scholarly journals On the Corrosion Mechanism of CO2 Transport Pipeline Steel Caused by Condensate: Synergistic Effects of NO2 and SO2

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 364 ◽  
Author(s):  
Le Quynh Hoa ◽  
Ralph Baessler ◽  
Dirk Bettge
Keyword(s):  
Chemical Nature ◽  
Reaction Kinetic ◽  
Pipeline Steel ◽  
Synergistic Effects ◽  
Corrosion Mechanism ◽  
General Corrosion ◽  
X Ray ◽  
Co2 Transport ◽  
Co2 Flow ◽  
Acidic Components

To study the effects of condensed acid liquid, hereafter referred to as condensate, on the CO2 transport pipeline steels, gas mixtures containing a varying concentration of H2O, O2, NO2, and SO2, were proposed and resulted in the condensate containing H2SO4 and HNO3 with the pH ranging from 0.5 to 2.5. By exposing the pipeline steel to the synthetic condensate with different concentration of acidic components, the corrosion kinetic is significantly changed. Reaction kinetic was studied using electrochemical methods coupled with water analysis and compared with surface analysis (scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometry (XRD)) of corroded coupons. The results showed that, although the condensation of NO2 in the form of HNO3 causes faster general corrosion rate, it is the condensation of SO2 in the form of H2SO4 or the combination of SO2 and NO2 that may cause much more severe problems in the form of localized and pitting corrosions. The resulting corrosion forms were depended on the chemical nature of acids and their concentration at the same investigated pH. The effects of changing CO2 flow rate and renewing condensate on pitting corrosion were further studied.

Effect of Temperature and H2S Concentration on Corrosion of X52 Pipeline Steel in Acidic Solutions

2013 ◽  
Vol 743-744 ◽  
pp. 589-596 ◽  
Author(s):  
Meng Liu ◽  
Jian Qiu Wang ◽  
Wei Ke
Keyword(s):  
Corrosion Rate ◽  
Pipeline Steel ◽  
Corrosion Products ◽  
Effect Of Temperature ◽  
Corrosion Mechanism ◽  
General Corrosion ◽  
Ferrous Sulfide ◽  
Immersion Corrosion ◽  
Different Temperatures ◽  
Diffraction Patterns

The corrosion behavior of X52 pipeline steel in H2S solutions was investigated through immersion corrosion test which was carried out in a high temperature and high pressure autoclave at different temperatures and H2S concentrations. General corrosion rates were calculated based on the weight loss of samples. The morphology and the chemical composition of the corrosion products were obtained by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The crystal structure of corrosion products was analyzed by X-Ray diffraction patterns (XRD). The corrosion products consisted mainly of the sulfide compounds (mackinawite, cubic ferrous sulfide, troilite and pyrrhotite). The corrosion products included two layers: the inner iron-rich layer and the outer sulfur-rich layer. Under H2S concentrations of 27g/L, the corrosion rate increased with the increase of temperature up to 90°C and then decreased at 120°C, finaly increased again. The corrosion rate first increased with H2S concentrations then decreased at 120°C. The structure and stability of the corrosion products due to different corrosion mechanism had a major impact on the corrosion rate. The corrosion resistance of the corrosion products increased as follows: mackinawite < cubic ferrous sulfide < troilite < pyrrhotite.

A New Corrosion Mechanism for X100 Pipeline Steel Under Oil-Covered Chloride Droplets

CORROSION ◽  
10.5006/2804 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 947-957 ◽  
Author(s):  
Hongxing Liang ◽  
Jing Liu ◽  
Rebecca Filardo Schaller ◽  
Edouard Asselin
Keyword(s):  
Pipeline Steel ◽  
Localized Corrosion ◽  
Corrosion Mechanism ◽  
General Corrosion ◽  
Paraffin Oil ◽  
Initial Stage ◽  
X100 Pipeline Steel ◽  
Corrosion Pits ◽  
Stage 1 ◽  
Two Stages

A 1.7 mM NaCl droplet on X100 pipeline steel covered by paraffin oil is used to simulate the corrosive environment encountered in heavy oil or bitumen pipelines. The development of corrosion under the droplet was monitored and explored in two stages. In the initial stage (1 h), the distribution of corrosion pits was heterogeneous with one area under the droplet presenting a higher pit density. As the corrosion proceeded (24 h), the localized corrosion in the area under the droplet with the higher pit density switched to general corrosion, while the other region of the droplet continued to pit. The mechanisms driving this new distinctive corrosion form developed beneath an underoil droplet are explained.

scholarly journals The Synergistic Effects of Alloying on the Performance and Stability of Co3Mo and Co7Mo6 for the Electrocatalytic Hydrogen Evolution Reaction

Hydrogen ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 11-21
Author(s):  
Youyi Sun ◽  
Alexey Y. Ganin
Keyword(s):  
Hydrogen Evolution ◽  
Synergistic Effects ◽  
Alkaline Media ◽  
Price Of Stability ◽  
X Ray Diffraction ◽  
Free Standing ◽  
X Ray ◽  
Current Decay ◽  
Earth Abundant ◽  
Current Densities

Metal alloys have become a ubiquitous choice as catalysts for electrochemical hydrogen evolution in alkaline media. However, scarce and expensive Pt remains the key electrocatalyst in acidic electrolytes, making the search for earth-abundant and cheaper alternatives important. Herein, we present a facile and efficient synthetic route towards polycrystalline Co3Mo and Co7Mo6 alloys. The single-phased nature of the alloys is confirmed by X-ray diffraction and electron microscopy. When electrochemically tested, they achieve competitively low overpotentials of 115 mV (Co3Mo) and 160 mV (Co7Mo6) at 10 mA cm−2 in 0.5 M H2SO4, and 120 mV (Co3Mo) and 160 mV (Co7Mo6) at 10 mA cm−2 in 1 M KOH. Both alloys outperform Co and Mo metals, which showed significantly higher overpotentials and lower current densities when tested under identical conditions, confirming the synergistic effect of the alloying. However, the low overpotential in Co3Mo comes at the price of stability. It rapidly becomes inactive when tested under applied potential bias. On the other hand, Co7Mo6 retains the current density over time without evidence of current decay. The findings demonstrate that even in free-standing form and without nanostructuring, polycrystalline bimetallic electrocatalysts could challenge the dominance of Pt in acidic media if ways for improving their stability were found.

Corrosion Mechanism of Iron from an X-ray Structural Viewpoint

2006 ◽  
pp. 105-129 ◽  
Author(s):  
Eiichiro Matsubara ◽  
Suzuki Shigeru ◽  
Yoshio Waseda
Keyword(s):  
Corrosion Mechanism ◽  
X Ray

Time Dependence of Hydrogen Induced Cracking of X70 Pipeline Steel Under Severe and Mild Sour Service Conditions Using Ultrasonic Analysis

2020 ◽  
Author(s):  
S. Gawor ◽  
J. B. Wiskel ◽  
D. G. Ivey ◽  
J. Liu ◽  
H. Henein
Keyword(s):  
Pipeline Steel ◽  
Test Sample ◽  
Test Time ◽  
Hydrogen Cracking ◽  
Signal Ratio ◽  
X Ray ◽  
Surface Corrosion ◽  
High Sulfur Content ◽  
Service Conditions ◽  
Sour Service

Abstract A standard NACE hydrogen induced crack test was used to evaluate the resistance of two compositions of X70 steel (X70-X (Ca/S ratio of 2.5) and X70-B (Ca/S ratio of &lt; 0.5)) under severe (pH = 2.7 and 100% H2S) and mild (pH = 5.5 and 100% H2S) sour service conditions. An ultrasonic technique was developed to quantify the severity of hydrogen cracking in both steels as a function of test conditions, steel type and time. In this procedure, a series of local ultrasonic measurements was taken for each test sample to determine a local crack to backwall signal ratio (LCBR). The LCBR values were integrated over the entire sample to give a global crack to backwall ratio (GCBR). A larger GCBR value corresponds to greater hydrogen cracking severity in the sample. Energy dispersive X-ray (EDX) spectroscopy and glancing angle X-ray diffraction (XRD) were used to characterize the surface corrosion products that formed during testing. For severe sour service conditions, the GCBR value reached an asymptotic value of approximately 33% and 47% for X70-X (after 4 days) and X70-B (after 2 days) steels, respectively. For mild sour service conditions, no cracking was observed for testing of less than 16 days. After 32 days, X70-B showed a GCBR of approximately 18%. The onset of cracking of X70-X steel occurred between 32 and 64 days. Samples tested for 64 days showed a GCBR of 30% and 16% for X70-X and X70-B, respectively. Glancing XRD measurements showed the presence of surface FeS on both steels tested under mild sour service. Quantitative XRD (QXRD) analysis was used to obtain the surface coverage of FeS as a function of test time. EDX mapping confirmed the presence of a high sulfur content over a significant fraction of the surface. XRD measurements of X70-B steel under severe sour service after 8 days did not show a significant amount of FeS. The surface FeS is believed to alter hydrogen ingress into the steel, making it difficult to directly compare measured GCBR values obtained under mild and severe sour service.

ANTIMICROBIAL ACTIVITY OF COPPER KAOLINITE AND SURFACTANT MODIFIED COPPER KAOLINITE AGAINST GRAM POSITIVE AND GRAM NEGATIVE BACTERIA

2016 ◽  
Vol 78 (3-2) ◽  
Author(s):  
Nor Syafawani Sarah Md Saad ◽  
Nik Ahmad Nizam Nik Malek ◽  
Chun Shiong Chong
Keyword(s):  
Antimicrobial Activity ◽  
Synergistic Effects ◽  
Wide Spectrum ◽  
Copper Nitrate ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray ◽  
Gram Positive Bacteria ◽  
Diffusion Technique

The aim of this research was to determine the antimicrobial activity of kaolinite modified with antimicrobial compounds against Gram positive and Gram negative bacteria. Copper kaolinite (Cu-kaolinite) was prepared by loading raw kaolinite with copper nitrate trihydrate (CuNO3) while surfactant modified Cu-kaolinite (SM-Cu-kaolinite) was prepared by adding cationic surfactants hexadecyltrimethyl ammonium (HDTMA) on Cu-Kaolinite. Samples was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyzer. The antimicrobial activity of the samples was tested against Gram negative bacteria (Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 15442), and Gram positive bacteria (Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 29212) through disc diffusion technique (DDT) and minimum inhibition concentration (MIC). The results showed that the antimicrobial activity of Cu-kaolinite increased after modified with HDTMA due to the synergistic effects of Cu ions and HDTMA molecules on the kaolinite. The antimicrobial activity for surfactant modified Cu-kaolinite was greater for Gram positive bacteria compared to Gram negative bacteria. In conclusion, the attachment of HDTMA on Cu-kaolinite contributed to the enhanced antimicrobial activity against wide spectrum of bacteria (Gram positive and Gram negative bacteria).

Mussel-inspired polydopamine-mediated surface modification of freeze-cast poly (ε-caprolactone) scaffolds for bone tissue engineering applications

2020 ◽  
Vol 65 (3) ◽  
pp. 273-287 ◽  
Author(s):  
Farnaz Ghorbani ◽  
Ali Zamanian ◽  
Melika Sahranavard
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Synergistic Effects ◽  
Engineering Application ◽  
Lamellar Microstructure ◽  
Tissue Engineering Application ◽  
Osteosarcoma Cell ◽  
Freeze Casting ◽  
X Ray

AbstractThere are many methods used to fabricate the scaffolds for tissue regeneration, among which freeze casting has attracted a great deal of attention due to the capability to create a unidirectional structure. In this study, polycaprolactone (PCL) scaffolds were fabricated by freeze-casting technology in order to create porous microstructure with oriented open-pore channels. To induce biomineralization, and to improve hydrophilicity and cell interactions, mussel-inspired polydopamine (PDA) was coated on the surface of the freeze-cast PCL constructs. Then, the synergistic effects of oriented microstructure and deposited layer on efficient reconstruction of injured bone were studied. Microscopic observations demonstrated that, the coated layer did not show any special change in lamellar microstructure of the scaffolds. Water-scaffold interactions were evaluated by contact angle measurements, and they demonstrated strong enhancement in the hydrophilicity of the polymeric scaffolds after PDA coating. Biodegradation ratio and water uptake evaluation confirmed an increase in the measured values after PDA precipitation. The biomineralization of the PDA-coated scaffolds was characterized by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD). Obtained results confirmed biomineralization of the constructs after a 28-day immersion in a simulated body fluid (SBF) solution. Mechanical analysis demonstrated higher compressive strength after PDA coating. L929 fibroblast cell viability and attachment illustrated that PDA-coated PCL scaffolds are able to support cell adhesion and proliferation. The increased secretion of alkaline phosphatase (ALP) after culturing osteosarcoma cell lines (MG-63) revealed the initial capability of scaffolds to induce bone regeneration. Therefore, the PDA-coated scaffolds introduce a promising approach for bone tissue engineering application.

scholarly journals X-ray Structure Elucidation of a Pt-Metalloporphyrin and Its Application for Obtaining Sensitive AuNPs-Plasmonic Hybrids Capable of Detecting Triiodide Anions

2019 ◽  
Vol 20 (3) ◽  
pp. 710 ◽  
Author(s):  
Eugenia Fagadar-Cosma ◽  
Anca Lascu ◽  
Sergiu Shova ◽  
Mirela-Fernanda Zaltariov ◽  
Mihaela Birdeanu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Synergistic Effects ◽  
Ion Concentration ◽  
Detection Methods ◽  
Sensitive Material ◽  
X Ray ◽  
Spectrophotometric Methods ◽  
Sensing Material ◽  
Physiological Tests ◽  
Molecule Conformation

The development of UV–vis spectrophotometric methods based on metalloporphyrins for fast, highly sensitive and selective anion detection, which avoids several of the practical challenges associated with other detection methods, is of tremendous importance in analytical chemistry. In this study, we focused on achieving a selective optical sensor for triiodide ion detection in traces based on a novel hybrid material comprised of Pt(II) 5,10,15,20-tetra(4-methoxy-phenyl)-porphyrin (PtTMeOPP) and gold nanoparticles (AuNPs). This sensor has high relevance in medical physiological tests. The structure of PtTMeOPP was investigated by single crystal X-ray diffraction in order to understand the metal surroundings and the molecule conformation and to assess if it qualifies as a potential sensitive material. It was proven that the Pt-porphyrin generated 1D H-bond supramolecular chains due to the weak C-H···O intermolecular hydrogen bonding. The presence of ordered voids in the crystal encouraged us to use PtTMeOPP as the sensing material for triiodide ion and to enhance its potential in a novel AuNPs/PtTMeOPP hybrid by the synergistic effects provided by the plasmonic gold nanoparticles. The spectrophotometric sensor is characterized by a detection limit of 1.5 × 10−9 M triiodide ion concentration and a remarkable confidence coefficient of 99.98%.

The Role of Electrochemical Conditions in Near-Neutral pH SCC Initiation Mechanism(s)

2010 ◽  
Author(s):  
Abdoulmajid Eslami ◽  
Mohammadhassan Marvasti ◽  
Weixing Chen ◽  
Reg Eadie ◽  
Richard Kania ◽  
...  
Keyword(s):  
Cathodic Protection ◽  
Pipeline Steel ◽  
Synergistic Effects ◽  
Co2 Concentration ◽  
Initiation Mechanism ◽  
Ph Values ◽  
Neutral Ph ◽  
Comprehensive Test ◽  
Disbonded Coating

In order to improve our understanding of near-neutral pH SCC initiation mechanism(s), a comprehensive test setup was used to study the electrochemical conditions beneath the disbonded coatings in cracking environments. In this setup the synergistic effects of cyclic loading, coating disbondment, and cathodic protection were considered. Our previous results showed that there can be a significant variation in the pH of the localized environment under the disbonded coating of pipeline steel. The pH inside the disbondment can change significantly from near-neutral to high pH values, strongly depending on the level of cathodic protection and CO2 concentration. Both of these variables affected the electrochemical conditions on the steel surface and therefore the initiation mechanisms. This work highlights the role of electrochemical conditions in near-neutral pH SCC initiation mechanisms.

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