Water Glycol Research Articles

Desulfurization of natural gas condensate using polyethylene glycol and water intercalated activated γ-bauxite

Three different active γ-bauxite were developed from a low-grade raw boehmite ore, as a cheap and efficient adsorbent for the desulfurization of gas condensates. The first adsorbent (RBa) was developed directly through a two-stage thermochemical activation (thermal activation process followed by an acid treatment) of the boehmite ore. The other two adsorbents (PBa and WBa) were initially intercalated with polyethylene glycol (PEG) solution or water, respectively, at the optimum temperature and pressure followed by thermochemical activation to modify the pore size and active surface area. The process parameters such as pulp density and leaching time were optimized using response surface methodology (RSM) based on central composite design (CCD).Comparing the performance of prepared adsorbents to remove sulfur-containing compounds from natural gas condensate indicated the superior sulfur removal efficiency of PBa compared to WBa and non-intercalated adsorbents. Using PBa, the sulfur content was significantly reduced from 2821 ppm to <35 ppm. Characterization of the developed adsorbents indicated that after thermal activation, the pore size of the non-intercalated adsorbent was significantly reduced, which negatively affects its desulfurization efficiency. Nevertheless, the pore diameter of PBa was maintained similar to that of raw bauxite while its surface area was approximately 12-fold larger, which confirms the successful role of PEG as a lattice expansion element, improving its desulfurization efficiency.

Experimental investigation of thermal efficiency and thermal performance improvement of compound parabolic collector utilizing SiO2/Ethylene glycol-water nanofluid.

A compound parabolic collector has been used in the present study to lower operating costs per unit of heat increase compared to other tracker concentrators. This type of collector has been given more attention in industrial and domestic applications in the temperature range of 60 to 300°C. Also, to increase the thermal efficiency, nanofluid containing SiO2 nanoparticles in ethylene glycol-water hybrid base fluid (10-90 vol.%) have been used in three different volumetric fractions. The innovation of this present study includes the utilization of mentioned nanofluids for the first time in this collector, which has good stability and is cost-effective compared to other nanoparticles. In addition, the experimental measurement of thermal and hydraulic properties of nanofluids represents new aspects of the present study. The experiments used three volumetric fractions of 0.5%, 1%, and 1.5% under extensive solar radiation. Thermal performance of the collector at four volumetric flow rates of 1, 1.5, 2, and 2.5 Lit/min have been investigated according to ASHRAE standard 93-2010 (RA2014). According to the experimental data, the thermal efficiency of the collector improved by 5% to 11.6% when the nanofluid was applied. The maximum enhancement of the average Nusselt number of the nanofluid versus the base fluid at the volumetric flow rate of 1 Lit/min and the volumetric fraction of 1.5% was equal to 7.3%. Besides, nanofluid increased the pressure drop, and consequently, the pumping power slightly. Finally, considering both the impacts of heat transfer and pressure drop, performance evaluation criteria and overall efficiency for nanofluid have been analyzed. The results represented that in all volumetric fractions, the values of performance evaluation criteria and overall efficiency enhanced compared to the base fluid. This research provides researchers and engineers with important information to better understand the thermal and hydraulic parameters of the parabolic compound concentrator in the presence of nanofluid to improve its thermal performance. The results also highlight the potential of using SiO2 nanoparticles to improve the thermal efficiency of solar collectors despite their low thermal conductivity compared to other conventional nanoparticles.

Zeta potential and particle size in dispersions of alumina in 50–50 w/w ethylene glycol-water mixture

HypothesisDispersions of solid particles in glycols and in their mixtures in water have been proposed as promising heat transfer fluids, and the zeta potentials in such systems are often reported. We challenge a popular approach in which high absolute value of zeta potential implies excellent stability in such systems. ExperimentsNanoparticles of alumina were dispersed in 50–50 ethylene glycol-water mixture, and zeta potential and particle size were studied as a function of concentration of various solutes. FindingsAddition of HCl and CTMABr induced positive zeta potentials. A maximum value of about 120 mV was obtained at CTMABr concentration of about 10−5 M, and further increase in the concentration of the surfactant had moderate effect on the zeta potential. A maximum value of about 120 mV was obtained at HCl concentrations of 10−5 - 10−4 M, and further increase in the HCl concentration led to depression of the zeta potential. Addition of NaOH and KOH, and of anionic surfactants induced negative zeta potentials. With NaOH and KOH the maximum negative zeta potential of − 60 mV was obtained at base concentration of about 10−3 M, and increase in the base concentration to 10−2 M had moderate effect on the zeta potential. Negatively charged particles showed substantial aggregation in spite of high negative zeta potentials.

Thermal conductivity and surface tension of graphene–Al2O3/ethylene glycol–water hybrid nanofluid at sub-zero temperatures: an experimental study

Thermal conductivity and surface tension of graphene–Al2O3/ethylene glycol–water hybrid nanofluid at sub-zero temperatures: an experimental study

Experimental study on the spray cooling heat transfer performance and dimensionless correlations for ethylene glycol water solution

With the increase of airborne electronic equipment heat dissipation, spray cooling with ethylene glycol as working fluid may be an effective way. In this paper, the influence of ethylene glycol mass fraction, mass flow rate, and nozzle inlet temperature on the spray cooling heat transfer performance are experimentally studied. Results show that the ethylene glycol mass fraction significantly affects the heat transfer performance. When the mass fraction increases from 0 to 100%, the maximum reduction of surface heat transfer coefficient is about to 58% at different heat flux. The increase of dynamic viscosity and the decrease of specific heat capacity and thermal conductivity are the direct cause, which significantly weaken heat transfer performance. As the nozzle inlet temperature rises from –2 to 50℃, the surface heat transfer coefficient increases gradually and tends to be stable. The evaporation intensity has the same trend with inlet temperature, and also evaporation is a non-negligible heat transfer form in spray cooling. In addition, a more widely applicable Nusselt number dimensionless correlation of ethylene glycol solution is proposed within the 10% error. The investigation in wider range of temperature and mass fraction will provide theoretical analysis and data support for the airborne application of spray cooling.

The effect of hybrid nanofluid CuO-TiO2 on radiator performance

This study aims to improve the performance of the vehicle's cooling system called the radiator, which is part of increasing energy efficiency. Research has been done to investigate the convective heat transfer of hybrid nanofluid, using CuO and TiO2 nanoparticles and water-ethylene glycol (RC) as base fluids on a radiator. The mass concentration of the hybrid nanoparticles varied from 0.25 %, 0.30 %, and 0.35 %. For the preparation of the hybrid nanofluid through a two-step method, by mixing dry samples of CuO and TiO2 nanoparticles (50:50) and then the mixture of radiator coolant, RC (60 % water and 40 % ethylene glycol). The fluid flow varies from 20 liters per minute to 28 liters per minute. Temperature variations range from 70 °C to 90 °C by using controlled heating. Four thermocouples measure the inlet and outlet hot fluid flow and the airflow before and after the radiator. The experiment showed that the overall heat transfer coefficient increases remarkably with the increase of the hybrid nanoparticle concentration under various flow rate values. The maximum overall heat transfer coefficient increases by about 83 % compared to pure radiator coolant under 0.35 % mass concentration at a flow rate of 22 liters per minute and a temperature of 70 °C. It has also been found that the heat transfer rate is highly dependent on the radiator's mass fraction and flow rate. Increasing the mass concentration shows maximum enhancement in heat transfer rate. Inlet temperature also enhances the heat transfer rate, but its effect is small compared to nanofluid's mass concentration and flow rate. This study reveals that hybrid nanofluids can be suitable as a working fluid, especially in small-scale heat transfer devices.

Carboxylate functionalized NaDy(MoO4)2 nanoparticles with tunable size and shape as high magnetic field MRI contrast agents

Uniform sodium-dysprosium double molybdate (NaDy(MoO4)2) nanoparticles having different morphologies (spheres and ellipsoids) and tunable size have been synthesized for the first time in literature. The procedure is based on a homogeneous precipitation process at moderated temperatures (≤220 °C) from solutions containing appropriated precursors dissolved in ethylene glycol-water mixtures, in the absence (spheres) or the presence (ellipsoids) of tartrate anions. The effects of the morphological characteristics (size and shape) of the nanoparticles on the magnetic relaxivity at high field (9.4 T) have been evaluated finding that the latter magnitude was higher for the spheres than for the ellipsoids, indicating their better suitability as contrast agents for high-field magnetic resonance imaging. Such nanoparticles have been successfully coated with polymers bearing carboxylate functional groups through a layer-by-layer process, which improves the colloidal stability of the nanoparticles in physiological media. It has been also found that the coating layer had no significant effects on the nanoparticles relaxivity and that such coated nanoparticles exhibited a high biocompatibility and a high chemical stability. In summary, we have developed NaDy(MoO4)2 based bioprobes which meet the required criteria for their use as contrast agents for high-field magnetic resonance imaging.

Surface treatment of polymer matrix nanocomposites for adhesion enhancement by cold plasma

Innovative surface technology processes offer a wide range of surface preparation options, allowing engineers to make major changes to the properties of products. Surface modification can also improve the quality and the strength of the bond created by technologies such as bonding, painting, coating, sealing and other adhesion. By activating molecular groups on the surface, wetting properties can be improved, while altering the microtopography of the surface can create roughness and texture. Surface modification suitable for industrial conditions in cold plasma surface modification. The the wetting boundary angles are measured with ethylene glycol and distilled water, and the results are used to calculate the surface free energy of the modified surface in mN/m according to Fowkes surface free energy theory. The demonstration of adhesion improvement of specimens with good wetting surfaces should be carried out by a series of bonding experiments, showing the changes in strength due to surface treatment. In addition, the technical advantages obtained by modifying the topography can be characterised by examining the separated surfaces.

Phase Equilibria in Sections of the Potassium Acetate–Ethylene Glycol–Water System at Temperatures from 0 to –66°C

Phase Equilibria in Sections of the Potassium Acetate–Ethylene Glycol–Water System at Temperatures from 0 to –66°C

Phase Equilibria in Sections of the Urea–Ethylene Glycol–Water System at Low Temperatures

Phase Equilibria in Sections of the Urea–Ethylene Glycol–Water System at Low Temperatures

Solubility of paracetamol in binary mixtures of biodegradable betaine/ethylene glycol deep eutectic solvent and water: measurement and correlation

ABSTRACT The goal of this work is determining paracetamol (PCM) equilibrium solubilities in aqueous pseudo-binary mixtures of betaine/ethylene glycol deep eutectic solvent (Bet/EG DES) through the shake-flask technique from 293.15 to 313.15 K and atmospheric pressure (≈ 85 kPa). The equilibrium solid phase crystal of PCM is characterized with X-ray powder diffraction analysis to identify no polymorphic transformation, solvate formation or crystal transition during the whole solvent crystallization process. The results indicate that addition of DES to water significantly enhances PCM solubility; so that, by adding 0.9 mass fraction of Bet/EG DES to water increases PCM solubility by more than 42.9 times. Moreover, the solubility data are successfully represented with the commonly used cosolvency models including Jouyban Acree, Jouyban-Acree-van’t Hoff and so on together with the activity coefficient models of NRTL and Wilson. The accuracy of each model is determined through calculation of average relative deviations (ARD%) and the results present that the Jouyban-Acree (ARD% = 6.3) and Wilson activity model (ARD% = 0.8) have better capabilities in PCM solubility correlation than the others. Finally, thermodynamic behavior of PCM in Bet/EG DES + water is studied by determination of apparent thermodynamic functions of dissolution obtained from the van’t Hoff and Gibbs equations.

Pretreatment of sugarcane bagasse with acid catalyzed ethylene glycol–water to improve the cellulose enzymatic conversion

In this work, HCl catalyzed ethylene glycol–water pretreatment (HCl/EG-H2O) of sugarcane bagasse (SCB) was explored with response surface methodology (RSM) and single factor analysis, which aim to investigate the influence of pretreatment variable on pretreated solid cellulose enzymatic conversion. The result showed that HCl/EG-H2O pretreatment could selectively extract ∼89.9 % xylan and ∼61.2 % lignin in SCB, meanwhile maintain a relatively high cellulose retention (∼86.8 %). Pretreatment of SCB at 120 °C for 60 min with 1.00 % HCl and 90 % EG obtained the pretreated solid having maximum cellulose enzymatic conversion of 88.7 % under 10 FPU/g enzyme dosage, this enhancement of cellulose enzymatic conversion mainly attributed to structure change of SCB in pretreatment. The adding of enzymatic additives into the hydrolysis process could not only improve hydrolysis efficiency but also lower the enzyme dosage. Besides, the linear relationship between substrate characteristic parameters (such cellulose content, lignin removal rate etc.) and cellulose conversion were observed.

Zinc glycolate Zn(OCH2CH2O): Synthesis and structure, spectral and optical properties, electronic structure and chemical bonding

This article presents new findings obtained from the study of formation conditions, crystal structure, thermal, spectral, optical properties and electronic band structure of zinc glycolate Zn(OCH2CH2O). This compound was synthesized by heating the solutions of zinc formate Zn(HCOO)2·2H2O in ethylene glycol (A) or in a mixture of ethylene glycol and distilled water (B). The crystal structure of Zn(OCH2CH2O) has been studied using the X-ray powder diffraction method. It is shown that the crystal structure is built via zigzag joining of [Zn4O12C8H16] tetracycles with the tetrahedrally coordinated zinc (ZnO4). Zinc atoms inside the tetracycles and the tetracycles themselves are interconnected with oxygen bridges. Complex anions OCH2CH2O2- are bonded to zinc atoms by chelation. The unit cell parameters of Zn(OCH2CH2O) are as follows: the tetragonal structure, space group I41/a (88−2), Z = 16, a = b = 11.08673(9) Å, c = 11.5902(1) Å, V = 1424.62(2) Å3. The IR and Raman spectra of Zn(OCH2CH2O) correlate fully with the results of structural analysis. Under UV excitation, the luminescence spectra of Zn(OCH2CH2O) samples synthesized following the methods (A) and (B) are characterized by emission maxima at 460 nm (blue luminescence) and 540 nm (yellow-green luminescence), respectively. Yellow-green luminescence is due to the presence of an admixture of zinc oxide nanoparticles of size 10 nm in the sample. The electron density functional method is employed to study the electronic band structure and chemical bonding in Zn(OCH2CH2O). It is shown that the 3dZn orbitals are covalently bonded to 2pO orbitals so that an octagon is formed, where the zinc atoms of four neighboring ZnO4 tetrahedrons are linked through their vertices. The feasibility of synthesizing a layered structure of Zn(OCH2CH2O) is analyzed on the basis of ab initio calculations and Voigt-Reuss-Hill theory.

Thermal performance of water‐based brines as a heat carrier for ground heat exchanger under severely cold environments

AbstractThe aim of the present study is to investigate the performance of water‐based brine solutions in the ground heat exchanger (GHX) for space heating applications under severely cold climate conditions. The conventional ethylene glycol (EG) and propylene glycol (PG)‐based water solutions have been considered for investigation. For the closed‐loop vertical U‐tube GHX, a mathematically built model is developed for ambient temperature below 0°C. The thermal performance analysis of GHX is carried out for the variation in fluid flow rate and brine solutions for different mixture percentages of water in EG and PG. The percentage of the mixture and fluid flow rate varied from 25% to 60% and 0.2 to 0.6 LPS, respectively. GHX performance parameters, namely convective coefficient, pressure drop, borehole resistance, and GHX effectiveness are determined for both EG and PG brines. Better performance of GHX is noticed with EG brines as compared to PG brines for similar operating conditions. The drop in convective coefficient from 22% to 44% in the case of PG brines as compared to EG brines with the increase in mixture percentage from 25% to 60%, for the same operating conditions. The pressure drops decreased from 15% to 74% for EG mixture as compared to PG mixture at considered flow rate and mixture percentage. The effectiveness and overall borehole resistance were higher for EG as compared to the PG solution.

Heat Transfer Augmentation: Experimental Study with Nanobubbles Technology

The experimental research on heat transfer characteristics is an ever-ending scheme since the life of all thermoelectronic devices relies on the effective management of thermal energy. In some cases, the gradient of temperature for heat transfer is to be minimum to avoid energy loss, but also there are numerous applications where the requirement of heat transfer to be maximum and could be achieved with a higher temperature difference between the heat transfer medium. In our current research, distilled water-ethylene glycol heat transfer fluid (HTF) was tested with different inlet mass flow rates and temperature as the hot fluid. Atmospheric air was chosen as the cold fluid. The natural convection heat transfer rate between hot and cold fluid streams was analyzed with and without the generation of micronanobubbles in the hot fluid. It was observed that compared to the base heat transfer fluid, the nanobubbles heat transfer fluid resulted in a 10–12% increase in heat transfer rate at hot fluid inlet temperatures of 28°C, 30°C, 32°C, 34°C, and 36°C. The method of generation of nanobubbles in HTF and their behavior are also highlighted.

Entropy Generation and Statistical Analysis of MHD Hybrid Nanofluid Unsteady Squeezing Flow between Two Parallel Rotating Plates with Activation Energy

Squeezing flow is a flow where the material is squeezed out or disfigured within two parallel plates. Such flow is beneficial in various fields, for instance, in welding engineering and rheometry. The current study investigates the squeezing flow of a hybrid nanofluid (propylene glycol–water mixture combined with paraffin wax–sand) between two parallel plates with activation energy and entropy generation. The governing equations are converted into ordinary differential equations using appropriate similarity transformations. The shooting strategy (combined with Runge–Kutta fourth order method) is applied to solve these transformed equations. The results of the conducted parametric study are explained and revealed in graphs. This study uses a statistical tool (correlation coefficient) to illustrate the impact of the relevant parameters on the engineering parameters of interest, such as the surface friction factor at both plates. This study concludes that the squeezing number intensifies the velocity profiles, and the rotating parameter decreases the fluid velocity. In addition, the magnetic field, rotation parameter, and nanoparticle volumetric parameter have a strong negative relationship with the friction factor at the lower plate. Furthermore, heat source has a strong negative relationship with heat transfer rate near the lower plate, and a strong positive correlation with the same phenomena near the upper plate. In conclusion, the current study reveals that the entropy generation is increased with the Brinkman number and reduced with the squeezing parameter. Moreover, the results of the current study verify and show a decent agreement with the data from earlier published research outcomes.

Analysis of heat transfer in a helical exchanger using different correlations

This research focuses on the evaporation process carried out in a helical exchanger where the R134a refrigerant passes through the internal diameter as primary fluid, the saturation temperatures are in the range of 10-20 oC with mass flows of 0.022 to 0.043 kg/s. Water-Ethylene Glycol 50% as secondary fluid that passes through the external diameter. Different correlations are applied to determine the convective coefficients, later the theoretical results will be compared with experimental results shown in the literature. It was observed that the coefficients increase when the quality of the coolant increases, increases

Acrylate polymer prepared by dispersion polymerization and its crude oil emulsion demulsification performance

AbstractThe development of a new crude oil emulsion demulsifier to replace the block polyether has always attracted attention. In this article, a novel crude oil emulsion demulsifier was prepared by dispersion polymerization using a mixture of ether and water as the dispersion medium and acrylate, methacryloxyethylthrimethyl ammonium chloride (DMC), and acrylamide as the comonomers. Taking the stability and demulsification performance as the index, the effects of acrylate type, ether/water mass ratio, monomer mass ratio, monomer concentration, initiator type, ether type, and reaction temperature on the polymerization results were investigated. The experimental results showed that when the acrylate was butyl acrylate (BA), the mass ratio of BA to DMC was 1:1, and dispersion medium was the mixture of dipropylene glycol methyl ether and water (ether/water mass ratio 1.5:1), monomer concentration was 20 wt%, initiator was V50, reaction temperature was in range of 50 to 55°C, and polymerization reaction was 10 h, the product P (BA‐DMC‐AM) had a good demulsification performance for the crude oil emulsion (crude oil density 0.9625 g/cm3, water content in emulsion 50%). When the dosage of P (BA‐DMC‐AM) was 200 mg/L and the temperature was 75°C, its dehydration was higher than 90% after demulsification for 4 h. This efficiency was similar with the block polyether demulsifier BH133. In addition, interfacial properties showed that P (BA‐DMC‐AM) can adsorb onto the oil–water interface and reduce the strength of W/O interfacial film, thereby achieving demulsification.

Significance of Axisymmetric Flow of Casson Darcy Unsteady Slip Flow in a Suspension of Nanoparticles with Contracting Walls

Current research inspects the influences of heat and mass transfer features of a Casson nanofluid flow over a growing or contracting porous medium with distinct permeability and thermal radiation. The free convection of ethylene-glycol and water as SWCNT Casson nanofluid and base fluid and it is impacted by a magnetic force field in two-dimensional flow. We have employed the governing equations of momentum, thermal radiation; boundary layers are lessened into a series of PDEs. And then, they are transformed to a series of non-linear ODEs by using similarity transformation technique. Numerical solutions of these are obtained with the help of shooting method together with the approach of fourth order R-K method. The decent correspondence between the investigative and numerical solutions is observed. Including to this, we contemplate and examine the impact of associated parameters like the coefficient of skin friction, Darcy number, Radiation parameter and Nusselt number on the velocity and temperature profiles. The outcomes demonstrated that ethylene-glycol and water as SWCNT Casson nanofluid and base fluid has the least local Nusselt number, minimum velocity and towering temperature. Moreover, our outcomes are tabulated and presented graphically. Illustrations made excellent agreement with the physical notions like the coefficient of skin friction and the Nusselt number. These outcomes are too analysed completely with existing results. We observed that, hard carbon nanoparticles guide to a greater velocity close to the as compared with the base fluid water ethylene glycol for the case of collective injection in addition to wall contraction. The Brownian motion increases the temperature profile while compare to profiles in the contraction case.

Anodization of Ti6Al4V in Water-Ethylene Glycol Solution Containing NH4F and Its Corrosion Behavior in Ringer’s Solution

Anodization of Ti6Al4V in Water-Ethylene Glycol Solution Containing NH4F and Its Corrosion Behavior in Ringer’s Solution