جستجوی مقالات مرتبط با کلیدواژه « permeability » در نشریات گروه « مهندسی شیمی، نفت و پلیمر »

Hypothesis: 

One potential method for improving nanocomposite mixed matrix membranes is through the use of nanoparticles and compounds containing hydroxyl and carboxyl groups, which may aid in the penetration of CO2 gas. In this study, we investigated the selectivity and permeability of a polyether block amide/polyvinyl alcohol (Pebax/PVA) nanocomposite membrane containing magnesium oxide (MgO) nanoparticles. Previous research has shown that the addition of MgO to the Pebax/PVA matrix can increase CO2 permeability by creating an intermolecular space.

Prepared a Pebax/PVA nanocomposite membrane with a weight ratio of 80:20, containing 10% MgO nanoparticles, through a solution casting method. Evaluated the performance of the Pebax/PVA/MgO nanocomposite membrane for separating CH4 and CO2 gases using various tests.

Characterized the membranes through Fourier transform infrared (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) tests. FESEM images showed increased surface roughness with the addition of nanoparticles, and the nanoparticles were well dispersed within the polymer matrix. XRD analysis indicated that MgO nanoparticles had more interaction with PVA chains than with Pebax chains, and peaks at 42° and 62° regions were formed due to the placement of MgO nanoparticles among the polymer chains. We studied various parameters, including polyvinyl alcohol and MgO nanoparticle content, pressure, and temperature, as independent variables and examined their effects on the permeability of CH4 and CO2 gases. We measured the permeability of the constructed membranes and found that the addition of MgO significantly increased the permeability of CH4 and CO2.

The demand for rare earth elements has increased significantly due to potential industrial applications such as catalysts, magnets, battery alloys, ceramics. However, the separation and recovery of rare earth metals are very difficult due to their similar chemical properties and ionic radius, so progress in the separation process of these elements will bring many global benefits. Among the improved methods, the membrane technique has received much attention as a stable method with easy operation in the separation of such metals, and several membranes have been designed for separation. This article provides a summary of the types of membranes in the separation of rare earth elements in terms of extraction performance, transfer efficiency, and membrane stability. Polymer inclusion membranes are a new generation of non-liquid membrane that is made by a simple method of casting a solution containing liquid phases (carrier, plasticizer /modifier) and base polymers. Polymer inclusion membranes due to the possibility of simultaneous extraction and back-extraction, high selectivity, excellent stability, reusability, simple applicability, relatively low cost, and low energy consumption, it provides a great advantage in both the separation and purification of metal ions. Therefore, in this study, an overview of the PIMs reported in the studies to date is presented and the performance, permeability and stability of the membrane are discussed according to the base polymer, carrier, plasticizer and modifiers used.

Research subject:

 Investigation of the effect of temperature on the polymer flooding performance at the pore scale, leads to an understanding of the behavior of the polymer solution in porous media with varying permeability.

Research approach:

 In this study, the effect of temperature on flooding of polyacrylamide polymer on enhanced oil recovery in two homogeneous micromodels at 25 and 70 °C was investigated. The polymer solution and DW were injected at the injection rate of 1 μl/min up to 1 PV into the micromodel and the amount of produced oil and the movement of the injected fluid in the porous medium were analyzed. In addition, polymer rheology and injected fluid viscosity were measured for better analysis of results. Then the results were compared with flooding of distilled water as the control test.

Examining the flood results, it was found that on the one hand, the temperature factor helped to increase oil recovery by reducing the viscosity of the oil. On the other hand, it has reduced the role of injected fluid viscosity in oil extraction by reducing the viscosity of the polymer. The results showed that the phenomenon of fingering decreases in the case of polymer injection, and the rate of improvement of oil recovery during polymer and water flooding in both micromodels increases with increasing temperature. Also, the rate of improvement of oil recovery during polymer flooding in the A micromodel increased from about 43% at ambient temperature to more than 51% and in the B micromodel from about 51% to more than 60% at 70 °C. In fact, it can be said that the flow pattern and stability of the polymer solution front and consequently the ultimate oil recovery are significantly affected by the morphology of the pores, the shape and the throats pores.

Sand production in sandstone reservoirs is a vital issue in oil and gas fields due to the damage and economic problems it entails. Sand production leads to many problems such as erosion of facility of well and surface equipment, environmental problems, reduction and interruption in production and Sometimes it causes the loss of wells. Therefore, controlling sand production from wells prone to sand production is very important. So far, various methods, including mechanical and chemical, have been proposed and performed to control sand production, which are consolidated in chemical methods by injecting polymer fluids such as resins, etc. to the sand formation. The main purpose of this study is to provide aqueous-based resin that, in addition to creating compressive strength and slightly reducing permeability, is environmentally friendly and effective in terms of health and safety in comparison with solvent-based resins. By combining different percentages of resin and its suitable hardener with the produced sand sample, different core samples were made with different percentages. The fabricated cores were tested for permeability and compressive strength. Experiments showed that the fluid used has the ability to chemically consolidate the sand and the compressive strength and permeability values also change with the amount of resin and hardener composition.

Rate production and final recycling rates are heavily influenced by permeability as a dynamic parameter, but this parameter is low in some carbonate reservoirs and requires an appropriate solution to increase it. The purpose of this study was to investigate the effect of injection and confining pressure in a laboratory study of the permeability of reservoir rocks during acid-bed corrosive operations. Considering this approach, 6 samples of carbonate reservoir rock from one of Iran’s oil fields have been prepared. After determining the physical and mechanical properties of the samples, the effect of the confining pressure and the injection pressure on permeability variations and optimal flow rates were studied. Examination of the results of the experiments as well as the CT scans of the samples after acidizing operation showed that permeability increased to an acceptable level in all samples. In lower injection rates, the acid has enough time to react with the rock, wormholes are well-formed, and the rest of the sample space retains its density to a large extent, but by increasing acid injection rates, there are wormholes changing themselves with the complete destruction of the primary core section, and the remaining density has been reduced. This is accompanied by a combination of the two above-mentioned behaviors, by increasing the rate to a maximum. This has led to an increase in over 530 times permeability over the initial value of the sample. However, there is a slight difference between the formation time of the formation of wormholes in the injected sample with maximum discharge and the sample injected with a minimum. However, there is a slight difference between the formation time of wormholes in the injected sample with maximum rate and the sample injected with a minimum.

In this study, the mechanism of penetration of various coatings on wood texture was investigated. Based on the results of microscopic studies, the penetration of the coating into the texture of soft and hard wood has been different. Among the factors affecting the penetration rate, the effect of anatomical structure is more important than other factors. In this study, wood cells were examined from an anatomical point of view and then, the mechanisms of coating penetration into wood tissue were investigated.In general, understanding the anatomical structure of wood and the characteristics of the coating has greatly contributed to the improvement of wood coating methods.The results showed that the preparation of the substrate surface such as grating and sanding causes changes in the penetration of the coating in the wood texture.Also, sanding causes the cell to deform and clog pores, or even completely prevent the coating from penetrating.The coating penetrates the wood tissue inside the vessel, wood rays and punctuation. Water-based coatings have been able to have more penetration than solvent-based coatings in wood. In addition, wood with a rough surface absorbs more of the coating and improves performance in absorbing pigments.