Amine Corrosion Research Articles

Effect of brine salinity on the partitioning, distribution and corrosion inhibition performance of a quaternary amine corrosion inhibitor

Surfactant corrosion inhibition performance in water–oil environments is influenced by complex relationships between their physical properties, solution chemistry and interfacial characteristics. The existence of polar heads/nonpolar tails influences both the preferential distribution of the surfactant between the two media as well as the phase in which micellisation occurs. Both phenomena affect the efficiency of the surfactant inhibitor and its adsorption at the metal-solution interface. To demonstrate the complexity of such interactions, the effect of brine salinity on the critical micelle concentration (CMC) and partitioning/distribution behaviour of a quaternary amine corrosion inhibitor (alkyldimethylbenzylhexadecylammonium chloride, or BAC-C16) in a brine and toluene system (at 1:1 ratio) was explored. All experiments were conducted at 50 °C and pH4 over varying salinities (0.1, 1 and 10 wt%) of NaCl brine. Both CMC and partitioning characteristics of BAC-C16 are significantly affected by aqueous phase salinity, with an inversion of the partitioning response observed between concentrations of 0.1 and 1 wt% NaCl. The effect of BAC-C16 partitioning/distribution behaviour on corrosion inhibitor performance was examined using rotating cylinder electrode experiments. The results illustrate that in order to establish the true corrosion inhibition behaviour, consideration of the chemical distribution characteristics is crucial.

Development of experimental error-Driven model for prediction of corrosion rates of amines based on their chemical structures

This work investigated the relationships between amine corrosion rates and their chemical structural properties for application in the development of a Gaussian Process Regression (GPR) model for chemical structure-based prediction of corrosion rate of any amine. The GPR model accounted for experimental errors, which widened its scope to accurately predict the true corrosion rates, being restricted only to error associated with the trained model. The Average Absolute Deviation (AAD) between experimental corrosion rates and model predicted rates was 4.26 % for the test data, and 5.32 % for two test data unknown to the model. This showed that the model is generalizable and its predictions are accurate. This work also developed a user-friendly Graphical-User Interface, which allows a user to define any amine's structure to provide needed information to calculate its surface tension and steric effects for use as input variables to the model in predicting the corrosion rate of the amine.

DNA breaks evaluation of two water-based metalworking fluids by an occupational exposure design

Thermal degradation of water-based metalworking fluids (MWFs) produces carcinogen by-products. Since different additives have been used to eliminate hazardous material, the carcinogenic potential of two water-based MWFs was investigated in the lung epithelial cell line (A549). Two MWF types were studied in pure and on-used. The chemical content of all samples was assessed by gas chromatography–mass spectrometry (GC-MS). DNA damage of samples was evaluated in the doses range of 0.05–0.8 mg by comet assay. Comet images were analyzed with Open comet software. Amine borate and ethanolamine were found in B and C fluids respectively. Pyridazine compound by the potency of nitrosamine production was found in on-used C fluid. After using MWFs in the metal processing, a polycyclic component with bore central groups was produced in on-used B fluid. DNA damage of on-used fluid with boron component occurred at a level lower than ethyl amine-containing fluid. Moreover, the genotoxicity of air samples in B fluid was higher than C airborne samples significantly. More careful management have to be considered for the replacement of amine corrosion inhibitors with boron-containing chemical in MWFs. In conclusion design of a plan was required for the control of high-risk chemicals in the metal processing industry.

Corrosion Prevention of Additively Manufactured Aluminum Packing Devices Developed for Process Intensification of CO2 Capture by Aqueous Amines

Corrosion of additively manufactured (i.e., 3D printed) aluminum packing devices, developed to enhance heat and mass transfer in CO2 absorption columns using amine-CO2 scrubbing solutions, is investigated in this paper. The aluminum structures printed by selective laser melting with Al-10Si-0.3Mg feed powder are susceptible to corrosion in aqueous monoethanolamine, both fresh and used CO2-saturated solutions. The efficacy of corrosion-protective surface layers of aqueous polyether–ketone–ketone (PEKK) dip coating to provide amine corrosion resistance to the 3D printed aluminum structure is also evaluated. PEKK nanothick layers were coated on the corrugated surface of a 3D printed structure, identical to that of the intensified device, yielding 27 times higher corrosion resistance than the uncoated Al alloy surface. A systematic long-term electrochemical corrosion analysis revealed that a multilayer PEKK dip coating protocol enables protection of the 3D printed Al alloy surface in various CO2–monoethanolamine solutions.

Failure analysis in heat exchanger tubes from the top system of the regeneration tower of the hydrotreatment unit in an oil refinery: a case study

ABSTRACT This paper presents a failure analysis performed on tubes of a heat exchanger. Heat exchangers are among the most common equipment in an oil refining industry, as heat transfer is one of the most important and common processes in chemical and petrochemical industries. The equipment analyzed was the condenser of the top system of the diethanolamine regeneration tower of the naphtha hydrotreating unit of an oil refinery. The tubular bundle consists of 78 tubes in the ASTM A213 Grade 316L specification, with 19.05 mm in diameter and 1.65 mm in wall thickness. The tubes are subjected to the aqueous flow of H2S and diethanolamine on the outside and cooling water on the inside. After a scheduled general shutdown in July 2011, after six years of continuous operation, the loss of thickness in several tubes was observed. The result of the failure analysis indicated that, through visual inspection, the corrosive process occurred from outside to inside the tubes. The eddy current test indicated an active corrosive process with a corrosion rate of 0.16775 mm / year. The ultrasonic inspection performed through the internal rotating inspection system (IRIS) confirmed the loss of thickness and the presence of perforated tubes, with consequent loss of containment. Amine corrosion in the presence of H2S was identified as the basic failure mechanism, aggravated by DEA concentration higher than 20 wt.% in the analyzed equipment. In October 2019, the tubes of this exchanger were replaced and the proposed solution to mitigate the problem was to dilute the solution with washing water, to obtain amine solution concentrations below 5% by mass in the beam tubes of the heat exchanger.

Field test of high hardness o-rings made from Viton extreme with advanced polymer architecture in pipeline valves containing very sour gas

High hardness Flouroelastomers (copolymer of ethylene-tetrafluoroethylene-perfluoro methyl vinyl with Advanced Polymer Architecture) compound was used to make thick and large size O-rings and field tested in pipeline valves containing very sour gas. The sour gas contains 23% H2S, 11% CO2, CH4, low molecular weight hydrocarbons, amine corrosion inhibitors, methanol and water at 32°C and 1200 psi. The results show that after the field test these O-rings were in good conditions and were completely resistance to sour gas and no cracks, bubble, blister, swelling, hardening and softening in the O-rings were observed and they were resistant against the H2S, methanol, amine corrosion inhibitors and steam. High pressure of the system did not produce any defects due to explosive decompression phenomenon or did not cause extrusion in these O-rings. A lower hardness compound also were used to prepare small size and thin O-rings, after O-rings test in very sour gas pipelines valves they were in good conditions. However when thick and large size O-rings were prepared with this compound and tested in the above mentioned field test there were cracks and blisters on the surface of O-rings. Therefore only higher hardness compound can be used to make thick and large size O-rings and its mechanical properties and chemical resistance are proper for this application.

Corrosion Inhibition Study of Dodecylamine as long Chain Amine Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

Corrosion Inhibition Study of Dodecylamine as long Chain Amine Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

Amine corrosion and amine cracking of API 5L X52 carbon steel in the presence of hydrogen sulphide and carbon dioxide

ABSTRACTIn this research, stress corrosion cracking (SCC) and corrosion behaviour of API 5L X52 carbon steel in 25 wt-% diethanolamine solution, saturated/unsaturated with carbon dioxide and containing 0 and 200 ppm hydrogen sulphide at different temperatures were investigated using slow strain rate test, electrochemical measurement and microscopic analysis. In addition, the presence of heat stable amine salts (HSASs) in the test solution was studied using spectrophotometry and Fourier transform infra-red spectroscopy. Analysis of the results showed that the primary components to form HSASs exist in the solution. The results indicated that SCC is more likely in solutions without amine. Increase in corrosion rate of carbon steel by increase in temperature was clearly observed and concluded that the simultaneous presence of hydrogen sulphide and carbon dioxide in the solution can increase the corrosion rate of carbon steel more than having one of the gases in the solution.

The Effect of Temperature and Acid Gas Loading on Corrosion Behavior of API 5L X52 Carbon Steel in Amine Unit

The effect of temperature and H2S concentration on amine corrosion of API 5L X52 carbon steel in a CO2-saturated 25 wt.% diethanolamine solution was investigated via electrochemical techniques. It was found that increase in temperature from 25 to 80 °C resulted in severe increase in corrosion rate from 0.88 to 16.24 mpy due to increase in degradation rate of amine. Also, it was concluded that increase in H2S concentration led to increase in corrosion rate because of formation of more heat stable amine salts. The effect of temperature on corrosion rate was more significant than acid gas loading.

Screening and Quantification of Aliphatic Primary Alkyl Corrosion Inhibitor Amines in Water Samples by Paper Spray Mass Spectrometry.

Direct analysis and identification of long chain aliphatic primary diamine Duomeen O (n-oleyl-1,3-diaminopropane), corrosion inhibitor in raw water samples taken from a large medium pressure water tube boiler plant water samples at low LODs (<0.1 pg) has been demonstrated for the first time, without any sample preparation using paper spray mass spectrometry (PS-MS). The presence of Duomeen O in water samples was confirmed via tandem mass spectrometry using collision-induced dissociation and supported by exact mass measurement and reactive paper spray experiments using an LTQ Orbitrap Exactive instrument. Data shown herein indicate that paper spray ambient ionization can be readily used as a rapid and robust method for in situ direct analysis of polymanine corrosion inhibitors in an industrial water boiler plant and other related samples in the water treatment industry. This approach was applied for the analysis of three complex water samples including feedwater, condensate water, and boiler water, all collected from large medium pressure (MP) water tube boiler plants, known to be dosed with varying amounts of polyamine and amine corrosion inhibitor components. Polyamine chemistry is widely used for example in large high pressure (HP) boilers operating in municipal waste and recycling facilities to prevent corrosion of metals. The samples used in this study are from such a facility in Coventry waste treatment facility, U.K., which has 3 × 40 tonne/hour boilers operating at 17.5 bar.

Effect of Nano-Encapsulated Corrosion Inhibitors on Self-Healing Corrosion Protection of Steel Sheets

A nano-encapsulation system of organic corrosion inhibitors has been designed, which is capable of improving the self-healing corrosion protection without degrading the barrier protection of the coating layers. Core-shell nanoparticles loaded with six types of amine corrosion inhibitors such as ethanolamine, 5-amino-1-pentanol, diethanolamine, triethanolamine, propylamine and dipropylamine, were synthesized by multi-stage emulsion polymerization. Amines were successfully encapsulated into nanocapsules by reacting with carboxylic acid in core and shell polymer during alkalization swelling process. Water-soluble amines were effectively introduced in nanocapsules, and the basicity was the most predominant parameter for amine encapsulation. In alkaline condition, the encapsulated amines were generally well released and the release of the encapsulated amines was pH dependent regardless of the exposure time. In addition, the molecular structure and aqueous solubility were critical factors in the release behaviors. Linear amines and highly water-soluble amines were more easily released to the environments from inside capsules than branched and water-insoluble ones. The nanocapsules were incorporated into the coating resin and were coated on cold-rolled steel sheets to investigate corrosion protection efficiencies. The corrosion inhibitive efficiencies of the nanocapsule-containing coating layers were evaluated by semi-immersion tests and electrochemical tests, electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). The organic coatings with inhibitor-loading nanocapsules showed better corrosion performance than the organic coating with inhibitor-free nanocapsules. Among six amines used in this study, 5-amino-1-pentanol, diethanolamine and triethanolamine exhibited self-healing anti-corrosion performance with recovering coating resistance. The coating resistance of the coating film gradually decreased and then increased via the self-healing corrosion protection of amines release from the nanocapsules. On the other hand, ethanolamine, propylamine and dipropylamine exhibited a rapid drop in the coating resistance, and the resistance continued to decrease without self-recovery. The inhibition efficiencies of encapsulated amines were affected by both intrinsic inhibition activities of amine and encapsulation/release behaviors.

Encapsulation of aliphatic amines into nanoparticles for self-healing corrosion protection of steel sheets

A noble approach based on the encapsulation of corrosion inhibitors has been presented, which are capable of improving the active corrosion protection without negatively influencing the barrier properties of the coating layers. Polymeric nanocapsules loaded with six types of amine corrosion inhibitors were synthesized by multi-stage emulsion polymerization. Depending on the basicity and water solubility of amines, different amounts of releasable corrosion inhibitors were encapsulated into the polymer capsules. Encapsulated organic amines were generally well released under alkaline conditions, and linear amines were more easily released from inside capsules than branched ones. The nanocapsules were incorporated into the coating resin and were coated on cold-rolled steel sheets to investigate corrosion protection efficiencies. The corrosion inhibitive efficiencies of the nanocapsule-containing coating layers were evaluated by electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). In this study, it was revealed that the intrinsic properties of the amines as well as their encapsulation/release behaviors determined the barrier property and self-healing protection capability of the coating layer.

Sodium Diethyldithiocarbamate Inhibitor Inhibition of 316L Steel

Sodium diethyldithiocarbamate (SDDTC) is a new type of organic amine corrosion inhibitor. The corrosion inhibitor is not only good but also inhibition, bactericidal, antioxidant and other effects. Using dynamic potential polarization curves and the CMB-4510A inhibitor of the rapid assessment instrument its 316L steel in various concentrations of sodium chloride solution in the corrosion inhibition. Through the rapid evaluation of corrosion inhibitors and the determination of polarization curves, the results show that: corrosion rate increases with chloride concentration, with the increasing concentration of the solution SDDTC, inhibition effect was significantly better, when the concentration of 0.76g/l, inhibition efficiency is the best.

Validity of dynamic electrochemical impedance spectra of some amine corrosion inhibitors in petroleum/water corrosive mixtures by Kramers–Kronig transformation

In our previous works, the corrosion inhibition properties of propylamine (PA), iso-propylamine (i-PA), butylamine (BA), tert-butylamine (t-BA), hexylamine (HA), ethylenediamine (EDA), diethanolamine (DEA), 3-amino-1-propanol (3-AP), 2-dimethylethanolamine (2-DEA), cyclohexylamine (CHA), N-methylcyclohexylamine ( N-MCA) and dicyclohexylamine (DCHA) have been investigated by means of electrochemical impedance spectroscopy (EIS) with a carbon steel rotating disc electrode in some petroleum/water corrosive mixtures containing acetic acid and NaCl at 25 °C. In this work, the Kramers–Kronig transformations (KKTs) were applied to evaluate the validity of the impedance data of these amine compounds in hydrodynamic condition. The results obtained showed that experimental impedance data did not satisfy in K–K relations completely viz. indicated some errors. These errors were related to stray capacitances, external transmission line effects, pits formation and change in interface during data acquisition at high and low frequencies regions. In addition, the selection of a suitable equivalent circuit strongly emphasized to better interpret of EIS data which in turn cause better resulted KKTs spectra. With considering obtained transformations, more effective inhibitor was selected with regard to its charge transfer resistance, the corrosion capacitance and well satisfying in K–K relations.

Conjoint Action of CO2 Corrosion and Reciprocating Sliding Wear on Plain Carbon Steel Part II — Electrochemical Studies

Abstract The presence of sliding contact between metals in a corrosive medium significantly affects the metal loss rate of the surfaces in contact. In this study, corrosion tests were carried out on plain carbon steel undergoing sliding wear in CO2 saturated 3%NaCl solution with and without an amine corrosion inhibitor. Corrosion rates of the sliding surfaces were estimated using the polarization resistance technique. Sliding wear tests were carried out using steel specimens sliding against each other and steel specimens sliding against corundum specimens both continuously and intermittently. The corrosion rates of the specimens increased with the increase in contact pressure in the presence and absence of the corrosion inhibitor. The inhibitor decreased the corrosion rates for all of the specimens throughout the range of applied contact pressure. The corrosion rates of the specimens subjected to continuous sliding contact were higher than those undergoing intermittent sliding contact. The wear rate of a continuously sliding specimen in the absence of corrosion was determined by the application of cathodic protection and compared to the corrosion rate and the corrosion wear rate under the same loading conditions. The relative contributions of corrosion and wear to the overall metal loss are discussed.

Conjoint Action of CO2Corrosion and Reciprocating Sliding Wear on Plain Carbon Steel Part I — Effect of Contact Pressure and Amine Inhibitor

Abstract The conjoint action of CO2 corrosion and reciprocating sliding wear on sucker rod couplings and tubing constitutes a serious problem in directionally drilled oil wells. In this study, sliding wear corrosion tests were carried out in a 3% NaCl aqueous solution saturated with CO2 gas in the absence or in the presence of an amine corrosion inhibitor. Weight loss measurements were made at various contact pressures. Scanning electron microscopy was used to study the surface features of specimens tested under various loading conditions with or without inhibitor addition. The weight loss measurements showed that the samples representing the sucker rod couplings, which are subjected to continuous sliding contact, lost more metal than those representing the tubing at all times in the presence and in the absence of the corrosion inhibitor. The rate of metal loss increased with an increase in contact pressure. Inhibitor additions resulted in lower metal loss rates for all specimens.

Selecting an algicide for use with aluminum alloys

Six commercially available algicidal compounds were evaluated for (1) relative toxicity to various concentrations of seven species of algae and (2) potential for causing pitting corrosion of aluminum alloys. Diuron (a common herbicide) and the acetic acid salt of a technical grade of dehydroabietylamine were the two compounds most toxic to algae. A filming amine corrosion inhibitor ranked third in toxicity. Potassium permanganate, which ranked fourth in algicidal effectiveness, was least corrosive and was the only compound for which no pitting corrosion was measurable. Hydrogen peroxide ranked fifth in toxicity. The chlorine-liberating algicide sodium hypochlorite was found to be substantially inferior to the other five compounds in both toxicity and corrosiveness. New techniques for the evaluation of algicides are described.