Water-soluble Corrosion Inhibitors Research Articles

Phase Equilibriums of Ammonium Chloride Systems as Model Hydrogenolysis Products of Organochlorine Compounds under Naphtha Hydrotreating Conditions

The study focuses on corrosion challenges for naphtha hydrotreating equipment (installed upstream of a reforming unit) caused by ammonium chloride deposits and on the development of adequate chemical engineering protection measures. Using an experimental setup, we investigated the sublimation/desublimation of ammonium chloride at varying pressures and temperatures in a medium typical of naphtha and hydrogen-bearing gas streams flowing from a naphtha hydrotreater. Superstoichiometric concentrations of hydrogen chloride were found to significantly decrease the desublimation temperature (by 30–50°C) compared to a system that has a stoichiometric HCl concentration. Consequently, solid-phase ammonium chloride exists in a wider range of temperatures and pressures. Introducing surfactants (especially higher alcohols) into the system reduces adhesion and affects the crystalline structure of salt deposits—despite the solid phase being stabilized by an excess (superstoichiometric) concentration of hydrogen chloride—which makes surfactants suitable for mitigating the salt deposition challenge. Based on the data obtained, we proposed effective chemical engineering protection methods that use water-soluble corrosion inhibitors in combination with an online automated system for organochlorine control.

Synthesis and Structure of Water-Soluble Sb Quantum Dots and Enhanced Corrosion Inhibition Performance and Mechanisms

Generally, single organic or inorganic inhibitors could effectively inhibit corrosion for metallic materials; however, there are rarely reports about the hybrid corrosion inhibitors consisting of organic and inorganic inhibitors. Thus, in this work, we synthesize a hybrid environment-friendly water-soluble corrosion inhibitor (Sb quantum dots) containing Sb, Sb2O3, Sb2O4, and carbon using the electrochemical exfoliation method. The inhibition effectiveness in short- and long-term immersion tests is measured using electrochemical methods, weight loss, and surface analysis. The results exhibit that the corrosion inhibition efficiency sensitively relates to the concentration of Sb quantum dots (SQDs), which achieves the largest value as the concentration of SQDs increases to 200 mg/L. Atomic force microscopy, scanning electron microscopy, and contact angle analysis reveal that the SQDs well-disperse on and cover the Q235 steel surface at 200 mg/L. According to the Langmuir adsorption data, the physicochemical adsorption and effective antioxidation of SQDs on the passivated Q235 steel surface are in charge of the effective corrosion inhibition efficiency in 0.5 M H2SO4 solution.

Utilization of ethoxylated pentamine oleamide as new Gemini surfactants for corrosion inhibition effectiveness in 1 M HCl solution

This research aims to convert tetraethylene pentamine Gemini surfactants from oil to water-soluble corrosion inhibitors for applying in oil field at temperatures up to 65 °C. To achieve this aim, four new ethoxylated Gemini surfactants denoted as (T1, T2, T4 and T6) bearing different ethylene oxide units of 19, 28, 45 and 65, respectively were prepared and evaluated as corrosion inhibitors. The chemical structures of the prepared inhibitors were verified using FT-IR and 1H NMR spectroscopic analysis. The performance of the prepared surfactants was determined using surface tension measurements and thermodynamic parameters. Weight loss and electrochemical measurements were utilized to measure their corrosion inhibition efficiencies at a temperature range of 25–65 °C. Through the obtained results, the maximum inhibition efficiency of 95.74% was obtained by T6 at 25 °C in 1 M HCl.

Protective Efficiency of Water-Soluble Corrosion Inhibitors

Introduction. As a result of damage to agricultural and forestry machines from corrosion, the costs of maintaining their performance are increasing. The use of water-soluble inhibitors can slow or halt the destructive process. However, many of the inhibitors have disadvantages, for example, flammability or toxicity. The purpose of this work is to study the protective effectiveness of aqueous solutions of boric acid ester and triethanolamine and to develop recommendations for their use for anticorrosive protection of agricultural and forestry machinery in long-term storage. Materials and Methods. Protective compositions were prepared by dissolving boric acid ester and triethanolamine in distilled and industrial water at room temperature. Aqueous solutions with a concentration of water-soluble inhibitors of 5–50 g/l (0.5–5 mass %) were used for research. The linear polarization resistance method was used to assess their protective efficiency. Solartron (UK) measuring complex was used for electrochemical studies. Accelerated corrosion tests were carried out on steel plates according to GOST 9.054-75 in the g-4 humidistat. The aftereffect of water-soluble corrosion inhibitors was evaluated by the residual film protective efficiency. Results. The influence of the concentration of the ester of boric acid and triethanolamine in aqueous solutions for their protective properties is studied. It was found that boric acid and triethanolamine slow the anode reaction. The analysis of the research results has showed that the corrosion rate of the steel electrode decreases with increasing the concentration of water-soluble inhibitor in process water. This decrease is the most noticeable when the concentration in the range of 10–50 g/l with an increase in the concentration in the solution of boric acid and triethanolamine to 50 g/l, their protective efficiency varies by 6–14 %. The optimal concentration of the inhibitor in the composition is obtained, which is 10 g/l during corrosion tests of steel plates, the protective efficiency of the solution with a concentration of 10 g/l of the water-soluble inhibitor was more than 70 %. In case of precipitation on the samples, the protective efficiency of the solutions decreased to 20–25 %. When tested in a closed unheated room on steel samples during the year there were no traces of corrosion. Conclusions. The study demonstrates that boric acid and triethanolamine is a watersoluble inhibitor of anodic corrosion. When the concentration of water-soluble inhibitor in process water increases, the corrosion rate of the steel electrode decreases. Optimum concentration of ester of boric acid and triethanolamine in the protective solution should be 10 g/l. For corrosion tests of steel plates, the shielding effectiveness of a solution of water- soluble inhibitor was more than 70 %. In the conditions of direct exposure to atmospheric precipitation on the samples of the protective efficiency of the solutions decreased to 20–25 %. When tested in a closed unheated room on steel samples there were no traces of corrosion during the year. Thus, the ester of boric acid and triethanolamine is effective to protect against atmospheric corrosion in a closed room. it Is recommended to apply it for protecting cars against corrosion at short-term storage on open platforms. The application field of water-soluble inhibitor when agricultural and forestry machines are retained for long-term storage is defined; combine stages of cleaning cars from pollution and preserving their surfaces for protection against corrosion are offered. The article will be useful to specialists in the field of protection of agricultural machinery from corrosion.

A Study on the Applicability of Corrosion Inhibitor for Outdoor Copper Alloy

Outdoor copper alloy is exposed to the atmospheric environment, accelerating corrosion progress compared with indoor copper alloy. In order to prevent corrosion, the outdoor copper alloy is coated with wax to block external corrosion factors. However, corrosion of the inside of the coating film is highly likely to continue without the internal corrosion prevention treatment. B.T.A, which is used as a copper alloy water-soluble corrosion inhibitor, has a high possibility of being harmful to the human body and is mainly used to treat excavated artifacts. This study had selected the water-soluble corrosion inhibitor, which was easier to use than the existing wax and B.T.A being used in corrosion inhibition treatment for outdoor copper alloy. A comparative study was conducted on B.T.A, which is a water-soluble corrosion inhibitor used on excavated artifacts, and VCIⓇ, RusⓇ, and L-cys, an amino acid corrosion inhibitor, used for tin bronze test pieces. The experimental method was conducted for a certain period of time with the salt, acid, and air pollution affecting the corrosion of outdoor copper alloy. Based on experiment results, it was concluded that the best water - soluble copper alloy corrosion inhibitor in the atmospheric environment is VCIⓇ. and it could be considered to be applied in replacement of B.T.A due to its low harmfulness. In addition, VCIⓇ is judged to serve as a corrosion inhibitor for outdoor copper alloy because it showed the best result even in the outdoor exposure test which is a real atmospheric environment.

SOME WATER-SOLUBLE POLYMERS AS CORROSION INHIBITORS FOR CARBON STEEL IN ACIDIC MEDIUM

Encouraged by the excellent performance of organic polymers as scale inhibitors and anticorrosive coatings, we reasoned that polymers with properly designed structures might also be used as efficient water-soluble corrosion inhibitors. New kind of water soluble hyperbranched polyamide ester (HPAE) synthesized using trimethylol propane as a precursor via Michael addition reaction with diethanolamine. The chemical structure of the prepared polymers was determined by FT-IR. The inhibitive effect of HPAE on the corrosion of steel in 1 M HCl solution has been investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results indicated that HPAE inhibited the corrosion of steel and the extent of inhibition increased with HPAE concentrations. Potentiodynamic polarization data suggests mixed-mode of corrosion inhibition.

Water soluble corrosion inhibitors for copper in 3.5 wt% sodium chloride solution

In this study, synthesis of water soluble and efficient corrosion inhibitors PBTB carrying single benzotriazole part and PDBTB containing double benzotriazole segments for copper in 3.5wt% sodium chloride solution was proposed. PDBTB showed greater corrosion inhibition effect than PBTB basing on survey results of polarization curves, impedance spectroscopy and scanning electron microscopy. Adsorption mechanism of the studied inhibitors on copper surface was studied by FT-IR spectra, X-ray photoelectron spectroscopy, X-ray diffraction spectra as well as adsorption isotherm.

Water-soluble thiosemicarbazide-imidazole derivative as an efficient inhibitor protecting P110 carbon steel from CO2 corrosion

Purpose The purpose of this paper is to adopt both the fragments of imidazole and thiosemicarbazide as reaction centers, to synthesize a water-soluble corrosion inhibitor named as thiosemicarbazide-imidazole derivative (TH-IM). Design/methodology/approach This paper presents potentiodynamic polarization tests, electrochemical impedance spectroscopy tests and morphology study of metal surface by scanning electron microscope and thermodynamic study. Findings In the aggressive condition of CO2 saturated Wt. NaCl solution at 333 K for 72 h with 400 ppm inhibitor dosage, the efficiency of inhibition increases approximately 98 per cent through the method of weight loss. Originality/value This paper finds a new corrosion inhibitor about TH-IM which has a good solubility in water.

Studies on corrosion control of naphtha fractions in overhead condensing system using laboratory distillation device

Corrosion in the overhead condensing system of atmospheric distillation units is a common occurrence in petroleum refineries worldwide. These corrosion problems are influenced by the presence of three phases: vapours, liquid hydrocarbons and aqueous phase containing hydrochloric acid formed during distillation by decomposition of chloride salts of calcium and magnesium. Present studies highlight the corrosion control of naphtha fractions of Bombay High and Dubai crude oils in laboratory distillation device by chemical treatment using various corrosion inhibitors having different functional groups. These studies were carried out using two phase systems (aqueous–hydrocarbon) in the distillation device having facilities for monitoring the corrosion and temperatures in vapour condensing region and liquid condensate. Corrosion monitoring was carried out by potentiodynamic polarization technique and dissolved iron analysis using inductively coupled plasma atomic emission spectroscopy (ICPAES). Experimental findings indicate that Dubai naphtha fraction is more corrosive in nature when compared to Bombay High naphtha. This observation can also be explained on the basis of characterization of both crude oils and their naphtha fractions. At normally recommended dosage level as in refinery overhead systems, water soluble corrosion inhibitors are more effective than hydrocarbon soluble ones in the vapour condensing region as well as in the liquid condensate of both naphtha fractions.

Synthesis and evaluation of a new water soluble corrosion inhibitor from recycled poly(ethylene terphethalate)

Polyethylene terephthalate waste (PET) was depolymerized by triethanolamine into glycolyzed product (GT), followed by esterification with bromacetic acid in the presence of manganese acetate as a catalyst to give (GT-Br). The obtained ester was reacted with thiourea to give thiol derivative (GT-SH). The effectiveness of the synthesized compound as corrosion inhibitor for API XL65 carbon steel, in 2 M hydrochloric acid solution was investigated by various electrochemical techniques such as open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of these investigations showed enhancement in inhibition efficiencies with the increasing of inhibitor concentration. The protective film formed on carbon steel surface was analyzed using an energy dispersive X-ray analysis (EDX) technique. Also, scanning electron microscope (SEM) was used to study the surface morphology of steel surface in the absence and presence of 400 ppm of the additive.

A rapid screening multi-electrode method for the evaluation of corrosion inhibitors

A method is described for the rapid screening of water-soluble corrosion inhibitors, which involves a fixed potential being applied between identical electrodes while immersed in an inhibitor solution. The current flowing between the electrodes is measured and the electrochemical response of the anodic and cathodic reactions, with and without the inhibitor, is then compared. The incorporation of nine pairs of metallic wires (Al, AA2024, AA7075, Fe, mild steel, SS316, Mg, Mg-AZ31 and Zn) into a single assembly enables the effect of inhibitors on different metals to be assessed rapidly. The technique is sensitive to both anodic and cathodic inhibition mechanisms and can provide information on the concentration dependency of inhibitors. This paper provides an electrochemical analysis of the method and demonstrates its application using several soluble chemical species (potassium dichromate, cerium nitrate, sodium vanadate, sodium diphosphate, sodium octanoate) on AA2024-T3 and mild steel at 10 −2 and 10 −4 M and correlates the results with those obtained by conventional potentiodynamic polarization analysis. The errors in the approach were higher for poor inhibitors, however, efficient corrosion inhibitors have decreased experimental errors, thus, ensuring that promising inhibitor candidates are not overlooked.

Inhibitor of hydrogen sulfide corrosion of steel based on di- and polypropylene polyamines

Several aminoimidazolines and their derivatives are produced from di-and polypropylene polyamines and higher isomeric acids. Varying of the composition and ratio between the components of preparative form enabled us to produce a water-soluble corrosion inhibitor that effectively protects steel against hydrogenation and corrosion in hydrogen sulfide media.

Water-soluble inhibitor on microbiologically influenced corrosion in diesel pipeline

The effect of water-soluble corrosion inhibitor on the growth of bacteria and its corrosion inhibition efficiency were investigated. Corrosion inhibition efficiency was studied by rotating cage test and flow loop techniques. The nature of biodegradation of corrosion inhibitor was also analyzed by using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR) and Gas chromatography and mass spectrometer (GC–MS). The bacterial isolates ( Serratia marcescens ACE2, Bacillus cereus ACE4) have the capacity to degrade the aromatic and aliphatic hydrocarbon present in the corrosion inhibitor. The degraded products of corrosion inhibitor and bacterial activity determine the electrochemical behaviour of API 5LX steel. The influence of bacterial activity on degradation of corrosion inhibitor and its influence on corrosion of API 5LX have been evaluated by employing weight loss techniques and electrochemical studies. The main finding of this paper is that the water-soluble corrosion inhibitor is consumed by the microbial action, which contributes to the decrease in inhibitor efficiency. The present study also emphasis the importance of evaluation of water-soluble corrosion inhibitor in stagnant model (flow loop test) and discusses the demerits of the water-soluble corrosion inhibitors in petroleum product pipeline.

Mechanism of protective action of certain oil-soluble corrosion inhibitors

1. It has been established that the protective effectiveness of oil-soluble corrosion inhibitors of the MSDA-11 type is related not only to their ability to form adsorbed barrier films to make the metal surface hydrophobic, but also to their migration to the aqueous phase and their effects on the kinetics of the electrode reactions responsible for the corrosion process. 2. Effective oil-soluble inhibitors of this type improve the electrode potential of the metal and retard the anodic process of metal ionization in aqueous extracts from inhibited oils, in a manner analogous to that of anodic water-soluble corrosion inhibitors. 3. It has been shown that measurements of electrode potentials and recording of polarization curves of metals in aqueous extracts from oils containing corrosion inhibitors can be used as a means of rating the relative effectiveness of oils with certain inhibitors, provided these inhibitors are partially water-soluble.