Development of Corrosion Inhibitors to Mitigate Elemental Sulfur Induced Pitting Corrosion

2021 ◽  
Author(s):  
Douglas C. Dickey ◽  
Nihal U. Obeyesekere Obeyesekere ◽  
Jonathan J. Wylde
Keyword(s):  
Mild Steel ◽  
Pitting Corrosion ◽  
Elemental Sulfur ◽  
Extreme Environments ◽  
Oil And Gas Industry ◽  
Working Environment ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Gas Industry ◽  
High Hydrogen

Abstract The effects of elemental sulfur on the corrosion of mild steel is a serious problem in the oil & gas industry costing millions of dollars annually in lost production and assets. Mitigating the corrosive effects of elemental sulfur on mild steel in the oil and gas industry is a challenge and finding a viable solution would provide a more cost effective and safer working environment and as well as be environmentally conscious. Currently, there are no highly effective products for elemental sulfur corrosion in the marketplace. More than fifty new chemical formulations were blended and screened by rotating cylinder electrode method (RCE). These formulations were tested in the presence of 0.1% elemental sulfur in mildly sour conditions. The promising candidates were identified and tested again in the presence of elemental sulfur under the same mildly sour conditions. The most promising candidates from the initial screening were then subjected to rotating cage autoclave (RCA) testing for extended periods of time in the presence of 0.1% and 0.15% elemental sulfur. The general corrosion rates were calculated via weight loss and the metal surfaces were examined under a high-power digital microscope for pitting and localized corrosion. A detailed analysis of the above testing yields promising results. The results from the testing show that formulations mitigate pitting in environments containing elemental sulfur. In less harsh conditions, such as low chloride brines or low CO2 environment, formulations seem to provide excellent protection against general corrosion while mitigating pitting due to elemental sulfur. In more extreme environments such as harsh brines with elevated chloride levels, high hydrogen sulfide and CO2 levels, the formulations mitigate pitting but need further development in inhibiting general corrosion The best product currently developed inhibits corrosion and pitting in the presence of elemental sulfur in various conditions and performs well against elemental sulfur in more aggressive sour systems. We are currently improving the performance against elemental sulfur and developing chemistries to mitigate polysulfide induced corrosion in sour systems. This paper describes the development of effective inhibitors for corrosion and pitting in the presence of elemental sulfur under sour conditions. This study focuses more on pitting corrosion due to the corrosive characteristics of elemental sulfur than on uniform general corrosion. The general corrosion with the selected inhibitor was highly mitigated and was less than 3.0 mpy while yielding excellent protection against sulfur induced pitting.

The Critical Condition for the Initiation of Localized Corrosion of Mild Steels in Contact with Bentonite Used For Nuclear Waste Package

1991 ◽  
Vol 257 ◽  
Author(s):  
Guen Nakayama ◽  
Masatsune Akashi
Keyword(s):  
Mild Steel ◽  
Nuclear Waste ◽  
Pitting Corrosion ◽  
Natural Water ◽  
Crevice Corrosion ◽  
Water Environment ◽  
Underground Water ◽  
Localized Corrosion ◽  
Critical Conditions ◽  
General Corrosion

ABSTRACTIt has been established that the mild steels which undergo the general corrosion in the acidic to neutral environments, attain the passivity status in alkaline environments, thereby becoming liable to the localized corrosion, such as pitting corrosion and crevice corrosion. Now, for the case of using bentonite as a buffer to stand between the hostrock and the geological disposal packages of high level nuclear waste, localized corrosion behaviors of mild steel as a candidate for such a package has been studied quantitatively for environments where the the otherwise neutral ground water would be turned slightly alkaline with pH = 9.5 - 10.0.In view of the lack of quantitative data on the passivity-to-localized corrosion of mild steel in natural water environments of weak alkalinity, the present authors have previously determined an empirical E-pH diagram for mild steel with a 20 °C, 1 m mol/L [HC03-], 10 ppm [CI -] solution simulating the natural water environment concerned; it has been shown that the general corrosion-to-passivity transition condition was determined to be pHd =9.4, and the mild steel was shown to be liable to localized corrosion over a large portion of the passivity domain. The present paper discusses behaviors, mechanisms, and critical conditions for initiation of localized corrosion in mild steel placed in bentonitesuspending natural water environment, in terms of the critical potentials for pitting (Vc), and crevice corrosion (ER,CREV). Bentonite was addid to the solution in varying amounts to give bentonite-to-solution ratios up to 0.1, while the pHvalue was adjusted appropriately with sodium carbonate, always keeping the bentonite particles in suspension.It is demonstrated that bentonite particles suspended in water will deposit upon the steel on receipt of Fe2 + ions, thereby promoting pitting corrosion by preventing repassivation and promoting crevice corrosion by acting as an effective crevice, once the environment conditions become favorable for localized corrosion.We conclude therefore that disposal package made of mild steel and placed in an underground water environment with bentonite as buffer will be liable to localized corrosion.

scholarly journals A STUDY OF CORROSION CONTROL IN PIPELINES

2021 ◽  
pp. 48-49
Author(s):  
Shree Meenakshi. K
Keyword(s):  
Oil And Gas ◽  
Indirect Costs ◽  
Oil And Gas Industry ◽  
The United States ◽  
Working Environment ◽  
Total Annual Cost ◽  
Pipe Material ◽  
Gas Industry ◽  
Copper Aluminum ◽  
Pipeline Corrosion

Pipeline corrosion is the deterioration of pipe material and the related system due to its interaction with the working environment. It affects pipeline and accessories made of both metals and non-metals. Pipeline corrosion—and the related catastrophic failures that it can cause—cost billions of dollars to the economy. The total annual cost of corrosion in 2016, including direct and indirect costs, was estimated at over USD $1.1 trillion in the United States. In other words, corrosion is a big problem. It predominantly affects pipelines made of metals such as copper, aluminum, cast iron, carbon steel, stainless steel and alloy steel pipes used for buried, underground, submerged or other pipelines. That makes designing and selecting the best available systems and materials for pipelines and their corrosion protection systems an extremely important issue for the oil and gas industry. In this research paper we will investigate and take a look at the key types of corrosion that affect pipelines, and some of the methods that are used to protect this infrastructure.

The Critical Condition for the Initiation of Localized Corrosion of Mild Steel Used for Nuclear Waste Package

1990 ◽  
Vol 212 ◽  
Author(s):  
Gen Nakayama ◽  
Mastsuna Akashi
Keyword(s):  
Mild Steel ◽  
Crevice Corrosion ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Alkaline Water ◽  
Propagation Behavior ◽  
Neutral Water ◽  
High Level ◽  
Term Performance ◽  
Critical Ph

ABSTRACTThe general corrosion rate of mild steel is so small in neutral water environments that adequately provided corrosion allowance can ensure the requirement of one thousand years’ integrity of geological disposal package of high-level nuclear wastes. In alkaline water environments, however, mild steels can passivate themselves and often undergo localized corrosion in much the same manner stainless steels do in neutral water environments. This paper describes a study of localized corrosion behavior of the mild steel conducted to assess the long-term performance of the disposal packages. The critical potentials for pitting and crevice corrosion and critical pH for general corrosion-to-passivity transition were determined for neutral and alkaline water environments. Effects of temperature, pH, and chloride and other anion concentrations on the critical potentials and the critical pH were discussed. The initiation and propagation behavior of crevice corrosion was also analyzed under potentiostatic conditions.

The Effect of Alloying Cu on Pitting Corrosion Resistance of Copper-Bearing Ferritic Stainless Steel

2008 ◽  
Vol 569 ◽  
pp. 197-200 ◽  
Author(s):  
Wei Zhang ◽  
De Ning Zou ◽  
Hong Hong Yao ◽  
Jun Yang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Antibacterial Properties ◽  
Ferrite Matrix ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Pitting Corrosion Resistance ◽  
Effect Of Alloying

Copper is a well-known alloying element which is used to improve the resistance to general corrosion of stainless steels. Our previous experiments show that the increase of copper content can acquire the excellent antibacterial properties and can also increase the tendency to cold formability of the ferritic stainless steels. However, the effect of alloying Cu on the resistance to localized corrosion has not been clarified sufficiently. In order to understand the effect of copper on pitting corrosion resistance of the ferritic antibacterial stainless steel, the electrochemical experiments were carried out and the anodic polarization curves were performed in 3.5% NaCl solution for two kinds of steels. The results reveal that the ε-Cu phase in ferrite matrix diminishes pitting corrosion resistance of the antibacterial stainless steel in the chlorides medium. It is connected with the poor passive behavior of the ε-Cu phase inclusions.

scholarly journals DNA Inhibition of Hydrogen Ion-Induced Corrosion of Mild Steel Used for Pipelines in Oil and Gas Industries

2021 ◽  
Vol 33 (4) ◽  
pp. 767-774
Author(s):  
Oluranti Agboola ◽  
Toluwani Adedoyin ◽  
Ojo Sunday Isaac Fayomi ◽  
Ayoola Ayodeji ◽  
Samuel E. Sanni ◽  
...  
Keyword(s):  
Mild Steel ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Open Circuit ◽  
Corrosive Media ◽  
Gas Industry ◽  
Inhibitor Efficiency ◽  
Loss Analysis ◽  
Corrosive Solution ◽  
Sem Micrograph

Corrosion of mild steel via chemical reaction in a corrosive environment is a problematic occurrence that is very common in oil and gas industries. Corrosion constitutes a huge part of the total costs in the production of oil and gas. Corrosion inhibitors have found interest in the scientific domain because they are mainly understood by their chemical complexes and formulations. Their utilization in small amount on metal surface used in oil and gas industries can help shield the metal from corrosion devoid of any significant alteration in the concentration of the corrosive media in the environment. An effort was made to study the possibility of using calf thymus gland DNA (CTGDNA) inhibitor in chlorine induced mild steel for possible usage in piping in oil and gas industry. The SEM micrograph shows that the adsorption of the CTGDNA biomacromolecules coat on the mild steel surfaces functions as a protection against HCl corrosive solution. Electrochemical study and weight loss analysis showed that the inhibitor efficiency (70.48 and 72%, respectively) of the tested DNA (CTGDNA) in HCl acidic corrosion environment for the mild steel was high at 1.5 M of HCl. The inhibitor efficiency decreased with increasing HCl concentrations. The open circuit potential (OPC) revealed that the mild steels got corroded until the end of the immersion. The intensities of XRD peak substantiate the existence of corrosion products of FeCl2.

Potential inhibitor of adenylyl sulfate reductase isolated from Desulfovibrio desulfuricans with PU/PU-Ag to control pitting corrosion of oil tanks and pipelines.

2021 ◽  
Vol 17 ◽  
Author(s):  
Wafaa A. Koush ◽  
Ahmed Labena ◽  
Hany Elsawy ◽  
Laila A. Farahat ◽  
Tarek M. Mohamed ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Pitting Corrosion ◽  
Oil And Gas ◽  
Desulfovibrio Desulfuricans ◽  
Oil And Gas Industry ◽  
Inhibitory Effect ◽  
Nanocomposite Coating ◽  
Ag Nps ◽  
Gas Industry ◽  
Aps Reductase

Background and Aim: This study aims to alleviate the microbiologically affected corrosion that occurred by sulfate-reducing bacteria (SRB) through synthesizing a bio-based polyurethane polymer and its nanocomposite coating, silver nanoparticles (PU-Ag). Moreover, this study aims to evaluate the effect of PU alone and PU-Ag as inhibitors for adenylyl sulfate reductase (APS), which is the main enzyme for sulfate reduction. Methods: In this study, the PU was prepared from the vegetable soybean oil, and the silver nanoparticles (Ag-NPs) with a concentration of 1% were coated to the PU, forming a nanocomposite. The PU and the PU-Ag were characterized and evaluated as inhibitors of the APS reductase enzyme. Results: The results obtained from FTIR, UV, DLS, TEM, and XRD confirmed the preparation structure of the PU and PU-Ag. Furthermore, the PU/PU-Ag competitively inhibited the APS reductase with an inhibition constant equal to 35.7 and 11 mg, respectively. These indicated the exert inhibitory effect of PU/PU-Ag upon the activity of the APS reductase enzyme. Conclusion: The APS reductase enzyme produced by SRB, which is recorded as a big problem in the oil and gas industry, such as pitting corrosion of tanks and pipelines, could be inhibited by PU and PU-Ag.

scholarly journals Wavelet Transform Modulus Maxima and Holder Exponents Combined with Transient Detection for the Differentiation of Pitting Corrosion Using Electrochemical Noise

CORROSION ◽  
10.5006/2788 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 1001-1010 ◽  
Author(s):  
A.M. Homborg ◽  
P.J. Oonincx ◽  
J.M.C. Mol
Keyword(s):  
Wavelet Transform ◽  
Pitting Corrosion ◽  
Electrochemical Noise ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Hölder Exponent ◽  
Transient Detection ◽  
Time Frequency ◽  
Wavelet Transform Modulus Maxima ◽  
Modulus Maxima

A potentially powerful tool to detect and classify corrosion mechanisms is the analysis of electrochemical noise (EN). Data analysis in the time-frequency domain using, e.g., continuous wavelet transform (CWT) allows the extraction of localized frequency information, providing information on the type of corrosion, i.e., uniform or localized corrosion, from the EN signal. The CWT provides the opportunity to analyze changes in frequency behavior of EN signals over time. In the presence of transients generated by pitting corrosion that occur only during short instants of time, this is an important property. This paper introduces the combination of automated transient detection with wavelet transform modulus maxima (WTMM) and the Holder exponent. WTMM enhances the determination of transient frequencies by indicating the ridges of a CWT spectrum. The Holder exponent, a measure of singularity of an EN signal, provides a single parameter discrimination tool based on WTMM and serves to differentiate between general corrosion and two types of pitting corrosion of stainless steel Type 304 exposed to aqueous HCl solutions of different concentrations and as such at different pH values.

The Centaur Engine: Operational Progress Report

1978 ◽  
Author(s):  
C. W. Emmerson
Keyword(s):  
Oil And Gas ◽  
Operating Experience ◽  
Oil And Gas Industry ◽  
Working Environment ◽  
Test Program ◽  
Gas Industry ◽  
Basic Model ◽  
Before And After ◽  
Qualification Testing ◽  
Made In

The Centaur engine, introduced by Solar in 1970, pioneered the application of turbine power in the 3000- to 4000-hp class for the oil and gas industry. Today, with over 500 units operating in some of the toughest industrial environments in the world, the documented reliability of the basic model continues to improve, surpassing original life objectives. Many changes have been made to the Centaur engine since 1970. This paper deals specifically with those based on field operating experience. Each modification is described in terms of the field experience, both before and after the change, the in-house and/or field test program, and the qualification testing involved. The scope of the discussion includes modifications applied throughout the major components of the engine. Of particular interest are the changes incorporated due to operation in arctic environments. Other modifications were made in response to specific problems encountered in unusual or particularly abusive service. The overall effect has been to greatly strengthen the engine improving both durability and reliability in the industrial working environment it serves.

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