H2S Medium Research Articles

Effect of H2S gas flow rate on the stoichiometric ratio of S:Zn and transparency of ZnS nanostructure ceramic in IR region

In this research, zinc sulfide (ZnS) nanostructure powder was successfully synthesized via two-stage annealing (Ar + H2S). The annealing under argon medium was responsible for eliminating impurities such as SO4, SO3 and SO2. The annealing under hydrogen sulfide (H2S) medium also led to compensation of sulfur and establishment of Zn to S stoichiometric ratio following sintering. Investigation of different flow rates of H2S gas indicated that 30 mL/min would contribute to optimal Zn to S stoichiometric ratio. The Zn to S stoichiometric ratio before sintering under H2S medium was 1.28, which increased to 1.55 after annealing under H2S medium. The ceramic obtained from ZnS powder annealed under H2S medium at 30 mL/min had density of 99.98% and IR transmission of 62% within 8–12 μm range (wavenumbers of 1250–850 cm−1).

Study of the effectiveness of a mild steel corrosion inhibitor in H2S medium

Study of the effectiveness of a mild steel corrosion inhibitor in H2S medium

Experimental and computational study of aromatic ring effects on corrosion inhibition in the H2S media

In this work, four quaternary ammonium salts (QAS) were synthesized and applied as corrosion inhibitors for carbon steel (CS) in the H2S media, with different concentrations at 293 and 333 K. The performance and mechanism of QAS inhibitors were studied by electrochemical techniques (OCP, PDP, EIS, and PZC), weight loss (WL), and surface topography methods (SKP, AFM, SEM/EDS, and contact angle). Moreover, computational investigations (DFT and MD) were carried out to clarify the inhibition mechanism of inhibitors. The QASs act as mixed-type inhibitors with a maximum inhibition efficiency of up to 98.5 % in 100 mg L−1. Surface analysis well supported the experimental data. Furthermore, the computational results showed that QASs have comparatively high adsorption energy on the CS, which agrees with the experimental data.

INVESTIGATION OF STRUCTURAL PROPERTIES OF ZnS AND Mo-DOPED ZnS NANOPARTİCLES ANNEALED IN H2S MEDIUM

In this study, the structural properties of Mo-doped ZnS nanoparticles (NPs), which were synthesized at room temperature using the successive ionic layer adsorption and reaction (SILAR) method and annealed in H2S gas for 1 hour at 550 oC, were investigated. The XRD result shows that ZnS and Mo Doped ZnS NPs are in lattice cubic structure. The average crystal size of NPs was calculated using the Debye − Scherrer formula. The crystal size of the pure ZnS NPs varied with doping. The average crystalline size of ZnS and Mo- doped ZnS NPs were found as 5.5nm nd 4.3 nm, respectively.

Time-dependent corrosion behavior of electroless Ni–P coating in H2S/Cl− environment

As a mature technology, electroless Ni–P alloy coating is widely applied in the protection of chemical equipment and pipelines owing to its excellent corrosion resistance, but its application and long-term service evaluation in the field of high-sulfur oil and gas are rare. Therefore, the time-dependent corrosion behavior of Ni–P coating, which was plated on the L360 steel surface, was investigated in a saturated H2S medium by the method of surface analysis. The results indicate that Ni–P coating with a thickness of about 52.6 μm could significantly reduce the corrosion rate compared with uncoated pipeline steel. This is related to the structure of the dense, protective film on the surface. The uncoated pipeline steel suffered local corrosion during the immersion process, and then it developed into uniform corrosion with the formation of a large number of corrosion products. In comparison, Ni–P coatings corroded relatively mildly with only a thin corroded layer. However, during prolonged corrosion testing, the corrosive medium penetrated the coating/substrate interface at inherent defects, leading to severe local corrosion of the substrate.

STRUCTURAL TRANSFORMATION OF THE NICRMNSI – FE NANODISPERSE SYSTEM IN A CORROSIVE ENVIRONMENT

Structural changes in the NiCrMnSi nanodisperse system deposited on a metal Fe substrate by the HVOF method in a CORROSIVE H2S medium (pH-2,4) were studied. Structural transformation in the NiCrMnSi - Fe system is caused by the oxidation process in a hydrogen sulfide-containing medium. It was found that 216 hours later, when interacting with a corrosive medium, the boundary zone of the interfacial boundaries of the iron substrate with the NiCrMnSi nanodisperse system was destroyed. The evolution of the destruction of the border zone is studied using the IMAGEJ software package.

Investigation of the inhibitory-bactericidal effect of amidoamine-based inorganic complexes against microbiological and atmospheric corrosion

Abstract In the process, inorganic complexes of amidoamines obtained from the interaction of natural petroleum acid and oleic acids with diethylenetriamine have been developed and their effectiveness as inhibitor-bactericides has been investigated. The effect of the synthesized reagents on the kinetics of the corrosion process of steel and the activity of sulphate-reducing bacteria in 3% NaCl solution saturated with CO2 and in the biphasic water–isopropyl alcohol medium with H2S dissolved has been analyzed. The thermodynamic and kinetic parameters of the corrosion process were calculated. The adsorption of the complexes was investigated using the Langmuir isotherm and the correlation constant was determined. State of the metal surface was investigated by SEM method in CO2 and H2S media, with and without inhibitors, and the metal surface contact of complexes was studied by computer molecular simulation.

Pollutant photo-conversion strategy to produce hydrogen green fuel and valuable sulfur element using H2S feed and nanostructured alloy photocatalysts: Ni-dopant effect, energy diagram and photo-electrochemical characterization

Design and synthesis of effective, eco-friendly, low-price semiconductor-based photocatalyst/solar-energy materials and their application for photocatalytic transformation of plentiful/perilous hazardous chemicals (e.g. H2S) into hydrogen green fuel and other valuable elements is a promising/sustainable strategy, which is highly in demand from environmental, energy and fuel as well as chemical and technological standpoints. To this end, herein, a set of new quaternary, Ni-doped n-type solid-solution (alloy) semiconductor compounds, viz. NixIIFe0.2IIIZn0.7−xIIS (x=0, 0.02, 0.05 and 0.1) were synthesized through a facile one-pot hydrothermal route and employed for the photocatalytic conversion of alkaline H2S medium (pH=11) to hydrogen fuel and elemental sulfur. The investigations revealed that by adding Ni into the ternary photocatalyst-base (Fe0.2Zn0.7S), with decreasing the size of constituting nanoparticles and enlarging the photocatalyst surface area, the absorption intensity was strengthened. Among the materials under consideration, the lowest charge recombination (photoluminescence emission), highest photocurrent, and greatest displacement in open circuit and flat-band potentials were witnessed for x=0.05, the photocatalyst with maximum performance to produce H2 and S. Finally, by using photoelectrochemical data and depicting the energy-diagram of system, a detailed discussion was provided and the phenomenon was justified from physicochemical viewpoint.

An excellent heterojunction nanocomposite solar-energy material for photocatalytic transformation of hydrogen sulfide pollutant to hydrogen fuel and elemental sulfur: A mechanistic insight

Hydrogen sulfide (H2S) is a noxious gas for living organisms and devastating/corrosive agent for metallic structures, which is generated in large scale through natural [geothermal/bacterial] activities or industrial processes, particularly by petroleum and gas industries. Photocatalytic elimination of this plentiful-perilous pollutant and its transformation into hydrogen green fuel and elemental sulfur is a novel/sustainable strategy, which is intriguing from energy and environmental science as well as technological viewpoints. To this end, the design and synthesis of low-price, environmentally friendly, effective photocatalyst/solar-energy materials are highly in demand. Herein, through a facile hydrothermal route, a set of new pn junction xBi2S3·yMnS nanocomposite photocatalysts were synthesized and employed in an alkaline H2S medium (pH = 11) to generate hydrogen fuel and elemental sulfur under atmospheric pressure at room temperature conditions. The maximum conversion yield was attained at the molar ratio xy=2, where the photocatalyst exhibited the lowest charge recombination, strong photon absorption, and the greatest surface area among the synthesized nanocomposite materials. Furthermore, it was witnessed that disulfide (S22-) was the only oxidation product in the reaction medium, which could be effortlessly precipitated as elemental sulfur by acidification of the medium and lowering the pH to about 5.

Microstructural and Mechanical Characterization of the Transition Zone of 9%Ni Steel Cladded with Ni-Based Superalloy 625 by GTAW-HW

9%Ni steel was recently used for the first time in the field of injection unit (IU) for the injection of CO2 into oil wells. Because such steels are operated in H2S medium and are susceptible to sulfide stress cracking, their pipes are cladded with Ni-based superalloy 625 by using gas tungsten arc welding with a hot wire to prevent this phenomenon from occurring. The transition zone of substrate/clad can have high hardness and low toughness, and promote failure of the component during service; therefore, it is very important to know its characteristics. In this work, this transition zone was analyzed through optical and scanning electron microscopy with energy dispersive X-ray spectrometry and electron backscatter diffraction, as well as Vickers microhardness, shear and bend tests. Metallographic analysis identified type I and II boundaries with distinct chemical gradients, MC-type carbides, Laves/γ eutectics, peninsulas macrosegregation, crystallographic texture close to <100> in the clads, residual strain, and drop of microhardness across the transition zone. The clads were approved in the shear and bend tests. This work proposes a new type II boundary formation mechanism in dissimilar welds of steels that do not exhibit the allotropic transformation δ → γ during the welding thermal cycle and do not experience a change in the solidification mode.

A new efficient eco-friendly quaternary solid-solution nanoenergy material for photocatalytic hydrogen fuel production from H2S aqueous feed

Hydrogen sulfide is a harmful, corrosive and flammable gas being generated in large scale, during various industrial as well as natural processes. A novel sustainable strategy to eliminate H2S and produce hydrogen solar fuel is based on its photocatalytic degradation inside a water photosplitting reactor. Concerning this strategy, herein, through a facile hydrothermal route, a new set of nano-particulate quaternary solid-solution solar-energy materials Fe0.2(III)Cox(II)Zn0.7-x(II)S was synthesized and employed as effective energy-harnessing photocatalysts of hydrogen fuel production from an alkaline H2S medium. The investigations revealed that among the nanostructured energy materials synthesized here, the best photocatalytic activity [energy efficiency: 13.3%, quantum yield: 25% (at 434 nm), rate: 8391 μmolH2gr.h] was observed for x = 0.1, the optimal composition in which the largest surface area, the greatest light absorption, and the lowest charge (e/h) recombination were attained. Finally, based on the hole-scavenging capability of the bisulfide anions (the dominant species at pH 11), a mechanistic perspective was sketched for the photocatalytic production of hydrogen fuel using the H2S medium.

Photocatalytic degradation of H2S aqueous media using sulfide nanostructured solid-solution solar-energy-materials to produce hydrogen fuel

H2S is a corrosive, flammable and noxious gas, which can be neutralized by dissolving in alkaline media and employed as H2-source by utilizing inside semiconductor-assisted/photochemical reactors. Herein, through a facile hydrothermal route, a ternary nanostructured solid-solution of iron, zinc and sulfur was synthesized in the absence and presence of Ag-dopant, and applied as efficient photocatalyst of hydrogen fuel production from H2S media. The effect of pH on the photocatalyst performance was scrutinized and the maximum activity was attained at pH=11, where HS− concentration is high. BET, diffuse reflectance and photoluminescence studies indicated that the ternary solid-solution photocatalyst, in comparison to its solid-solvent (ZnS), has a greater surface area, stronger photon absorption and less charge recombination, which justify its superiority. Moreover, the effect of silver-dopant on the photocatalyst performance was examined. The investigations revealed that although silver could boost the absorption of photons and increase the surface area, it could not appreciably enhance the photocatalyst performance due to its weak influence on retarding the charge-recombination process. Finally, the phenomenon was discussed in detail from mechanistic viewpoint.

Effect of natural aging on the microstructural regions, mechanical properties, corrosion resistance and fracture in welded joints on API5L X52 steel pipeline

A characterization study was done to analyze how microstructural regions affect the mechanical properties, corrosion and fractography of the Heat Affected Zone (HAZ), weld bead and base metal for pipe naturally aged for 21 years at 30 °C. Results showed that microstructures exhibited damage and consequently decrease in properties, resulting in over-aged due to service. SEM analysis showed that base metal presented coarse ferrite grain. Tensile test indicated that microstructures showed discontinuous yield. Higher tensile strength was obtained for weld bead, which exhibited a lower impact energy in comparison to that of HAZ and base metal associated with brittle fracture by trans-granular cleavage. The degradation of properties was associated with the coarsening of nano-carbides observed through TEM images analysis, which was confirmed by SEM fractography of tensile and impact fracture surfaces. The weld bead reached the largest void density and highest susceptibility to corrosion in H2S media when compared to those of the HAZ and base metal.

Corrosion and metallurgical investigation of two supermartensitic stainless steels for oil and gas environments

The corrosion properties of two supermartensitic stainless steels were studied in chloride and H2S environments. A comparison between 1.4542 and 1.4418 SS grades was made considering the effects of microstructure, different steps of the heat treatment on the pitting and sulfide stress cracking SSC properties. The SSC limits of 1.4418 were determined in terms of different pH and PH2S conditions. In H2S media, the 1.4418 presented a higher stability and passivation compared to 1.4542. The Electron back-scattering and X-ray diffraction were used to characterize the amount of’ retained austenite in the 1.4418 and then its influence on pitting and SSC resistance was investigated.

Failure analysis of impeller made of FV520B martensitic precipitated hardening stainless steel

This paper presents the failure analysis of a centrifugal compressor impeller. The impeller made of FV520B martensitic precipitated hardening stainless steel, fractured after service for 4months in moist H2S condition. Efforts were made to analyze the failure impeller in both experiment and FE methods. Sulfide Stress Cracking (SSC) was the primary failure mechanism for this investigated impeller. The martensite structure, the H2S medium, and the applied stress consisted of the SSC system. This paper exhibits the details of investigation and suggests remedial measures to improve performance of this type impeller under H2S corrosive environment.

Catalyst for methane vapor reforming fabricated on the basis of natural oxides and stable in H2S medium: Activity, selectivity, and nanostructure evolution

This work presents the results of studies on the activity of an iron-nickel catalyst fabricated on the basis of mixed oxides separated from layered vermiculite in the process of methane vapor reforming. It has been demonstrated that the degree of methane transformation in the conversion process is close to the equilibrium one, whereas the catalyst manifests stability to coke formation and the presence of hydrogen sulfide in the vapor-gas mixture. The structure and phase state of the active components of the system have been investigated using the XRD and Moessbauer spectroscopy methods. It has been shown that, during the formation of the catalyst and the catalysis itself, the system surface hosts solid-phase transformations of deposited active components with iron ions present in the substrate. The formation of superparamagnetic clusters of iron oxide strongly bound to the substrate structure on the surface of the catalyst (particles of invar alloy FeNi) determined its polyfunctional properties: high activity in both methane vapor reforming and hydrogen sulfide oxidation decomposition up to elementary sulfur.

Comparative study of the morphological degradation in nickel thin films exposed to H2S media and deposited by magnetron sputtering and electrolytic process

Nickel thin films with regular configuration and similar thickness were deposited on steel AISI 1018 (UNSG 10180) by two different techniques: magnetron sputtering and electrolytic process. The main aim of this work is to compare the surfaces deposited films made by the two techniques using the scanning electronic microscopy and to identify their morphological differences and imperfections. We evaluate the protective coatings properties when the films are in contact with an acid medium. We also study the thin films coatings by the spectroscopy impedance technique. We obtain that the sputtering deposits present a homogeneous thin film coating that is better than the one obtained by the electrolytic technique. It is expected that the thin film coatings made in this work can protect the steel against corrosion when it is in contact with an acid environment.

Estudio de la susceptibilidad de un acero inoxidable austenítico estabilizado con niobio al dañado por tensocorrosión en medio H<sub>2</sub>S (SSC) y corrosión intergranular (IGC) en otros medios agresivos

Behavior to hydrogen damage caused by stress corrosion in a H2S medium (SSC) and to intergranular corrosion (IGC) in different mediums, such as oxalic acid (C2H2O4-2H20), iron sulphate-50 % sulfuric acid [Fe2(SO4)3-50 % H2SO4], nitric acid (HNO3), copper sulphate-16 % sulfuric acid (CuSO4-5H2O-16 % H2SO4) and cooper sulphate-50 % sulfuric acid (CuSO4-5H2O-50 % H2SO4), is studied in an AISI 347 austenitic stainless steel stabilized with 0.61 mass % Nb and hot rolled to a seamless pipe with 273.1 mm in diameter and 18.2 mm in thickness.

Estudio de la susceptibilidad de un acero inoxidable dúplex del tipo 22Cr5NiMoN al dañado por hidrógeno en condiciones estáticas (HIC) y bajo carga (SSC)

The behavior to hydrogen damage caused by corrosion in a H2S medium is studied in a molded ferrite- austenite (52-48 %) duplex stainless steel 22Cr5NiMoN type (UNS-J9.22.05) under both, static (damaging mechanism called Hydrogen Induced Cracking (HIC)) and sustained load (damaging mechanism called Sulfide Stress Cracking (SSC)), conditions.

H2S papers as presumptive tests for Salmonella contamination in tropical drinking water

Coliform bacteria may not be adequate as sole indicators of recent faecal contamination in tropical waters. Salmonella spp. in particular have been found in tropical waters in the absence of traditional indicator bacteria. Remote areas without access to a laboratory have no opportunity for salmonellae analysis as portable tests are currently not available. H2S papers indicate the presence of hydrogen sulphide producing bacteria, a characteristic shared by the majority of Salmonella spp.. The potential of H2S papers to act as a presumptive test for salmonellae in the absence of coliform bacteria was assessed. Salmonella spp. grew in the H2S medium, with an optimum incubation temperature of 37°C and a recommended length of incubation for a negative result of 48 hours. The presence of high numbers of the type of noncoliform bacteria commonly found in drinking water did not affect the performance of the H2S strips. H2S papers are recommended for use in conjunction with a coliform test as a presumptive test for the presence of Salmonella spp. in drinking water.