Search

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many fatal inhalational accidents occurring during construction typically involving confined spaces and structures that confine the atmosphere continue to defy identification. Very little information is available, principally from accident summaries and government reports. Increasingly, these identify CO2 (carbon dioxide) as a probable cause. This article discusses situations identified in accident summaries and worldwide databases. CO2 lacks an odor and other means of identification without the use of monitoring instruments. Emissions typically involve exhaust gases; aerobic and anaerobic respiration in microbiological systems in wastewater and landfills; geological deposits capable of chemical reaction to produce CO2; and unintended discharge from pressurized systems. Emissions can occur continuously or abruptly subject to the type of system and conditions involved. Anaerobic systems that behave as shear-thinning, pseudoplastic, non-Newtonian fluids emit abruptly on the application of a shear force. A lethal concentration can develop almost instantaneously. Upon cessation of the stress, the ambient condition restores rapidly. Chemical and physical processes provide reservoirs for the storage of gas. Very limited methods are available for the prevention of these accidents because of the infrequency and unpredictability of the emission. Preventive measures include mandatory atmospheric monitoring and ventilation at all times, where hazardous conditions can develop, and sometimes the use of high-level respiratory protection.

Many fatal inhalational accidents occurring during construction typically involving confined spaces and structures that confine the atmosphere continue to defy identification. Very little information is available, principally from accident summaries and government reports. Increasingly, these identify CO2 (carbon dioxide) as a probable cause. This article discusses situations identified in accident summaries and worldwide databases. CO2 lacks an odor and other means of identification without the use of monitoring instruments. Emissions typically involve exhaust gases; aerobic and anaerobic respiration in microbiological systems in wastewater and landfills; geological deposits capable of chemical reaction to produce CO2; and unintended discharge from pressurized systems. Emissions can occur continuously or abruptly subject to the type of system and conditions involved. Anaerobic systems that behave as shear-thinning, pseudoplastic, non-Newtonian fluids emit abruptly on the application of a shear force. A lethal concentration can develop almost instantaneously. Upon cessation of the stress, the ambient condition restores rapidly. Chemical and physical processes provide reservoirs for the storage of gas. Very limited methods are available for the prevention of these accidents because of the infrequency and unpredictability of the emission. Preventive measures include mandatory atmospheric monitoring and ventilation at all times, where hazardous conditions can develop, and sometimes the use of high-level respiratory protection. [ABSTRACT FROM AUTHOR]

With the development of global oil and gas industry expands， pipeline steel corrosion in CO2 and H2S environments has become a significant impediment to oil and gas industry growth.The corrosion of pipeline steel is gradually receiving attention from scholars at home and abroad.In this paper， the corrosion behavior and mechanisms of pipeline steels under individual CO2， H2S， and combined CO2-H2S systems were summarized.It was highlighted that the partial pressures ratio of CO2 and H2S influences the extent of pipeline steel corrosion， with recent findings indicating that the critical value of CO2 and H2S partial pressures ratio was temperature-dependent.For the complex environment where CO2 and H2S coexist， this paper mainly introduced the protection technology of corrosion inhibitors and the optimization of corrosion resistant pipes to slow down the corrosion of pipeline steel.Furthermore，the future development direction in CO2 and H2S coexistence systems as well as more economical and effective anti-corrosion measures was prospected.

The risk of corrosion failure of submarine pipeline increases sharply，and it is necessary to study the corrosion behavior and corrosion rate of submarine pipeline.In this work，18 groups of six factors and three-level orthogonal experiments were carried out for the submarine pipelines commonly used steel X65 steel in high temperature and high pressure reactors.The synergistic corrosion behavior of X65 steel by CO2，H2S，pH value，Cl-，temperatures and flow rates was studied，and the main controlling factors for corrosion were determined as CO2partial pressure ＞H2S partial pressure ＞Cl-concentration ＞pH value ＞flow rate ＞temperature.From the results of scanning electron microscope，the synergistic corrosion behavior of H2S，CO2and Cl-was clarified: CO2formed dense FeCO3，which was located at the bottom of the corrosion product film，and the surface was Fe sulfide.Moreover，Cl-passed through the corrosion product film to promote the occurrence of corrosion.Finally，based on the orthogonal experimental data，a six-factor corrosion rate prediction model was established，and the prediction model error was less than 20%.

Understanding the reduction of CO2 and the origin and evolution of early life on Earth is an important research endeavor. Pyrite, due to its semiconductor properties, is believed to play a pivotal role as a reactant or catalyst in converting reducing gases, such as CO2, into organic matter. In this study, we employed density functional theory (DFT) to investigate the reduction of CO2 in the presence of H2S on the surface of pyrite. Our findings reveal that the presence of sulfur vacancies enhances the adsorption of H2S and CO2 molecules onto the pyrite surface. Interestingly, we observed the generation of the HCOOH molecule on the defective pyrite surface. Additionally, the transition state analysis indicates that H2S and CO2 molecules require the overcoming of an energy barrier (Ea) of 36.93 kJ/mol to form the HCOOH molecule. This study sheds light on the role of pyrite in the early creation of life on Earth by elucidating its impact on the reduction of carbon dioxide. [ABSTRACT FROM AUTHOR]

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Separation of the acid gases and reducing their amount from natural gas is very important in the gas purification industries. In this study, the solubility of natural gas (a mixture of CO2, H2S, CH4, C2H6, etc.) was experimentally measured in three different ionic liquids: 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([Hmim] [Tf2N]), 1-hexyl-3-methylimidazolium nitrate ([Hmim][NO3]) and 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]). The experimental solubility data was obtained for the temperatures of 298.15 K, 318.15 K, and 338.15 K in pressure range up to 40bar. Selectivity of CO2/CH4, CO2/H2S and H2S/CH4 in the studied ionic liquids was also reported in this work. [Bmim] [Ac] showed the best performance of absorbing CO2 and H2S compared to other ionic liquids. However, [Hmim][Tf2N] showed higher selectivity for CO2 over CH4 in comparison with [Hmim][NO3] and [Bmim][Ac]. Finally, the sPC-SAFT equation of state was successfully used to predict the natural gas solubility in ionic liquids. The results show that the model predictions are consistent with experimental data. [ABSTRACT FROM AUTHOR]

To understand the corrosion environment of a set cement at high temperature, high pressure and high H2S/CO2 conditions and the complex work condition thus formed, a series of experiments were conducted to study the property change and short-term corrosion mechanisms of elastic tough cement slurries under the “three-high” conditions. A class G cement slurry was treated with three main elastic tough additives commonly used, i.e., rubber powder at 10%, basalt fiber at 0.3% and styrene-butadiene latex at 10%. The cement slurry thus formulated was rendered elasticity to some extent. Using several methods such as mechanical property measurement, XRD, FTIR, MIP and SEM-EDS etc., changes were studied in the mechanical properties, distribution of pore throat sizes, types of hydration products and micro-structures before and after the cement slurry was treated with the three additives and was cured under corrosion conditions. The measurement results show that the addition of the three elastic tough additives is beneficial to the decrease of the brittleness and to the increase of the toughness of the set cement. Among these additives, the basalt fiber is the best additive for controlling the fracture development in the set cement when it fails, and the styrene-butadiene latex is the best additive for reducing the elastic modulus and maintaining a high flexural strength of the set cement. After undergoing a short-term corrosion in liquid environment, the mechanical strengths of the cement samples were all improved, especially the set cement containing basalt fiber and styrene-butadiene latex. Basalt fiber under the corrosion conditions showed stable properties, the dense calcium carbonate crystals produced in the corrosion process were piled in the pores located at the interfaces between the basalt fiber and the cement matrix, leading to a decrease in the total pore volume in the corroded set cement and a substantial increase in the mechanical strength of the set cement. The styrene-butadiene latex can form a polymer membrane inside the set cement, which covers and wraps up the cement matrix, thereby improving the anti-corrosion property of the cement surfaces. [ABSTRACT FROM AUTHOR]

This research output is focused on the modified design of a low-cost biodigester using a 295L of steel drum. The system has a 15kg bio-methane storage tank of 182L with a water displacement tank of 20L standard steel drum. Incorporated into the design is a cast iron with centrally positioned four impeller shaft to enhance mixing of substrate. A floating storage tank was designed, fabricated, and used for effective storage of bio-methane; biogas was produced from mixture of cowdungs, which was filtered to remove substituent of biogas. The retention time was for 4 weeks during which the pH valve and temperature variation were noted. Maximum biogas production was attained on the 8th, 9th, and 19th day, and the total volume of gas produced ranges between 92.6 and 102 mL/day. The test result showed that methane gas produced the highest percentage of biogas. Additionally, from the result, the displacement of ethane, ethylene, propane, propylene, I-butane, nitrogen, carbon monoxide, carbondioxide and other gases were minimal compared to methane gas. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Eastern Carpathians host CO2-rich, low temperature, dry gas vents, bubbling pools and wells/drillings, which were established for the extraction of mineral water and CO2 for the bottling industry. These wells can provide important information on the structure of the geological deposits, the depths, and the source of the gases, because they are often located at important geologic/tectonic sites. Our aim was to test the applicability of a hand-made and low-cost tool in preselected wells/drillings, in order to measure the concentration of different gas species. This was challenging due to the high water and gas discharge of the wells, and their intermittent behavior. The method made possible the separation of gas and water phase, the extraction of gas, and the measurement combined with a Multi-GAS portable device. The hand-made barrel technique, and the closed cell for gas and water phase separation, proved to be a suitable and cheap tool to gain information about the CO2, CH4, and H2S concentration of the gases derived from the wells/drillings. [ABSTRACT FROM AUTHOR]

• A review from the thermodynamic and kinetic aspects for CH 4 -H 2 S reforming and CO 2 -H 2 S reaction. • Current technological methods used in CO 2 -H 2 S reaction to H 2 are reviewed. • Advancements in catalyst research for CH 4 -H 2 S reforming are summarized. • A summary of dry reforming of CH 4 reaction from a thermodynamic viewpoint. • Research progress on catalysts for dry reforming of CH 4 reaction is reviewed. H 2 is widely acknowledged as an essential renewable energy source. Approximately 96 % of the global H 2 is derived from fossil resources namely petroleum, natural gas, and coal, with natural gas producing H 2 at a significantly lower cost. When natural gas is processed and used, it often produces acid gases like H 2 S and CO 2. Current acid gases treatment technologies predominantly recover sulfur from H 2 S using the Claus process without treating CO 2 , leading to wastage of H 2 resources and substantial carbon emissions. In light of this, there is an attractive prospect in directly utilizing acid gases (H 2 S, CO 2 , CH 4 , etc.) for multi-component synergistic conversion. The approach not only facilitates the harmless treatment of H 2 S and CO 2 but also sustainably generates H 2. There are now a number of potential techniques for directly converting acid gases into H 2 , such as dry reforming of methane (DRM), reforming CH 4 with H 2 S, H 2 S pyrolysis, and CO 2 -H 2 S reaction. However, comprehensive reviews on these topics are still lacking. This paper provides a comprehensive review of the research progress in the synergistic conversion of CO 2 -H 2 S, reforming CH 4 with H 2 S, H 2 S pyrolysis, and DRM. It discusses in detail the thermodynamics, kinetics, and catalyst design of these reactions. Finally, the prospects and challenges for the application of the technical methods and catalysts for these three reactions are outlined. [ABSTRACT FROM AUTHOR]

X65 carbon steel is widely used in subsea gathering and transportation pipelines. In the gathering and transportation process, the natural gas medium is complex and often contains corrosive gases such as H2S and CO2. Due to the use of wet gas transportation, condensate water was formed, resulting in serious corrosion perforation accidents of pipelines. In this work, through the experiments of high - temperature and high - pressure reactor, the corrosion mechanism of gas phase, liquid phase and gas - liquid interface were analyzed, which provided a basis for the formulation of corrosion prevention and control measures for X65 steel wet gas gathering and transmission pipeline. Moreover, high - temperature and high - pressure reactor experiments were carried out with X65 steel in the presence of CO2, H2S and Cl - respectively. Each experiment was carried out for 7 d for gas - liquid interface corrosion, and the characteristics of corrosion products were analyzed by surface analysis technologies, such as scanning electron microscope (SEM) and X - ray diffraction (XRD). Results showed that with the injection of CO2 and H2S, the local corrosion rate increased in three regions of gas phase, liquid phase, and gas - liquid interface. In the presence of CO2 and H2S, the order of corrosion rate was liquid phase corrosion rate > gas phase corrosion rate > interface corrosion rate. Under the condition of gas - liquid interface, X65 steel formed anode below the interface and cathode above the interface, so that the local corrosion rate of liquid phase was faster.

The purpose of the present work is to investigate the corrosion sensitivity of pipelines of oil and gas wells under complex environmental conditions (i.e., the primary and secondary relationship of the influence of different environmental factors on pipeline corrosion). The orthogonal experiment is introduced to design the experimental scheme. The weight loss method is employed to analyze the average corrosion rate of N80 steel under different environmental conditions. And then the scanning electron microscope is used to explore the surface and cross-section corrosion morphology of the corrosion products. Besides, the components of corrosion products are obtained by the energy spectrum analysis. The research results indicate that H2S partial pressure is the most sensitive factor to the corrosion of N80 pipeline and the influence of CO2 partial pressure on corrosion of N80 pipeline is weaker than Cl− concentration and temperature in the South China Sea. The study can help the oil drilling engineering search for direct and effective corrosion inhibitors under complex environmental conditions. [ABSTRACT FROM AUTHOR]

A simulation study and a series of autoclave experiments were performed, reproducing gas-rock-water systems under reservoir conditions, after injection of CO 2 and the mixture of CO 2 with H 2 S into rocks representing the Upper Silesian Coal Basin and the adjacent Małopolska Block (Central Europe). The water-rock-gas interactions were modeled in two stages: the first–aimed at simulating the short-term changes in system impacted by the gas injection, and the second–long-term effects of sequestration. On the basis of the simulations, the reactions behind mineral transformations were identified. These phenomena are different for the injection of CO 2 alone. and CO 2 +H 2 S mixtures, resulting in the formation of secondary minerals responsible for mineral sequestration. Depending on the original mineral composition of the rock, in the case of pure CO 2 , these are mainly carbonate minerals siderite, dawsonite, magnesite, dolomite and calcite, while in the case of mixture injection: elemental sulfur, sulfur sulfides–pyrite and pyrrhotite. In experiments with the H 2 S+CO 2 mixture, dissolution of skeletal grains was observed, which was most visible in the case of carbonates, feldspars, and chlorites. The analysis of rocks containing hematite revealed the formation of elemental sulfur surrounded by FeS 2 crystals, which had not been previously reported. The experiments generally confirmed the interactions in gas-rock-water systems identified by numerical simulation. This allowed to estimate the amount of mineral phases precipitated or dissolved in the analyzed reactions, and consequently the impact on changes in porosity and the amount of sequestered carbon dioxide and sulfur. In samples abundant in carbonate minerals (the Dębowiec Formation psephites), the decomposition of ankerite, due to the injection of CO 2 +H 2 S, is not compensated for by the precipitation of sufficient amounts of other carbonates, which leads to the desequestration process–CO 2 release. Based on the calculations, it was found that the potentially most favorable conditions for the sequestration occur in the Paralic Series mudstones, rich in chlorites–a maximum of 22.36 kg CO 2 /m3 and 12.50 kg S/m3, trapping capacity after 10,000 years of storage. • Experiments and modeling reproduced effects of CO 2 +H 2 S injection into reservoir rock. • Chlorites promote porosity increase and CO 2 trapping in magnesite. • Ankerite decomposition not balanced by carbonates precipitation leads to CO 2 release. • Rhombic sulfur as H 2 S-rock interaction product was identified after experiment. • Storage trapping capacity reached 22.36 kg CO 2 /m3 and 12.50 kg S/m3 in 10000 years. [ABSTRACT FROM AUTHOR]

The corrosion behaviour of a new titanium-based alloy, with nickel, molybdenum and zirconium as the main alloying elements, was studied in a simulated geothermal environment at various phase conditions of a corrosive fluid. Corrosion testing of carbon steel was also conducted for comparison. Both materials were tested at an elevated temperature between 180 and 350 °C and at a 10 bar gauge pressure in H2O containing HCl, H2S, and CO2 gases with an acidic condensate of pH = 3. The study found that the titanium alloy demonstrated good corrosion resistance in a single- and multiphase geothermal environment. In the testing volume, where the boiling of testing fluid occurred, the carbon steel was prone to localized damage of oxide, sulphide and chloride corrosion products. In the superheated testing volume, a homogeneous oxide corrosion layer was observed on the carbon steel. In the testing volume where condensation of the testing fluid occurred, a sulphide layer with an oxide sublayer was formed on the carbon steel.

As an important infrastructure for offshore petroleum development, submarine pipelines are the lifeline of offshore petroleum resources development. However, the medium flow containing H25 and (02 threatens the normal production of oil fields. Based on 18 groups of orthogonal experiments, considering COZ partial pressure, H2S partial pressure, temperature, pH, chloride concentration and liquid flow late, the general and local corrosion rate were obtained. The corrosion products were characterized with SEM/EDS and XRD. The main controlling factors and corrosion mechanism were explored. Under the experimental conditions, (02 and H25 were the main controlling factors of general and local corrosion. With the increase of gas partial pressure, the corrosion rate increaseed gradually. Flow accelerated the synergistic corrosion mechanism and model were established. Within the working condition range, the prediction error was less than 20%, which was better than ECE prediction model. The results can improve the integrity management of submarine pipelines. [ABSTRACT FROM AUTHOR]

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

Aquivion® E87-12S Perfluorosulfonated acid ionomer material (PFSA) has been studied as a membrane technology for natural gas sweetening from CO2, H2S due to its interesting chemical and mechanical stability and good separation performance for polar compounds in humid environments. In the present work, permeation of the H2S/CO2/CH4 ternary mixture in this short-side PFSA chain was investigated at pressures up to 10 bar, temperatures up to 50 °C, and in a range of relative humidity (RH) from 20% to 90%. The results obtained confirm the strong dependence of Aquivion® on water activity and temperature, and its ability to separate gases based on their water solubility without substantial differences between pure and mixed gas experiments. Indeed, even when tested in ternary mixture, the permeation behavior remains similar to that observed for pure components and binary mixtures. In particular, the permeability of H2S is higher than that of CO2 and methane CH4, reaching values of 500 Barrer at 50 °C and 80% RH, against 450 and 23 Barrer for the other two gases respectively. Additionally, when tested at higher pressures of up to 10 bar under humid conditions, the membrane properties remained largely unchanged, thus confirming the overall stability and durability of Aquivion® E87-12S in acid environments.

The effect of stress on the crevice corrosion of P110 carbon steel in the CO2-saturated 3.5 wt-% NaCl solution with a small amount of thiosulphate/H2S was investigated. The results showed that the composition of corrosion products on the steel surface did not change with elastic stress while the mackinawite film formed at the crevice mouth was more easily spalled off under higher stresses. Further, the elastic stress likely promoted localised corrosion but inhibited uniform corrosion both inside and outside crevice. Increasing the applied stress led to a deeper and sharper corrosion groove covering with corrosion products at the crevice mouth, suggesting the crevice corrosion was promoted by the applied stress. This is likely due to the peeling of mackinawite film and stress concentration at the crevice mouth. [ABSTRACT FROM AUTHOR]

By referring to the fact that corrosion rates alter upon variation of different conditions and no research relevant to Lebanon address corrosion issues yet, this study was conducted based on accurate Lebanese offshore data and water composition. Based on "Alloy Select Software", identifying the most suitable material from different alloys was revealed, which turned out to be Copper and Aluminum based alloys. Moreover, corrosion rates were detected under different conditions of Temperature, CO2, and H2S and then repeated in the presence of a corrosion inhibitor. Results of these studies proved the significant influence of high temperature accompanied with high CO2 percentage. However, different results concerning low temperature with different percentages of H2S were obtained. [ABSTRACT FROM AUTHOR]

The adsorption of CO2 and H2S gas molecules on pristine and defected ZnO nanotubes (ZnO-NTs) is theoretically investigated using the density-functional theory (DFT). The interactions of each molecule with various sites on the pristine and defected ZnO-NT, with oxygen vacancy “VO” and zinc vacancy “VZn” are put under scope. The results show that both pristine and defected graphene with VO cannot capture these two molecules and yield physisorption processes. Amazingly, the zinc-vacancy can strongly bind to these two molecules and yields chemisorption processes. Although the capture of CO2 on VZn is not associated with dissociation, it causes a large effect on the electronic structure in turning the characteristics into metallic as well as it induces a magnetic moment into the defect site. On the other hand, the chemisorption of H2S is associated with a molecular dissociation (H2S → H + HS), in which H-atom binds to the dangling bonds of oxygen from within the defect vicinity while HS molecule exhibits a physisorption. The molecule of CO2 is oxidizing to VZn while the molecule H2S is reducing to VZn with enormous charge transfer occurring between molecule and defect due to the large binding energy. For sake of selectivity, many other molecules were tested for adsorption on VZn and we concluded that VZn persists to yield selective adsorption to only CO2 and H2S molecules.

Increasing discharge of sewage sludge is a threat to the ecological environment, and sludge treatment via combustion is the most feasible alternative. However, the low calorific value and high‐water content of raw sludge results in poor firing performance and increases the risk of environmental pollution. Recently, co‐combustion has emerged as a more environment‐friendly technology. Herein, the combustion behaviours of sewage sludge, corn stalk and their mixture at four heating rates were studied via thermogravimetric experiments. Results yielded the division of weight loss into three stages for corn stalk: dehydration, combustion of volatiles and combustion of fixed carbon; four stages were identified for sewage sludge and the mixture of sludge and stalk: dehydration, combustion of volatiles, combustion of fixed carbon and thermal decomposition of a small amount of minerals. Synergistic analyses found that with a 60% blending ratio of sewage sludge, interaction between the components in the high‐temperature range was greatly promoted. Gas emission characteristics showed that CO2 was the main product during (co‐)combustion, while the NOx emissions at low (or high) temperatures for the blend were higher (or lower) than the theoretical values. Temperature had little effect on H2S emissions, though it significantly affected SO2 emissions during co‐combustion. [ABSTRACT FROM AUTHOR]

• CO 2 and H 2 S continue to be injected into subsurface basalts after 3 years. • Over 60% of the injected CO 2 is still mineralized within 4 months of injection. • Over 85% of the injected H 2 S is still mineralized within 4 months of injection. • Increased greenhouse gas injection rates accelerated mineralization rates. The CarbFix method was upscaled at the Hellisheiði geothermal power plant to inject and mineralize the plant's CO 2 and H 2 S emissions in June 2014. This approach first captures the gases by their dissolution in water, and the resulting gas-charged water is injected into subsurface basalts. The dissolved CO 2 and H 2 S then react with the basaltic rocks liberating divalent cations, Ca2+, Mg2+, and Fe2+, increasing the fluid pH, and precipitating stable carbonate and sulfide minerals. By the end of 2017, 23,200 metric tons of CO 2 and 11,800 metric tons of H 2 S had been injected to a depth of 750 m into fractured, hydrothermally altered basalts at >250 °C. The in situ fluid composition, as well as saturation indices and predominance diagrams of relevant secondary minerals at the injection and monitoring wells, indicate that sulfide precipitation is not limited by the availability of Fe or by the consumption of Fe by other secondary minerals; Ca release from the reservoir rocks to the fluid phase, however, is potentially the limiting factor for calcite precipitation, although dolomite and thus aqueous Mg may also play a role in the mineralization of the injected carbon. During the first phase of the CarbFix2 injection (June 2014 to July 2016) over 50% of injected carbon and 76% of sulfur mineralized within four to nine months, but these percentages increased four months after the amount of injected gas was doubled during the second phase of CarbFix2 (July 2016 – December 2017) at over 60% of carbon and over 85% of sulfur. The doubling of the gas injection rate decreased the pH of the injection water liberating more cations for gas mineralization. Notably, the injectivity of the injection well has remained stable throughout the study period confirming that the host rock permeability has been essentially unaffected by 3.5 years of mineralization reactions. Lastly, although the mineralization reactions are accelerated by the high temperatures (>250 °C), this is the upper temperature limit for carbon storage via the mineral carbonation of basalts as higher temperatures leads to potential decarbonation reactions. [ABSTRACT FROM AUTHOR]

In the process of natural gas quality detection, the detection is mainly carried out according to the four indexes of calorific value, content of CO2, H2S and total sulfur, as well as water dew point specified in GB 17820 - 2018 Natural Gas. The detection of H2S and water dew point is completed by the analyst on site, while the detection of calorific value, content of CO2 and total sulfur needs to be obtained by on-site sampling, sample transportation and laboratory analysis. The completion of a single sample analysis cycle is long and the economic cost is higher. For this reason, a new type of mobile detection system for natural gas quality has been developed. At the same time, a sample processing system, an anti-vibration system and a data processing system have been designed, which can realize the on-site rapid detection, data processing and report generation of five indicators. The successful application in a natural gas purification plant (Plant A) and a gas transmission station (Station B) shows that the mobile detection system of natural gas quality can be applied to the on-site fast detection of four indicators and water dew point specified in GB 17820 - 2018 after the long-distance move and under the complex working condition. [ABSTRACT FROM AUTHOR]

The effect of thiosulphate/H2S on crevice corrosion behaviour of P110 carbon steel in the CO2-saturated 3.5 wt% NaCl solution was investigated. The results showed that crevice corrosion of P110 steel could not occur in the CO2-saturated solution, likely due to the inhibition of both anodic and cathodic reactions inside crevice. Further, the structure of corrosion product film along the crevice wall is influenced by the concentration of thiosulphate. Increasing the concentration of thiosulphate to 10−2 mol L−1 promotes the formation of fine flake-like mackinawite outside crevice. In addition, crevice corrosion of P110 steel in the CO2-saturated solution is promoted by increasing the concentration of thiosulphate. This is because the dense and fine mackinawite film on the steel surface has a better protectiveness and could enhance cathodic reaction rate outside crevice. [ABSTRACT FROM AUTHOR]

• Highly selective production of syngas from H 2 S–CO 2 was achieved by non-thermal plasma-MoS 2 /Al 2 O 3. • H 2 /CO molar ratio in gaseous product can be controllably adjusted on a large scale. • A synergy of non-thermal plasma and MoS 2 /Al 2 O 3 led to the improved behavior in energy efficiency. • The reaction performance of MoS 2 /Al 2 O 3 was stable in the 50-h-long runs. The highly selective conversion of H 2 S–CO 2 to syngas (a mixture of H 2 and CO), which assisted by non-thermal plasma and MoS 2 /Al 2 O 3 hybrid system, was obtained at low temperature and atmospheric pressure. The effects of reaction conditions, including the specific energy input (SEI), feed flow rate, feed gas composition (H 2 S/CO 2 molar ratio), and MoS 2 loading were carefully investigated. The 50-h-long runs indicate that MoS 2 /Al 2 O 3 was stable in the course of simultaneous H 2 S–CO 2 conversion into syngas with excellent reaction properties. High CO 2 conversion (>60 %) and almost full H 2 S conversion (98–100 %) can be achieved. The non-thermal plasma combined with MoS 2 /Al 2 O 3 offers a novel and energy-efficient strategy to produce syngas from concomitant H 2 S–CO 2 acid gases with great value for detoxifying H 2 S and reducing CO 2 emissions. [ABSTRACT FROM AUTHOR]

• Ultramicropores exert a strong influence on the adsorption capacity of the materials. • A method to block ultramicropores has been proposed based on molecular simulation. • The ultramicropore blockage causes a drastic drop in H 2 S retention. • The ultramicropore blockage affects not only physisorption, but also chemisorption. • Ultramicropores immobilize and then redistribute molecules to the pore network. The pore distribution in activated carbon is crucial for its performance on adsorption processes. In desulfurization applications, the literature highlights the importance of pores from 5 to 10 Å. However, little is known and reported about the range of ultramicropores smaller than 4 Å, which has been found in commercial samples used for H 2 S retention. In order to clarify the influence of this fraction of pores on the H 2 S retention of typical biogas mixtures, measurements of multicomponent adsorption of hydrogen sulfide in the presence of carbon dioxide for activated carbon samples further impregnated with potassium hydroxide have been performed in column dynamics. Molecular simulation, XRF analysis and textural characterization were applied to aid the study. Results have shown that the H 2 S retention capacity in the presence of CO 2 decreased significantly mainly in the impregnated samples. The degree of reduction in H 2 S retention indicates that ultramicropores can be of substantial importance through a synergistic immobilizing effect of H 2 S molecules. The better understanding of such an effect could improve the development of more efficient adsorbents for chemical industries. [ABSTRACT FROM AUTHOR]

The current study aims to provide a thorough understanding of the separation performance of the cellulose triacetate (CTA) membrane material in humid high H 2 S natural gas feed streams. A systematic study of the gas separation performances of CTA polymers has been carried out in self-standing symmetric films and asymmetric hollow fiber membranes. The separation performance in H 2 S-containing mixtures (CH 4 /CO 2 /H 2 S, 80/5/15 mol%) were evaluated at 30 and 50 °C at 20, 35 and 50 bar, including higher hydrocarbons (butane and toluene) in the presence of various levels of humidity, up to 4500 ppm or 80 % RH, depending on conditions of temperature and pressure. For the first time, the effect of these contaminants and humidity together under sour gas conditions has demonstrated the promising stability of CTA membrane separation performance, both in terms of H 2 S permeability and H 2 S/CH 4 selectivity. The improvement in H 2 S permeability is due to a combination of H 2 S plasticization and competitive sorption making this phenomenon even more attractive and worth studying further. Separation performance of cellulose triacetate dense film membrane in the presence of 15 % H 2 S containing gas mixtures with various levels of humidity at 20 bar and 30 °C: After baseline, first 15 % H 2 S, 5 % CO 2 and bal. CH 4 is introduced in the red region, followed by 15 % H 2 S, 5 % CO 2 , 3 % N-Butane, 300 ppm toluene and bal. CH 4 is switched in the orange region. Subsequently, the 15 % H2S and butane/toluene gas mixture with various levels of humidity is present in the blue region. Systematically, the reverse order of gas mixtures trend is also demonstrated for membrane robustness. [Display omitted] • Effect of sour gas with aggressive humidity levels on cellulose triacetate (CTA) membranes is systemically studied. • H 2 S separation benefits from high moisture content - encouraging H 2 S permeability and H 2 S/CH 4 selectivity is observed. • Combination of H 2 S induced plasticization and hydrophilic nature of CTA membranes enables increased mobility of H 2 S molecules. • Significant competitive sorption between gas molecules helps in preserving or slightly increasing the gas-pair selectivity's. [ABSTRACT FROM AUTHOR]

Acid gas enrichment (AGE) is a new method to increase the H 2 S conversion in conventional Clause process. In this paper effect of methyl diethanolamine (MDEA) flow rate, MDEA temperature, acid gas flow rate, and AGE tower pressure on the outlet H 2 S and CO 2 concentration and energy consumption have been studied. A novel procedure based on enthalpy of combustion in the reaction furnace and incinerator is conducted for energy consumption calculations. By changing MDEA and inlet acid gas flow rates, a maximum H 2 S concentration in the enriched stream could be attainable. Increasing MDEA temperature will decrease maximum H 2 S concentration and enriched acid flow rate; also, CO 2 concentration in off-gas will be decreased. By increasing AGE pressure, maximum H 2 S concentration in the enriched stream will be diminished. At higher MDEA flow rates, lower AGE pressures will bring higher H 2 S concentration in enriched acid gas stream. According to flame temperature simulation in the reaction furnace, energy consumption is directly related to H 2 S concentration in the sulfur recovery unit (SRU) feed stream. Results show that maximum H 2 S concentration in the enriched acid gas stream has the best conditions from energy point of view. At optimum conditions, H 2 S concentration in enriched acid gas is 62.45 mol%, which has been increased by 24.8%, compared with existing plant conditions, and energy consumption has been decreased by 25.05 GJ/h, and CO 2 concentration in off-gas is 94.94 mol%. • Study the effect of process variables on the AGE streams by ProTreat software. • Determine the relation between reaction furnace temperature and H 2 S concentration. • Generate an EES procedure for heat of combustion in reaction furnace. • Evaluate the fuel gas consumption and therefore energy consumption. • Multi-objective optimization based on the TOPSIS method. [ABSTRACT FROM AUTHOR]

Mineral waters from Ciucului Mountains are in a small number and sporadically distributed along the river valleys. In order to fill the lack in the bibliography of mineral waters described as sulfurous springs from Ciucului Mountains we gathered geographical and chemical information about the springs from upper Trotuș river basin by researching these sources. Eight water samples were analyzed in november, 2016. Springs located on our study area generally have low mineral content indicating their meteoric origin from shallow depths . On the western part of the study area springs have dissolved carbon dioxide, while in the center part they can be considered sulfurous. The majority of the spring waters are calcium-hydrogen carbonate type.

Ambient air quality in livestock buildings is one of the most important factors affecting environmental pollution and global warming. Carbon dioxide (CO2), methane (CH4), ammonia (NH3) and hydrogen sulphide (H2S) are among the most hazardous gases in terms of human and animal health. The aim of this study was to determine the effect of hourly, daily and seasonal variations in the levels of hazardous gases, such as CO2, CH4, NH3 and H2S in a solid-floor confinement sheep barn; as well as the effect of climatic parameters, temperature (T), relative humidity (RH) and air flow (AF) on animal welfare. The correlation between hazardous gases and climatic factors in the barn was also determined. The study was carried out on a sheep farm between July 2012 and June 2013 in Konya (Turkey) where few data are currently available on this subject. Climatic data were measured at intervals of five minutes at different points during this study, while hazardous gases were measured at the same intervals during the experimental periods (10 days for each season). All data were analysed by one-way analysis of variance (ANOVA) and Tukey's method was used to reveal intergroup differences. Cross-bilateral correlation between all data and different time periods was examined. There were significant differences between hourly and daily mean values of CO2, NH3, T, RH and AF. CO2 and NH3 levels showed a significant correlation with T and RH. Unfortunately, H2S and CH4 were below the level of detection in the study. Reducing the formation of these harmful gases, which have negative effects on animal production and cause environmental pollution, will be carried out with new sheep barn designs that take into account ambient air quality appropriate for animal welfare. [ABSTRACT FROM AUTHOR]

Abstract Simultaneously capture of CO 2 and H 2 S is vital for obtaining clean fuels from fossil fuels. This work proposes the hydrate formation process for simultaneously capture of CO 2 and H 2 S from simulated syngas with new synergic additives. The synergic additives comprises acidic gas solvent (tetramethylene sulfone (TMS)) and traditional hydrate promoter (tetra-n-butyl ammonium bromide (TBAB)). The effect of the synergic additives was evaluated based on kinetic curves, separation efficiency and gas selectivity. The results show that, with the help of the synergic additives, both CO 2 or H 2 S could be simultaneously captured from the simulated syngas by the hydrate formation process. Furthermore, the synergic additives could not remarkably accelerate the formation rate and improve the gas storage capacity for the simulated syngas hydrate, but also enhance the selectivity of CO 2 or H 2 S in the hydrate process. [ABSTRACT FROM AUTHOR]

In intelligent agriculture, the development of gas sensing technology has practical significance. In a bid to achieve fast, accurate and effective detection of noxious gases NH 3 , H 2 S and CO 2 from breeding farms, Ti 3 C 2 O 2 , an excellent gas sensing material in the MXene family, was investigated by means of density functional theory (DFT) calculations. The optimal configuration of Pt atomic catalyst doped Ti 3 C 2 O 2 sheet was obtained via the analysis of binding energy (−1.796 eV) and charge transfer (0.373 e). The adsorption energy, charge transfer, deformation charge density (DCD), density of states (DOS), average electrostatic potential, and work function of NH 3 , H 2 S and CO 2 adsorbed on Ti 3 C 2 O 2 and Pt-Ti 3 C 2 O 2 sheet were further scrutinized. From comparative analysis against Ti 3 C 2 O 2 , Pt-Ti 3 C 2 O 2 possesses excellent adsorption capacity, electron density rearrangement and electrostatic binding ability for the adsorption of NH 3 , H 2 S and CO 2 , among which the adsorption energy for NH 3 is the largest (−2.593 eV). The results verify that Pt-Ti 3 C 2 O 2 is a potential material for gas sensors, providing guidance for expanding the gas sensing application of MXene materials. [Display omitted] • The most stable structure of the Pt doped Ti 3 C 2 O 2 sheet was firstly constructed via DFT. • The Ti 3 C 2 O 2 sheet is not suitable for the NH 3 , H 2 S and CO 2 gas sensor material. • The Pt-Ti 3 C 2 O 2 sheet can be exploited as a potential NH 3 H 2 S and CO 2 gas sensing material. [ABSTRACT FROM AUTHOR]

Energy supply is a crucial issue in the world in the last few years. The increase in energy demand caused by population growth and resource depletion of world oil reserves provides determination to produce and to use renewable energies. One of the them is biogas. However, until now the use of biogas has not yet been maximized because of its poor purity. According to the above problem, the research has been carried out using the method of water absorption. Under this method it is expected that the rural community is able to apply it. Therefore, their economy and productivity can be increased. This study includes variations of absorbing water volume (V) and input biogas volume flow rate (Q). Raw biogas which is flowed into the absorbent will be analyzed according to the determined absorbing water volume and input biogas volume rate. Improvement on biogas composition through the biogas purification method was obtained. The level of CO2 and H2S was reduced significantly specifically in the early minutes of purification process. On the other hand, the level of CH4 was increased improving the quality of raw biogas. However, by the time of biogas purification the composition of purified biogas was nearly similar to the raw biogas. The main reason for this result was an increasing in pH of absorbent. It was shown that higher water volume and slower biogas volume rate obtained better results in reducing the CO2 and H2S and increasing CH4 compared to those of lower water volume and higher biogas volume rate respectively. The purification method has a good promising in improving the quality of raw biogas and has advantages as it is cheap and easy to be operated.

Graphical abstract Abstract Monocomponent adsorption of hydrogen sulfide and multicomponent adsorption with CO 2 and CH 4 mixtures were predicted in two samples of commercial activated carbons. We perform Monte Carlo calculations in the grand canonical ensemble in representative slit-pores of each carbon material and proposed a new energy parameter for H 2 S-carbon interaction from experimental adsorption heat in selected activated carbons. Further analysis of adsorption in representative pores demonstrated the importance of ultramicropores in H2S retention and a cooperative effect of CO 2 molecules favoring H 2 S adsorption. To the best of our knowledge this is the first time that a method based on molecular simulation is proposed to predict H 2 S adsorption on carbon. This study contributes to a better understanding of the role of pore size distribution and adsorption regimes in carbon materials. [ABSTRACT FROM AUTHOR]

Highlights • Results from injection of CO 2 -H 2 S gas mixture at the CarbFix2 site, SW-Iceland. • Soluble gas mixture was captured in water and injected into hot basaltic reservoir. • The injected CO 2 and H 2 S was mineralized within months providing safe and long term storage of the gases. • The cost of the integrated method is US $25/ton of the gas mixture at the CarbFix2 site. Abstract One of the main challenges of worldwide carbon capture and storage (CCS) efforts is its cost. As much as 90% of this cost stems from the capture of pure or nearly pure CO 2 from exhaust streams. This cost can be lowered by capturing gas mixtures rather than pure CO 2. Here we present a novel integrated carbon capture and storage technology, installed at the CarbFix2 storage site at Hellisheiði, Iceland that lowers considerably the cost and energy required at this site. The CarbFix2 site, located in deeper and hotter rocks than the original CarbFix site, permits the continuous injection of larger quantities of CO 2 and H 2 S than the original site. The integrated process consists of soluble gas mixture capture in water followed by the direct injection of the resulting CO 2 -H 2 S-charged water into basaltic rock, where much of the dissolved carbon and sulfur are mineralized within months. This integrated method provides the safe, long-term storage of carbon dioxide and other acid gases at a cost of US $25/ton of the gas mixture at the CarbFix2 site and might provide the technology for lower CCS cost at other sites. [ABSTRACT FROM AUTHOR]

Abstract The cement sheath used in H 2 S-CO 2 mixture gas storage and high-temperature and high-pressure (HTHP) production wells is easily corroded; thus the cement has strict requirements for corrosion-resistant properties. In this work, a new additive, HTHP-CRA, was used to improve corrosion-resistant properties of Fe 2 O 3 -amended cement by reducing the original permeability and the generation low-Ca/Si hydration products. The experimental results indicate that the addition of HTHP-CRA to cement can slightly increase the original compressive strength, significantly reduce the original permeability and CH. The additive can also react with high-Ca/Si hydration products to generate low-Ca/Si hydration products such as xonotlite and tobermorite. Moreover, the addition of HTHP-CRA remarkably weakens leaching and corrosion effects by reduce CH during the corrosion process. [ABSTRACT FROM AUTHOR]

Abstract: Graphene is potentially the perfect barrier material, being impermeable even to the smallest gas molecules, but in practice it is difficult to achieve defect‐free graphene layers at large scale. Here, exceptional barrier performance for laminates comprising graphene nanoplatelet (GNP) paper sandwiched between two discs of polyamide 11 (PA11) is demonstrated. Results are compared with sandwich structures incorporating melt‐processed GNP/PA11 composites, and with chemical vapor deposition (CVD) monolayer graphene transferred onto PA11. PA11 is of interest as a polymer commonly utilized within the oil and gas industry for antiwear and barrier layers in flexible risers. Permeation studies were undertaken for a feed mixture of carbon dioxide (CO2) with 1.48% hydrogen sulfide (H2S) at a temperature of 60 °C and pressures up to 400 bar, providing the first data for the performance of graphene as a barrier to a supercritical fluid. Whereas a GNP/PA11 composite and a CVD graphene monolayer have little effect on permeability, compared to a pure PA11 control sample, a GNP/PA11 laminate reduces CO2 permeability by more than an order of magnitude, and reduces H2S permeability to an undetectable level. [ABSTRACT FROM AUTHOR]

Pressure swing adsorption experiments were carried out for the separation of equimolar mixtures of carbon dioxide and methane containing small amounts of hydrogen sulfide, utilizing 4A, 5A, and 13X molecular sieves. High-purity methane of zero or nearly zero hydrogen sulfide concentration was produced in the adsorption stage with 13X and 5A sieves, at high product recovery rates; high-purity carbon dioxide was obtained with the same sieves in the desorption stage. Zeolite 4A was found capable of raising considerably the hydrogen sulfide concentration in the accumulated desorption product (vs. the adsorption feed) at high recovery rates too. Adsorption selectivity values derived from the experimental results for all three gas pairs were in line with some theoretical predictions and experimental data of the literature. [ABSTRACT FROM AUTHOR]

An aqueous solution of potassium carbonate is a low-cost suitable absorbent for the simultaneous separation of CO2 and H2S from biogas. The promoted potassium carbonate with amino acid salt has the potential to combine the advantages of these two kinds of absorbents. In this communication, potassium glycinate (PG), potassium sarcosine (PS) and potassium L-proline (PLP) were considered promoters. The absorption performance of CO2 and H2S in promoted potassium carbonate was compared with non-promoted potassium carbonate. The results indicated that the CO2 absorption performance of the promoted potassium carbonate with various amino acid salts was much higher than that of the aqueous potassium carbonate solution. Furthermore, among three solutions, the promoted K2CO3 with PS had the highest CO2 and H2S absorption flux. The promoted K2CO3 with various amino acid salts and non-promoted K2CO3 had approximately the same H2S absorption flux, since the H2S removal rates of both can reach nearly 100%. [ABSTRACT FROM AUTHOR]

Plasma-chemical conversion of hydrogen sulfide in the atmosphere of methane with addition of CO and O in the nonequilibrium plasma of barrier discharge is studied. The degree of hydrogen sulfide removal reaches 97 vol%. The degree of methane transformation does not exceed 14 vol%. Gaseous reaction products contain hydrogen, carbon oxides, and C-C hydrocarbons. The energy consumption for the removal of hydrogen sulfide ranges from 84 to 182 eV molecule. The process is accompanied by the formation of deposits on the surface of reactor electrodes. The composition of deposits is studied. Organic linear and cyclic polysulfides, as well as sulfones of various structures are identified in soluble components of deposits. Based on the experimental data and the results of theoretical estimates, a radical chain reaction mechanism is proposed. It is shown that the formation of polysulfide compounds with terminal alkyl and oxygen-containing groups is provided by the reactions between atomic oxygen, SH, and alkyl radical which were formed in the initial stages of processes in the non-equilibrium plasma of barrier discharge. [ABSTRACT FROM AUTHOR]