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Natural gas's relevance has grown considerably because of recent key world events. One of the biggest challenges in processing raw natural gas is the presence of acid gases, particularly hydrogen sulfide, a highly toxic gas. This paper uses a proposed amine sweetening unit to treat sour gases with a high content of acid gases that exceed 12 wt% in Ras Gharib oil fields (Eastern Desert, Egypt). The present study aims to use these gases rather than transmitting them to flares as it is applied to the existing case with no benefit and significant environmental pollution. HYSYS (version 9) is used as a simulation software to study and simulate the introduced sweetening process using Monoethanolamine (MEA), Diethanolamine (DEA), and Methyl Diethanolamine (MDEA) as solvents to reach an acceptable limit of hydrogen sulfide at a reasonable cost. Furthermore, this paper summarizes a sensitivity study to optimize the operating parameters of the process considering optimum cost and energy consumption. The simulation results show that the sweetening unit applying MDEA is the preferable and cost-effective unit with a high-anticipated outcome that reaches 22 million USD annually. Additionally, the flared gas quantities are reduced by 85 wt% which reduces the pollution with an attractive environmental impact to the atmosphere. [ABSTRACT FROM AUTHOR]

Abstract Removing sour gas from any suitable gas sweetening technology in a cost-effective and environmentally responsible manner is a major challenge. This paper discusses how to safely and economically dispose of small amounts of acid gases resulting from the amine sweetening process. A two-stage Claus desulfurization unit was studied and simulated to treat acid gases resulting from natural gas sweetening operations in Ras Gharib oil fields (Egypt). These acid gases are used as feedstock for the proposed plant to produce a valuable product, such as elemental sulfur, which is used as a raw material in many industries. Although many sulfur recovery techniques are available for various conditions and applications, the Claus process is a critical and widely used method for recovering elemental sulfur from gaseous hydrogen sulfide. This work represents the potential benefits of treating acid gases with high hydrogen sulfide content. In addition, operational variables that could affect sulfur production and sulfur recovery efficiency of the studied Claus unit were studied and optimized. Aspen HYSYS simulation software (version 9) was used to evaluate the economic aspects and optimize the operational parameters of the unit for producing sulfur from acid background gases. The results showed that the maximum sulfur production was achieved at a catalytic converter reactor temperature of 270 °C and 210 °C for the first and second catalytic reactor, respectively, with an air flow rate of 933.3 kg mol/h. The economic study of the proposed desulfurization unit showed that the Claus unit would be economically acceptable with an expected return on investment of approximately 10% and an average payback period of 10 years. Moreover, the introduced plant has a positive impact on the environment by reducing the concentration of hydrogen sulfide in the gas from 69.58 to 0.16%.

Removing sour gas from any suitable gas sweetening technology in a cost-effective and environmentally responsible manner is a major challenge. This paper discusses how to safely and economically dispose of small amounts of acid gases resulting from the amine sweetening process. A two-stage Claus desulfurization unit was studied and simulated to treat acid gases resulting from natural gas sweetening operations in Ras Gharib oil fields (Egypt). These acid gases are used as feedstock for the proposed plant to produce a valuable product, such as elemental sulfur, which is used as a raw material in many industries. Although many sulfur recovery techniques are available for various conditions and applications, the Claus process is a critical and widely used method for recovering elemental sulfur from gaseous hydrogen sulfide. This work represents the potential benefits of treating acid gases with high hydrogen sulfide content. In addition, operational variables that could affect sulfur production and sulfur recovery efficiency of the studied Claus unit were studied and optimized. Aspen HYSYS simulation software (version 9) was used to evaluate the economic aspects and optimize the operational parameters of the unit for producing sulfur from acid background gases. The results showed that the maximum sulfur production was achieved at a catalytic converter reactor temperature of 270 °C and 210 °C for the first and second catalytic reactor, respectively, with an air flow rate of 933.3 kg mol/h. The economic study of the proposed desulfurization unit showed that the Claus unit would be economically acceptable with an expected return on investment of approximately 10% and an average payback period of 10 years. Moreover, the introduced plant has a positive impact on the environment by reducing the concentration of hydrogen sulfide in the gas from 69.58 to 0.16%. [ABSTRACT FROM AUTHOR]

Wet sour gas pipelines are subjected to corrosion deterioration mechanisms resulting from interactions between the fluid and piping material. Acid gases, condensation rates, water chemistry, and temperature are the key factors in determining the corrosivity of sour gas streams. This work investigated the corrosion risk of a new wet gas pipeline through laboratory experiments and corrosion modeling. The tests were carried out in Hastelloy autoclave rotating cage system used to generate controlled dynamic conditions inside the reactor to mimic the environment inside the pipeline. The results showed high bottom of the line corrosion (BLC) rate reaching 38.9 mpy (0.99 mm/year), while the measured pitting rate was 17 mpy (0.43 mm/year). The corrosion modeling results showed a severe BLC rate exceeding 200 mpy (5.08 mm/year). The observed high BLC was attributed to the absence of bicarbonate which led to a low pH of 3.9. At this pH, the formation of stable iron sulfide is unlikely. Top of the line corrosion (TLC) rate was observed to be moderate reaching up to 7.8 mpy (0.20 mm/year). This is mainly because of the low condensation rate and formation of a protective iron sulfide layer, which confirmed that iron sulfide scale characteristics are the main factor influencing the TLC rate in sour environments. The expected threshold concentration required of bicarbonate to show some reducing effect on the corrosion rate and pH based on historical data analysis and predictive modeling of real-field conditions is discussed in this work. The results and conclusion detail the path forward for the findings. [ABSTRACT FROM AUTHOR]

This study investigated the efficiency of various absorbents in the gas-sweetening process for removing corrosive acidic gases, specifically hydrogen sulfide (H₂S) and carbon dioxide (CO₂), from natural gas. The study used molecular dynamics simulations to investigate how well MEA, DEA, MDEA, and PC work as absorbents in various heat flux (HF) situations. The simulations demonstrated that all absorbents reached equilibrium within 10 ns, with potential and total energies stabilizing at 10.45 and 11.50 kcal/mol, respectively. The absorption efficiencies were 88.28 % for MEA, 81.06 % for DEA, 73.25 % for MDEA, and 64.11 % for PC, highlighting MEA as the most effective and PC as the least. MEA had an interaction energy of −131.58 kcal/mol, DEA had an interaction energy of −115.63 kcal/mol, MDEA had an interaction energy of −121.38 kcal/mol, and PC had an interaction energy of −73.09 kcal/mol. Increasing the external HF from 0.001 to 0.005 W/m2 enhanced the absorption rate of H₂S and CO₂ from 89.26 % to 95.18 % and increased interaction energy from −146.31 to −159.38 kcal/mol. These findings provided insights into optimizing gas-sweetening processes and selecting effective absorbents.

There are relatively few standards and specifications related to the engineering construction, equipment manufacturing, and material selection of high sulfur natural gas purification units, and most of them adopt or refer to the standards of the petroleum refining industry. Since the Natural Gas Purification Plant of Puguang Gas Field was put into operation in 2009, high sour gas corrosion, as well as the coupling corrosion of multiple factors such as sour gas, manufacturing defects, and material defects, have caused multiple leaks of equipment and facilities, becoming the main problem that restricts the safe, efficient, and long-term operation of the plant. Through statistical analysis of abnormal events over the years, equipment inspection and maintenance records, and pressure vessel pipeline inspection records, the key corrosion areas, influencing factors, and corrosion mechanisms of high sulfur purification units are summarized. It is found that wet hydrogen sulfide corrosion, high-temperature sulfur corrosion, sulfur dioxide corrosion, and underdeposit corrosion are the main corrosion forms; the distribution patterns of corrosion are summarized from region, category, and inducement, corrosion in desulfurization and sulfur recovery systems accounts for over 80% ; typical corrosion cases based on factors such as hydrogen sulfide, liquid sulfur, and manufacturing defects are analyzed in detail, and corrosion prevention and control measures are proposed for high sulfur natural gas purification units. [ABSTRACT FROM AUTHOR]

Relevance. The fluids of the deposits in the Russian Federation have high content of sulfur-containing compounds, in particular, hydrogen sulfide. Due to this feature, many gas and oil companies lose revenue from the sell of such hydrocarbons. The content of hydrogen sulfide in the fluid at the X field is above 5 wt. %. At the moment, associated petroleum gas is supplied at the gas processing plant at a cost of 2400 rubles per 1000 m3, as a result of which the economic efficiency of the project under consideration decreases. To solve this problem, it is proposed to build an associated petroleum gas treatment unit to meet the requirements of the standardization system of PJSC «Gazprom» (STO Gazprom) «Fuel, natural gas supplied and transported through main gas pipelines» (089-2010) as part of the reengineering of an oil and gas treatment facility, which will allow selling associated petroleum gas at a price of 4500 rubles for 1000 m3. Purpose: to form a concept for increasing the profitability of the project of reengineering using the proposed solution for the purification of associated petroleum gas from hydrogen sulfide and the production of sulfur from acid gas. Methods: search and analysis of the advantages and disadvantages of gas purification technologies, simulation of the selected technology in the Hysis software for a certain capacity and obtaining a material balance for plant design. Results. Gas preparation includes separation, a unit for absorption purification of associated petroleum gas from hydrogen sulfide and carbon dioxide by amines, a unit for adsorption gas dehydration for the extraction of mercaptans and drying with NaX (13X) zeolites, and a unit for the extraction of elemental sulfur. Conclusions. In the course of modeling, an amine gas purification scheme was obtained with material balance parameters consistent with the requirements of the standardization system of PJSC «Gazprom» (STO Gazprom) «Fuel, natural gas supplied and transported through main gas pipelines» (089-2010). The resulting gas is recommended to be admitted into a single gas supply system. Acid gases are utilized using a simulated Claus plant.

Pressure control of oil and gas wells in high-sulfur natural gas reservoirs (well control) is critical in oil and gas drilling. Well control accidents have caused great losses of life and property. From 1960 to 1996, more than 1,120 blowout accidents occurred in the Gulf of Mexico and neighboring state capitals. Studying the principles of annulus flow with sour gas can help in early monitoring of overflow and provide theoretical guidance in actual drilling. Research of gas properties and phase behavior can reveal the reasons that sour gas is prone to blowout. The fluid flow principles of the annulus are analyzed with different contents of sour gas. In this study, a multiphase flow model of sour gas in the annulus is established based on sour gas solubility and critical parameters. The model is used to calculate and analyze the changes in sour gas properties and wellbore flow parameters with well depth. It was found that when high-content sour gas overflows, the gas expands violently near the wellhead, and the risk of blowout increases. [ABSTRACT FROM AUTHOR]

Industrial sour gas flaring is difficult to operate appropriately, especially when the gas stream contains high concentrations of sulfur compounds such as hydrogen sulfide and mercaptans. However, most of the detailed combustion mechanisms for hydrocarbons are too complicated, and the computation can be time consuming. In addition, most of the available combustion mechanisms for sulfur compounds are not tailored for sour gas flaring. A reduced combustion mechanism for sour gas will be highly desirable for practical application. In this work, a reduced combustion kinetic mechanism for sour gas combustion, namely the H&S mechanism, was created. This mechanism was validated against experimental data from the literature with proven accuracy. During mechanism analysis, it was found that the addition of H2S had a significant impact on the radical pool. A small amount of H2S leads to a fast buildup of H, OH, and O radicals and a rapid decomposition of CH4. The impact on ignition delay time due to an increase in H2S concentration by 3 vol. % was also analyzed. The impact needs to be compensated by the addition of supplementary fuel. This research will contribute to the clean combustion of sour gas, especially sour gas flares. [ABSTRACT FROM AUTHOR]

A flare stack is an indispensable device in the oil and gas industry for allowing the safe combustion of gases into the atmosphere, especially during emergencies. However, it is not ideal for the routine disposal of gaseous waste, as it is subject to meteorological influences and poor operational control. In addition, it can be affected by toxic currents and thus pose a potential risk of odors; in view of this, an assessment must be made of the implications of burning on the environment and health. Atmospheric dispersion modelling has proved to be a very useful tool for this purpose. In light of this, an attempt has been made in this work to evaluate the impact of H2S on the well-being (odor perception) of the community in the surrounding area of an oil refinery, where the temporary burning of rich gas in H2S occurs in a chemical flare, and operational factors have an influence on atmospheric dispersion. The odor assessment was carried out with the aid of AERMOD which was adapted to estimate the maximum odor concentration for very short periods by means of peak-to-mean ratios. The results showed that H2S detection can reach a probability rate of 42% at 3.5 km distance from the flare (in a time interval of 5 s) with a relatively high degree of annoyance (3.0 AU). However, some operational procedures can reduce the probability of odor detection to 29% and the degree of annoyance to 2.6 AU. [ABSTRACT FROM AUTHOR]

In conventional sour water stripping (SWS) in petroleum refineries, H2S and NH3 of the sour water are separated simultaneously at the top of a tray column by sending sour gases to the sulfur recovery unit (SRU). At SRU furnaces, ammonia is oxidized to NOx playing the role of a deactivator for downstream catalytic beds. From an industrial engineering viewpoint, it is proposed to strip ammonia and hydrogen sulfide separately using two stripper columns. The striped ammonia may be incinerated if it is allowed or traded as gaseous or aqueous ammonia. In this study, the two-column sour water stripping approach is implemented for the feed stream of an SWS unit currently working in Iran using a simulation model that was verified based on the design data of an industrial unit. It is concluded that the higher the pressure of the H2S stripper is, the higher the H2S recovery is, and the lower H2S impurity with ammonia stream is. Moreover, preheating of the feed stream and sending a lower portion of cold feed stream as a representative of liquid reflux resulted in increased utility consumption and also changed the amount of water sent with sour gas and ammonia stream. Finally, aqueous ammonia (less than 10% purity) or ammonia vapor stream (about 90% purity) can be traded as a value-added product for this unit.

The increasing need for energy sources and the decreasing available reserves have promoted oil and gas companies to explore and manage marginal reservoirs, such as the sour gaseous environment. This is to maintain the balance of energy supply and demand. Due to the supply of Natuna Gas Field, the gap in gas supply-demand is likely to decrease by 20%, as regards the example of a potential sour gaseous environment (Batubara, 2015). Therefore, the immediate development of this potential source is very relevant. The sour field approximately shares 40% of Indonesia’s total gas reserve with 75% recovery, at an estimated OGIP of 222 TSCF. However, this environment is economically unproductive due to having high carbon dioxide (CO2) and hydrogen sulfide (H2S) contents, which are toxic and corrosive. Based on previous studies, the X-reserves reportedly contained 32% CO2 and 7072 ppm H2S, with fluid gravity of 42 API. This discretionary source of CO2 was recently brought into production from a well with a depth of 8400 ft, perforated at a limited interval of 7100 to 7700 ft. The harsh environment presented many challenges to the completion of the design, as well as the need to incorporate corrosion effects with unique equipment and material selection for the tubular structure. Therefore, this study aims to determine reservoir fluids and production performance, as well as also predict the corrosivity of dissolved CO2 in the natural gas. With the simulation and prediction, the proper material and equipment selection was obtained, based on the required sour service. The results showed that the wet gas reservoir of the X-field produced an optimum rate of 19.1063 MMSCFD. For the completion of the design, Nickel Alloy SM2535 or SM2242 was needed, due to damages in form of corrosion and pitting

The investigation of elemental sulfur solubility plays critical roles on sour gas reservoir development. In this paper, the solubility of elemental sulfur was directly measured by static method with gas samples from well M1 of a sour gas reservoir in Sichuan Basin. The results show that the solubility of elemental sulfur ranges from 0.001 g/cm3 to 0.968 g/cm3 at 40–98.9 MPa and 15–49.8 MPa. The elemental sulfur solubility increases with increasing temperature and pressure, especially when the pressure is greater than 30 MPa. Moreover, the H2S content in sour gas mixtures is also an important factor affecting elemental sulfur solubility. The elemental sulfur solubility increases with increasing H2S content of the sour gas mixtures. The experimental data in this paper display a consistent trend with the reported experimental data. Based on the experimental results, the chrastil-type model, Robert’s model and Hu’s model were investigated and compared. The results show that the chrastil-type model by fitting experimental data in this paper has less error and higher accuracy in calculating elemental sulfur solubility in M gas reservoir. The chrastil-type models proposed in the literature, meanwhile, are only based on the regression of specific gas components and experimental conditions, which lead to a large error in the calculation of elemental sulfur solubility of sour gas samples in this research. The research results provide important basic data and technical support for the development of M gas reservoir.

Abstract Sour gas reservoirs have faced critics for environmental concerns and hazards, necessitating a novel outlook to how the produced sour gases could be either utilized or carefully disposed. Over the years of research and practice, several methods of sour gas processing and utilization have been developed, from the solid storage of sulfur to reinjecting the sour gas into producing or depleted light oil reservoir for miscible flooding enhanced oil recovery. This paper seeks to investigate the impact of injection parameters on the performance of sour gas injection for enhance oil recovery. In designing a miscible gas flooding project, empirical correlations are used and the key parameter which impacts the phase behavior is identified to be the minimum miscibility pressure (MMP). A compositional simulator was utilized in this research work to study the effect of injection parameters such as minimum miscibility pressure, acid gas concentration, injection pressure and injection rate on the performance of miscible sour gas injection for enhanced oil recovery. The findings showed that methane concentration had a significant impact on the MMP of the process. Additionally, an increase in acid gas concentration decreases the MMP of the process as a result of an increase in gas viscosity, consequently extending the plateau period resulting in late gas breakthrough and increased overall recovery of the process.

Use of amine solutions for the removal of acid gases such as carbon dioxide (CO2) and hydrogen sulfide (H2S) from natural gas is the most common method, and, in this process, operational problems because of foaming are reported. Foaming can lead to the entrainment of liquid into downstream process equipment and might result in a situation in which the process specifications cannot be met for acid gases. Alkanolamines in general have a negative effect on downstream process equipment, and the loss of amines has a negative effect on the health, safety, and environment (HSE). The foam reducing agents are often used to reduce the risk of heavy foaming in amine plants. This study concerns with foaming in amine-based CO2 plants. To investigate foaming related to CO2 removal from natural gas by amine solutions, the fundamental theory of foaming in gas-liquid contactors was first reviewed. Then, experimental techniques related to this phenomenon in diethanolamine (DEA)/CO2 absorbers were considered. After that, foaming of diethanolamine solution polluted with different impurities was noticed, and the tendency of foam was measured by considering their foaming indices. To analyze the experimental measurements and experimental observations, a mathematical model was developed too. The model could justify the experimental measurement reasonably.

In this work, the influence of NaCl on natural sweet and sour gas hydrate formation in the pressure of 115 bar and isothermal conditions (8 °C) have been compared. Salt concentration in the experiments was in the range of 1-7 wt% and the inhibitor was used at a constant concentration of 0.5 wt%. The results show that the presence of salt has been more effective on inhibition time, hydrate growth and also kinetic inhibitor performance in the sour gas system due to the role of ions in decreasing the solubility of acidic gases of sour gas (including H2S and CO2) in water. [ABSTRACT FROM AUTHOR]

Sour gas reservoirs have faced critics for environmental concerns and hazards, necessitating a novel outlook to how the produced sour gases could be either utilized or carefully disposed. Over the years of research and practice, several methods of sour gas processing and utilization have been developed, from the solid storage of sulfur to reinjecting the sour gas into producing or depleted light oil reservoir for miscible flooding enhanced oil recovery. This paper seeks to investigate the impact of injection parameters on the performance of sour gas injection for enhance oil recovery. In designing a miscible gas flooding project, empirical correlations are used and the key parameter which impacts the phase behavior is identified to be the minimum miscibility pressure (MMP). A compositional simulator was utilized in this research work to study the effect of injection parameters such as minimum miscibility pressure, acid gas concentration, injection pressure and injection rate on the performance of miscible sour gas injection for enhanced oil recovery. The findings showed that methane concentration had a significant impact on the MMP of the process. Additionally, an increase in acid gas concentration decreases the MMP of the process as a result of an increase in gas viscosity, consequently extending the plateau period resulting in late gas breakthrough and increased overall recovery of the process. [ABSTRACT FROM AUTHOR]

• A new microscopic scenario is proposed to simulate sulfur dissolution in sour gas. • H 2 S is the decisive component in sour gas leading to sulfur dissolution. • Influencing factors and variation law of sulfur solubility are analyzed. • The microscopic dissolution mechanism of sulfur is revealed. • Gas/sulfur interaction energy results in different sulfur solubility. The solubility characteristics of sulfur in sour gas are crucial in addressing the issue of sulfur deposition and comprehending the multiphase flow behavior in high-H 2 S gas reservoirs. To this end, a pioneering molecular simulation method was proposed in this study to investigate the dissolution of sulfur in sour gas at the molecular scale. The solubility of sulfur in methane (CH 4), carbon dioxide (CO 2), hydrogen sulfide (H 2 S) and their mixtures were quantified. Additionally, the microscopic dissolution process of sulfur was elucidated and its differences among different gas components were highlighted. The results show that H 2 S is the predominant component that facilitates the dissolution of sulfur in sour gas. More specifically, the density in the central region of the sulfur phase diminishes linearly with the escalation of sulfur solubility in the H 2 S component. Meanwhile, the density at the edge of the sulfur phase increases linearly, and the thickness of the transition zone of the sulfur phase tends to increase initially and then remain constant. As temperature and pressure rise, the interaction energy between H 2 S molecules and sulfur augments, resulting in the entry of more gas molecules into the central region of the sulfur phase. Consequently, a smaller sulfur-sulfur intermolecular interaction energy ensues, leading to an increase in sulfur solubility. Similarly, the difference in solubility of sulfur among CH 4 , CO 2 , and H 2 S is also attributed to the variation in interaction energy between gas components and sulfur molecules. These findings hold important implications for sulfur control and treatment in high-H 2 S gas reservoirs. [ABSTRACT FROM AUTHOR]

Desulphurising of oil based fuels and industrial gases is a widespread practice. The combustion process in the sulphur recovery unit (SRU) involves the reaction of H 2 S with oxygen to produce SO 2 , which is then converted to elemental sulphur through a series of catalytic reactions. Oxygen enrichment is a technique used to enhance the performance and efficiency of the SRU. By introducing a higher concentration of oxygen into the combustion process, the overall combustion reaction can be optimised, resulting in an increased sulphur recovery from sour gas and reduced emissions of sulphur compounds. The present study analyses the gate-to-gate comparative environmental impact of air versus oxygen enriched air used for combustion to recover 1.0 ton sulphur using GaBi software (8.5.0.79 version). The primary data was collected from the literature. The GaBi Indian extension database is used for the secondary data source. The results are reported using midpoint impact assessment methods CML 2001. The global warming potential for oxygen-enriched SRU is 232 kg CO 2 eq. compared to 276 kg CO 2 eq. for air enriched SRU. Similarly, the potential for abiotic depletion (elements + fossil), acidification, eutrophication, human toxicity, freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, photochemical ozone creation and terrestric ecotoxicity are higher for air based SRU than oxygen-enriched SRU. The analysis concludes that oxygen enrichment technology is a highly effective way to reduce the environmental impact of the SRU. [Display omitted] • Gate-to-gate environmental footprint of Sulphur recovery unit (SRU) is analysed for recovery of 1.0 ton sulphur using GaBi software. • Effect of oxygen and air enrichment on emissions trend from SRU is compared. • The oxygen enrichment reduces global warming potential to 16% compared to air enrichment SRU. • The primary climate impact for air enriched SRU is emissions after incineration (125 kg CO 2 -equiv.). [ABSTRACT FROM AUTHOR]

The growing demand of natural gas inspires existing and new projects in topographical areas where the hydrocarbon extraction meets severe safety challenges due to the presence of hydrogen sulfide (H2S) in natural gas, i.e. sour gas. Indeed, the combined effect of flammability and toxicity of such gases has the critical potential to increase the hazard level in the industrial installation, thus aggravating the consequences for human and assets. In this work, a detailed kinetic model was validated and adopted to estimate the laminar burning velocity and the flammability limits of sour gas at different initial temperatures, within the range 250–325 K, equivalence ratio from 0.4 to 2.5, and content of H2S up to 15%v/v with respect to methane. For larger amount of the acid, almost negligible variations of the burning velocity of the mixtures have been observed, even if slight variations are detected either at lean (decrease) or rich (increase) conditions. On the contrary, flammability limits results show also that the addition of H2S has a strong relevance on safety parameters, more specifically for the upper flammability limit. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide is a major contaminant that is expelled into the atmosphere by chemical industry. So, the mechanism for absorption of sulfur from sour gas by carbon nano-tubes in a packed bed under a magnetic field is considered, in this paper. Therefore, empirical and theoretical studies have been done to obtain the sulfur content in the outlet gas stream. The independent variables studied in this paper include: the magnetic field (1.5 amperes), initial sulfur content (0, 0.003, 0.008, 0.013, 0.05 and 0.1 mole/m3) and gas temperature (33°C, 37°C and 40°C). The gas flow rate is (0.18, 0.2 and 0.22 m3/min). The minimum amount of hydrogen sulfide in the output stream is selected as the aim of the experiments and related conditions as optimal operating conditions. Results indicate that the sulfur oxidation curves contains an approximately linearly increasing segment when the applied field intensity increases from 90 to 160 Oe, and that the sulfur oxidation percentage is improved by nearly 5.8% when the magnetic field is increased from 90 to 400 Oe. Obtained results state the optimum flow rate and temperature for maximum desulfurization is 0.22 m3/min and 40°C, respectively. Results show, the increase in the initial concentration under the operating temperature and magnetic field increases the effective mass transfer coefficient from 2.2–8.3. In addition the effective mass flux of hydrogen sulfide removal can be extended to 5.9, in this state. Finally, the experimental results have a fairly good fit with theoretical results. [ABSTRACT FROM AUTHOR]

Abstract The use of non-conventional fuel sources, such as shale gas, brings new research requisites for its proper use in an environmental friendly manner. In this context, shale gas may include different sulphur containing compounds, such as methanethiol, that is also formed as intermediate during sulphur containing residues processing. The present work includes an experimental and kinetic modelling study of the oxidation of methanethiol, CH 3 SH, in a quartz flow tubular reactor at atmospheric pressure and in the 300–1400 K temperature range. The influence of the temperature, the O 2 concentration and the presence of H 2 O on the conversion regime of CH 3 SH and the formation of different compounds has been analysed. The experimental results have been interpreted in terms of a detailed gas-phase mechanism compiled in the present work, and the elementary steps involved in the conversion of CH 3 SH have been identified. In general, oxidation of CH 3 SH is favoured by both oxygen level and temperature, while the presence of H 2 O does not modify the CH 3 SH conversion profile. The main sulphur containing products are SO 2 , H 2 S and CS 2 , pointing to a significant role of other products, apart from SO 2 , for the control of pollutant emissions. [ABSTRACT FROM AUTHOR]

• First-time measurements were taken for CH 4 + H 2 S + N 2 + O 2 S L with varied oxygen ratio. • The S L tendencies against ϕ , x O 2 , x H 2 S were systematically compared and analysed. • The Mulvihill mechanism reproduces well all experimental data, without optimization. • Distinct kinetic features in fuel-rich CH 4 + H 2 S + N 2 + O 2 flames were identified. • Enhanced S formation in rich low- x O 2 flame simulations may help in applications. Sour gas is a special type of natural gas that contains H 2 S and takes a large percentage of present natural gas reserves. Facing the increasing world energy demand, direct combustion of sour gas has been proposed as a potential choice, which requires systematic investigations on the sour gas combustion characteristics. In this work, the laminar burning velocities S L of 85% CH 4 + 15% H 2 S + N 2 + O 2 and CH 4 + N 2 + O 2 flames were measured using the heat flux method at 1 atm and 298 K, where the oxygen ratio x O 2 and equivalence ratio ϕ ranges covered 0.17–0.24 and 0.7–1.4, respectively. Part of the conditions have never been reported before in the literature, and the S L tendencies against all the three dimensions of ϕ , x O 2 , x H 2 S were systematically compared. Simulations using the Mulvihill mechanism were carried out, showing good agreement with all the experimental data measured. By the kinetic analyses including maximum flame temperatures, reaction sensitivities, reaction paths, and maximum mole fractions of key radicals, distinct kinetic features of the fuel-rich CH 4 + H 2 S + N 2 + O 2 flames were found, which are different from the lean and stoichiometric flames. S-containing products in the CH 4 + H 2 S + N 2 + O 2 flames were also discussed using the simulation results. Besides the most dominant SO 2 among all the conditions investigated in the present study, it's noticed that the formation of the element sulfur, especially S 2 , is enhanced at fuel-rich conditions with small x O 2 . This phenomenon can be helpful for the design of real applications as the S 2 particles can be easily condensed and reduce the load of desulfurization. [ABSTRACT FROM AUTHOR]

Accurately predicting the solubility of elemental sulfur in sour gas mixtures is a primary task. As a current and widely-used model on the solubility of elemental sulfur in sour gas mixtures, Chrastil's association model has a big error in the process of predicting experimental data based on different fitting methods. This paper combined with experimental data reported by relevant scholars about elemental sulfur solubility in sour gases and selected density, temperature and pressure as three important influential factors. According to different fitting methods, we can calculate the correlation parameters in Chrastil's model. Then different solubility formulas can be used to predict the solubility of elemental sulfur in sour gas mixtures. Through in-depth research and analysis of Chrastil's solubility model from numerical aspects, it's easy to find the irrationality about Chrastil's solubility model and fitting methods. Especially in fitting methods, further improvement of the fitting method is proposed and used to predict the solubility of elemental sulfur in sour gas mixtures. The calculation results show that some improvements of the predicting precision have been achieved by using the improved fitting method in Chrastil's association model.

The elemental sulfur solubility in sour gas plays an important role in H2S-rich gas reservoir development and transportation. While the solubility of elemental sulfur in sour gas can be measured in macroscopical respect, the interaction of solid deposition is not clear at microscale. In this work, molecular dynamic simulation (MD) was adopted to predict the solubility of elemental sulfur in hydrogen sulfide at nanoscale. It is found that the results of new nanoscale solubility model are close to the reported experimental data. The average relative error of the solubility of elemental sulfur in hydrogen sulfide by using the new model is 11.05% compared with the experimental data. Therefore, the new model can be used to predict the solubility of elemental sulfur in hydrogen sulfide. [ABSTRACT FROM AUTHOR]

In this study, the phase equilibria of semi-clathrate hydrates of methane (CH4), carbon dioxide (CO2), nitrogen (N2), and hydrogen sulfide (H2S) in an aqueous solution of tetra-n-butyl ammonium bromide (TBAB) were modeled using a correlation based on a two-stage formation mechanism: a quasi-chemical reaction that forms basic semi-clathrate hydrates and adsorption of guest molecules in the linked cavities of the basic semi-clathrate hydrate. The adsorption of guest molecules was described by the Langmuir adsorption theory and the fugacity of the gas phase was calculated by Peng–Robinson (PR) equation of state (EOS). The water activity in the presence of TBAB was calculated using a correlation, dependent on temperature, the TBAB mass fraction, and the nature of the guest molecule. These equations were coupled together and form a correlation which was linked to a genetic algorithm for optimization of tuning parameters. The results showed an excellent agreement between model results and experimental data. In addition, an outlier diagnostic was performed for finding any possible doubtful data and assessing the applicability of the model. The results showed that more than 97 % of the data were reliable and they were in the applicability domain of the model. [ABSTRACT FROM AUTHOR]

Abstract The conventional method for gas sweetening is the conversion of hydrogen sulfide to solid sulfur. Although this method has some advantages, researchers are trying to come up with more beneficial technologies. In light of this requirement, a modified experimental method based on the method previously proposed by Yermakova and Mashkina in 2004 is used in the current study. The main idea of this method is modified as the novelty of this investigation which is utilization of mixture of H 2 S, propane and butane, as a sour gas instead of pure hydrogen sulfide. Modified mathematical approach based on the model previously proposed by Yermakova and Mashkina in 2004 is used to convert the hydrogen sulfide to methyl mercaptane. In this way, in the first stage of this study, experimental investigation is performed to investigate the possible effect of three different parameters of molar ratio, mass flow rate and inlet temperature. After that the obtained results are utilized to mathematically model the proposed sweetening method. The overall results demonstrated that although application of H 2 S mixtures leads to lower conversion rate of H 2 S to methyl mercaptane due to lower partial pressure of H 2 S regarding the presence of impurities of propane and butane, the catalytic conversion of H 2 S to valuable chemicals can be an applicable and feasible tool for industrial purposes. Highlights • A rigorous mathematical model is developed. • Two different cases (pure H 2 S and sour gas in the feed stream) are verified and compared. • The effect of other hydrocarbons, such as propane and butane, on the reactions kinetic is investigated. • The accuracy of the model is examined by comparing the results with the experimental data, derived from a pilot scale. [ABSTRACT FROM AUTHOR]

Abstract Hydrogen sulfide (H 2 S) composes up to 30% of certain natural-gas resources ("sour gas") and can considerably alter combustion properties of methane (CH 4), but few data on H 2 S/CH 4 are available in the literature. In this work, new shock-tube and laminar flame speed data were obtained to facilitate future model validation. For the shock-tube experiments, a fuel-lean (φ = 0.5) 30/70 H 2 S/CH 4 blend in 99% argon by volume was shock-heated to temperatures between 1538 and 2144 K and pressures near 1 atm. Laser absorption diagnostics at 4.5 and 1.4 µm were employed to measure CO and H 2 O time-histories, respectively. OH* chemiluminescence profiles were measured using an emission diagnostic at 307 nm. For the laminar flame speed experiments, measurements were carried out in a constant-volume vessel at 295 K and 1 atm for CH 4 /argon and H 2 S/CH 4 /argon (8.25% H 2 S) mixtures from φ = 0.7 to φ = 1.4. The predictions of several recent chemical kinetics mechanisms were compared to the data, leading to the conclusion that species containing both carbon and sulfur are unimportant for shock-tube conditions but can be quite influential for laminar flames. By combining the modeling efforts of two recent works, a tentative new model is proposed that shows marked improvement over the older models in terms of shock-tube ignition delay times. Flame speed predictions show a discrepancy with the new model but follow general experimental trends. To the best of the authors' knowledge, this study provides the first shock-tube data and laminar flame speeds measured in the H 2 S/CH 4 system. [ABSTRACT FROM AUTHOR]

Abstract Oxidation of H 2 S at atmospheric pressure has been studied under different reaction atmospheres, varying the air excess ratio (λ) from reducing (λ = 0.32) to oxidizing conditions (λ = 19.46). The experiments have been carried out in a tubular flow reactor, in the 700-1400 K temperature range. The concentrations of H 2 S, SO 2 and H 2 have been determined and the experimental results have been simulated with a detailed chemical mechanism compiled in the present work. The experimental results obtained indicate that H 2 S consumption is shifted to lower temperatures as the stoichiometry increases, starting at 925 K for reducing conditions and at 700 K for the most oxidizing ones. The model reproduces well, in general, the experimental data from the present work, and those from the literature at high pressures. Supported by theoretical calculations, the isomerization of HSOO to HSO 2 has been determined as an alternative and possible pathway to the final product SO 2 , from the key SH + O 2 reaction. [ABSTRACT FROM AUTHOR]

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Abstract Gas compressibility factor plays a vital role in various engineering applications related to natural gas reservoir management, planning, transportation and processing. Compared to dry gases, gas condensates are thermodynamically complex and require thorough attention. The main challenge is phase segregation and compositional change during temperature variations or pressure depletion. Therefore, this study is focused on proposing novel compositional models based on a Genetic Programming (GP) framework for the accurate calculation of the gas condensate compressibility factor below dew point pressure. The new models are developed based on 1800 gas condensate datasets obtained from open literature. Both qualitative and statistical quantitative assessments were used to compare the precision and accuracy estimation of the new models to existing literature models. Moreover, the proficiency of the proposed models for compressibility factor calculations of gas condensate samples for sweet and sour gas samples was investigated. In addition, a sensitivity analysis based on Spearman and Pearson techniques was performed to carry out the degree of influence of each input parameter on the target value. It is expected that the developed models will pave the way for the accurate calculation of compressibility factors for gas condensates, which can be used by engineers for performance monitoring, optimization and production management in gas condensate systems. Highlights • Genetic framework is employed for developing predictive models to be used in gas condensate simulation softwares. • More than 1800 data series are employed for developing comprehensive models. • Sensitivity of each correlating parameter on the target value is determined. • The prediction results are in close agreement with the target data with R-value > 0.97. • Validity of developed models for sour and sweet condensate gas samples is illustrated. [ABSTRACT FROM AUTHOR]

Hollow fiber membranes were prepared from TEGMC ( T ri E thylene G lycol M onoesterified C rosslinkable) 6FDA-DAM:DABA (3:2) polyimide and shown to retain their stability and permselectivity under aggressive sour gas feed conditions. The H 2 S/CH 4 and CO 2 /CH 4 permselectivities of these cross-linked fibers exceeded those of dense-film membranes, which is attributed to polymer-chain alignment induced during the spinning process. Morover, when the crosslinked fibers were post-treated to deposit a polydimethylsiloxane (PDMS) layer on the skin, high-pressure performance under mixed-gas feeds improved even further. We hypothesize that the PDMS layer healed subtle morphological imperfections in the chain-oriented fiber skin even under challenging feed conditions. The high-performance membranes showed CO 2 /CH 4 and H 2 S/CH 4 permselectivity values as high as 55 and 29, respectively for a 5% H 2 S, 45% CO 2 , and 50% CH 4 feed at 35 °C. An even more aggressive 20% H 2 S, 20% CO 2 , 60% CH 4 mixed gas feed with 500 psig feed pressure was also used and showed CO 2 /CH 4 and H 2 S/CH 4 permselectivity values of 47 and 22, respectively. [ABSTRACT FROM AUTHOR]

Accurate knowledge of the solubility of sulfur in supercritical sour gas is essential in highly effective development of sour gas reservoirs. However, it is well-acknowledged that experimental measurements are expensive, time-consuming and cumbersome especially due to the highly nocuous H 2 S. As a direct consequence, a new meta-heuristic technique namely grey wolf optimizer-based support vector machine (GWO-SVM) was proposed to accurate prediction of the sulfur solubility in supercritical sour gases. The proposed GWO-SVM model considered the reservoir temperature, pressure and the mole fraction of methane, hydrogen sulfide and carbon dioxide as input parameters and the sulfur solubility as target parameter on the basis of grey correlation analysis. The accuracy and reliability of the presented model were evaluated through 170 data sets accessible to the literature and compared with three empirical correlations (Guo-Wang, Hu et al., Chrastil correlation) reported in previous literature. The results showed that the proposed model provides the closest agreement with experimental data with the global average absolute relative deviation of 4.65% and significantly outperforms all the existing methods considered in this work. Additionally, the outlier diagnostics was also operated for detection of the probable doubtful sulfur solubility data and identification of the validity and applicable range of all models considered in this work. [ABSTRACT FROM AUTHOR]

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Highlights • Different solvent alternatives have been studied for gas treating unit in Iran. • That more than 98.85% of total exergy efficiency are achieved using 37–40 wt% of Sulfolane in the Sulfinol-M solvent. • 8–20 wt% lower MDEA consumption for plant using Sulfinol-M process. • Reduction in solvent circulation for new plant with Sulfinol-M process. • 30–42% energy saving for plant using Sulfinol-M process. Abstract A feasibility simulation study evaluates the utilization of the physical–chemical solvent Sulfolane plus Methyl di-ethanol amine (MDEA) plus H 2 O (Sulfinol-M), to replace the aqueous amine solvent (MDEA) currently used in the sour-gas treatment unit of the large-scale Khangiran gas processing plant (Iran). Physical–chemical solvents, such as Sulfinol-M, have the advantages over chemical solvents in that: (1) their absorption of pollutants is not limited by their stoichiometry; (2) they can be easily regenerated by reduction of pressure alone; and, (3) they demonstrate a strong capability to remove sulphur compounds. The simulation and exergy analysis of this gas treatment plant compare the performance of the currently used MDEA solvent with the Sulfinol-M solvent in various concentrations. The influences of different parameters, including inlet solvent temperature, composition and flow rate of solvents on the removal of H 2 S and CO 2 , together with associated exergy and energy losses are evaluated for the MDEA solvent and a range of concentrations of the Sulfinol-M solvent. The simulated exergy analysis demonstrates suitable absorption of acid gases by the Sulfinol-M solvent for less energy and cost than the MDEA solvent. [ABSTRACT FROM AUTHOR]