جستجوی مقالات مرتبط با کلیدواژه "inhibitor" در نشریات گروه "مهندسی شیمی، نفت و پلیمر"

This study investigates the potential of 5-amino-1,3-diphenylpyrazole and nitrogen-enriched 5-hydroxy-1,3-diphenylpyrazole to inhibit corrosion of mild steel in acidic environments. A comprehensive approach combining weight loss measurements and Density Functional Theory (DFT) calculations was employed to analyze the inhibitory effect under various concentrations, immersion times, and temperatures. At an optimal concentration of 0.5 mM, 5-amino-1,3-diphenylpyrazole displayed an impressive 94.7% inhibition efficiency, while 5-hydroxy-1,3-diphenylpyrazole achieved 86.4% efficiency at 303 K after 10 hours of exposure. Both compounds exhibited a mixed-type inhibition behavior, with increasing efficiency observed at higher concentrations. DFT calculations provided insights into the interaction between the molecules and the metal surface, along with their electronic properties, aiding in understanding the corrosion inhibition process. The investigation revealed that Langmuir isotherms govern the adsorption mechanism, and the calculated thermodynamic parameters suggest a complex interplay at the metal/solution interface, involving both chemisorption and physisorption. These findings provide valuable knowledge about the mechanisms of corrosion inhibition by these molecules, paving the way for the development of effective strategies to protect mild steel in corrosive environments.

Clathrate hydrates (gas hydrates) are solid crystalline compounds formed from water molecules as host molecules and gas molecules as guest molecules. Due to the hydrogen bonds, water constructs a framework that entraps some small nonpolar molecules (typically gases) and in suitable conditions (i. e. low temperature and high pressure) gas hydrate forms. The objective of this research is to estimate the gas and refrigerant hydrate dissociation conditions with and without alcohols and sodium chloride aqueous solutions using simple empirical correlations. Generally, the empirical suggested correlations to estimate the equilibrium clathrate hydrate pressure of CH4, C2H6, C3H8, CO2, N2, H2S, R22, R23, R134a, R116, R125a, R152a, R141b, R410a, R407c, R507c, CH4 + methanol, CH4 + ethylene glycol, CH4 + triethylene glycol, CH4 + ethanol, CH4 + sodium chloride, CO2 + methanol, CO2 + glycerol, CO2 + sodium chloride, R134a + sodium chloride, R507c + sodium chloride and R410a + sodium chloride systems are a function of equilibrium hydrate temperature and concentration. A genetic algorithm was employed as an optimization method to determine correlation coefficients, and the mean squared error was selected as its fitness function. Due to the low values of the calculated absolute average deviations (between 0.00 and 7.65), except for H2S + pure water with the highest amount of the absolute average deviation percent (AAD% equal to 11.51), these correlations are capable of predicting the studied hydrate dissociation conditions.

With the current emergence of green chemistry to keep the environment safe, attention is being shifted towards using plant extracts as corrosion inhibitors. The inhibitive performances of Talinum triangulare leaf extract and Musa sapientum peel extract on the ZA-27 in 1.0 M and 1.5 M hydrochloric acid solutions were studied for 18 days using mass loss measurement. The corrosion inhibition efficiencies of the extracts were evaluated. The results showed promising anticorrosive performance in 1.0 M HCl. The average inhibition efficiencies recorded for Talinum triangulare leaf extract and Musa sapientum peel extract in 1.0 M HCl using 1 w/v of each extract after 18 days were evaluated as 62.30% and 63.27%, respectively, while in 1.5 M HCl; 40.54% and 38.45% were recorded for Talinum triangulare leaf extract and Musa sapientum peel as inhibitors, respectively, in 1.5 M HCl

The inhibition properties of synthesized imine compounds N,Nʹ-bis(2,4-dihydroxyhydroxybenzaldehyde)-1,3-Propandiimine, N, N′-bis(2,4-dihydroxypropiophenone)-2,2-dimethylpropandiimine, N,Nʹ-bis(2,4-dihydroxyacetophenone)-1,3-Propandiimine has been investigated for API-5L-X65 steel corrosion in hydrochloric acid by scanning electron microscopy, potentiodynamic polarization and impedance spectroscopy. Aqueous hydrochloric acid was applied to simulate the oil and gas well acidizing fluid. Potentiodynamic polarization studies indicated that compounds retard both the anodic and cathodic reactions through adsorption and blocking the active corrosion sites. The inhibition efficiency increased with inhibitor concentration. Electrochemical impedance spectroscopy data were studied by equivalent circuit and showed that with increasing inhibitor concentration, the resistance of charge transfer enhanced and the capacitance of double layer reduced. The measured data proposed that the inhibition efficacy was increased for inhibitor in the absence of alkyl addition. The geometrical steric hindrance offered by the alkyl groups in the imine compounds plays an important role in its corrosion inhibition properties. Scanning electron microscopy was used to study the steel surface with and without inhibitors.

The aqueous mixtures of light gas molecules under low-temperature and high-pressure conditions are candidates to form gas hydrate clathrates. The formation of gas hydrate may lead to various problems and extra charges in natural gas production and processing. The presence of hydrate crystals forming a stable solid phase can potentially block the wells, pipes, and process facilities. To avoid such problems, hydrate formation must be studied in different conditions. In this regard, this study aims to design an experimental procedure to determine gas hydrate formation in water based drilling mud. In addition to this, the effect of different inhibitors (i.e. NaCl, methanol, and ethylene glycol) on the hydrate temperature suppression is studied. The designed apparatus is capable of determining hydrate formation conditions in both static and dynamic conditions. Based on the obtained results, among the combinations of NaCl with methanol or ethylene glycol at different concentrations, a mixture of 10 wt.% NaCl 10 wt.% methanol shows the best inhibition effects (i.e. higher temperature suppression and longer induction time). Furthermore, the experimentally obtained temperature suppression data were fitted and compared against two different thermodynamic models. Temperature suppression variation with inhibitor concentration is described in an acceptable manner by both models.
The present contribution is aimed to design an experimental procedure to determine gas hydrate formation in water based drilling mud. In addition to this, effect of different inhibitors (i.e. NaCl, methanol, and ethylene glycol) on the hydrate temperature suppression is studied. The designed apparatus is capable to determine hydrate formation conditions in both static and dynamic conditions. Based on the obtained results, among the combinations of NaCl with methanol or ethylene glycol in different concentrations, a mixture of 10 wt. % NaCl 10 wt. % methanol shows the best inhibition effects (i.e. higher temperature suppression and longer induction time). Furthermore, experimentally obtained temperature suppression data were fitted and compared against two different thermodynamic models. Temperature suppression variation with inhibitors concentration is described in an acceptable manner by both models.

The organic deposition particularly asphaltenes has many detrimental effects on the oil industries, such as plugging in pipelines, wellbore and facilities and subsequently, considerable reduction in well productivity.Asphaltenes are the most polar fractions, which they have been dispersed as colloidal clusters in crude oil. The accumulation of these clusters lead to the flocculation of colloids, and accordingly, formation of precipitation. Adding inhibitor is one of the ways to prevent clustering of asphaltene precipitation in crude oil. In this study, the effect of inhibitors to prevent asphaltene precipitation was investigated by viscometric method. At first, the different concentrations (1000 ppm, 2000 ppm, 10000 ppm and 20000 ppm) of some aromatic, anionic and nonionic inhibitors were prepared in a dead crude oil sample, and then the inhibition strength of samples was measured. The results showed that inhibition strength of inhibitors in low to moderate (1000 ppm – 10000 ppm) concentrations has a regular pattern, and it is associated with functional groups in chemical structure of inhibitors.

The aim of the current study is to evaluate the effects of inhibitors or solvents on asphaltene precipitation under reservoir conditions. To this end, the interaction between live oil and solvent, and its side effects on precipitated/dissolved asphaltene were predicted via Miller’s entropy modified polymer solution theory under reservoir conditions. Then, the adjustable parameters of the model were tuned using experimental the data of asphaltene precipitation within a live oil sample. The obtained adjusted parameters were considered to monitor the effects of solvent injection, miscible gas injection, and natural depletion on asphaltene deposition through an oil sample. Finally, Peng-Robinson equation of state was applied to calculate vapor-liquid equilibrium conditions. The results showed that the output of the model was really in good agreement with all experimental, field, and theoretical data.

The corrosion inhibition performance of acetylacetonate complexes of zinc(II), manganese(II), cobalt(II) and copper(II) on the mild steel substrate in 1M H3PO4 was studied using DC polarization. It was seen that the mentioned complexes decreased corrosion rate of mild steel in phosphoric acid media due to the adsorption on metal surface. The potential of mild steel shifted toward more active potentials. The cathodic Tafel slopesincreased showing that acetylacetonate complexes are cathodic inhibitors. Presence of chloride ions in the electrolyte enhanced inhibition performance of acetylacetonate complexes due to synergism. Chloride ions provided by HCl had a better performance compared to NaCl. Prog. Color Colorants Coat. 2(2009), Institute for Color Science and Technology.