H2S Solution Research Articles

An Electrochemical Impedance Spectroscopy Study of Inhibition Effect of SONKOR Composition on Hydrogen Sulfide Corrosion of Carbon Steel

The protective properties of five corrosion inhibitors of SONKOR series on low-carbon steel St20 in a 1 M HCl with the addition of 0–0.6 g/L H2S have been studied by the electrochemical impedance spectroscopy method. The series of changes in the adsorbability of corrosion inhibitors on a steel electrode in 1 M HCl and 1 M HCl + 0.6 g/L H2S solutions have been established. Equivalent electrical circuits have been proposed for various media. It is shown that some elements of equivalent circuits are associated with the kinetics of inhibitors adsorption.

Impact of oxygen contamination on the electrochemical impedance spectroscopy of iron corrosion in H2S solutions

Oxygen pollution in hydrogen sulfide (H2S) saturated test solutions can compromise the results of standardized tests, which guide materials selection in safety-critical components. To examine the temporal evolution of such contamination, we have used the electrochemical methods of impedance spectroscopy and hydrogen permeation to study the corrosion of iron exposed to oxygen-polluted H2S-saturated solutions. EIS analyses were performed with a previously developed model, which explicitly accounts for the contribution of a conductive and porous iron sulfide overlayer. A good correlation is found between corrosion estimates from EIS and weight loss, measured to be higher than the O2-free case. Hydrogen permeation studies across the iron membrane were conducted to qualitatively evaluate the impact of dissolved O2 on hydrogen entry. We observe that O2 contamination was found to significantly reduce hydrogen charging into the metal.

CO2 corrosion behavior of sensitized 304 and 316 austenitic stainless steels in 3.5 wt.% NaCl solution and presence of H2S

The CO2 corrosion behavior of sensitized and non-sensitized 304 and 316 stainless steels in the absence and presence of H2S was investigated using cyclic polarization and electrochemical impedance spectroscopy techniques. The sensitization resulted in significant negative shift on pitting potential for both alloys. The general CO2 corrosion rate of sensitized and non-sensitized samples was not significant. However, increasing H2S concentration up to 200 ppm resulted in severe increase in general corrosion rate and also significant negative shift for pitting potential. It was concluded that, the major role of sensitization is influencing the pitting potential and pitting corrosion of both alloys.

Permeability enhancement of low rank coal through acidization using H2S solution: An experimental study in the Kuqa-Bay Coalfield, Xinjiang, China

Coalbed methane (CBM) wells with abnormally high H2S contents present higher CBM productivity in the low rank coal development areas of Xinjiang, China. The influence of abnormally high H2S contents on the coal reservoir properties is an important research topic. Therefore, acidization experiments using a H2S solution on low rank coal of the Kuqa-Bay coalfield were conducted. The pore structure characteristics and permeability at the horizontal and vertical stratifications were compared before and after the acidization experiments using various methods including X-ray diffraction (XRD), permeability test, high pressure mercury injection porosimetry (HPMIP), and field emission scanning electron microscope (FESEM). The results show that the H2S solution can significantly enhance the permeability of low rank coal. The higher the primary permeability, the greater the permeability amplification would be. The total pore volume (TPV) of the coal increased after the acidization experiment, and the pore distribution and connectivity among micropores, transition pores, and mesopores were also improved. Additionally, the pore volume ratio of the semi-closed pores increased, while that for the macropores showed an opposite trend. The permeability enhancement mechanisms after the H2S solution acidizing experiments indicated that the H2S solution can dissolve the carbonate minerals in the coal, thus, increasing the permeability, and this was considered as a positive permeability enhancement effect. Meanwhile, the clay minerals in the coal expanded with the H2S solution, and this decreased the permeability and was considered a negative permeability enhancement effect. The positive effect precedes the negative effect, leading to an increase in the coal permeability. Additionally, the acidization experiment indicated that the closed pores transform to semi-closed pores, improving the connectivity of the pores and indicating that the permeability of the coal can be further increased.

Sulfide Stress Corrosion Cracking Behavior of G105 and S135 High-Strength Drill Pipe Steels in H2S Environment

Slow strain rate testing was employed to investigate the sulfide stress corrosion cracking (SSCC) behavior of low-carbon high-strength drill pipe steels (G105 and S135) in the simulated drilling environment containing H2S. Results reveal that both G105 and S135 steels have a high SSCC susceptibility in the simulated drilling environment containing H2S. In the range of experimental slow strain rate, the SSCC sensitivity of drill pipe steel increases with the decrease in slow strain rate, and the ductility and fracture properties of drill pipe steels also decrease obviously. With the increase in the steel strength, the SSCC sensitivity of the drill pipe steel increases, and the S135 drill pipe steel has higher SSCC sensitivity than G105. There is no obvious plastic deformation on the fracture surface of G105 and S135 steels in H2S solution. The cracks of fracture sprout on the surface of the specimen, the instantaneous fracture zone is in the middle, and the fracture can be divided into the cracking and the final fracture zone. The SSCC mechanisms of two drill pipe steels are hydrogen embrittlement. The hydrogen enters the steel and reduces the binding force of the iron atom, resulting in cleavage fracture.

Fatigue and corrosion fatigue behaviors of G105 and S135 high−strength drill pipe steels in air and H2S environment

Fatigue and corrosion fatigue (CF) tests were carried out to investigate the behaviors of G105 and S135 low carbon high−strength drill pipe steels under different stress amplitudes in air as well as simulated H2S contained drilling environment. The regression analysis method was applied to obtain empirical equations governing the fatigue and CF lives of drill pipe steels in different environmental conditions. Results revealed that there exist fatigue limits for G105 and S135 drill pipe steels in air, and the fatigue life equations for G105 and S135 are Nf=3.28×108(Seqv−406.1)−2 and Nf=3.81×108(Seqv−472.5)−2 respectively. For both types of pipe steels, quasi−cleavage and cleavage fracture was identified as the main feature in the fatigue source zone of the two steels, while fatigue striations were the main feature in the stable crack growth zone. However, in H2S solution, no obvious fatigue limits were found for G105 and S135, and the corresponding CF life equations are Nf=3.58×108(Seqv−143.7)−2 and Nf=2.91×108(Seqv−119.6)−2. The CF sensitivity levels of G105 and S135 in H2S solution are high (64.6% and 74.7%, respectively), but S135 displays a higher sensitivity (74.7%) than G105 (64.6%). Further, no apparent plastic deformation appeared on the fracture surface in H2S solution, and the fatigue cracks sprout from the surface and expand into the specimen with radiation pattern.

Anti-H2S corrosion property of bipolar epoxy-resin coatings

SiO2 nanoparticles were modified with the surfactants sodium dodecylbenzene sulfonate and hexadecyl trimethyl ammonium bromide. The modified SiO2 nanoparticles were added to epoxy-resin coatings to obtain anion- and cation-selective coatings. Two kinds of bipolar epoxy-resin coatings were prepared by exchanging the sequence of anion- or cation-selective coating (i.e., cation/anion and anion/cation). The coatings were immersed in H2S solution, and electrochemical impedance spectroscopy was used to investigate their performance. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to observe the morphology of the metals and metal/coating interface. Experimental results indicated that the coating sequence of inner and outer ion-selective coatings affected the protection performance of the bipolar coatings. The good protection property of the bipolar coatings was attributed to the existence of a space-charge region and an electric field between the inner and outer ion-selective coatings.

Corrosion fatigue crack propagation behavior of S135 high–strength drill pipe steel in H2S environment

Abstract Corrosion fatigue crack propagation (CFCP) tests were employed to investigate the behavior of S135 low carbon high−strength drill pipe steel under different strain rates in a simulated H2S containing drilling environment. Results revealed that the CFCP rate curve of the S135 steel has the characteristics of stress corrosion and corrosion fatigue (CF), which can be divided into near threshold, platform and rapid propagation zone. H2S has an obvious acceleration effect on the CFCP rate of S135 steel, the propagation rate of S135 steel in H2S solution is about 10 times more than that of in air. The stress ratio R has different effects on rapid propagation and near threshold zone. In the rapid propagation zone, the order of CFCP rate from high to low is R = 0.1 > R = 0.3 > R = 0.5, while the order of near threshold zone just shows the opposite. In the near threshold zone, the CFCP rate increases with the increasing of the stress ratio R. Based on the proposed Corrosion–Passivation–Fracture model and elastic fracture mechanics, the CFCP rate expression of S135 steel in H2S solution is d a d N cf = 1.927 × 10 ‐ 9 Δ K − 6.15 1 − R 0.59 2 , which can be used to predict the CFCP life in practical engineering. Fracture analysis results shows that the CFCP of S135 steel in H2S solution is mainly controlled by anodic dissolution and hydrogen embrittlement.

The Microbiologically Influenced Corrosion of L245NS Carbon Steel by Sulfate-Reducing Bacteria in H2S Solutions

The Microbiologically Influenced Corrosion of L245NS Carbon Steel by Sulfate-Reducing Bacteria in H2S Solutions

Effect of Cl− Concentration on the Corrosion Behavior of 16Mn Steel in Saturated H2S/CO2 Solution

The corrosion behavior of 16Mn steel was studied in saturated H2S or H2S/CO2 solutions containing different Cl− concentrations at 80 °C. The microstructure and chemical composition of the corrosion products were investigated through scanning electron microscopy, energy-dispersive X-ray spectroscopy, EPMA, and X-ray diffraction. Results showed that the corrosion rate decreased with increasing Cl− concentration in saturated H2S or H2S/CO2 solution at pH 4. Conversely, the corrosion rate increased with increasing Cl− concentration in saturated H2S solution at pH 6. The relative H+ concentration decreased because of the increase of Cl− concentration at pH 4, and Cl− acted as a catalyst in the corrosive medium at pH 6 because the net H+ concentration decreased obviously compared with the condition at pH4. Cl− promoted the formation of Fe-deficient iron sulfide at pH 4, and the opposite effect was observed in the nearly neutral solution. The corrosion rate increased firstly with increasing Cl− concentration and then decreased in the saturated H2S/CO2 solution at pH 6. The corrosion products were mainly composed of two kinds of iron sulfide. Sulfide FeS1−x was a kind of tetragonal crystal, whereas the other was the hexagonal/monoclinic iron sulfide Fe1−xS. The corrosion film that was mainly composed of FeS1−x did not confer a protective effect on the base metal. The atomic ratio of Fe/S was more than 1 for FeS1−x. The appearance of sulfide FeS1−x resembled a square block or small, needle-like, flocculent particles. The atomic ratio of Fe/S was less than 1 for Fe1−xS, and the corrosion film mainly composed of Fe1−xS conferred some protective property on the base metal. The sulfide FeS1−x exhibited a long claviform morphology with a hexagonal or quadrilateral cross-sectional shape.

Electrochemical Corrosion Behavior of Q235B Carbon Steel in 10%NaCl and H2S Solutions with Different pH

The electrochemical corrosion behavior of Q235B carbon steel in 10% NaCl and H2S solutions with different pH was studied by means of electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization curves. The results show that when the pH is less than 3, the corrosion is mainly controlled by the acidic dissolution process of the anode, and the electrochemical impedance spectrum not only has a capacitive arc in the high frequency region, but also exists an inductive arc in the low frequency region; when the pH is in the range of 3.05 to 6.01, the radius of the capacitive arc increases as the pH increases, and Rr also increases, reaching a maximum at a pH of 5.06, which is related to the deposition and coverage of the black sulfide generated on the surface of the working electrode. Rt and Qdl also increase with the increase of pH; when the pH is higher than 7, the surface of the electrode forms oxide film and sulfide, and the potentiodynamic polarization curve gradually shows passivation characteristics with increasing pH. As large as 9.06, three stages of activation, passivation, and over-passivation can be clearly seen in the potentiodynamic polarization curve. Obvious Warburg impedance characteristics can also be seen in the electrochemical impedance spectrum.

Environmentally assisted degradation of spinodal copper alloy C72900

In this work, a spinodal Copper alloy – C72900, was tested to investigate the resistance against environmentally assisted degradation. The material was tested according to ISO 15156-3 Level V in sour H2S solution and to cathodic polarization in simulated seawater with stressed samples. The results showed no indications of hydrogen stress cracking under cathodic polarization in seawater. However, cracks up to 3 mm deep were found on the samples exposed to sour H2S environment. Energy Dispersive Spectroscopy showed severe depletion of copper close to the cracks which is associated with selective corrosion. Stress corrosion cracking was the dominating crack mechanism in the ISO 15156-3 Level V test.

Pitting Corrosion of Supermartensitic Stainless Steel in Chloride Solutions Containing Thiosulfate or H2S

Deepwater oil and gas extraction environment have high salinity, low oxygen content, and the presence of carbon dioxide and hydrogen sulfide (H2S). Handling of H2S-containing gaseous mixtures should be carried out in laboratories with special installations, owing to the high toxicity of this gas. An alternative is the use of non-toxic substances that can generate H2S in the medium, such as sodium thiosulfate. The objective of this work is to study the viability of substituting H2S by thiosulfate for the evaluation of the susceptibility to pitting corrosion in sour environments of the supermartensitic stainless steel (SMSS). The electrochemical behavior of SMSS in NACE TM0177-2016 solution C solution containing different concentrations of H2S or thiosulfate ions at 10−3 mol/L was performed by using cyclic potentiodynamic polarization (CPP). The condition of shorter OCP time (300 s) prevents the formation of a passive layer and allows the generation of H2S due to the reaction of the solution with the metal surface. The CPP curves of SMSS in the media containing 3% H2S/Ar (2.96 kPa) and 10−3 M of thiosulfate ions (OCP 300 s) were similar, the pitting potential was about − 322.5 ± 8.7 and − 338.8 ± 11.4 mVAg/AgCl, respectively, and the pit morphology showed several small pits on the steel surface in both conditions, suggesting the viability of the use of thiosulfate-containing brines to simulate H2S solutions.

Electrochemical impedance spectroscopy of iron corrosion in H2S solutions

Corrosion of iron exposed to H2S saturated solution at pH 4 was studied by electrochemical impedance spectroscopy, weight loss coupons and surface analysis. Hydrogen permeation was also used as indirect means of evaluating the intensity of the proton reduction reaction leading to hydrogen entry into the metal.Since corrosion in this type of test solution results in the rapid build-up of a conductive and highly porous iron sulfide scale, a specific contribution of the film has to be considered. An impedance model was thus proposed. The faradaic anodic impedance consists of a two-step reaction with charge transfer and adsorption – desorption. An additional contribution, associated with the conductive and highly porous iron sulfide film was added in parallel. This contribution, mostly visible in the low frequency domain, presents a 45° tail associated with a porous electrode behavior. This model was well adapted to describe impedance diagrams measured at various exposure times, up to 620 h. Charge transfer resistance determined from impedance analysis allowed calculating the evolution with time of the corrosion current density. A very good correlation was found between this corrosion current density and the hydrogen permeation current density. As expected in our experimental conditions, a permeation efficiency close to 100% is demonstrated. Corrosion rate of 490 μm/year was measured by weight-loss specimens, confirming the validity of the impedance analysis, which resulted in a calculated corrosion rate of 530 μm/year.

On the Efficacy of Cardio-Pulmonary Resuscitation and Epinephrine Following Cyanide- and H2S Intoxication-Induced Cardiac Asystole.

This study was aimed at determining the efficacy of epinephrine, followed by chest compressions, in producing a return of spontaneous circulation (ROSC) during cyanide (CN)- or hydrogen sulfide (H2S)-induced toxic cardiac pulseless electrical activity (PEA) in the rat. Thirty-nine anesthetized rats were exposed to either intravenous KCN (n = 27) or H2S solutions (n = 12), at a rate that led to a PEA within less than 10min. In the group intoxicated by CN, 20 rats were mechanically ventilated and received either epinephrine (0.1mg/kg i.v. n = 10) followed by chest compressions or saline (n = 10, "control CN") when in PEA. PEA was defined as a systolic pressure below 20mmHg and a pulse pressure of less than 5mmHg for 1min. In addition, seven spontaneously breathing rats were also exposed to the same CN protocol, but infusion was stopped when a central apnea occurred; then, as soon as a PEA occurred, epinephrine (0.1mg/kg IV) was administered while providing manual chest compressions and mechanical ventilation (CPR). Finally, 12 rats were intoxicated with H2S, while mechanically ventilated, and received either saline (n = 6, "control H2S") or epinephrine (n = 6) with CPR when in PEA. None of the control-intoxicated animals resuscitated (10 rats in the control CN group and 6 in the control H2S group). In contrast, all the animals intoxicated with CN or H2S that received epinephrine followed by chest compressions, returned to effective circulation. In addition, half of the spontaneously breathing CN-intoxicated animals that achieved ROSC after epinephrine resumed spontaneous breathing. In all the animals achieving ROSC, blood pressure, cardiac output, peripheral blood flow and [Formula: see text]O2 returned toward baseline, but remained lower than the pre-intoxication levels (p < 0.01) with a persistent lactic acidosis. Epinephrine, along with CPR maneuvers, was highly effective in resuscitating rodents intoxicated with CN or H2S. Since epinephrine is readily available in any ambulance, its place as an important countermeasure against mitochondrial poisons should be advocated. It remains critical to determine whether the systematic administration of epinephrine to any victims found hypotensive following CN or H2S intoxication could prevent PEA, decrease post-ischemic brain injury and increase the efficacy of current antidotes by improving the circulatory status.

Synergistic inhibition effects of octadecylamine and tetradecyl trimethyl ammonium bromide on carbon steel corrosion in the H2S and CO2 brine solution

The corrosion inhibition performances of octadecylamine (OCT) and tetradecyl trimethyl ammonium bromide (TTAB) for carbon steels in H2S and CO2 brine solution were investigated by weight loss, potentiodynamic polarization, molecular dynamic simulation and XPS analysis. TTAB showed better inhibition effects on H2S and CO2 induced corrosion than OCT. Synergistic corrosion inhibition effect was found between OCT and TTAB with proper mass ratios and the best inhibition performance was achieved with 10mgL−1 OCT and 20mgL −1 TTAB. The synergism was correlative to the fractional free volume of the inhibitor film of OCT and TTAB.

Origin of deep carbonate reservoir in northeastern Sichuan Basin: New insights from in-situ hydrothermal diamond anvil cell experiments

In situ Raman analysis on the segregated near-equilibrium carbonate-fluid interaction at elevated temperatures (room temperature−260 °C) and pressures (13-812 MPa) in a hydrothermal diamond anvil cell (HDAC) reveals the preservation mechanism of porosity in deep carbonate reservoirs in the northeastern Sichuan Basin. The carbonate-fluid interaction was investigated by separately heating carbonate minerals and rocks with four different acid solutions (saturated CO2 and H2S solutions, HCl, CH3COOH) in a sealed sample chamber. A minor continuous precipitation with increasing temperatures and pressures was observed during the experiments which caused minor sample volume change. The closed system is a preservation of pores and burial dissolution may not be the dominant diagenesis in the origin of porosity. Thin section photomicrographs observations in Changxing and Feixianguan Formations demonstrate that eogenetic pores such as moldic or intragranular pores with late small euhedral minerals, intergranular, intercrystal and biological cavity pores are the main pore types for the reservoirs. Early fast deep burial makes the porous carbonate sediments get into the closed system as soon as possible and preserves the pores created in the early diagenetic stage to make significant contribution to the deep reservoir quality. The anomalous high porosity at a given depth may come from the inheritance of primary pores and eogenetic porosity is fundamental to carbonate reservoir development. The favorable factors for deep reservoir origin include durable meteoric leaching, early fast deep burial, early dolomitization, etc. This deep pores preservation mechanism may be of great importance to the further exploration in deep carbonate reservoirs in the northeastern Sichuan Basin.

Low-Cycle Fatigue Behaviors of Pre-Corroded Q345R Steel under Wet H2S Environments

Low cycle fatigue (LCF) behaviors of pre-corroded Q345R steel under different corrosion environments were investigated where both concentration of H2S solution and pre-corrosion time served as two environmental factors. Low cycle fatigue tests were conducted at room temperature in air after the specimens were pre-corroded in H2S solution. The low cycle fatigue behaviours of pre-corrosion test material, such as strain-life relationships and cyclic stress-strain responses were investigated and compared. Results show that environmental factors had little effect on the cyclic stress response while it had much effect on the fatigue life. And pre-corrosion time had more significant effect on low cycle fatigue life of test material than the solution concentration of H2S. Furthermore, the fracture surfaces of the fatigue samples were characterized by scanning electron microscope (SEM) and the fracture mechanisms were discussed under different environmental conditions.

Physicochemically modified peat by thermal and oxidation processes as an active material for purification of wastewaters from certain hazardous pollutants

The physicochemical modification of peat through thermal and oxidation processes was carried out, in order to obtain new, inexpensive and active material for purification of different types of waters. During the modification, surface chemical compounds of Shilov type were formed. Batch adsorption properties and suitability of physicochemically modified peat (PCMP) for odor removal were tested in aqueous solutions of H2S and colloidal sulphur. Additionally, PCMP was tested in the removal of As(V) which is hazardous ingredient in contaminated waters. Possible mechanisms of pollutants binding include interactions, which lead to formation of adducts and clathrates. All these processes are elucidated in detail. The results showed that the obtained material can be used for the removal of sulphide, colloidal sulphur and As(V) from different types of waters.

Nanostructured CdS sensitized CdWO4 nanorods for hydrogen generation from hydrogen sulfide and dye degradation under sunlight

In this report, CdS nanoparticles have been grown on the surface of CdWO4 nanorods via an in-situ approach and their high photocatalytic ability toward dye degradation and H2 evolution from H2S splitting under visible light has been demonstrated. The structural and optical properties as well as morphologies with varying amount of CdS to form CdS@CdWO4 have been investigated. Elemental mapping and high resolution transmission electron microscopy (HRTEM) analysis proved the sensitization of CdWO4 nanorods by CdS nanoparticles. A decrease in the PL emission of CdWO4 was observed with increasing amount of CdS nanoparticles loading possibly due to the formation of trap states. Considering the band gap in visible region, the photocatalytic study has been performed for H2 production from H2S and dye degradation under natural sunlight. The steady evolution of H2 was observed from an aqueous H2S solution even without noble metal. Moreover, the rate of photocatalytic H2 evolution over CdS modified CdWO4 is ca. 5.6 times higher than that of sole CdWO4 under visible light. CdS modified CdWO4 showed a good ability toward the photo-degradation of methylene Blue. The rate of dye degradation over CdS modified CdWO4 is ca. 7.4 times higher than that of pristine CdWO4 under natural sunlight. With increase in amount of CdS nanoparticle loading on CdWO4 nanorods the hydrogen generation was observed to be decreased where as dye degradation rate is increased. Such nano-heterostructures may have potential in other photocatalytic reactions.