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.
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.
ABSTRACTInhibitors have been used to mitigate corrosion in oil and gas producing assets. The efficiency of inhibitors are affected by several variables with the ability of an inhibitor to transport through the produced fluids onto the metal surface being one of the most important requirements. This can be achieved by formulating inhibitor products with a variety of chemistries that minimize their solubility in oil and are either soluble or dispersible in the brine.The partitioning of inhibitor products between the oil and aqueous phases require a reliable method to evaluate different inhibitor products. An analytical method using fluorescence spectroscopy has been developed as a means to measure inhibitor concentration. This new method offers several advantages over other commonly used techniques, such as dye transfer methods. The method offers a greater degree of accuracy, can be performed in the laboratory or at the well site, and individual analysis can be performed relatively quickly. Further, the performance of such formulations were evaluated under autoclave conditions in order to determine their applicability to existing producing systems.INTRODUCTIONCorrosion in metals is defined as the degradation of the materials' properties due to interactions with their environments1 and it has a significant impact on every stage of the oil and gas industry from production to transportation. In a study conducted from 1999 to 2001 by CC Technologies Laboratories, Inc., with support from the FHWA and NACE the total direct corrosion cost for the oil and gas exploration and production industry in the U.S. was estimated at 1.4 billion. The previous amount included expenses associated with surface pipeline and facilities, downhole tubing and capital expenditures related to corrosion.2 A recent report predicts this figure to be notably higher by 2015 due to the steady increase of direct and indirect costs of corrosion over the years, fueled by inflation and the expansion of oil and gas exploration and production.3
Carlos M. Menendez, Kathy Sowders, Charles Ake Baker Hughes 12645 West Airport Blvd Sugar Land, Texas USA ABSTRACT The need for green corrosion inhibitors is expanding to geographical areas beyond the North Sea and the Norwegian shelf as more countries adopt regulations that minimize the environmental impact of offshore production chemicals. The design process of corrosion inhibitors for these applications can be complex because of a limited number of chemistries with environmentally favorable properties and the rigorous qualification process necessary for subsea applications. The newly developed corrosion inhibitor complies with North Sea environmental regulations and physical properties such as cleanliness specifications, thermal stability, viscosity, and flammability while matching the corrosion performance of a conventional incumbent and methanol based corrosion inhibitor. Keywords: sweet environment, corrosion inhibition, offshore environmental regulations, subsea injection qualification INTRODUCTION Previous work addressed the development of green corrosion inhibitors for high shear applications in the North Sea. The need for green corrosion inhibitors is expanding to geographical areas beyond the North Sea and the Norwegian shelf as more countries adopt regulations that minimize the environmental impact of production chemicals offshore.
Encapsulation of Linseed Oil and Tung Oil in urea-formaldehyde shells was performed using in-situ polymerization technique. Optimization of process parameters for preparation of microcapsules were carried out using calculated amounts of oil and urea-formaldehyde, that were subjected to formation of spherical microcapsules of 25-45 µm size, that depend on the reaction time and stirring speed. The microcapsules thus prepared were analyzed using optical microscopy (OM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), for ensuring the encapsulation of oil in the thin shells of urea-formaldehyde. Thin film self-healing coatings with uniform and quick self-healing ability were achieved with microcapsules at an optimized concentration of 3 wt%. The anti-corrosive performance was evaluated using immersion test and electrochemical impedance spectroscopy (EIS).
Application of organic coatings is the most economical and common approach to combat corrosion. However, being the outermost layer on the component, these coatings are prone to suffer micro/nano level damages in service, either due to mechanical or chemical actions, failing the coating to last the estimated service life. These issues can be addressed, by using coatings that are tailored to have active functionality to respond against such damages and heal the damages autonomously. Such coatings are generally termed as self-healing coatings [1-8].
Self-healing coatings mimic natural healing process, similar to the healing of damaged skin . Therefore, self-healing coatings are very attractive as they can assure durability of the coated components even after damages in the coating due to chemical or mechanical reasons. Basic principle of self-healing coating is to heal the damaged area utilizing a buffer stock of either the raw materials, or quick healing materials. Three main methods of achieving barrier restoration in self –healing coatings are; (i) intrinsic self-healing; (ii) capsule based self-healing and (iii) vascular self-healing . Encapsulation of reactive materials and incorporating them in a suitable coating system is the most versatile method of self-healing coatings. Also, considerable literature is available on the synthesis methods and parameter optimization for encapsulation. There are different techniques available for encapsulation of reactive materials, which can be classified on the basis of a wall formation mechanism as reported by Pascault et al. .
Bavarian, Behzad (California State University) | Samimi, Babak (California State University) | Ikder, Yashar (California State University) | Reiner, Lisa (California State University) | Miksic, Boris (Cortec Corporation)
Explosions, fires, plant shutdowns, injuries and destruction, the majority of these failures are corrosion related. More specifically, for refining, petrochemical, marine environments and power plants, industries with vast amounts of piping, the cause of production delay is due to corrosion damage under insulation that make it very hard to inspect and detect damages prior to failures. For corrosion under insulation, there are further complications from having to inspect the structures to ascertain the existence and extent of corrosion. Maintenance and plant inspection become labor and time intensive when large quantities of insulation have to be removed. Despite advances in materials and inspection technologies, CUI remains a serious and costly industry problem. In this investigation four API 5L X65 steel pipes were insulated with thick foam to determine the effective protection of a commercially available vapor phase corrosion inhibitor (VCI) against CUI. Electrochemical potential and corrosion rate were monitored under isothermal and cyclic wet/dry test conditions. Test results have demonstrated that VCI can successfully reduce corrosion attack under insulation even in a chronic wet environment. When VCI was used, the corrosion rate was reduced by a factor of 30. These results showed that an effective protective coating system under the insulation is critical and requires the inclusion of VCI to prolong the pipe integrity and lower inspection and maintenance cost.
Ni-based UNS N07750 alloy is a corrosion resistant Ni-Cr-Fe alloy, used in a wide variety of corrosive environments. Among these environments is seawater, which is by far one of the most aggressive and complex environments. Performance of alloy UNS N07750 in seawater has been investigated in terms of pitting and crevice corrosion tendency.
For pitting corrosion resistance measurements, accelerated electrochemical potentiodynamic polarization technique was conducted to determine characteristic pitting parameters. Tests were done in normally aerated (no aeration/de-aeration being applied) synthetic seawater, at different temperature ranges (4, 10, 20, 30, 40 & 500C), with a scan rate of 0.5mV/s. It has been found that at 20, 30, 40 and 500C, alloy UNS N07750 suffered from pitting corrosion with pitting potentials of 493, 508, 444 and 444 mVSCE(250C), respectively.
This work has also shown that as temperature increases, pitting potential decreases to more active values. However, in terms of dimensions and number of pits, it has been observed that as temperature increases, number of pits decreases while their size becomes larger. On the contrary, previous investigations by Z.Szklarska-Smialowska,1 and Rosenfeld, 2 on iron and stainless steels, observed large number of pits with small size at higher temperatures. At lower temperatures (100C and less), the alloy underwent transpassive dissolution rather than pitting corrosion. However, small pits were observed in the transpassive region, which has been also reported by many authors. 3
Critical Pitting Temperature (CPT) measurements revealed that CPT of alloy UNS N07750 in seawater lies between 11 and 200C.
During potentiodynamic polarization measurements, ennoblement in corrosion potential with time was noticed, and no steady state corrosion potential was attained even when the test coupons kept in solution without polarization for more than 3 days.
Crevice corrosion tests were done by long-term exposure in stagnant artificial seawater for 30 days at two different temperatures (25 and 400C). The alloy did not suffer from crevice corrosion under the tested conditions. This may indicate that the alloy under crevice tests performs better, compared to accelerated electrochemical pitting tests.
Chebaro, Mohamed R. (Enbridge Pipelines Inc.) | Padgett, Barbara N. (Det Norske Veritas (U.S.A.), Inc.) | Beavers, John A. (Det Norske Veritas (U.S.A.), Inc.) | Norfleet, David M. (Det Norske Veritas (U.S.A.), Inc.) | Ironside, Scott D. (Enbridge Pipelines Inc.)
In early 2012, a metallurgical investigation was performed on a section of pipe that leaked in service. The pipeline transports crude oil and is located in Northern Canada. The investigation concluded that internal stress corrosion cracking (I-SCC) was the primary mechanism by which a crack initiated and propagated 96% through-wall, following an intergranular path. The remaining 4% of the wall thickness failed due to fatigue crack propagation. While I-SCC is extremely rare in underground petroleum pipelines, all other plausible cracking mechanisms were eliminated through a detailed metallurgical analysis. Methanol was suspected to be the agent responsible for the I-SCC . Following the completion of the investigation, a laboratory research program was initiated to confirm the mechanism of methanol-induced I-SCC using slow strain rate (SSR) testing under simulated environmental and physical conditions. In addition to the SSR testing, the circumferential, radial and axial distributions of residual stresses along the girth welds of two pipe sections removed from the pipeline were quantified. Residual stresses in the vicinity of the girth welds were found to be a contributing factor to the cracking identified in the investigation. This paper provides an overview of the comprehensive laboratory research program and details the efforts to replicate the atypical cracking mechanism in controlled methanol environments.
This standard practice provides format, content, and other guidelines for developing a materials selection diagram (MSD). An MSD documents the materials selection of new equipment and piping for the refinery, process chemical, power, and other industries.
This standard is intended for use by the owner/operators, licensors, and the contractor/fabricators of petroleum refineries, process chemical plants, power plants, and other industrial processing plants as a reference guide for developing an MSD to identify the materials of construction and the process conditions and other key technical issues that influence the selection of materials for use during the development and construction phases of projects.
This standard was originally prepared in 2007 and revised in 2013 by Task Group (TG) 302, “Refining and Chemicals Material Selection Diagrams: Standard.” TG 302 is administered by Specific Technology Group (STG) 34, “Petroleum Refining and Gas Processing,” is sponsored by STG 36, “Process Industry: Materials Performance in Chemicals.” This standard is issued by NACE under the auspices of STG 34.
Section 1: General
1.1 An MSD summarizes material requirements for process equipment and piping in the refining, chemical processing, power, and other industries, and provides information needed for the development of piping and instrumentation diagrams (P&IDs), piping material specifications, and equipment mechanical data sheets. In its simplest form, a typical MSD consists of a markedup or overlaid version of a simplified process flow diagram (PFD) that shows relevant operating conditions and process data, materials selection information, and application(s) of other material degradation preventive measures.
1.2 The scope of this standard is to provide format, content, and other guidelines for developing an MSD. The minimum and optional information to be included on the MSD are defined. Each user of this standard can decide whether and when the optional information shall be shown. Guidance is also provided on key issues that arise when materials are selected.
1.3 This standard does not define how to evaluate specific corrosion and materials degradation mechanisms or how to select materials for specific processes.
1.4 Sample MSDs are included in Appendix A (nonmandatory) of this standard to show format and content examples.
1.5 The intended use of MSDs is primarily associated with new capital projects, retrofit projects, and expansion projects (especially in cases in which process conditions may have changed). Because information stated on the MSD may change during project execution (because of optimizations, issues during fabrication, etc.), the MSD may become out of date. Some projects use the MSDs throughout the project, updating it as changes occur and making it “as-built,” while other projects use the MSDs only in the initial project stages. This standard covers primarily the initial MSD preparation.
1.6 The format and content of the initial MSD, its use, and its update philosophy should be agreed on by the owner/operator and the contractor/fabricator/licensor in the initial phases of the project, and meet any local regulatory requirements.
1.7 The person specifying materials of construction must be familiar with corrosion and materials degradation mechanisms particular to the type of unit being designed.
1.8 Suitable tools (e.g., NACE standards, API(1) standards including API RP 571,1 public domain isocorrosion diagrams, company proprietary corrosion data, company standards, prior operating experience, etc.) shall be used as necessary in selecting materials.