in the range of 15 %, whereas in case of polyacrylic acid, the difference was approximately 12 %. Thus, this research is important for patients with differentiated skin surface temperature conditions to whom a local analgesic is to be applied.     

Experimental Investigation on Yield Stress of Water-in-Heavy Crude Oil Emulsions in Order to Improve Pipeline Flow

An experimental study on yield stress of water-in-heavy crude oil emulsions has been carried out by using a HAAKE RS6000 Rheometer with a vane-type rotor. Several factors such as oil volume fraction, shear rate, temperature, and emulsifying agent on the yield stress of emulsions were investigated. Zero shear viscosity of heavy crude oil was 6000 mPas at 30°C, with a density 955 kg/m³. This study shows that the yield stress increases linearly with the increasing shear rate, and displays an exponential decay with increasing the temperature and oil volume fraction. Although the addition of emulsifying agent enhanced the stability of the emulsion, to some extent it also increased the yield stress, especially for the emulsions with high oil volume fractions. Therefore, to reduce the start-up force for the pipeline transport of water-in-heavy crude oil emulsions, the starting rate should be decreased, temperature increased, or oil volume fraction increased. These results are helpful to improve the transportation of water-in-heavy crude oil in pipeline.      

Naphthalene‐Functionalized,Photoluminescent Room Temperature Ionic Liquids Bearing Small Counterions

Obtaining π‐conjugated room temperature ionic liquids (RTILs) is difficult because of the relatively strong π–π interaction among the π‐moieties. Existing strategies by using bulky counterions greatly hindered further property optimization and potential applications of these intriguing functional fluids through simple ion exchange. Herein, four naphthalene‐functionalized, π‐conjugated RTILs with small counterions (Br^?) have been facilely synthesized with high yields. Our strategy is to attach branched alkyl chains to the cationic backbone of the target compounds ( 2 a – d ), which effectively tune inter‐ and intramolecular interactions. Compounds 2 a – d have satisfactory thermal stability (up to 300 °C) and low melting points (<?19 °C). Rheological measurements revealed the fluid character of 2 a – d , whose viscosity decrease with the increase of the alkyl chain length and temperature. The presence of the π‐conjugated naphthalene moiety imparts 2 a – d photoluminescent properties in bulk solutions. Moreover, the absence of strong π–π stacking among the naphthalene units in solvent‐free states enables them to be used as a new generation of photoluminescent inks.     

Thermal performance of stable SiO2 nanofluids and regression correlations to estimate their thermophysical properties

The present work investigates the best mix ratio of Glycerol in Water as a medium to prepare a stable nanofluid. Increasing the proportion of glycerol enhances the aqueous mix's dynamic viscosity and improves the prepared nanofluid's stability. The thermal conductivity and viscosity of the Glycerol and Water mixtures determination were undertaken at various Glycerol ratios. The best percentage of glycerol in the mixture is found to have the least amount of thermal conductivity loss and the optimum viscosity gain. Silica (SiO₂) nanofluid of 0.25%, 0.5%, 1%, and 1.5% weight concentrations was prepared with this optimal mixture of Glycerol and Water. The stability of these SiO₂ nanofluids is evaluated by determining the zeta potential at different time intervals. The nanofluids prepared were observed to be stable for one month. The thermal conductivity and viscosity of the nanofluids are measured between the temperature limits of 30°–70°C. A peak increment of 32.1%and 46.3% in thermal conductivity and viscosity is observed. Furthermore, when the percentage enhancement ratio (PER) and Mouromtseff ratio of these nanofluids is examined, it is observed that they have more excellent thermal performance at higher temperatures. Regression correlations are developed to estimate the thermal conductivity and viscosity of the prepared nanofluids with a maximum deviation of 9%.     

Prediction of characteristic properties of crude oil blending with ANN

Mineral oil is one of the most important materials on earth and it is used widely for its several features. Mineral oils derived from petroleum products are commonly used to decrease the friction effects in machine parts and, thus, they both prevent wear/overheating and facilitate power transmission. In this study, various binary mixtures of various base oils (SN-80, SN-100, SN-150, SN-50, SN-500) were prepared at different volumetric ratios. Kinematic viscosity (at 40°C and 100°C), viscosity index, flash point, pour point, and density (at 20°C) measurements were performed for characterization of the prepared mixtures. These values were modeled by an artificial neural network (ANN) and the model was tested with root mean squared error (RMSE), mean absolute percentage error (MAPE, %), and regression coefficient (R) values. A higher value of correlation coefficient and smaller values of MAPE and RMSE indicate that the model performs better. For predicting kinematic viscosity at 40°C, correlation coefficients were calculated for training and testing the network as 0.9999 and 0.9995, respectively. Respective MAPE values were determined as 1.011% and 1.8771%.     

External magnetic field effect on viscometer efflux times or calf thymus DNA in 0.0172 M KCI solution during the thermal denaturation process

Experiments show that during the thermal DNA denaturation process an applied magnetic field of 10 kG increases the shear viscosity (measured efflux time) of calf thymus DNA in 0.0172 M KCI solution over the viscosity of the same solution at the ambient earth field (or “no” field) condition. There is also observed an increase (although slight, about 0.1°C) in the thermal denaturation temperature of the process.     

Catalytic transformation of copaiba (Copaifera officinalis) oil over zeolite ZSM-5

The oil extracted from the trunk of the copaiba tree (Copaifera officinalis) is composed of sesquiterpenes, C₁₅H₂₄, and a small amount (>7 %) of sesquiterpenols, C₁₅H₂₆O; these were identified from their Kováts indices and mass spectra. The use of zeolites in the catalytic transformation of this renewable source of hydrocarbons is of interest in the search for new chemicals and ecologically clean fuels. Oil samples from copaiba trees growing in Colombia's Oriental Plains were circulated over zeolite ZSM-5 in a continuous flow fixed-bed micro reactor at 225, 265, and 325°C, for 1 h and subsequently analyzed by HRGC and GC-MS. Whereas only thirty four sesquiterpenes were identified in the original oil, over two hundred compounds were found in the product of the treatment of copaiba oil with zeolite ZSM-5. This complex mixture of sesquiterpenes, light aromatic compounds, and indene and naphthalene derivatives resulted from reactions such as isomerization, hydrogenation, cracking, and dehydrogenation with and without cracking. The amount of cracking products and aromatic compounds increased with reactor temperature but decreased with catalyst aging.     

Hydrothermal liquefaction of cypress: Effects of reaction conditions on 5-lump distribution and composition

Effects of reaction temperature, reaction time and water amount on the hydrothermal liquefaction of cypress, were studied in this paper. The reaction system was divided into gas lump, water-soluble oil lump, heavy oil lump, volatile organic compounds lump, and solid residue lump. Results showed that temperature was the critical parameter for 5-lump distribution in the cypress hydrothermal conversion process. The higher temperature and longer reaction time were not usually suitable for the production of bio-oil (water-soluble oil and heavy oil). The increase in the yields of gas and volatile organic compounds was also observed as temperature was increased. However, the yield of the volatile organic compounds increased first, and then decreased with the reaction time and the water amount. High amount of water led to high conversion and bio-oil yield. The FT-IR analysis of the solid residues showed that the major peaks of cypress diminished after 280 °C. The GC–MS analysis showed that the volatile organic compounds, water-soluble oil and heavy oil comprised a mixture of organic compounds of 5–7, 5–10 and 7–26 carbons, respectively, which mainly included furfural, phenol, acids, furans and their derivatives. The WSO had similar elemental compositions but the HO had a higher content of carbon and a lower concentration of oxygen as compared to cypress.