Miscible Oil Research Articles

Biodiesel production using unrefined methanol as transesterification agent and the research of individual effect of impurities

In this study, we produced biodiesel by utilising waste cooking oil as a raw material, unrefined methanol produced by a chemical plant as a transesterification agent and sodium hydroxide as a catalyst. The yield and heating value of the biodiesel produced with unrefined methanol were respectively 1.09% and 0.23 MJ/kg higher than those of the biodiesel prepared with pure methanol. The biodiesel characteristics met the standard of the ASTM (American Society for Testing and Materials). We investigated the effects of four impurity types in the unrefined methanol on biodiesel preparation. Alcohol impurities acting as co-solvents and transesterification agents can increase the yield and heating value. Organic solvent impurities can only act as co-solvents; thus, they can only improve the yield. Ester impurities (methyl formate) exhibited no effects on the yield and heating value because they evaporated in the ester exchange reaction. Water impurities significantly reduced the yield by affecting the miscibility of waste cooking oil and pure methanol. However, the negative effects of these impurities were alleviated when water was mixed with the organic solvent impurities. This study has a great significance for the resource and energy of unrefined methanol.

Ammonia evaporation in a mixed configuration chevron plate heat exchanger with and without miscible oil

An experimental study was conducted to determine the effects of miscible lubricant oil on evaporation of ammonia in a vertical chevron plate heat exchanger. The heat exchanger was configured in a U-type counter flow arrangement with mixed (30°/60°) chevron plate configuration. Experiments were carried out for four saturation temperatures ranging from −25 °C to −2 °C for a fixed ammonia mass flux rate of 6.5 kg m−2 s−1 and over a range of heat flux levels resulting in a vapor quality at the heat exchanger exit ranging between 0.5 and 0.9. For a given saturation temperature, experiments were performed for 0%, 3%, 6% and 9% oil concentrations, by volume in ammonia. The oil concentration, exit vapor quality, heat flux and saturation temperature were found to have significant effects on the heat transfer coefficient and pressure drop of ammonia. Based on the experimental data, correlations to estimate two phase Nusselt number and friction factor, generalized for the whole range of oil concentration have been presented.

Phosphonium-Organophosphate Ionic Liquids as Lubricant Additives: Effects of Cation Structure on Physicochemical and Tribological Characteristics

Our previous work suggested great potential for a phosphonium-organophosphate ionic liquid (IL) as an antiwear lubricant additive. In this study, a set of five ILs were carefully designed and synthesized, with identical organophosphate anions but dissimilar phosphonium cations, to allow systematic investigation of the effects of cation alkyl chain length and symmetry on physicochemical and tribological properties. Symmetric cations with shorter alkyl chains seem to increase the density and thermal stability due to closer packing. On the other hand, either higher cation symmetry or longer alkyl moieties induce a higher viscosity, though the viscosity index is dependent more on molecular mass than on symmetry. While a larger cation size generally increases an IL's solubility in nonpolar hydrocarbon oils, six-carbon seems to be the critical minimum alkyl chain length for high oil miscibility. Both the two ILs, that are mutually oil miscible, have demonstrated promising lubricating performance at 1.04% treat rate, though the symmetric-cation IL moderately outperformed the asymmetric-cation IL. Characterizations on the tribofilm formed by the best-performing symmetric-cation IL revealed the film thickness, nanostructure, and chemical composition. Results here provide fundamental insights for future molecular design in developing oil-soluble ILs as lubricant additives.

Comparison of Solvent Miscibility of Coconut Oil and its Modified Forms

Solvent miscibility is an important parameter for dosage form design, especially for liquid preparations. The purpose of this study was to investigate the polarity change of coconut oil (CO) after modification by glycerolysis and its consequence on solvent miscibility. Coconut oil and its modified form were separately mixed with various solvents which had different dielectric constant and then determined for their miscibility. The thin layer chromatography (TLC) was also used to clarify the composition of coconut oil and its modified form. The result indicated that coconut oil and modified coconut oil (MCO) were miscible with low polarity solvent having the dielectric constant from 1.94 to 21.5 (from hexane to acetone) and were immiscible with high polarity solvents possessing the dielectric constant over 42.5. However, MCO demonstrated miscibility with ethanol, propylene glycol and methanol (dielectric constant 24.5, 32.1, 32.7) while coconut oil did not compatible with those solvents. The result suggested the polarity increment of MCO after glycerolysis. The presence of high polar compounds, including monolaurin and lauric acid in MCO was later clarified by TLC. In conclusion, the knowledge gained from this research may provide the preliminary data for formulation of MCO into suitable liquid dosage form in the near future.

Study on Microcrystalline Chitin Cinnamon Nanoemulsion

To improve the miscibility of cinnamon oil with water, this study uses microcrystalline chitin as the surfactant to prepare cinnamon oil nanoemulsion. Firstly, use isopropyl alcohol and concentrated phosphoric to act with chitin, disperse molecular crystal structure of chitin, and then use hydrochloric acid for decalcification, and prepare microcrystalline chitin through centrifugation, washing, freezing and drying. Dissolve it in acetic acid solution as emulsification, and dissolve cinnamon oil in anhydrous ethanol, and mix both of which to obtain emulsion by drops. Judge the emulsification process and results of microcrystalline chitin on cinnamon oil through conductivity data. The conductivity decreases gradually to 0 from 1.4μS·cm-1. At room temperature, the solution is aqueous liquid without stratification and precipitation, but has good stability.

Miscible oil recovery utilizing N2 and/or HC gases in CO2 injection

Abstract Carbon dioxide miscible injection is one of the non-thermal effective enhanced oil recovery (EOR) methods. In the Middle East, particularly Abu Dhabi, pilot testing is already implemented in the Rumaitha Field for CO 2 miscible injection. This paper investigates the means of improving CO 2 miscible injection by enriching it with N 2 and HC gases. The emphasis is on identifying CO 2 solvent mixtures with reduced MMP to achieve miscibility at reasonable injection pressures in Abu Dhabi fields. The minimum miscibility pressure (MMP) of targeted oils from Abu Dhabi carbonate reservoirs with mixtures of N 2 , CH 4 , C 2 H 6 , and HC rich gases of varying composition with CO 2 injection gas are evaluated through simulation. The first contact miscibility (FCM) and the multiple contact miscibility (MCM) of injected gases/oil mixture under reservoir temperature have been determined using WINPROP module of the Computer Modeling Group (CMG) simulator. In addition, the corresponding oil recovery factors for various N 2 /CO 2 content displacements were calculated by 1-D compositional simulation of slim tube using BUILDER and GEM module of CMG Simulator. Results show that miscibility is predicted to occur with multiple contact miscibility (MCM): vaporization and/or condensation mechanisms. The increase of C 2 H 6 concentration in the CO 2 injected gas reduced MMPs for targeted Oil 1 by 100 psi/10 mol%. However, N 2 , CH 4 and HC rich gas increments in CO 2 injected gas increased the MMPs for targeted Oil 1. MMP was observed to be 2300 psi for pure ethane with Oil 1. In addition, MMPs for targeted oils with N 2 /C 2 H 6 and N 2 /CH 4 injected gas mixtures are assessed. This study can open possibilities for future enriching of CO 2 and N 2 miscible injection to improve miscibility and recovery of oil.

대체냉매 R436B를 적용한 정수기 냉각수 시스템 신뢰성 평가에 관한 연구

The alternative refrigerant R436B is applied, to assess the application feasibility for a commercial cooling water system. The characteristic stability was verified by Sealed glass tube test and Autoclave test. R436B is chemically stable with the compressor material. The Oil miscibility test shows the usual compressor oil mixed well with R436B. Through the life acceleration test, the cooling performance is maintained. Though slight changes in oil and capillary tube diameter were found, they were within the permitted range. R436B should be applied to commercial cooling water systems as a simple replacement for the usual refrigerant.

Continuous transesterification of coconut oil with pressurized methanol in the presence of a heterogeneous catalyst

In this study the effect of a heterogeneous catalyst on the transesterification of coconut oil with pressurized methanol was examined in a continuous operation system. The obtained experimental results indicated that the supercritical methanol transesterification was catalyzed by the surface of the stainless-steel 316 (SS316) reactor, but this catalyst became inactive after 10h. To maintain a high and stable transesterification rate, MnO2 was found to be the most effective catalyst among various metal oxides tested in this study. The presence of MnO2 was essential for the complete conversion of coconut oil to biodiesel under mild conditions; the conversion was less than 10% during catalyst-free operation. The effect of temperature on biodiesel yield was more pronounced than that of pressure; the latter was apparent only at pressures far below the critical pressure of methanol and before the formation of a homogeneous liquid phase from the methanol/coconut oil mixture. The significant effect of higher temperature resulted from increases in both the reaction rate and the miscibility of coconut oil and methanol. At 200°C and 4.14MPa, the methanol/coconut oil mixture formed a homogeneous liquid phase; the apparent activation energy decreased from 107.7kJ/mol at temperatures below 180°C to 35.3kJ/mol at temperatures above 220°C – that is, the conditions were more favorable for transesterification. When the molar ratio of methanol to coconut oil increased from 12:1 to 60:1 (i.e. fivefold), the apparent rate constant (k) also increased (4.45-fold) from 0.00476 to 0.02118s−1.

Monitoring the Role of Fracture Geometrical Characteristics on Fingering Initiation/Development during Heavy Oil Miscible Displacements in Fractured Porous Media

Finger initiation/development at fluid-fluid interface during miscible floods can cause poor displacement efficiency, which is undesirable in enhanced oil recovery processes. In this work, a series of hydrocarbon injection experiments performed on 5-spot glass micromodels that were initially saturated with the heavy crude oil. The fractured micromodels with different fracture geometrical characteristics were used in the tests. High quality image analysis was applied to determine the fluid flow behavior, solvent front movement, and viscous fingering associated with solvent movement in matrix and fractures. Observations showed that higher solvent dispersion in the fractures rather than matrix in both longitudinal and transversal directions cause the finger behavior to be affected by the fracture geometrical characteristics. It also diminishes and merges the fingers to a unit solvent front by increasing spreading in regions near fractures. Due to the heterogeneity induced by fractures in media, finger tip splitting initiates before solvent breakthrough. In fact, longitudinal dispersion improves shielding, while transversal dispersion increases the fingers spreading and splitting. In addition, it has been revealed that splitting, before and after breakthrough, as well as spreading in regions near fractures is directly proportional to the fracture scattering, fracture discontinuity, and fracture density of the medium. Also, it has been found that shielding phenomena is mostly affected by fracture orientation in which its maximum occurrence is for the case of zero degree to average flow path. The results of this work can be helpful for a better understanding of viscous fingering behavior, which is crucial for accurate prediction of oil recovery in fractured reservoirs during miscible displacements.

4D rock and fluid properties analysis at the Weyburn Field, Saskatchewan

This paper presents an analysis of CO2 rock and fluid properties and 1D seismic modeling from the Weyburn Field, Saskatchewan. Dry frame properties of the Marly and Vuggy units were computed using data from ultrasonic core measurements, and the fluid physics of oil/brine/CO2 mixtures was analyzed using established empirical relations and a multi-phase compositional simulator. The complex properties of supercritical CO2 and miscible oil systems were taken into account for the range of reservoir pressures and fluid saturations expected at Weyburn. These dry rock and fluid properties were combined to obtain saturated P- and S-velocities and densities that were used directly in generating 1D synthetic seismograms from well logs modified to simulate production-related changes in pressure and saturation. It was found that pressure effects at Weyburn are at least as large as, and often larger than, saturation effects. 1D modeling results confirm the sensitivities of rock properties to pressure and saturation changes found in the rock physics analysis, but they also include the complexities of spatially varying properties and wavelet effects, which can significantly alter the seismic response. This analysis is an important first step in successfully implementing CO2 monitoring and verification for enhanced oil recovery and long-term sequestration.

이산화탄소 지중저장과 원유 회수증진 공정을 위한 저류층 모델링

전 세계적으로 주목받는 탄소 포집 및 저장 기술(CCS)은 현재 많은 연구가 이루어져서 대규모 탄소 포집이 가능한 시점에 있다. 이에 대규모 이산화탄소 포집에 적합한 저장 기술 또한 주목을 받고 있는데, 그 중 하나가 이산화탄소 원유 회수증진 공정(<TEX>$CO_2$</TEX>-EOR)이다. 이는 이산화탄소의 지중저장은 물론 원유 회수를 증가시키므로, 환경적인 측면과 경제적인 측면을 모두 만족시킬 수 있는 방법이라고 할 수 있다. 본 연구에서는 다공성 매질인 저류층을 통과하는 원유와 이산화탄소 혼합유체의 흐름을 모델링하고, 모델링을 통해 이산화탄소 저장 및 원유 회수 증진의 효과를 보이고자 하였다. 혼합유체를 모델링하기 위해 Darcy-Muskat의 법칙으로부터 확산성, 점도 변화를 추가 고려하여 저류층 내 압력과 포화도를 계산하였고, 수치 해석적 모델링을 위해서 유한체적법(finite volume method)을 이용하였다. 그 결과, 저류층 내 원유와 물, 이산화탄소를 주입했을 경우 각 주입물질별 시간에 따른 압력과 포화도의 변화를 예측할 수 있었고, 이산화탄소 주입 방법이 물을 주입하는 방법보다 원유 회수 측면에서 더 유리한 것을 확인할 수 있었다. Manifold researches for carbon capture and storage (CCS) have been developed and large scale-carbon capture system can be performed recently. Hence, the technologies for <TEX>$CO_2$</TEX> sequestration or storage become necessary to handle the captured <TEX>$CO_2$</TEX>. Among them, enhanced oil recovery using <TEX>$CO_2$</TEX> can be a solution since it guarantees both oil recovery and <TEX>$CO_2$</TEX> sequestration. In this study, the miscible flow of oil and <TEX>$CO_2$</TEX> in porous media is modeled to analyze the effect of enhanced oil recovery and <TEX>$CO_2$</TEX> sequestration. Based on Darcy-Muskat law, the equation is modified to consider miscibility of oil and <TEX>$CO_2$</TEX> and the change of viscosity. Finite volume method is used for numerical modeling. As results, the pressure and oil saturation changes with time can be predicted when oil, water, and <TEX>$CO_2$</TEX> are injected, respectively, and <TEX>$CO_2$</TEX> injection is more efficient than water injection for oil recovery.

Integrated field operation and optimization

Integrated modeling and optimization is an important method in the petroleum industry, particularly for field development and continuous asset-management evaluation. Traditional modeling consists of the application of many independent models describing the various elements of a petroleum asset in a silo-model approach, such as reservoir models, well models, surface process models, export and sales models and economic models. The effort to integrate these models such that the overall system performance can be optimized presents many technological challenges.A common field asset is modeled with emphasis on: (1) Three different reservoirs (two gas condensate reservoirs and one miscible oil reservoir), (2) A surface facility model (focusing on water handling, NGL extraction, sales-gas spec, and gas reinjection), and (3) Economic model. The surface process model interacts with the three reservoir models through distribution of available produced gas for reinjection into the three reservoirs. The multi-field asset model is introduced as a benchmark case.A decision support tool is used to develop the model and provides long-term production forecasts of gas, oil, and NGL revenue. Cost functions are introduced for all major control variables (number of wells, surface facility selection and operating conditions, and injection gas composition). Net present value is used as the target objective function.This paper evaluates optimal production strategies using several key control variables and field operational constraints. Optimization performance is tested with a non-derivative optimization solver, a constrained implementation of Nelder–Mead Simplex Reflection method. The benchmark is provided to the industry through a website containing application data files, network infrastructure, and results from our integrated optimization model.

Research and Development of 20% Nicosulfuron·Atrazine Oil Miscible Flowable Concentrate

It was results show that nicosulfuron and Atrazine with the different ratio have the synergized action to plants of the monocotyledon and double seed leaf weed by the indoor bioassay of crabgrass (Digitaria ciliaris) and purslane. When Atrazine: nicosulfuron = 17:3 ratio of compatibility, the co-toxicity coefficient is the largest and showing an enhancement effect of the most significant. The 20% nicosulfuron and Atrazine of Oil Miscible Flowable Concentrate was processed by ultrafine grinding in the wetting emulsifier, dispersant, thickener, solvent, were screened test to decide the best formula. This preparation showed after (0±1)°C low temperature and (54±2)°C thermostble experiment's result the outward appearance not obvious lamination, in the water the dispersivity is good, each target conforms to the Oil-based Suspension related standard.

Investigation on minimum quantity lubricant-MQL grinding of 100Cr6 hardened steel using different abrasive and coolant–lubricant types

Large quantities of coolant–lubricants are still widely used in the metal working industry, generating high consumption and discard costs and impacting the environment. Alternatives to current practices are getting more serious consideration in response to environmental and operational cost pressures. In the grinding process, promising alternatives to conventional dry and fluid coolant applications are minimum quantity lubrication (MQL) or near dry grinding process. Despite several researches, there have been a few investigations about the influence of different types of coolant–lubricants and grinding wheels on the process results. The current study aims to show the effects of the above parameters on grinding performance such as grinding forces and surface quality. The tests have been performed in presence of fluid, air jet and eleven types of coolant–lubricants, as well as, in dry condition. The grinding wheels employed in this study were vitrified bond corundum, resin bond corundum and vitrified bond SG wheels. The results indicate that SG wheels and MQL oils have potential for the development of the MQL process in comparison to vitrified and resin bond corundums and water miscible oils. Also, the lowest thermal damages, material side flow on the ground surface and wheel loading were generated by using the SG grinding wheel in MQL grinding process.

Upwind finite difference method for miscible oil and water displacement problem with moving boundary values

The research of the miscible oil and water displacement problem with moving boundary values is of great value to the history of oil-gas transport and accumulation in the basin evolution as well as to the rational evaluation in prospecting and exploiting oil-gas resources. The mathematical model can be described as a coupled system of nonlinear partial differential equations with moving boundary values. For the two-dimensional bounded region, the upwind finite difference schemes are proposed. Some techniques, such as the calculus of variations, the change of variables, and the theory of a priori estimates, are used. The optimal order l2-norm estimates are derived for the errors in the approximate solutions. The research is important both theoretically and practically for the model analysis in the field, the model numerical method, and the software development.

Anomalous swelling of a polystyrene matrix in organic solvents

Swelling behavior of a commercial linear polystyrene, containing a small amount (<5% wt) of mineral oil, has been studied in three different classes of organic solvents (alkanes, alcohols and carboxylic acids) using both gravimetry and light microscopy. A comparison has been made with the results presented in earlier publications using a different linear polystyrene, without mineral oil. It is shown that the polystyrene containing mineral oil absorbs much higher amounts of solvent at lower temperatures then at higher temperatures. This anomalous behavior sharply contrasts with the polystyrene without mineral oil, which at lower temperatures absorbs much less solvent. Light microscopy of the diffusion layer reveals that in the polymer with mineral oil precipitation occurs during diffusion at low temperatures, but not at high temperatures. These results clearly show that the presence of small amounts of mineral oil (in quantities below the detection limit of FTIR) can cause significant changes in the sorption behavior of polymers. These results are interpreted by pre-existing nano-inhomogeneities, formed by the mineral oil, limited miscibility of oil in the polymer phase and high miscibility of solvent in the oil phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

A new heavy internal tamponade in vitreoretinal surgery: an in vitro study

AimTo study the solubility of perfluorohexyloctane (F6H8) in silicone oil (polydimethylsiloxane (PDMS) 1000) and to measure the viscosity and the specific gravity of the mixture obtained (heavy silicone oil or HSO tamponade) to define the ideal ratio of these components.MethodsThe solubility diagram of the mixture was obtained with the turbidimetric method, indicating the miscibility of F6H8 and silicone oil 1000 at all the useful temperatures. The viscosity was measured in steady shear conditions by using a controlled stress rheometer (Haake RS150) and a double cone/plate (DC 60/4) system, both at 25 and 37 degrees C for different volume per cent compositions of the mixture. The specific gravity was measured at 37 degrees C using a digital densimeter.ResultsA mixture of F6H8 30 v% and PDMS 70 v% was found to be transparent and stable at all the useful temperatures. By combining these proportions of the two substances, a resultant density of 1.06 g/cm(3) was obtained. The viscosity of the 30% F6H8 mixture was 203 mPa.s at 25 degrees C and 163 mPa.s at 37 degrees C respectively.ConclusionsThe ideal F6H8 and silicone oil mixture can be obtained combining 30% of F6H8 with 70% of silicone oil 1000. This mixture seems to have rheological properties useful for its use as an alternative intraocular heavy tamponade.Eye (2008) 22, 1082-1088; doi:10.1038/eye.2008.144; published online 6 June 2008.

NH 3 in-tube condensation heat transfer and pressure drop in a smooth tube

This paper presents an overview of the issues and new results for in-tube condensation of ammonia in horizontal round tubes. A new empirical correlation is presented based on measured NH 3 in-tube condensation heat transfer and pressure drop by Komandiwirya et al. [Komandiwirya, H.B., Hrnjak, P.S., Newell, T.A., 2005. An experimental investigation of pressure drop and heat transfer in an in-tube condensation system of ammonia with and without miscible oil in smooth and enhanced tubes. ACRC CR-54, University of Illinois at Urbana-Champaign] in an 8.1 mm aluminum tube at a saturation temperature of 35 °C, and for a mass flux range of 20–270 kg m −2 s −1. Most correlations overpredict these measured NH 3 heat transfer coefficients, up to 300%. The reasons are attributed to difference in thermophysical properties of ammonia compared to other refrigerants used in generation and validation of the correlations. Based on the conventional correlations, thermophysical properties of ammonia, and measured heat transfer coefficients, a new correlation was developed which can predict most of the measured values within ±20%. Measured NH 3 pressure drop is shown and discussed. Two separated flow models are shown to predict the pressure drop relatively well at pressure drop higher than 1 kPa m −1, while a homogeneous model yields acceptable values at pressure drop less than 1 kPa m −1. The pressure drop mechanism and prediction accuracy are explained though the use of flow patterns.

Improved energy efficiency for HFC134a domestic refrigerator retrofitted with hydrocarbon mixture (HC290/HC600a) as drop-in substitute

In India, more than 80% of the domestic refrigerators utilize HFC134a as refrigerant, due to its excellent thermodynamic and thermo-physical properties. But, HFC134a has a high global warming potential (GWP) of 1300. This paper presents experimental results of an energy-efficient hydrocarbon (HC) mixture consisting of 45% HC290 and 55% HC600a as a drop-in substitute for HFC134a at various mass charges of 40 g, 50 g, 70 g and 90 g in domestic refrigerators. The experiments were carried out in a 165-litre domestic refrigerator using HFC134a with synthetic oil as lubricant. The performance characteristics such as COP, energy consumption, pull-down time and discharge temperature of HC mixture were measured and compared with those of HFC134a. During the experimentation the ambient temperature was maintained at 30 ± 2°C. The results showed that the 70 g mixture has better COP, lower power consumption, lower pull-down time and lower discharge temperature than HFC134a. The miscibility of synthetic oil with HC refrigerant mixture was also found to be good.

A new heavy internal tamponade in vitreoretinal surgery: an in vitro study

Abstract Purpose: To study the solubility of perfluorohexyloctane (F6H8) in silicone oil (PDMS 1000 – polydimethylsiloxane 1000) and to measure the viscosity and the specific gravity of this mixture. Methods: The solubility diagram of the mixture was obtained with the turbidimetric method, indicating the miscibility of F6H8 and silicone oil 1000 at all the useful temperatures. The viscosity was measured in steady shear conditions by using a controlled stress rheometer (Haake RS150) and a double cone/plate (DC 60/4) system, both at 25 and 37°C for different volume percent compositions of the mixture. The specific gravity was measured at 37° using a digital densimeter. Results: A mixture of F6H8 v30% and PDMS 70 v% was found to be transparent and stable at all the useful temperatures. By combining these proportions of the two substances a resultant density of 1.06 g.cm‐3 was obtained. The viscosity of the 30% F6H8 mixture was 203 mPas at 25°C and 163 mPas at 37°C respectively. Conclusions: The ideal F6H8 and silicon oil mixture can be obtained combining 30% of F6H8 with 70% of silicon oil 1000.