Hydrogen Sulfide Partial Pressure Research Articles

Effect of Surface Hardness and Hydrogen Sulfide Partial Pressure on Sulfide Stress Cracking Behavior in Low Alloy Linepipe Steel

TMCP (thermo-mechanical controlled process) linepipes have long been used in severe sour environments, but recently sulfide stress cracking (SSC) caused by local hard zones has become a concern. In order to clarify the hardness threshold that leads to SSC, four-point bend (4PB) SSC tests as specified in NACE TM0316 were conducted under several H2S partial pressure conditions. At H2S partial pressures of 1 bar and higher, the surface hardness threshold (at 0.25 mm from the surface) observed in 4PB SSC specimens without SSC cracking was approximately correlated to a maximum acceptable hardness level of 250 HV0.1. A stable low surface hardness of 250 or less HV0.1 was achieved by suppressing hard lath bainite (LB) and obtaining a soft granular bainite (GB) microstructure, resulting in a superior SSC-resistant property. It was found that a SSC crack propagated when the surface hardness increased due to an increasing volume fraction of the LB microstructure. Under a 16 bar H2S partial pressure condition, the crack growth rate increased in the sour environment, and hydrogen embrittlement by H2S was promoted. However, in the 4PB SSC test at 16 bar, the stress concentration and the transition to a crack were suppressed because the shape of localized corrosion was semicircular due to low localized corrosivity. This can be the reason why the SSC susceptibility was similar to 1 bar condition, especially in the 4PB SSC test using the samples with lower surface hardness level of 250 or less HV0.1.

Effect of Surface Hardness and Hydrogen Sulfide Partial Pressure on Sulfide Stress Cracking Behavior in Low Alloy Linepipe Steel

Effect of Surface Hardness and Hydrogen Sulfide Partial Pressure on Sulfide Stress Cracking Behavior in Low Alloy Linepipe Steel

ACEME: Reducing of CO2 and H2S for biogas upgrading using accelerated mineralization

To reduce carbon dioxide and hydrogen sulfide concentration in simulated biogas, experiments were performed on a laboratory scale. The main goal was to use calcium, lead and zinc from fly ash from waste combustion power plants to form carbonates and sulfides for biogas upgrading within a process water cycle. Thereby, the contact time between the simulated biogas and the ionized process water was limited to less than 1 s. The investigation focused on the influence of hydrogen sulfide partial pressure, reaction time, reaction temperature, and process water volume flows. The experiments were performed with two different ashes.The results show that the kinetics for hydrogen sulfide reactions were better than for carbon dioxide where the mass transfer into the liquid phase slows down the upgrading process. This led to fast reactions for H2S in the initial volume and therefore to a bottleneck for further sequestration. For carbon dioxide the kinetics limit the process in the beginning until all reactants for carbonates and the process water volume flow limit the process also. For the process temperature, slightly better separation efficiencies were realized for carbon dioxide at 40 °C while the effect for hydrogen sulfide separation was contradictory for the used ashes. With higher process water volume flow, best results were achieved and the bottleneck of reactants ratios was compensated. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13144, 2019

Kinetic parameter estimation and simulation of trickle-bed reactor for hydrodesulfurization of whole fraction low-temperature coal tar

With whole-fraction low temperature coal tar (LTCT) as raw material, which boiling point range is 209–514 °C. This paper conducts hydrotreatment (HDT) test for 1176 h on trickle-bed reactor (TBR) with commercial NiMo/Al2O3-SiO2 catalyst. The reaction conditions are as follows: reaction temperature 613–653 K, reaction pressure 10–14 MPa, liquid hourly space velocity (LHSV) 0.2–0.4 h−1, and hydrogen-to-oil volume ratio 1000:1. Considering the short life of coal tar HDT catalyst, a kinetic model of whole-fraction LTCT hydrodesulfurization (HDS) including running time (t1) and catalyst half-life (tc) was established. The kinetic parameter estimation was conducted according to the experimental data, and the results are as follows: activation energy 94965 J/mol, reaction order 1.5, and the relative error of the model is less than 5%.Based on the premise of steady state operation, the HDS reaction happened in the three-phase trickle-bed reactor was simulated by combining the mass transfer, reaction kinetics model and physical property data of LTCT. The results show that the experimental and simulated values of sulphur content at the exit of the reactor are within the error range of 5%. By simulating the whole-fraction LTCT HDS reactor, the pattern of changes in the concentrations of hydrogen sulfide, hydrogen and sulfur in gas, liquid and solid phases according to the length of the reactor were obtained. Based on this, this paper discusses on the impacts of each process parameter and hydrogen sulfide partial pressure on LTCT HDS, and works out the reaction characteristics of whole-fraction LTCT HDS different from crude oil fraction. Finally, this paper analyzes the influence of different process conditions on internal gradients of catalyst, and concludes the influence of each parameter on effectiveness factor of particle. The increase of temperature, decrease of pressure or increase of LHSV can all cause the decrease of effectiveness factor, wherein the temperature has the most significant effect on the effectiveness factor, followed by LHSV, and pressure has the weakest effect. These findings contribute to a more in-depth understanding of the features and rules of LTCT HDS, and can also give us some guidance for industrial reactor simulation.

Determination of H2S Partial Pressures and Fugacities in Flowing Streams

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 179921, “Determination of H2S Partial Pressures and Fugacities in Flowing Streams for a More-Accurate Assessment of Integrity Threat in Sour Systems,” by Christopher Harper, Kanan Taghiyev, and Peter Wilkie, Baker Hughes, and Douglas Hall, Chevron, prepared for the 2016 SPE International Oilfield Corrosion Conference and Exhibition, Aberdeen, 9–10 May. The paper has not been peer reviewed. An Excel-based tool was developed that uses cubic-equation-of-state (EOS) and thermodynamic electrolyte-chemistry modeling to assess sour-production streams from a reservoir, through production tubing, pipelines, and facilities to an export pipeline within a range of temperature and pressure conditions. The approach is need to assess the integrity risk posed to system components in the Alba field in the North Sea. Theory and Methodology To accurately determine multiphase sulfide concentrations, and therefore hydrogen sulfide (H2S) partial pressures and the resulting integrity threat in sour-production streams, it is first important to understand the pH-dependent distribution of the three species of sulfide that may be present in an aqueous solution. Many commercially available EOS software packages do not take into account aqueous pH- and speciation-driven aqueous sulfide solubility. They merely assume that the gas-phase and oil-phase H2S remains as H2S in all three phases and, as such, that the aqueous solubility is limited by the solubility of the H2S species in water. The three species of sulfide that may be present in an aqueous solution are H2S, HS−, and S2−. How much of each species is present (as a fraction) is dependent largely upon the aqueous pH. H2S is the only species of sulfide that exists in all three phases; some aqueous sulfide must speciate to H2S before H2S is found in the oil and gas phases. Therefore, in an oil-production system in thermodynamic equilibrium, with an aqueous pH of 9.5 or higher, all sulfide must be in the water phase and oil and gas phases must be completely free of H2S. However, this would be very unusual in an oil- production system or reservoir where typical aqueous pH values are much lower. At very low pH values, three-phase H2S distribution is driven by temperature and pressure alone: Increasing pressure reduces gas-phase H2S and increases oil- and water-phase H2S, whereas increasing temperature increases gas-phase H2S and reduces oil- and water-phase H2S (Fig. 1).

Rate phenomena in the reaction of hydrogen sulfide with a zinc oxide‐based sorbent

AbstractA zinc oxide‐based sorbent was prepared by spraying drying a slurry containing 65% zinc oxide, 18% peptized alumina, and 17% perlite. The spray dried solids were dry sieved, wet sieved, dried at 150°C for 1 h, and subsequently calcined at 635°C for 1 h to produce the sorbent. The rate of sorption of hydrogen sulfide was measured as a function of time with a Cahn VersaTherm™ thermogravimetric analyzer. Sorption rate is reported as a function of hydrogen sulfide partial pressure, temperature, and external particle size. Sorption rate can be described by a hydrogen sulfide mass‐transport model for agglomerated particles. This agglomerate kinetics model satisfactory explains rate phenomena observed in this system. © 2010 American Institute of Chemical Engineers Environ Prog, 2011

Effect of H 2S partial pressure on the HDS of dibenzothiophene and 4,6-dimethyldibenzothiophene over sulfided NiMoP/Al 2O 3 and CoMoP/Al 2O 3 catalysts

The effect of hydrogen sulfide (H 2S) partial pressure on the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (46DMDBT) was studied over commercial NiMoP/Al 2O 3 and CoMoP/Al 2O 3 catalysts under conditions close to those commonly used in the hydrotreating of diesel fuels (280 or 340 °C; total pressure between 2.5 and 5.5 MPa). The sulfur compounds diluted in n-heptane were in proportions representative of those found in diesel fuels (0.0014 MPa of DBT or 46DMDBT, 0.0058–0.1 MPa of H 2S generated from dimethyldisulfide). A significant negative effect of H 2S on the HDS of the dibenzothiophenes (DBT and 46DMDBT) was observed whatever the total pressure (2.5–5.5 MPa) and the catalyst used. However, the reactivity of DBT was more reduced than that of 46DMDBT. Moreover, the “direct desulfurization pathway” (DDS) of both reactants was more inhibited by H 2S than the so-called “hydrogenation pathway” (HYD) over the two catalysts. It was also found that the NiMoP/Al 2O 3 catalyst was more sensitive to H 2S than its CoMoP/Al 2O 3 counterpart whatever the experimental conditions. Several hypotheses were considered and discussed to explain these findings: specific centres for each of the two reactions (DDS and HYD) or centres being similar in nature (sulfur vacancies associated to sulfur anions) but which would differ in their acid–base properties. It was also suggested that the centres could be identical but that DDS and HYD could have different rate-limiting steps which would not involve the same part of the dual site so that their sensitivity to H 2S would be different.

Conditions of Hydrogen-Induced Corrosion Occurrence of X65 Grade Line Pipe Steels in Sour Environments

Abstract Hydrogen-induced cracking (HIC) tests were performed on fourteen types of X65 line pipe steels in various environments in which the hydrogen sulfide (H2S) partial pressures (PH2S) were in the range from 1 × 10/5 MPa to 0.1 MPa and pH was in the range from 2 to 5. The conditions governing HIC occurrence were investigated and the following results were obtained: —Hydrogen permeability in steel ([PerFe]) was formulated as a function of PH2S and pH ([PerFe]) = 7.1 + 0.96 × (1.4logPH2S − 0.51 pH), where 0.1 MPa ≥ PH2S ≥ 1 × 10−3 MPa and 5 ≥ pH; [PerFe] = 3.3 + 0.75 × (0.3logPH2S − 0.51 pH), where 1 × 10−3 MPa > PH2S ≥ 1 × 10−5 MPa and 5 ≥ pH. —Critical hydrogen permeability in steel ([Percrit]) was expressed as a function of the critical length of inclusions (acrit) and the maximum hardness of the center-segregation zone (Hvmax) for the investigated thermomechanical-controlled process (TMCP) steels and the controlled rolled and air-cooled (CR) steels (log [Percrit] = [1.7 − 0.0030 Hv] − 1/4log[acrit])...

Influences of the Hydrogen Sulfide Partial Pressure and of a Nitrogen Compound on the Hydrodeoxygenation Activity of a CoMo/Carbon Catalyst

The influences of the hydrogen sulfide partial pressure and of a basic nitrogen compound (diaminopropane) on the activity of a sulfided CoMo/carbon catalyst in hydrodeoxygenation were studied from 10 to 150 kPa H2S, under a total pressure of 7 MPa, at 270 and 200°C in the transformation of a mixture of guaiacol, ethyldecanoate, and 4-methylacetophenone in p-xylene. It is likely that three different active sites are responsible for hydrogenolysis, hydrogenation, and acid-catalysed reactions. An increase in hydrogen sulfide partial pressure decreases the average degree of reduction and uncoordination of the active sites and inhibits the hydrogenolysis and hydrogenation pathways, the first being affected to a larger extent. This accounts for the decrease of guaiacol dehydroxylation and the increase of 4-methylacetophenone conversion. The reactions catalysed by acid sites located on the metal sulfide, namely decarboxylation and alcohol dehydration, are promoted by hydrogen sulfide. The addition of diaminopropane strongly inhibits the conversion of guaiacol and ethyl decanoate. The decarboxylation selectivity is decreased as well.

CoMo/carbon hydrodeoxygenation catalysts: influence of the hydrogen sulfide partial pressure and of the sulfidation temperature

This work concerns the influence of the hydrogen sulfide partial pressure and the sulfidation temperature on the hydrodeoxygenation activity and selectivity of a CoMo catalyst supported on activated carbon. An attempt is made to identify the active sites involved in the reaction of different oxygenated molecules: guaiacol demethylation and dehydroxylation, ethyldecanoate hydrogenation and decarboxylation, 4-methylacetophenone hydrogenation.

How to Pressurize Autoclaves for Corrosion Testing Under Carbon Dioxide and Hydrogen Sulfide Pressure

Abstract All the methods presently used for pressurizing autoclaves have advantages and disadvantages. Pressurizing with pure gases is undoubtedly the surest method, since it is insensitive to the autoclave filling rate, and the influence of temperature stability readily can be controlled. The only limitation is the impossibility of accurately reproducing very low hydrogen sulfide (H2S) partial pressures ( 150°C). Conventional pressurizing with gas mixtures is not at all practical, since it demands either excessively large autoclaves or the bubbling of prohibitive volumes of gas. To overcome these fundamental difficulties, alternative methods are proposed, such as high-temperature bubbling using a cooled reflux condenser or presaturation of the autoclave at 60°C at a fraction of the test pressure, enabling the latter to be attained during subsequent heating by the natural increase in pressure with temperature.

Inhibiting effect of hydrogen sulfide on toluene hydrogenation over a molybdenum disulfide/alumina catalyst

The influence of hydrogen sulfide partial pressure on the activity of a model MoS[sub 2]/[gamma]-Al[sub 2]O[sub 3] catalyst for toluene hydrogenation has been investigated over a wide range of hydrogen sulfide partial pressure, from 0 to 0.3 MPa, under a total pressure of 6 MPa, reaction temperature between 320 and 410 C, and liquid hourly space velocity between 0.5 and 7.5 h[sup [minus]1]. A moderate inhibiting effect of H[sub 2]S on the hydrogenation activity is found for H[sub 2]S partial pressure up to 60,000 Pa with an order of reaction relative to H[sub 2]S comprised between 0 and [minus]1/2. For H[sub 2]S partial pressure higher than 60,000 Pa, no apparent inhibiting effect of H[sub 2]S on the hydrogenation activity is detected. The results have been best interpreted in term of a kinetic model whereby the reaction occurs on a surface containing two sites, one unsaturated Mo ion and one stable sulfur host of the proton generated by the heterolytic dissociative adsorption of hydrogen and hydrogen sulfide.

Effect of the hydrogen and hydrogen sulfide partial pressures in the hydrodesulfurisation of thiophene and hydrogenation of cyclohexene on rhodium-tungsten catalysts

WS 2, alumina-supported rhodium sulfide, and mechanical mixtures of both were studied in the simultaneous hydrodesulfurisation (HDS) of thiophene and hydrogenation (HYD) of cyclohexene under hydrogen pressures of 2.2 and 1.1 MPa and with H 2S partial pressure varying from 0.0 to 15 kPa. Rhodium sulfide has a promotional effect on WS 2 both for HDS and HYD, as long as the H 2S pressure remains low. At a H 2S pressure in excess of about 3 kPa the activity of both the mechanical mixture and the pure rhodium sulfide decrease drastically. The control of the activity of WS 2 by spillover of hydrogen from rhodium sulfide seems to explain the promotional effect. The accompanying loss of the promotional effect could be explained by an inhibition of the production of spillover hydrogen by H 2S.

Surface Effects in Sulfidation Reactions

Pure iron and an Fe–41 wt% Ni alloy are reacted at temperatures in the range 793–1073 K with H2–H2S–N2 atmospheres corresponding to equilibrium P S2 levels from 6.5 × 10−5 to 0.65 Pat The kinetics of iron sulfidation are intermediate in form to linear and parabolic rate laws. The instantaneous parabolic rate constant is found to increase with extent of reaction until a constant value is reached. For fixed equilibrium sulfur pressures, the instantaneous rate increases with hydrogen sulfide partial pressure; for fixed hydrogen sulfide partial pressure, the instantaneous rate decreases as the equilibrium sulfur pressure is increased. It is demonstrated that hydrogen sulfide is the reactant species. A Langmuir-Hinshelwood kinetic model based on the slow dissociation of adsorbed hydrogen sulfide accounts satisfactorily for the unusual gas-phase compositional effects, and also for the rate at which the reacting system approaches steady state. Similar effects are found for the Fe–41%Ni alloy, where nickel sulfide whisker formation results from localized catalysis of the hydrogen sulfide dissociation reaction.

Stress Corrosion Cracking of 13Cr Steels in CO2-H2S-Cl− Environments

Abstract Stress corrosion cracking (SCC) behavior of two 13Cr steels was investigated in aqueous CO2-H2S environments. U-bend tests, constant load tensile tests, and corrosion tests were performed in CO2 environments containing different amounts of H2S. In addition, the slow strain rate tensile (SSRT) tests and hydrogen absorption measurements were done under cathodic hydrogen charging conditions to determine why 13Cr steels are more susceptible to SCC in H2S environments than low alloy steels are. The 13Cr steels were less resistant to SCC in the CO2-H2S environments than low alloy steels were, but some 13Cr steels were not subject to SCC even at a hydrogen sulfide partial pressure of 0.3 atm. Furthermore, it was found that SCC in a CO2-H2S environment was caused by hydrogen embrittlement and that the SCC susceptibility of 13Cr steels was affected by their intergranular cracking behavior. Thus, their microstructures and carbide dispersions are important factors in defining SCC susceptibility of 13Cr steels.

Influence of hydrogen sulfide partial pressures on cracking of carbon and low-alloy steels

Influence of hydrogen sulfide partial pressures on cracking of carbon and low-alloy steels

The structure and composition of rf reactively sputtered MoSx films

Molybdenum sulfide films have been deposited by reactive sputtering of molybdenum in a hydrogen sulfide/argon atmosphere and by sputtering of molybdenum disulfide in pure argon atmosphere at substrate temperatures between room temperature and 480 °C. The structure and composition of the films have been determined as a function of hydrogen sulfide partial pressure and substrate temperature by transmission electron microscopy (TEM) and Rutherford ion backscattering, respectively. The experiments showed that at hydrogen sulfide partial pressures above 2×10−4 Torr, MoSx films had a rhombohedral structure with 0<x<2.2. The dependence of the film thickness on the hydrogen sulfide partial pressure has been studied. The dependence of the composition on the substrate temperature is interpreted by a different dependence of the sticking coefficient of the components on the temperature.

Sulfiding of tungsten oxide supported on silica-alumina

Tungsten trioxide supported on silica-alumina was sulfided with mixtures of hydrogen sulfide and hydrogen at temperatures between 500 and 1100 °F and hydrogen sulfide partial pressure of 0.1–5 atm. Kinetic data were correlated with a logarithmic-type growth law, which accounts for the rather flat percentage sulfur versus time profiles. Rates were proportional to the square root of the hydrogen sulfide partial pressure. The apparent activation energy for sulfidation was 36 kcal/mole of W. Studies of partially reacted samples showed the sulfided species to be WS 2 and the unconverted oxide to be W 20O 58, suggesting that partial reduction precedes sulfidation. Evidence is advanced to support a pore-blocking model for the sulfidation. Differences in reactivity of bulk compared to supported tungsten trioxide are discussed.

Corrosion of Iron in an H2S-CO2-H2O System

Abstract Corrosion studies of iron in an H2S-CO2-H2O System were made under static and dynamic conditions. The data indicated that there existed a certain hydrogen sulfide partial pressure, approximately 0.02 psia, above which hydrogen blistering occurred. Similar results with sulfide stress cracking were obtained. The hydrogen sulfide partial pressure at onset of cracking was 0.150 psia. Hydrogen sulfide became the controlling factor at very low partial pressures causing an initial drop in the corrosion rate. Apparently, the type of corrosion film formed controlled the corrosion rate. Changes in these films were observed to take place coincident with changes in corrosion rate and prevalence of hydrogen blisters. The relationship of these phenomena is discussed. 6.2.2, 8.4.3, 3.2.2, 3.5.8

Collection and Correlation of High Temperature Hydrogen Sulfide Corrosion Data—A Contribution to the Work of NACE Task Group T-5B-2 on Sulfide Corrosion At High Temperatures and Pressures in the Petroleum Industry from: The M. W. Kellogg Co., New York, N. Y.

Abstract Corrosion by gas mixtures containing hydrogen sulfide at elevated temperatures is reviewed, with particular emphasis on the types of environments present in catalytic reforming and desulfurizing units of petroleum refineries. Data compiled from the published literature, from laboratory and field tests, as well as from pilot and commercial plant experience are summarized and correlated. Within the general limits of conditions existing in these types of units, corrosion is shown to depend primarily on temperature and hydrogen sulfide partial pressure. Summary curves showing corrosion rates as functions of these two variables are presented as a guide for equipment design. The corrosion resistance of carbon steel and chrome-moly alloys steels is approximately equal in the environments studied; the 12 Cr stainless steels offer slight improvement but their performance is erratic. The 18 Cr-8 Ni stainless steels possess excellent resistance except under the most severe service conditions. Aluminum coati...