A new method has been developed to differentiate and quantify the amount of primary amines through a simple chemical process. Colored cyclic adduct compounds are formed by reaction of selective chemicals with primary amine. This adduct formation is preferential to the primary amine, even in the presence of a mixture of secondary and tertiary amines. The adduct shows selective enhanced fluorescence emission at 475-nm wavelength under specific excitation with 420 nm. Due to enhanced fluorescence activity, quantification becomes possible, even below a 1-ppm concentration of specific primary amine. A chemical matrix, formulated with the mixture of different concentrations of primary, secondary and tertiary amines, helps to differentiate and quantify primary amines present in the mixture, even at lower concentrations. This method is validated under synthetic field brine conditions to detect and quantify primary amines towards field applications.
Wang, Yefei (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Yang, Zhen (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Wang, Renzhuo (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Chen, Wuhua (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Ding, Mingchen (Key Laboratory of Unconventional Oil & Gas Development, China University of Petroleum East China, Ministry of Education, P. R. China, School of Petroleum Engineering, China University of Petroleum East China) | Zhan, Fengtao (College of Science, China University of Petroleum East China) | Hou, Baofeng (School of Petroleum Engineering, Yangtze University)
A novel indolizine derivative inhibitor for acidization was introduced. It could exhibit effective corrosion inhibition at a much lower concentration without propargyl alcohol and shows economic and environmental advantages. From quinoline, benzyl chloride, and chloroacetic acid, two indolizine derivatives were prepared under certain conditions. These inhibitive indolizine derivatives were both synthesised from benzyl quinoline chloride (BQC), which one of the conventional quaternary ammonium corrosion inhibitors used for acidising. The target compound was purified and instrumental analysis methods including elemental analysis, high-resolution mass spectrometry (HRMS), and NMR were used to characterise the chemical structure. The inhibition performance of the indolizine derivatives in 15 wt.% HCl, 20 wt.% HCl, and mud acid (12%HCl + 3%HF) for N80 steel was investigated by weight loss measurement, electrochemical method (potentiodynamic polarization and EIS), and SEM surface morphology assessment.
When 0.1 wt.% indolizine derivative was added, the inhibition efficiency of N80 steel in 15 wt.% HCl at 90 °C increased to 98.8 % and 99.1 % respectively without the synergistic effect of propargyl alcohol: however, in terms of BQC, even at a dosage of 1.0 wt.%, the inhibition efficiency of N80 steel only reached 83.3 % under the same conditions. The novel derivative could impart an improved corrosion resistance effect. Compared with BQC, there are more active adsorption sites in the derivative and therefore the inhibitor could be better fastened to the steel surface. The firmly adsorbed inhibitors would thereby prevent the metal surface from making contact with H+ ions and finally increase the inhibitory effect. As a high-efficiency corrosion inhibitor, the novel indolizine derivatives may offer a new strategy for corrosion protection in acidising.
Yang, Zhen (College of Petroleum Engineering, China University of Petroleum) | Wang, Yefei (College of Petroleum Engineering, China University of Petroleum) | Wang, Renzhuo (College of Petroleum Engineering, China University of Petroleum) | Chen, Wuhua (College of Petroleum Engineering, China University of Petroleum) | Ding, Mingchen (College of Petroleum Engineering, China University of Petroleum) | Zhan, Fengtao (College of Science, China University of Petroleum) | Hou, Baofeng (School of Petroleum Engineering, Yangtze University)
Propargyl alcohol, at great expense and with high toxicity, is often used as an essential synergistic component of corrosion inhibitors for acidizing; however, in our recent work, a novel indolizine derivative was found to exhibit effective protection performance without the synergism of propargyl alcohol. These indolizine derivatives were easily prepared from quinoline, pyridine, and several halide compounds via 1,3-dipolar cycloaddition reaction. The derivative could prohibit the corrosion of metal at an extremely low concentration and fulfills the requirements of increasingly stringent environmental standards. The inhibition performance of the indolizine derivatives to N80 steel was investigated in 15 wt.% HCl and 20 wt.% HCl by weight loss measurements, potentiodynamic polarization method (Tafel curves), and electrochemical impedance spectroscopy (EIS).
In the absence of propargyl alcohol, when the dosage of indolizine derivatives in 15 wt.% HCl is 0.1 wt.%, the inhibition efficiency of N80 steel increases to approximately 99% at 90 °C. The indolizine derivative shows a superior anti-corrosion performance at a much lower concentration than that of benzyl quinolinium chloride (BQC, a commonly used compound in current acidizing corrosion inhibitors), which serves as the precursor to indolizine derivatives. More importantly, these protective indolizine compounds behave better than the synergistic inhibitor propargyl alcohol. The reinforced active adsorption groups in indolizine derivatives could provide extra adsorption sites and fasten the inhibitive molecule to the steel surface, thus augmenting the protective effect. Here, a new inhibitive indolizine derivative is presented as an acidizing inhibitor that may also offer a low-pollution technique for corrosion prevention.
Wang, Renzhuo (Key Laboratory of Unconventional Oil & Gas Development, Shandong Key Laboratory of Oilfield Chemistry, School of Petroleum Engineering, School of Petroleum Engineering ,China University of Petroleum, East China, Ministry of Education) | Yang, Zhen (Key Laboratory of Unconventional Oil & Gas Development, Shandong Key Laboratory of Oilfield Chemistry, School of Petroleum Engineering, School of Petroleum Engineering ,China University of Petroleum, East China, Ministry of Education) | Chen, Wuhua (Key Laboratory of Unconventional Oil & Gas Development, Shandong Key Laboratory of Oilfield Chemistry, School of Petroleum Engineering, School of Petroleum Engineering ,China University of Petroleum, East China, Ministry of Education) | Wang, Yefei (Key Laboratory of Unconventional Oil & Gas Development, Shandong Key Laboratory of Oilfield Chemistry, School of Petroleum Engineering, School of Petroleum Engineering ,China University of Petroleum, East China, Ministry of Education) | Ding, Mingchen (Key Laboratory of Unconventional Oil & Gas Development, Shandong Key Laboratory of Oilfield Chemistry, School of Petroleum Engineering, School of Petroleum Engineering ,China University of Petroleum, East China, Ministry of Education) | Zhan, Fengtao (College of Science, China University of Petroleum)
Among the numerous corrosion inhibitors for acidizing, the propargyl alcohol, with great expense and high toxicity, is often added as an important synergistic component. In this work, novel indolizine derivative high-effective inhibitor for acidizing was introduced. The indolizine derivative could exhibit an excellent protection performance at a much lower concentration without the synergism of the poisonous propargyl alcohol. The two inhibitive indolizine derivatives in this paper were synthesized easily from Benzyl Quinolinium Chloride (BQC, known as the a commonly used key component of acidizing inhibitor) via 1,3-dipolar cycloaddition reaction. The indolizine derivatives were purified by the column chromatography and the structure were characterized by NMR and elementary analysis etc.
The inhibition performance of the BQC, propargyl alcohol and the indolizine derivatives in 15 wt.% HCl and 20 wt.% HCl for N80 steel was investigated by weight loss test and potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The conclusion obtained from the electrochemical tests is in accordance with the results of gravimetric test. It is amazing to notice that the derivative could exhibit a much better anti-corrosion performance than its precursor BQC and propargyl alcohol in the abserence of the poisonous propargyl alcohol.
Compared with BQC, the active adsorption sites are reinforced and strengthed in indolizine derivatives, and therefore, the inhibitor would fasten the steel surface more stronger. The firmly adsorbed inhibitors would prohibit the steel from the contact of acid. Indolizine derivative is presented as a new concept of effective acidizing inhibitor for the first time in this paper. It may offer a new method for the corrosion prevention in acidification engineering.
He, Jie (Honeywell Corrosion Solutions) | Zhou, Rachel (Halliburton Company) | Ball, David (Halliburton Company) | Zhang, Lizheng (Leo) (Halliburton Company) | Herrera, Adan (Halliburton Company) | Ellis, Peter (Honeywell Corrosion Solutions)
Historically, the testing of sour corrosion and environmental-assisted cracking (EAC) in the oil and gas industry has focused on oil country tubular goods (OCTG) with design lives of tens of thousands of hours, while wireline and wireline tools are typically exposed to sour conditions for a few hundred hours per year at most. The existing corrosion/EAC information related to wireline materials is either overly conservative or inadequate, which significantly reduces the work scope of a great number of engineering materials that could potentially be used in wireline applications. To overcome this difficulty, the H2S application limits of wireline materials need to be realistically defined.
In this work, the corrosion and EAC resistance of 14 heats of wireline materials, including a cold-rolled carbon steel, low-alloy steels, stainless steels, titanium alloys, nickel-based alloys, and copper-based alloys, were evaluated in two extreme sour environments: 180,000-mg/L chloride brine at 350°F (176.7°C) with partial pressure of H2S (PH2s) 17.2 MPa and partial pressure of CO2 (Pco2) 3.5 MPa, with and without elemental sulfur. The weight-loss corrosion rates, pitting, and cracking behavior of the wireline material were obtained, the result of which could be used as first step to guide the selection of wireline materials in sour service.
H2S and CO2 gas in combination with chloride containing brine water are the main causes of internal corrosion and EAC of materials used in oil and gas production. Wet H2S is corrosive and electrochemically react with alloys to produce atomic hydrogen, which diffuses into the crystal lattice of alloys to induce hydrogen embrittlement. High pressure CO2 results in lower pH, enhances general corrosion, and accelerates the activity of H2S on metal. The chloride ion at low pH breaks down passivity on metal and generates localized pitting sites, which could be taken as stress riser to induce chloride-stress corrosion cracking (Cl-SCC).
As increasing activities of exploration and production of oil and gas in challenging locations, the selection of materials exhibiting high strength, low weight, and good tolerance to high temperature and hostile chemicals environment, is more and more critical. NACE MR 0175-20151 is used as a guideline for selecting materials for sour service. The standard is good for materials used for long-term exposure (e.g. OCTG) but not to those for short-term applications, such as wireline equipment. To overcome this difficulty, an application limit need to be developed to cover the materials used for short-term sour service. However, due to lack of reliable data to correlate the corrosion/EAC results with the failure condition found in practice, the application limit is challenging to be established.
Fan, Liang (Missouri University of Science and Technology) | Reis, Signo T. (Missouri University of Science and Technology) | Chen, Genda (Missouri University of Science and Technology) | Koenigstein, Michael L. (Roesch Inc.)
Cathodic protection (CP) integrated with a protective barrier (e.g., thick organic coating) has been widely applied for the corrosion protection of steel pipelines. However, CP may make the pipe-coating interface become a more alkaline environment, potentially leading to cathodic delamination of the coating. It is, therefore, essential to evaluate the compatibility of new coating with CP in steel pipeline applications. Porcelain enamel, as an inorganic coating material, is widely used in chemical reactors, heat exchangers, or food-processing vessels due to its excellent engineering properties such as high abrasion, corrosion, and heat resistances. In this study, enamel-coated steel pipe samples with various levels of cathodic protection were tested to investigate their impedance models by electrochemical impedance spectroscopy (EIS). One electrical equivalent circuit (EEC) models were used to fit the EIS data of coated samples without CP, while two EEC models were employed for samples with CP. Coating capacitance was used to investigate the water absorption characteristic in coating. Through scanning electron microscopy (SEM), no corrosion products and delamination of enamel coating were found at the interface of steel substrate and enamel coating due to its chemical bond with metal substrates.
Internal pipeline lining is widely accepted and used to minimize the pipeline internal corrosion. Concrete, rubber, and plastics are commonly used materials for internal pipeline linings. However, concrete lining can reduce the inner diameter of pipelines, and its roughness may consume high energy during operation. Rubber lining is not oil, flame and abrasion resistant, and it is susceptible to temperature change.1 Cathodic protection (CP), acting as a complementary corrosion protection technique, is often combined with epoxy coating to protect metallic pipelines. However, CP can make the cathodic surface strongly alkaline and generate hydrogen at exposed metal surfaces. Alkalization is the predominant reason for cathodic disbonding of epoxy lining, which proceeds mainly through hydrolysis of the interfacial bonds that attach the coating to the substrate.2-3
Porcelain enamel, as an inorganic material, is chemically bonded to substrate metals by fusing glass frits at a temperature of 750°C~850 °C. It can not only be finished with a smooth and aesthetical surface, but also provide good chemical stability and corrosion resistance, as well as excellent resistance to abrasion and thermal shocks in extreme erosion environment.4 Unlike epoxy coating, enamel coating has no under-film corrosion when locally breached due to its chemical bond with metal substrates.5 The corrosion resistances of enamel coating applied to the steel pipes in 3.5 wt. % NaCl solution were evaluated and compared with those of epoxy-coated pipes in our previous study.6-7 The test results showed that the enamel-coated samples outperformed the epoxy-coated samples.
Multiphase pipelines manufactured from carbon steel are susceptible to several forms of corrosion, including top-of-line (TOL) corrosion. In wet gas pipelines, produced water can condense at the top of the pipeline when the temperature and pressure along the length of the pipeline decreases. If this happens, TOL corrosion will occur, which can be severe as the pH of the condensed water will be very low (< 5). However, it is possible to mitigate TOL corrosion with the application of corrosion inhibitors.
Using corrosion inhibitors to control TOL corrosion in multiphase systems presents several challenges. The corrosion inhibitor must be carried long distances within the gas phase and partition to the condensed water when necessary to form a protective barrier on the pipeline surface. An additional issue concerns the development and testing of inhibitors that can effectively mitigate TOL corrosion. Traditional laboratory tests used to assess corrosion inhibitors (e.g., kettle tests, autoclaves and flow loop) are not suitable, as they have been designed to determine corrosion inhibitor performance in controlling corrosion in the bottom-of-line (BOL) environment. Therefore, it is necessary to develop test methods that can be used to test TOL corrosion inhibitors. In addition, corrosion inhibitors used to control BOL corrosion are not effective in preventing TOL corrosion. Conversely, inhibitors that mitigate TOL corrosion are not suitable for controlling BOL corrosion. Therefore, multiphase inhibitors are needed that will control corrosion occurring on the entire pipe surface.
This paper describes the work carried out to develop test methods suitable for assessing inhibitor performance in controlling TOL corrosion. Using the novel test methods, new corrosion inhibitors have been developed that effectively mitigate TOL corrosion. Furthermore, a hypothesis is proposed to explain the TOL corrosion inhibition mechanism. This hypothesis is based on the findings of a liquid chromatography mass spectrometry (LC-MS) analysis that was used to measure the concentration of individual corrosion inhibitor components present in the condensing brine and pH measurements of this brine. Finally, the paper examines the issues that need to be overcome when developing TOL inhibitors in the laboratory and applying them in the field to achieve effective mitigation.
This paper gives brief descriptions of the mechanisms of common types of corrosion attacks in petrochemical and refinery environments viz. Wet H2S, Caustic, Amine, Carbonate corrosion and cracking. It then provides suggested guidelines for classifying the severity of the Wet H2S services and for all the listed services, accordingly provides a ready reckoner tool for Design Engineers to prescribe control measures to mitigate these risks. The control measures fall into three categories. The first is added material requirements such as mill heat treatments, chemistry restrictions, or additional requirements on material physical properties. The second class of control measures involves fabrication steps such as heat treatment, testing and inspection. Even with these practices, for some of the mechanisms, it is recommended to also have process or operational controls which are typically applied as Integrity Operating Windows (IOW), and it is beneficial to highlight these IOWs on the Materials Selection Diagram (MSD) and Piping and Instrumentation Diagrams (P&ID). Examples are velocity limit in amine services or temperature limits in caustic service. Collectively, these three categories of practices mitigate the risks associated with these corrosive services.
In a petroleum refinery, cost of corrosion-caused failures is a high percentage of maintenance cost. According to a comprehensive survey in US (year 1996), the total annual direct cost in refineries was estimated at 3.76b USD. Moreover, indirect cost of corrosion due to unit shut downs, loss of productivity and environment pollution can be even one order higher than the direct corrosion cost. In addition corrosion failures not only increase direct and indirect cost to industries but can also be associated with accidents for which cost can’t be estimated. It has been indicated that about 10-40% of corrosion cost can be avoided with appropriate engineering during the design phase and corrosion management during operation practices. In view of that it is emphasized to adopt best engineering practices at the engineering design and construction stages as a primary and effective measure for corrosion and cracking control at facilities.
Garfias, Louis F. (Seven Lakes H. S.) | Taylor, S. R. (University of Houston) | Klapper, Helmuth Sarmiento (Baker Hughes) | Klower, Jutta (VDM Metals International GmbH) | Botinha, Julia (VDM Metals International GmbH) | Garfias-Mesias, Luis F. (Environmental and Corrosion Testing of Advanced Materials)
Electrochemical methods in combination with in-situ microscopy were considered for studying precursor sites for pitting on nickel alloy UNS N07718 in chloride-containing environments at high temperatures. Therefore, the optimum size of the working electrode and a suitable pseudo-reference electrode must be selected for the electrochemical setup. Simultaneous in-situ micro-visualization and electrochemical testing was done on small electrodes from UNS N07718 immersed in artificial seawater at room temperature. The tests were performed using millimeter-size electrodes (minielectrodes) and micron- size electrodes (microelectrodes). Passivity with little or no metastable activity was observed during potentiodynamic polarization tests conducted using the microelectrodes. In contrast, several metastable events were observed in the minielectrodes during potentiodynamic polarization tests. The differences encountered when using a platinum (Pt) pseudo-reference electrode versus the Ag/AgCl reference electrode were established. A shift of 100 mV or more in the corrosion potential and in the potential where metastable pitting initiated was obtained for the Ag/AgCl reference electrode compared to the values obtained when using a Pt pseudo-reference electrode.
Because of the extensive use of UNS N07718 (alloy 718) for demanding applications in the oil and gas industry,1 it is crucial to determine the limitations in the resistance to localized corrosion of this alloy. Additionally, to optimize the resistance to pitting corrosion of the material, it is important to establish the microstructural particularities in the material that act as precursor sites for pitting. Pits can also lead to initiation of environmentally assisted cracking. The precipitation hardenable alloy UNS N07718 exhibits a complex microstructure. For most oilfield applications, alloy UNS N07718 is specified as: solution annealed and precipitation hardened (precipitation hardening, age hardening, and precipitation heat treatment are synonymous terms). Alloy UNS N07718 is hardened by the precipitation of secondary phases (e.g.y and γ’’) into the metal matrix. The precipitation of these coherent phases is induced by heat treating in the temperature range of 1100 °F to 1500°F. Depending upon the selected agehardening treatment, the δ-phase may also be present in the microstructure of the material. In addition, UNS N07718 contains carbides and carbonitrides.2 Some work has been done in the past to determine the influence of the heat treatment and resulting microstructure on the resistance of UNS N07718 to localized corrosion.3-6 However, these experimental results were not conclusive.7 Electrochemical results have suggested that carbides may be preferential sites for pit initiation on UNS N07718,3,6 but the role of these particles in the initiation for pitting in UNS N07718 at higher temperatures is currently not well understood.
Oluwabunmi, Kayode (University of North Texas) | Rizvi, Hussain (University of North Texas) | D’Souza, Nandika (University of North Texas) | Nazrazadani, Seifollah (University of North Texas) | Sanders, Steve (University of North Texas) | Hemmati, Vahid (University of North Texas) | Argade, Gaurav (University of North Texas)
The corrosion properties of PBAT/LDH coating on mild steel substrate was investigated. Tafel tests and electrochemical impedance spectroscopy tests (EIS) was used to analyze the corrosion resistance of the coating on the mild steel substrates. The morphological characteristics of the coatings was done using the scanning vibrating electrode technique (SVET) and environmental scanning electron microscopy (ESEM). Buffered saline solution containing NaCl-0.138 M, KCl-0.0027 M at room temperature and pH of 7.4 was used as electrolyte in the 3 corrosion tests. The tafel results showed that least corrosion current density value of 0.315 (μΑ/cm2) was recorded for 50 % LDH concentration in PBAT. This suggests that 50 % LDH in PBAT was about 98.5 % more corrosion efficient than 1018 bare mild steel and 0.7 % more that the 65 % concentration. The EIS results showed a similar trend. The 65 % LDH concentration showed about 25 % greater impedance to current flow over the 50 % LDH concentration in both the nyquist and bode plots. The SVET results revealed that the greatest corrosion protection of the mild steel substrates was observed with 50 % and 65 % LDH coating. This proved that an increased concentration of LDH in PBAT could potentially improve the corrosion resistance of mild steel when in service in a phosphate buffered saline environment.
Metallic materials used in the biomedical field are susceptible to localized corrosion especially pitting when they come in contact with body fluids and other solutions.1 The phenomenon of corrosion, a natural process that all metallic materials irrespective of the service environment suffer from have been examined using different techniques.2,3 Various forms of protective coatings have been used in the past to mitigate this effect.4 The use of organic coatings has recently gained more attention in the medical field as an environmentally friendly and economical technique for the corrosion protection for metals that come in contact regularly with body fluids. Surface coating of many products have to be carried out not only for aesthetic reasons, but specifically to maintain the integrity of the metallic substrate during their service life.5 Poly (butylene adipate-co-terephthalate) (PBAT) an aliphatic-aromatic biodegradable polyester primarily utilized in packaging industry;6,7 was investigated for its potential medical application.8 The non-cytotoxic behavior of the polymer using different cation exchange montmorillonites as filler at less than 10% by weight showed that through cytotoxicity tests, protein absorption analysis and total blood counts, PBAT composites are valuable in biomedical applications.9,10 Though, low hardness values and inherent non-conducting properties makes it suffers rapid delamination when used as a corrosion resistant coating, it was observed that it possessed the ability to enable platelet mobility which improved its mechanical properties with (less than 6%) of layered clay11,12. Based on this, we hypothesized that, reinforcing PBAT with LDH fillers a type of anion exchanged clays also known as hydrotalcite, with a brucite like structure; having a general formula [MII1-xMIIIx(OH)2x]x+(An”)x/n.mH2O, where Mn represents a divalent metal, Mra a trivalent metal, and An- an anion will help to increase the corrosion resistance of PBAT and give birth to a new set of bioinspired coatings suitable for use in medical implants.