Author: Bryon Daniels WingetPublisher:
ISBN:
Category :
Languages : en
Pages : 178
Book Description
Mechanism of Localized Corrosion of Carbon Steel Pipe in Corrosion-inhibited, CO2-saturated Brine
Author: Bryon Daniels WingetPublisher:
ISBN:
Category :
Languages : en
Pages : 178
Book Description
Localized Corrosion Initiation of Steel in CO2 Environments
Author: Xin GaoPublisher:
ISBN:
Category : Acetic acid
Languages : en
Pages : 191
Book Description
The objective of this dissertation research was to investigate initiation mechanisms for CO2 localized corrosion on mild steel, encompassing the effects of chloride, oxygen, and acetic acid. In CO2 corrosion, iron in steel will be oxidized to ferrous ions under deareated conditions. The ferrous and carbonate ions can combine to form FeCO3 and precipitate once exceeding the solubility limit. When the precipitation of FeCO3 occurs evenly on the steel surface it forms a compact and protective layer. This acts as a diffusion barrier hindering the mass transfer of electrochemical species and covers/blocks the surface making it unavailable for corrosion, which enhances the resistance of mild steel to further uniform CO2 corrosion. However, there are various scenarios where localized corrosion may occur. When the environment becomes more aggressive, the FeCO3 could be partially removed. This leads to localized regions of the bare steel surface that become exposed to the corrosive solution and, subsequently, localized corrosion could be initiated. To study CO2 localized corrosion, two-stage experiments were performed: (1) a uniform protective FeCO3 layer was first formed on a carbon steel with high initial FeCO3 saturation; (2) localized CO2 corrosion scenarios were then developed by adding additional salts (NaCl or NaClO4), oxygen or acetic acid to challenge the protective FeCO3 layer. The experiments were conducted in a two-liter glass cell with a three-electrode system, working electrode (X65 carbon steel), reference electrode (Ag/AgCl saturated electrode), and counter electrode (platinum). Electrochemical measurements (linear polarization resistance) were carried out to observe electrochemical behaviors and calculate the corrosion rates.
Trends in Oil and Gas Corrosion Research and Technologies
Author: A. M. El-SherikPublisher: Woodhead Publishing
ISBN: 0081012195
Category : Science
Languages : en
Pages : 928
Book Description
Trends in Oil and Gas Corrosion Research and Technologies: Production and Transmission delivers the most up-to-date and highly multidisciplinary reference available to identify emerging developments, fundamental mechanisms and the technologies necessary in one unified source. Starting with a brief explanation on corrosion management that also addresses today's most challenging issues for oil and gas production and transmission operations, the book dives into the latest advances in microbiology-influenced corrosion and other corrosion threats, such as stress corrosion cracking and hydrogen damage just to name a few. In addition, it covers testing and monitoring techniques, such as molecular microbiology and online monitoring for surface and subsurface facilities, mitigation tools, including coatings, nano-packaged biocides, modeling and prediction, cathodic protection and new steels and non-metallics. Rounding out with an extensive glossary and list of abbreviations, the book equips upstream and midstream corrosion professionals in the oil and gas industry with the most advanced collection of topics and solutions to responsibly help solve today's oil and gas corrosion challenges. - Covers the latest in corrosion mitigation techniques, such as corrosion inhibitors, biocides, non-metallics, coatings, and modeling and prediction - Solves knowledge gaps with the most current technology and discoveries on specific corrosion mechanisms, highlighting where future research and industry efforts should be concentrated - Achieves practical and balanced understanding with a full spectrum of subjects presented from multiple academic and world-renowned contributors in the industry
Petroleum Abstracts. Literature and Patents
Author: Inhibition of Weld Corrosion in Flowing Brines Containing Carbon Dioxide
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The aim of this research was to study the effectiveness of a typical oilfield corrosion inhibitor, which is considered to be a green inhibitor (non toxic to the environment) in controlling internal corrosion of welded X65 pipeline steel in brines saturated with carbon dioxide at one bar pressure, under dynamic flowing conditions, over a range of temperatures. Several experimental configurations were used ranging from a simple flat plate design to a novel rotating cylinder electrode, to allow high shear stress to be achieved. The rotating cylinder electrode (RCE) apparatus was designed to allow steel from the weld metal, heat affected zone (HAZ) and parent material to be galvanically coupled and tested in high shear stress conditions. In producing the RCE, the three regions of the weld were identified by optical metallography and samples of each were machined to produce cylindrical electrodes, which were mounted on a motor driven shaft. Electrical connections were made to the three electrodes via a high quality slip-ring assembly. The galvanic currents flowing between the regions of the weld were recorded using zero-resistance ammeters and their self-corrosion rates were found by uncoupling the electrodes and performing polarization resistance measurements. For static conditions the inhibitor had an effective performance and after a short initial period during which film formation took place, at longer exposure times a dramatic reduction of corrosion rate was obtained. Under flowing conditions, both the galvanic currents and the self-corrosion rates were found to increase with the shear stress, as the rotational speed of the RCE was increased. The total corrosion rate of each weld region was assessed from the sum of the self-corrosion and galvanic contributions. In most cases, the weld metal and HAZ were shown to be cathodic to the parent material and this was considered to be a desirable situation as localised corrosion of the weld was minimised. However, in some ci.
Corrosion Inhibitors in the Oil and Gas Industry
Author: Viswanathan S. SajiPublisher: John Wiley & Sons
ISBN: 352734618X
Category : Technology & Engineering
Languages : en
Pages : 458
Book Description
Provides comprehensive coverage of corrosion inhibitors in the oil and gas industries Considering the high importance of corrosion inhibitor development for the oil and gas sectors, this book provides a thorough overview of the most recent advancements in this field. It systematically addresses corrosion inhibitors for various applications in the oil and gas value chain, as well as the fundamentals of corrosion inhibition and interference of inhibitors with co-additives. Corrosion Inhibitors in the Oil and Gas Industries is presented in three parts. The first part on Fundamentals and Approaches focuses on principles and processes in the oil and gas industry, the types of corrosion encountered and their control methods, environmental factors affecting inhibition, material selection strategies, and economic aspects of corrosion. The second part on Choice of Inhibitors examines corrosion inhibitors for acidizing processes, inhibitors for sweet and sour corrosion, inhibitors in refinery operations, high-temperature corrosion inhibitors, inhibitors for challenging corrosive environments, inhibitors for microbiologically influenced corrosion, polymeric inhibitors, vapor phase inhibitors, and smart controlled release inhibitor systems. The last part on Interaction with Co-additives looks at industrial co-additives and their interference with corrosion inhibitors such as antiscalants, hydrate inhibitors, and sulfide scavengers. -Presents a well-structured and systematic overview of the fundamentals and factors affecting corrosion -Acts as a handy reference tool for scientists and engineers working with corrosion inhibitors for the oil and gas industries -Collectively presents all the information available on the development and application of corrosion inhibitors for the oil and gas industries -Offers a unique and specific focus on the oil and gas industries Corrosion Inhibitors in the Oil and Gas Industries is an excellent resource for scientists in industry as well as in academia working in the field of corrosion protection for the oil and gas sectors, and will appeal to materials scientists, electrochemists, chemists, and chemical engineers.
Electrochemical Corrosion of Carbon Steels in H2S-containing Brines
Author: Ruishu FengPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The electrochemical corrosion behaviors of high strength low alloy carbon steel, Grade S-135, and ultra-high strength low alloy carbon steel, Grade UD-165, were investigated in alkaline brines at pH of 7.9, 10.7, and 12.4 and four H2S partial pressures (PH2S) from 0 to 69 kPa at 85 oC using in situ electrochemical measurements, ex situ surface analyses, and software modeling. HS-(aq) was calculated to be the dominant sulfide species from pH 7.9 to 12.4. After 60 hours, polarization resistance (Rpol) of S-135 and UD-165 generally increased as pH increased at lower PH2S (0 and 0.83 kPa), whereas Rpol decreased and then increased as pH increased at higher PH2S (8.3 and 69 kPa). At each pH, the lower PH2S increased Rpol or did not significantly change Rpol, whereas the higher PH2S decreased Rpol. Two opposite effects from H2S were proposed, an accelerating effect due to H2S(aq) and HS-(aq) facilitating the Faradaic reactions and the localized corrosion, and an inhibiting effect due to the protectiveness of the corrosion products. The inhibiting effect was often observed at relatively low H2S concentrations at pH 7.9 and 12.4. The electrochemical impedance did not change significantly at different stir rates for both S-135 and UD-165, indicating that mass transport in the bulk solution was not the rate determining step. The corrosion products generally changed from iron carbonate and sulfides to iron oxide as pH increased, which agreed with the Pourbaix diagrams. Solution pH in the three solutions were calculated to be 8.1, 9.8, and 10.8 at 200 oC, respectively. Polarization resistance values of UD-165 at 200 °C were consistently one to two orders of magnitude lower than at 85 °C, which corresponded to a drastic increase in corrosion rate at elevated temperature. At 200 °C, Rpol at 9.8 was the smallest after 60 hours among the three solutions. The modeled results were in reasonable agreement with the experimental CR values within a factor of 4. A new method derived from the generalized Butler-Volmer equation allowed to obtain anodic Tafel slopes from LSV even with the effect of limiting current. At 200 oC, the ba values indicated that the anodic reactions followed the Bockris mechanism at pH 8.1 and a two-electron mechanism at pH 9.8 and 10.8. As pH increased, the major corrosion products changed from pyrrhotite/siderite to magnetite although the corrosion products were a mixture of iron carbonate, sulfide and oxide. At 4 °C and 10 MPa total pressure, experimental results for two drill steels, Grade S-135 and Grade UD-165, showed a distinct drop in corrosion rate when transitioning from sweet (CO2) corrosion to sour (H2S) corrosion in 5% wt. NaCl brine. It was found that a CO2:H2S ratio as high as 1000 was still enough for sour corrosion to dominate the conditions tested. The CO2+H2S condition and H2S condition had the similar anodic and cathodic Tafel slopes, which were smaller than the CO2 condition. The presence of H2S could have caused the formation of FeS(s) at the steel surface where the pH and Fe2+(aq) concentration might be higher than in the bulk solution.
Metals Abstracts
Author: Galvanic Mechanism of Localized Corrosion for Mild Steel in Carbon Dioxide Environments
Author: Jiabin HanPublisher:
ISBN:
Category : Carbon dioxide
Languages : en
Pages :
Book Description
Author: J. E. Dorgu