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Sewage pump stations SPS usually represent a principal item of sewerage system. As other construction sites, adverse environmental impact of SPS construction phase may be controlled, but the operational phase represents continuous potential source of pollution. The SPS within a city have environmental impact on nearby residential areas through different means and levels. The most important mean is effecting surrounding air quality, especially, with gases like ammonia and hydrogen sulfide. Water quality effect is also potential impact, followed by noise, then land pollution. Impact on culture heritage and landscape are also considered. These impacts enforce restrictions while selecting locations to construct SPS within a city. Attention is paid towards keeping city activities, especially those related to residential areas, at safe distance from the impact. The Iraqi sewerage code contains useful limitations for the SPS distances from a verity of activities related to residential areas. [ABSTRACT FROM AUTHOR]

Assessment of hydrogen sulfide fate and emission in a full-scale plant type A2/O in Karbala sewage treatment plant STP. The odorous sulfur compounds released from treatment plants endanger workers and the general environment. Hydrogen sulfide, in particular, is responsible for odors similar to rotten eggs. During summer months of 40 °C, the H2S concentration (effluent to wastewater) decreases in an ascending trend while the emission rate to air increases. As winter season develops, the temperature is likely to decrease by 15°C. On the other hand, due to the low temperatures, H2S gas production increases and then begins to decline by the end of the season, resulting in a decrease in the rate of emission into the air. Several parameters impacting H2S fate and emission at the treatment plant, like temperature, pH, BOD5, and dissolved oxygen, were all presented in this study. The effectiveness of the odor control system as a result, no hazardous gases accumulated within the plant building, indicating that both the workplace and the environment were safe. [ABSTRACT FROM AUTHOR]

The period of operation of the overwhelming number of domestic oil refineries is more than 50 years, while the degree of depreciation of the fixed assets of these facilities is 80%. The tightening of requirements on the part of consumers to deepen the processing of raw materials and the quality of products, respectively, leads to an increase in requirements for the operating conditions of process pipelines and the need to improve the technology for restoring their serviceability and operability. Therefore, there is a problem of increasing the efficiency of repair processes using welding, taking into account the characteristics of the properties, transported products and their effect on the welding process. The article presents the results of experimental studies of technological processes of welding of process pipelines operated in the environment of hydrogen sulfide. According to the obtained results, welding technology for repairing process pipelines is justified and proposed. Conclusions on efficiency of proposed method of pipeline serviceability and serviceability restoration are made. [ABSTRACT FROM AUTHOR]

The article considers the issue of cleaning natural gas from hydrogen sulfide and organic compounds containing sulfur. In order to select the most effective zeolite adsorbents for the conditions of gas filling stations, a large number of experimental studies were conducted on the value and speed of sorption of moisture, H2S, RSH, CO2, CO2 and other components of natural gas. In order to choose the optimal mode of regeneration, its various options were compared in a modeled industrial process pilot plant. The results of these studies made it possible to choose the optimal option, which consists in the following: the driven gas is injected at 320°C, but first (∼1 hour) it is diluted with cold purified gas (30 vol.%) at the entrance to the adsorber. Regeneration duration is 4-5 hours, fuel gas consumption is 185000-230000 m3 per one adsorber. [ABSTRACT FROM AUTHOR]

For the import substitution of sodium sulfide, which is necessary for the industries of the republic, a new method and technological scheme, as well as the necessary equipment, have been developed. As a result, the cost of the products obtained has been reduced due to the available local cheap feedstock of sodium hydroxide and hydrogen sulfide, which is an impurity of the produced natural gas, and the simplification of the technological scheme of the equipment used. [ABSTRACT FROM AUTHOR]

One of the gases that has a direct harmful influence on workers and network facilities is hydrogen sulfide gas. The lift station of the Al-Hur region in Karbala, south of Iraq's capital, Baghdad, was simulated for four seasons using the TOXCHEM software. Samples for this lift station were collected over the course of a year, with all of the station's relevant parameters included in the model. The model was calibrated for the spring season and validated for the remainder of the seasons, and the findings were extremely similar to reality following statistical analysis, with R2 and RMSE results near to (1) and (0), respectively. A sensitivity study was performed with various pH, temperature, discharge, and filling time levels. The results showed that all emissions in this lift station are hazardous, notably during the summer, when the emissions concentrations for the seasons reached 2646, 3998, 2972, and 2196 ppmv, respectively. Several parameters, including temperature and pH, and filling time, influenced hydrogen sulfide gas release. Using a TOXCHEM model, the study contributed to understanding the fate and emission of hydrogen sulfide gas at the lift station. Raising the pH value was discovered as a factor that can be used to reduce hydrogen sulfide emissions in lift stations. Thus, following successful calibration and validation, this model, which was employed for the first time in lift station simulation, produced satisfactory and acceptable results. [ABSTRACT FROM AUTHOR]

Despite the fact that zero valent iron (ZVI) has been used to improve anaerobic digestion (AD) processes, the ability of ZVI to improve AD treatment is dependent on operational factors that result in improved methane (CH4), which has been contradictory in different studies. In this study, the effects of ZVI concentration, chemical oxygen demand (COD), and sulphate (SO42-), and the initial pH in the bio-ZVI system on the AD treatment of SO42--rich wastewater were investigated to obtain key parameter effects on the performance of ZVI. The concentration of ZVI, COD, and SO42-, and the initial pH were varied using batch assays. The result shows the increase of ZVI concentration stimulates an increase of CH4 production. However, CH4 production was further reduced when the ZVI dosage was increased to 24 g/L due to the excessive production of OH− ions via the oxidation reaction of ZVI. Consequently, the pH values could not be in the suitable pH range for methane-producing archaea. Effects of the initial pH on the ability of ZVI, the initial pH was varied at 5, 6, and 7. The result shows the initial pH of 5 cannot improve the CH4 production whereas the initial pH of 6 or 7, the CH4 production was higher than in the control. The COD of 2 g/L (SO42- 1 g/L), 4 g/L (SO42- 2 g/L), and 6 g/L (SO42-3 g/L) were investigated to study the effects of COD concentration on the ZVI performance. The result showed that the bio-ZVI reactor of 6 gCOD/L was improved and the CH4 production level with and without ZVI addition were ca. 0.196±0.002 and 0.058±0.007 L/ gCODadded, respectively. The result indicated that the increased COD and SO42-concentration affected the increase of sulfide levels. When the pH was increased by ZVI oxidation, the level of undissociated hydrogen sulfide decreased, resulting in the CH4 production being higher than in the control. These results indicated that pH, COD and SO42- concentration play a key parameter for the ZVI performance in AD treatment of SO42--rich wastewater. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide is yet to be considered in the several countries in the world to become biogas quality standard development and its acceptance has not been studied. This paper explored the comparison of H2S in low-pressure biogas, acceptance to develop its quality standard, and its desulphurizer compliance. A literature study was presented to obtain relevant data of H2S content in biogas across others countries. It was used to develop the biogas standard, and a survey of the developed standard was conducted. Four desulphurizers with different adsorbents were performed and tested using a PID (Photoionization detector) to meet the standard. H2S was found in biogas up to 500 ppm across several countries of small-scale biogas plants. Considering the hazard potential of H2S to humans, the maximum value of 150 ppm for H2S content in biogas for households was proposed as the standard value. The survey of the H2S parameter in biogas standard showed a positive response from 81% out of 69 biogas practitioners across Indonesia to require H2S at a maximum concentration of 150 ppm. To support the H2S criteria, simple and inexpensive desulphurizers, each containing ferric oxide, iron lathe waste, limestone calcine, and zeolite, were installed to biodigesters and found capable to reduce the H2S level to below ten ppm. It may be used to achieve standard developed value. The good agreement of H2S criteria in the survey and the potential desulphurizers were the supports to consider H2S as one of the parameters in the international quality standards for low-pressure biogas, to make the application more applicable and safer. [ABSTRACT FROM AUTHOR]

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This research was conducted to determine the optimal performance of the otto engine using a mixture of Pertamax and bioethanol fuel and to determine the exhaust emissions from each type of fuel used. The parameters used for the performance value of the Otto engine are torque, power, and air-fuel ratio. The Otto engine used in this study is one cylinder with 150 ccs used by the 2018 Honda CRF 150L with fuel variations, namely Pertamax, Pertamax E5, Pertamax E10, and Pertamax E15. From the calculation results of the test data, the average heating value of the fuel is 42647.1 kJ/kg (Pertamax), 42794.1 kJ/kg (Pertamax E5), 48970.6 kJ/kg (Pertamax E10), and 50441. 2 kJ/kg (E15). The maximum torque obtained from the dyno test results is 15.0 Nm at 5000 rpm using Pertamax E5. The maximum power received from the dyno test results is 9.7 kW at 7000 rpm using Pertamax E15. The maximum air-fuel ratio obtained from this test is 20.295 using Pertamax E15 fuel at 3000 pm. The maximum value of Carbon Monoxide (CO) in Pertamax E15 is 939 ppm. For Hydrogen Sulfide (H2S) levels, the maximum value in Pertamax E10 fuel is 20 ppm. For Combustible Gas (EX) levels, the maximum value for Pertamax E10 and Pertamax E15 is 6% LEL. For oxygen content (O2), the maximum value in Pertamax is 20.9 %vol. [ABSTRACT FROM AUTHOR]

Individual nanofibers from composite layers «manganese oxide/multi-walled carbon nanotubes» and «manganese oxide doped with copper oxide/multi-walled carbon nanotubes» were obtained. It has been established that individual nanofibers have improved gas sensitivity to nitrogen dioxide, hydrogen sulfide and ammonia. The response and recovery times in the exposed gases for obtaining nanofibers were several seconds. The current flow in this nanustructures through the potential barrier between gold contact, oxide and nanotube was shown. The influence of «Au/MnO2-x/nanotube» and «Au/MnO2-x(CuO)/nanotube» heterojunctions on the gas sensitivity of nanofibers was demonstrated. [ABSTRACT FROM AUTHOR]

In this work, we studied the processes of adsorption of carbonyl sulfide, hydrogen sulfide, ethyl mercaptan, the most common sulfur compounds in natural gas, in samples with a deamination degree of 27 and 36%, obtained by acid modification of clinoptilotite from the Karmanskoe deposit. Adsorption experiments were carried out on a laboratory setup as follows. In the experiment, a flow device was used, the main component of which is a heat-insulated glass vessel with a diameter of 10 mm, equipped with an electric heating system to maintain a constant temperature set for the stages of adsorption and regeneration - an adsorber. placed inside an adsorber with a glass column. The thickness of the size of the adsorbent varied from 10 cm to 30 cm. Before each experiment, the layer was cleaned with a nitrogen purge and the adsorbent was regenerated at a temperature of 250°C for four hours. The amount of nitrogen used in the experiment was 0.1-0.2 l/min. formed. At the end of the regeneration process, the adsorber taps were closed and held until the adsorbent cooled down to the required temperature. According to the results of acid treatment of natural clinoptilolite, modified samples with a dealumination degree of 27 and 36% were selected for research. Carbonyl sulfide and hydrogen sulfide were studied in samples with a deamination degree of 27%; ethyl mercaptan adsorption was studied in samples with a deamination degree of 36%. It has been established that the use of modified clinoptilolite instead of synthetic zeolite in the process of gas cleaning in the temperature range of 20-50°C is economically advantageous when the concentration of sulfur compounds in the gas being cleaned is in a certain range of partial pressure.The purpose of this work is to study the processes of adsorption of sulfur compounds in natural gas on sorbents obtained by acid modification of clinoptilolite. [ABSTRACT FROM AUTHOR]

Setting up of decentralized biogas plants in rural areas can be an effective solution to mitigate growing energy demands among the rural community. Biogas produced from anaerobic digestion of organic matter is mainly composed of methane and carbon dioxide along with other trace components like hydrogen sulphide, carbon monoxide and nitrogen. Removal of H2S from biogas is essential to prevent corrosion of the gas stoves and also to reduce air pollution. This study reports a low cost, easy to operate, portable biogas purification system that utilizes natural base ash solutions to remove H2S from raw biogas by absorption process. Banana is reported to be the second largest produced fruit, accounting for 16% of the total fruit production worldwide, and simultaneously generates a lot of waste biomass. In this study, performance assessment of ash solutions prepared from solid waste banana peels and pseudostem as a scrubbing agent for the removal of H2S from raw biogas is reported. The absorption scrubber, filled with natural base ash solutions prepared from Musa balbisiana peel effectively removes 88.03% H2S from raw biogas followed by Musa acuminata peel ash solution (85.27%) and banana pseudostem ash solution (80.98%). The absorption of H2S by all the natural base ash solutions is provisional and has to be refilled after reaching saturation period. The biomass availability, easy preparation method and environment-friendly nature of this natural base solution renders it as a potential candidate for rural applications. [ABSTRACT FROM AUTHOR]

Yeast is a leavening agent used to aid the fermentation process in bread making, by producing ethanol, as well as carbon dioxide, to improve the aroma, and increase the dough's volume, respectively. In Indonesia, the yeast used in bread making is imported. Thus, there is a need for homegrown alternatives. This study, therefore, aims to obtain yeast isolates with the capacity to act as bread leavening agents from the skin and flesh of Mangifera indica var. Podang. In this study, a total of three endophytic isolates, YDM-1, and YDM-3, from the fruit's flesh, as well as YKM-1 from the skin, were obtained. YDM-1 and YKM-1 were identified macroscopically and microscopically as Ascomycota class and Hemiascomycetes sub-class. In comparison, YDM-3 was identified as Ascomycota class and Archiascomycetes sub-class. Subsequently, the isolates were subjected to carbohydrate fermentation, 50% glucose tolerance, flocculation, hydrogen sulfide compound, temperature tolerance, and ethanol tolerance analyses. The three isolates have met the criteria for leavening yeast. YDM-3 and YKM-1 are able to produce a similar increase in the volume of bread dough commercial yeast, with an incubation period of 12 hours. Meanwhile, YKM-1 produced the best aroma as well as the best potential in developing bread and is, therefore, suitable to be used as commercial yeast. [ABSTRACT FROM AUTHOR]

A new approach for the separation of sulfide from cement samples by chemically converting it to hydrogen sulfide and spectrophotometric determination was described. The method is based on converting the sulfide into hydrogen sulfide (H2S) gas using hydrochloric acid (HCl) and Tin (II) chloride dihydrate (SnCl2.2H2O) to reducing the ferric ions present in the cement samples that will prevent interfering with a recommended method, the liberated H2S gas was determined spectrophotometrically. This method provides a calculating the sulfide percentage in cement samples and using this percentage to background correction the percentage of the sulfate, which was calculated in an instrumental method, when using instrumental methods total sulfur will be determined, such as these instrumental methods, sulfide sulfur will be determined with the sulfate. The method was simple, rapid, sensitive, selective, accurate and the final orange-red solution was shown a maximum absorption at 510 nm. Beers law was obeyed percentage range of 0.04-0.4 S2-% with a molar absorptivity (1.12 × 104) L.mol−1.cm−1, and Sandell's sensitivity (5.34 × 10−2) µg.cm−2. The limit of detection (LOD) and limit of quantification (LOQ) were calculated as sulfide percentage and its values are 0.0081 S2-% and 0.0024 S2- %, respectively. [ABSTRACT FROM AUTHOR]

Gas-liquid contacting is the basis for many chemical separation operations, including gas absorption (e.g., removing contaminates like ammonia and hydrogen sulfide from a biogas), humidification and distillation. Many different types of contactors have been developed, recently, in the field of chemical engineering to achieve this type of contacting, depending on different contacting principles. The present work is focused, squarely, to achieve two main goals regarding these contacting methods. The first is reviewing, not exhaustive but critically, the most common conventional and non-conventional contactors. This includes packed bed, bubble, spray and plate columns as conventional contactors and the novel and innovative methods such as rotating spiral channel, falling-film microcontactors and others as non-conventional methods. The second goal is evaluating, quantitatively, the performance of non-conventional contactors and putting them into context with other conventional contacting methods. Two essential parameters are developed in this paper to assess mass-transfer performance of a contractor: mean processing time and purification factor, considering both physical absorption and desorption operations. Interestingly, the comparison results based on mass-transfer data reported in the relevant literature showed that some of the non-conventional contactors can allow a step improvement in mass transfer relative to the conventional contactors and offer solutions for some of inherent limitations of contacting fluid phases. [ABSTRACT FROM AUTHOR]

The aim of this research is to study the effect of carbon percentage on corrosion rates. Four types of carbon steel with different carbon percentage (0.112% C, 0.196% C, 0.314% C, 0.394% C) were used in this study. The samples were submerged in a erosion medium composed of sulfur water for periods of (30,45, 60) days. The corrosion rate was calculated using a weight loss method. The results showed corrosion rates depend on carbon percentage in carbon steel, the highest corrosion rate was found in carbon steel which contains(0.394% C), while the lowest corrosion rate was found in carbon steel contain (0.112% C). Sulfur water has a major role in increasing the corrosion rates of carbon steel, because it contains a large percentage of chlorides, salts and sulfates in addition to the presence of hydrogen sulfide. The presence of the calcareous layer on the surface of samples resulting from calcium ions may contribute to reducing corrosion rates, as it works to prevent oxygen from reaching the metal surface. [ABSTRACT FROM AUTHOR]

An Indirect spectrophotometric method for the determination of sulfate in the cement samples was described. The method is based on converting sulfate into hydrogen sulfide (H2S) gas using hydroiodic acid (HI) and sodium hypophosphite (NaH2PO2) then the amount of generated hydrogen sulfide gas was determined spectrophotometrically. The method was simple, rapid, sensitive, selective, accurate and the final orange-red solution was shown a maximum absorption at 510 nm. Beers law was obeyed in the sulfate percentage range of 0.5-5 SO3% with a molar absorptivity (1.03×104) L.mol-1.cm-1, and Sandell's sensitivity (5.76 x 10-2) μg.cm-2. Limit of detection (LOD) and limit of quantification (LOQ) are 0.27 SO3% and 0.08 SO3%, respectively. This method shows accurate results and reduced the time of sulfate estimating to approximately 1 hour. [ABSTRACT FROM AUTHOR]

The paper considers the process of thermal decomposition of hydrogen sulfide with the formation of hydrogen and sulfur. The energy source is plasma generated by a radio frequency (RF) inductively coupled plasma (ICP) torch. The composition of hydrogen sulfide plasma, its thermodynamic and transport properties are calculated depending on temperature at various pressures. This information is used in further calculations of thermal, gas-dynamic and electromagnetic processes occurring in the ICP torch, the results of which are also presented and analyzed in the work. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is an extremely toxic acid gas and is regarded as one of the primary sources of corrosion and odor problems. The work proposed the Claus process, considering the economic, environmental, and safety requirements are the three pillars of sustainability. The proposed Claus process annual benefit, global warming potential (GWP), fire explosion damage index (FEDI), and toxicity damage index (TDI) were estimated utilizing techno-economic analysis, life-cycle assessment, and hazard identification rating techniques. Then, a multi-objective optimization problem was devised and solved to maximize benefit while minimizing GWP, FEDI, and TDI. The process is simulated using Symmetry simulation software to vary acid feed gas capacity and hydrogen sulfide concentration. The simulation results were used to assess the operating conditions of the sustainability pillars in a comparative manner. According to the findings of this study, the Claus process performed better in terms of profitability, the fire and explosion damage index (FEDI), the toxicity damage index (TDI), and the probability of global warming are all factors to consider (GWP). Based on variable feed capacities and hydrogen sulfide concentrations, the regression models created demonstrated the ability to predict the sustainable approach for hydrogen sulfide conversion employed in the industry. According to the results, the Claus process is expected to be the most sustainable strategy for hydrogen sulphide conversion throughout most of the conversion spectrum. [ABSTRACT FROM AUTHOR]

The minerals in oil and gas wells are exposed to really corrosive media, as the grade of salinity in the water associated with oil and gas rises, as well as because some oil wells contain large quantities of carbon dioxide and hydrogen sulfide gas, which increases the acidity of the well. Corrosion occurs in oil wells inside and outside the production pipelines, and for this, the oil and gas extraction industry consume large quantities of organic inhibitors that are injected into the well continuously. In the laboratory, the method of inhibiting mild steel in 1.5 Molar hydrochloric acid solution was done with Phenyltetrazole compounds, such as 5-(4-chlorophenyl)-1H-tetrazole (CPHT), and 5-p-tolyl-1H-tetrazole (MPHT), were studied at room temperature (25 °C), Phenyl compounds consist of benzene, groups of mono- substituted phenyl in which di-substituted benzenes relate to the reactions of electrophilic aromatic substitution, and tetrazole that refers to the heterocyclic compounds. The effects of the concentration of inhibitor with immersion time in corrosive media are studied using the weight loss technique. Present work has shown that the efficiency of inhibition increases and corrosion rate decreases with an increase in the used concentration of inhibitors. There is little efficiency variation with the immersion time of the mild steel piece. Moreover, the operational conditions used in this work are inhibitors' concentrations with a range (0.001 – 0.0025 M) and immersion time at (5-15 hr) within corrosive media. Phenyltetrazole inhibitor type CPHT affects better than the Phenyltetrazole inhibitor type MPHT in protecting mild steel from corrosion. [ABSTRACT FROM AUTHOR]

Layers of composites based on manganese dioxide (MnO2-x) with the addition of copper (CuO), yttrium (Y2O3), and cobalt (CoxOy) oxides were obtained and their morphological characteristics were investigated. Gas sensitivity and selectivity of composites to various gases was found. High gas response to hydrogen sulfide for the non-stoichiometric manganese oxide and MnO2-x-based composites was shown. Doping by other oxides enhances the selectivity of the layers to other gases. The gas response increasing to acetonitrile for the MnO2-x/CuO layer was achieved. The introduction of yttrium oxide into MnO2-x significantly increases the sensitivity to formaldehyde and sulfur dioxide. The presence of copper and yttrium oxides in the MnO2–x layer enhances the gas response to ethanol vapors. The MnO2-x/CoyOz composite demonstrates selectivity to hydrogen sulfide compared to other gases. [ABSTRACT FROM AUTHOR]

Data on the features of the composition of the Upper Jurassic rocks of the Vostochno-Paiduginskaya exploration well of the section of the Maryanovsk and Naunaksk suites are presented. The distributions of normal and isoprenoid alkanes, phenanthrenes, steranes, hopanes, alicyclic and aromatic hydrocarbons are characterized. It was found out that organic matter (OM) was deposited throughout the section under study under oxidizing conditions. The sediments of the Naunaksk formation were formed in a shallow basin uncontaminated with hydrogen sulfide, while the OM of the Maryanovsk formation was formed in lacustrine environment. The presence of low concentrations of gammacerane in the Maryanovsk formation and the lower parts of the Naunaksk formation indicates weakly saline waters of the sedimentation basin during this period. The participation of higher plants in the formation of the OM composition of the Naunaksk rocks is evidenced by the high concentrations of cadalene, retene, and the presence of simonellite and C25 and C27 n-alkanes. [ABSTRACT FROM AUTHOR]

The paper presents the results of the water quality of the St. George branch, one of three Danube River distributaries, using the combined physical and chemical analyses from June 2017. Three cutoff meander reaches (the Mahmudia, Upper Dunavat and Lower Dunavat meanders) were selected to assess the water ecological state. The cut-offs of the meanders by navigational canals since 1984-1988 caused significant changes in the distribution of the water discharge. Water samples were acquired throughout several cross-sections of both natural and artificial canals of the three rectified meanders, in order to investigate the physical and chemical characteristics of the water. The analyse of the physical and chemical parameters, such as water temperature, conductivity, pH, dissolved oxygen, degree of mineralization, nitrates, nitrites, phosphates, suspended sediments, sulphate, chlorophyll "a", hydrogen sulfide, etc., has shown the predominance of the good ecological state of the water for nitrites and nitrates and lowquality state for phosphates. The water quality assessment was made according to Order 161/2006 [1]. The conclusions regarding the ecological state of the study area could be drawn by observing the water quality variations as conditioned by the position of the sampling points and distance to the main channel. [ABSTRACT FROM AUTHOR]

Studies aimed at improving the efficiency of the field preparation of hydrogen sulfide and mercaptan-containing oil are especially relevant in connection with the tightening of regulatory requirements for quality and safety indicators of commercial oil. The Technical Regulation (TR) of the Eurasian Economic Union TR 045/2017 "On the safety of oil prepared for transportation and (or) use" establishes uniform requirements for the safety indicators of oil delivered through trunk pipelines, as well as used as a raw material in oil refineries or petrochemical plants: hydrogen sulfide content - no more than 20 ppm, the total content of methyl and ethyl mercaptans - no more than 40 ppm. The proposed technology for cleaning oil stripping gas from hydrogen sulfide and mercaptans meets the requirements of modern oil safety standards and can be implemented in the format of a modular-block plant. It is possible to adapt the plant to operating conditions, modify and complete the plant, taking into account the content of light hydrocarbons and hydrogen sulfide in the oil being purified and mercaptans. The selected technological version of the installation scheme is the most rational for the construction of the installation according to the block-modular principle (for installation of the installation on site from blocks of various functional purposes). [ABSTRACT FROM AUTHOR]

Nanocomposites based on multiwalled carbon nanotubes (MWCNTs) functionalized with vanadium oxides were obtained. Morphology and gas sensitivity of individual V2O5/MWCNT and V3O7/MWCNT were investigated. For the test nanostructures, the average gas response time was 18 sec and the gas recovery time was 1-1400 sec. The increasing response of individual V2O5- and V3O7-coated MWCNTs to ammonia, sulfur dioxide, nitrogen dioxide, and hydrogen sulfide was demonstrated. It is shown that the sensitivity of nanostructures is controlled by heterojunctions between n-type MWCNTs and vanadium oxides n- and p-type. [ABSTRACT FROM AUTHOR]

Hydrogen sulphide is a chemical compound that carries the formula H2S a colourless, combustible, to a great degree perilous gas with bad smell. It happens normally in raw petroleum, flammable gas, and hot springs. Furthermore, hydrogen sulphide is removed from the gas related the oil and is isolated by warm and is prepared and heightened to encourage the procedure of exchange where it is traded to other foreign countries. It used as a part of the make of a few medications and is generally used as a part of substance analysis. Industrial activities that can produce the gas include crude oil, natural gas drilling and refining. The research aims to Simulate & study different options to enable H2S removal from crude oil in oil and gas plant. In previse literature; the searching of hydrogen Sulphide is the chosen strategy for decreasing the corrosion and operational dangers in oil production facilities. Hydrogen Sulphide removal from multiphase created fluids preceding phase partition and preparing by injection of EPRI H2S scrounger arrangement into the gas phase by using the considered chemical system relates to a standing oil well. As a result, three different methods were used in this study to extract H2S from heavy crude oil: a stabilization column, a stripping column, and a heater and knock drum. The research carried to study of hydrogen Sulphide removal from heavy crude oil using UNISIM software version 400. The result of project is choosing the best options based technical and economic selection is stripping column. After completely understanding the research, it can presume that data said through it, in reality is recipient to comprehend the human effect of hydrogen Sulphide gas. [ABSTRACT FROM AUTHOR]

This report provides the findings of analysis intended to determine the reasons for the hydrogen sulfide formation in anaerobic conditions of urban sewage systems. The studies have shown that the technogenic content of sulphates in urban networks and the presence of organic components in wastewater lead to the formation and release of hydrogen sulfide into the atmosphere. Various methods of hydrogen sulfide removal from wastewater have been analyzed. The authors of the report have developed a complex alumina-ferrous coagulant to purify wastewater from hydrogen sulfide based on local raw materials of the natural ferruginous diatomite and alumina production middlings; they have also tested it on model wastewater and demonstrated its effectiveness. The novelty of the work is in the determination of the coagulant mechanism of action due to the formation of activated ferric hydroxide forms that bind dissolved hydrogen sulfide, as well as aluminum hydroxide that promotes the formation of rapidly precipitating floccules in the presence of amorphous silicon diatomite. The principal difference of the proposed coagulant from analogs is the use of the ferrous variety of Kazakhstani natural diatomites as a source of the active iron hydroxide form. The extremely active forms of iron compounds formed in an aqueous solution readily interact with a hydrogen sulfide solution to form insoluble sulfides. The use of cakes (containing ferrite and sodium aluminate), alumina production middlings to reach medium alkalinity provides the accelerated course of reactions to form iron sulfides and their precipitation by coagulation with aluminum hydroxide forms. [ABSTRACT FROM AUTHOR]

The process of removal of hydrogen sulfide from methane in the plasma of a barrier discharge in the presence of octane vapor is studied. The use of octane vapors in the initial mixture with methane and hydrogen sulfide permits to avoid the formation of a deposit on the electrodes of the plasma-chemical reactor. The degree of hydrogen sulfide removal reaches 98%, the methane conversion does not exceed 10%. Energy consumption for hydrogen sulfide removal is 83 kW h/kg. The main gaseous products of the treatment of the initial mixture in the barrier discharge are hydrogen (30%) and ethane (30%). Among sulfur-containing products, mainly mono- and dialkylsulfides are identified. A possible mechanism of the process is presented. [ABSTRACT FROM AUTHOR]

The present work investigates the potential of Pseudomonas putida (ATCC 49128) in the mitigation of sulfide from aqueous medium under optimum batch culture conditions. This was approached statistically using response surface methodology (RSM) as a tool to predict the synergistic effects of initial hydrogen sulfide concentration (100-500 ppm), temperature (30-40 °C) and aeration rates (0.5-2.5 vvm) on biological sulfide oxidation at fixed agitation of 140 rpm and 8 h hydraulic retention time (HRT). A total number of 20 experimental runs with 6 center points were carried out. The results were analyzed and validated using statistical indices for the fitness of the obtained quadratic models. The analysis of variance showed that more than 99% of the variation was explained by the models. There was a good agreement between predicted and observed values. The optimum sulfide removal of 449.87 ppm was achieved at the influent hydrogen sulfide concentration, temperature and aeration rates of 500 ppm, 35 °C, and 1.5 vvm in 8 h, respectively. Therefore, the finding depicted the adequacy of the obtained model in enhancing P. putida sulfide oxidation. The model was further affirmed with SEM-EDXS analysis, revealing oxidized sulfide geomicrobiological aggregates coupled with elemental composition spectrum. [ABSTRACT FROM AUTHOR]

Mount Ijen Crater is one of the popular tourist destinations in East Java, Indonesia. Mount Ijen Crater presents a beautiful blue fire view. However, behind its beauty, the Mount Ijen area has the potential danger of toxic gases. In old time there have been casualties due to the disasters of toxic gases that appear in the Ijen Mountain area. This study developed a toxic gas monitoring system which can be accessed online through the website. An array sensor is integrated into the raspberry-mini pc, and the data is stored in the online database. The levels of carbon monoxide and hydrogen sulfide gas can be real-time monitored from anywhere via the internet network. This study can be used for an early warning system for toxic gas disasters in the Mount Ijen area. [ABSTRACT FROM AUTHOR]

An increase of anthropogenic load and intake of organic matter and nutrients leads to extremely negative consequences for coastal marine ecosystems. This is due to the fact that organic matter, deposited in the bottom sediments, contributes to the consumption of oxygen for its oxidation. With a lack of oxygen on the processes of mineralization of organic matter, its accumulation occurs. Oxygen consumption and organic matter accumulation in bottom sediments lead to appearance of anaerobic conditions in sediments and bottom waters. Oxygen deficiency (hypoxia) zones are formed, that defines ecological characteristics and biodiversity of marine ecosystems. Coastal areas of the Crimean shelf and bays of the Sevastopol region (Balaklava, Kruglaya, Kazach’ya and Sevastopol Bays), which have high recreational, social and economic importance, are considered in this work. The data obtained in September 2018 and July 2019 was analyzed. Samples were taken with plexiglass tubes hermetically sealed above and below. To obtain key redox species profiles of pore water, a voltammetry analysis with a glass Au-Hg microelectrode was used. The oxygen fluxes were calculated at bottom water-sediment boundary. Based on the obtained data, the main biogeochemical processes in the bottom waters and sediments of considered areas were studied; a forecast of oxygen deficiency and anaerobic conditions appearance in the bottom waters was given. In the bays of the Sevastopol region, oxygen deficiency is affected by anthropogenic activity, as well as restricted water dynamics. In the open coastal regions of the Black Sea, with the exception of areas suffer from severe anthropogenic pressure (Yalta, Feodosia Gulf, Karkinitsky Gulf), water dynamics contribute to the saturation of the bottom waters with oxygen The value of oxygen flux and it in bottom water’s concentration were used to calculate the time of development of oxygen deficiency. It was stated periods changed from 5 years in open areas, up to 1 month in regions with restricted water exchange. It was found, that hypoxia is observed at the surface of bottom sediments of the Western part of the Crimean coast, Feodosia Gulf and the coastal part of Crimea in the Sea of Azov. In areas with aerobic conditions, the main factor determined redox conditions is water dynamics. It effects on the oxygen saturation of the bottom waters. However, in case of changing conditions and limiting water exchange in these areas, oxygen deficiency zones may also appear. [ABSTRACT FROM AUTHOR]

The pulse gas preparation unit is an important part of the compressor station. The quality of the pulsed gas sent to the needs of the entire workshop depends on the degree of its purification from acidic impurities, such as CO2 and H2S. This process takes place in an absorption column.The use of industrial control systems at such enterprises makes it possible to control processes remotely. At the same time, both technical and economic costs of production become less.The impulse gas preparation unit must ensure uninterrupted supply of natural gas for technological needs, therefore, in terms of CO2 and H2S content, it must meet the following requirements: CO2 content not more than 2% and hydrogen sulfide content not more than 0.0004 mol. % Automated system should function without the constant presence of maintenance personnel.The pulsed gas preparation unit (PGPU) must provide a constant supply of pulsed gas for the operation of the compressor shop with the highest possible cleaning of unwanted impurities. In accordance with the requirements of PGPU, it must be equipped with facilities ensuring the highest possible environmental safety.The article discusses the technological process of natural gas purification from impurities, proposes a spatially distributed control system for a pulsed gas preparation plant,and describes a synthesis technique for a distributed high-precision controller consisting of amplifying differentiating and integrating units. The model was built in Aspen's HYSYS 9.0 program. [ABSTRACT FROM AUTHOR]

The process of hydrogen sulfide removal from methane with the addition of C6–C8 liquid n-alkanes in a barrier discharge plasma is investigated. It is found out that the formation of high molecular weight polysulfide compounds is due to the lack of a liquid hydrocarbon in the initial mixture, while thiols and alkyl sulfides are formed in a mixture containing an excess of liquid hydrocarbon. The supposed mechanism of transformations is given. A method of process controlling is proposed. [ABSTRACT FROM AUTHOR]

Biogas produced from biomass is a form of clean and renewable energy. However, it is not as pure as a natural gas and requires a series of purification steps before it can be commercialized. Among the impurities of biogas, hydrogen sulfide (H2S) is one of the most toxic and corrosive elements. H2 should be removed to reduce its impact on the quality of methane gas produced. Hence, in this study, the feasibility of using diatomite to remove H2 from the biogas was studied using adsorption technique. Raw and treated diatomite was tested for its capability of adsorbing H2. The treated diatomite was prepared by washing the diatomite with water at a various temperature and sulphuric acid at different concentration. Characterization was carried out using SEM, XRD, and FTIR to understand the removal process and adsorption mechanisms. It was found that raw diatomite has very low adsorption capacity (0.18 mg/g). Water treated diatomite shows higher adsorption capacity (3.82 mg/g) compared to raw diatomite, whereas the highest capacity was recorded by 5M acid treated diatomite (6.87 mg/g). From the characterization, it was found that the acid treated diatomite has more refined surface area and functional groups compared to the raw and water treated diatomite, which makes it a better adsorbent. [ABSTRACT FROM AUTHOR]

The generation of palm oil mill effluent (POME) alongside with the production of crude palm oil has created an environmental issue for the palm oil mill industry in Indonesia due to its polluting characteristics. Indonesia as the largest producer of palm oil in the world has the perspective to generate additional benefits such as electricity by utilizing Palm Oil Mill Effluent (POME). The high Chemical Oxygen Demand (COD) content of 35,000 ppm POME is a great potential for conversion to methane and hydrogen through a fermentation process. In this study, fermentation using continuous-stirred-tank-reactor with capacity 40 L (Patent ID P00201000740) to produce biomethane and biohydrogen. After fermentation process in CSTR for 24 hours in this system, the process succeeds in producing biomethane and biohydrogen of 60 % and 32 vol.%, and other impurities gas such as hydrogen sulfide up to 2000 ppm, which is an acidic gas that would cause severe corrosion to the mechanical parts of combustion engines. Therefore, hydrogen sulfide must be separated from biogas prior to combustion. Among the conventional methods, the use of a cheap an absorbent appears to be one of the most promising methods for H2S removal. NaOH with various concentration (3N, 5 N, and 10 N) was used as an absorbent to remove H2S. The result showed that NaOH 10 N (307 ppm) was better to remove H2S than NaOH 3 N (1790 ppm) and NaOH 5 N (1014 ppm), they were NaOH was successfully used to remove H2S from a simulated biogas stream. [ABSTRACT FROM AUTHOR]

The numerical solution results of the lidar equations for Raman scattering of light by hydrogen sulphide molecules and for differential absorption and scattering in case of lidar the sensing of the hydrogen sulphide molecules in the atmosphere with concentration close to the maximum permissible are presented, from the space orbit at the heights about hundreds kilometers and from flying platform at the heights up to 500 m in the synchronous photon counting mode. [ABSTRACT FROM AUTHOR]

It is known that one of the methods for purifying gas fraction from hydrogen sulfide is amine treatment. Various types of amines are used to remove hydrogen sulphide, carbon dioxide and carbon dioxide from petroleum gases. The choice of specific amine depends on the needs of the process. Mono-ethanolamine (MEA) (C2H4OH) NH2 and diethanolamine (DEA) (C2H4OH) 2NH are commonly used. Both are ammonia derivatives. To develop recommendations on the choice of material from which to make equipment for amine plants, comparative studies of corrosion resistance of traditionally used low-temperature carbon steel and nano-composite coatings obtained by electrodeposition method. The research have shown, that average corrosion rate on a standard sample (without coatings) is 0.9969 mm / year. Because of this, the frequency of changing equipment for cleaning oil from acidic components (hydrogen sulfide, carbon dioxide and carbon dioxide) on average is 1 time per two years. During the one year testing period nano-composition coatings showed protective efficacy when exposed to acidic corrosion / erosion. It should be noted that there is a likelihood of damage to the coating during mechanical action. It is established that the use of protective coatings leads to an increase in corrosion resistan [ABSTRACT FROM AUTHOR]

Steel industry has a huge impact on the environment and the air, in particular, producing thousands of tons of gases, including blast furnace gas, gases from oxygen converter processes, coke industry gases, ferroalloy industry gases. Due to this fact, the removal of gas impurities is essential nowadays. In this paper we did the literary analysis of how to remove sulfur impurities from air emissions using different types of sorbing agents. This paper contains the researches about sorption of impurities using zeolites, activated carbon and a variety of manganese ores, also their capacities and other characteristics are compared. Different adsorption units are observed as well as the optimal temperatures, pressure and gas flow rates. [ABSTRACT FROM AUTHOR]

Plasma-chemical conversion of hydrogen sulfide in the presence of carbon dioxide from methane in the dielectric barrier discharge plasma 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 C2–C4 hydrocarbons. 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 dielectric barrier discharge. [ABSTRACT FROM AUTHOR]

The impurities such as hydrogen sulphide (H2S) and carbon dioxide (CO2) are unwanted components and may cause corrosion and environmental pollution. The Gulf of Mexico area is one of the biggest fossil fuel markets around the world. It encourages more investments to recover and process the natural gas.The Gulf of Mexico natural gas contains high quantities of CO2 about (1.47%) and barely low amounts of H2S. Therefore, this study endeavour to simulate and optimize the prospective gas sweetening process by using the Aspen HYSYS V.8.4 program. Moreover, the simulation study is adopted amine sweetening technique by utilizing MDEA solution activated by Piperazine and it has achieved high CO2 removal, for example, CO2 gas concentration in sweet gas stream was about 40 ppm at (800 m3/h) circulation rate. In addition, gas sweetening process optimization is also achieved by employing different amine types and amine mixes such as MEA(Monomethylamine) and DEA (Dimethylamine). Further amine process parameters are examined for all amine types, for example, circulation rate, amine concentration and other operation conditions. However, the optimization step of the process recognized that the use of (30 wt.% MDEA(Methyldiethanolamine) +2.5wt.% PZ(Piperazine)) amine is the most efficient and recommended amine technique. [ABSTRACT FROM AUTHOR]

The paper presents the results of calculating and justifying the absorber contact device type for the acid components (mainly carbon dioxide as well as hydrogen sulphide if the initial fuel contains sulphur compounds) extraction from gas condensatepartial oxidation products. For the contact device proposed variant by applying the cost function in the form of the estimated costs variable part, the relative operating velocity constituting 60-70% of the column flooding velocity is optimized. [ABSTRACT FROM AUTHOR]

The detailed analysis of resistive and magnetic measurements with sulfur hydrides at high pressure is performed. The hydrogen system at high pressure can exhibit ferromagnetic (FM) as well as superconducting (SC) properties with layered structure. The onset temperature of resistive transition at 200 K in metallic sulfur hydrides corresponds to magnetic (AF SDW) phase transition rather than SC one. SC transition in these sulfur hydrides occurs only when magnetic (AF SDW) phase transition is over (~ 40 K). The SC mechanism in metallic sulfur hydrides is not conventional but corresponds to Keldysh-Kopaev model characteristic for systems with coexistence of dielectric and SC pairing. [ABSTRACT FROM AUTHOR]

Absorption of H2S is one of the important part in biogas purification.. This process requires a purification system to reduce the content of harmful gas. The maximum tolerance of H2S content for biogas generator set input is 5 ppm, while measured input of H2S in cow manure has a concentration range from 43 to 45.5 ppm. Therefore, it needs proper optimization design to represent the performance of the purification system. Particle Swarm Optimization refers to the process of identifying the best element (according to one or more user-specified criteria) among a set of possible alternatives. In this research, we compare the results from modeling plant and experimental plant in order to the reaction and mass at the biogas purification plant. Based on the experiment plant, measurement of produced biogas shows the reduction of H2S concentration up to 94.5% and produce H2S with concentration of 0.55 ppm. Meanwhile, in modified plant model the reduction of H2S is up to 94.44% with the gas concentration of 0.53 ppm. Validation of plant model has showed the data trend that approaches the measurement results of experimental plant with an average of absolute error of 0.018, respectively. [ABSTRACT FROM AUTHOR]

With the development of technology, the detection of hydrogen sulfide gas concentration not only requires simple operation, but also requires measurement range is large. In this research, an additional detection port is added on the basis of harmonic detection technology, and the two are used together. According to the different concentration of gas, the corresponding output port is selected as the detection port. When the gas concentration is low, the difference I1 between the output I and the constant 0.9I0 is selected, and the differential output I2f is detected at a high concentration. The output results of harmonic detection span the 5 orders of magnitude when the gas concentration from 0.001% to 40%. However, the output of this method takes only 2 orders of magnitude, and the measurement range is widened under the same range. When the input light intensity changes, the magnitude of the overall measurement value is changed and does not affect the magnitude of the magnitude. [ABSTRACT FROM AUTHOR]

The quality of water sources used for drinking water production is highly varied. Many problems arise in groundwater due to the content of hydrogen sulfide and ammonia. Thei presence of its in water affects the organoleptic properties, in disosolved form the hydrogen sulphide confering undesirable taste and irritating rotten egg smell which make it unpalatable. Ingestion of sulphides through drinking water can result in stomach discomfort, nausea and vomiting. Ammonia in concentration above 1.5 mg/L can cause odour and taste problems and compromise disinfection efficiency by increasing the oxidant demand, and corrode copper alloy pipes and fittings. A chemical method used for their removal from the water is oxido-reduction by aeration and using oxidizing agents (O2, Cl2, O3, KMnO4 etc). This paper presents a comparative study regarding various oxidation methods used for ammonia and hydrogen sulphide removal. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide is a gas that is formed in various water bodies due to the flow of sulphate reduction and putrefaction of organic matter of bottom sediments. Hydrogen sulfide can also get in the water of reservoirs and watercourses with wastewater of various industries and farms. In the water objects of fishery and drinking water use concentration normalized, since due to the toxicity of hydrogen sulfide deteriorates the water quality, occur hypoxic effects and death of aquatic organisms, while for ponds with mud this gas is an important therapeutic component. This paper presents the analysis and generalization of the data of the literature sources and original author's materials on the content of total hydrogen sulfide in the water of freshwater reservoirs and watercourses, as well as in the water of water objects of increased mineralization (seas, bays, estuaries and mud lakes). Mineralization of water in the studied water objects of Russia varied from less than one g/dm3 to 400 and more g/dm3, and dissolved oxygen from less than 0.2 mg/dm3 to 10.0 mg/dm3.The total hydrogen sulfide content in water (H2S,HS-,S2-) varied in a wide range from 0.0 to 50 mg/dm3. Freshwater reservoirs and watercourses characterized the minimum values of H2S - from 0.0 to 0.833 mg/dm3. The content of total hydrogen sulfide and dissolved oxygen in the studied water bodies had respectively direct and inverse close relations with the pollution and the level of eutrophication. In the waters of marine water bodies and mud lakes brine content of total hydrogen sulfide varied in a wider range than in fresh water, and was on average significantly higher. Regression dependences indicating an increase in the total hydrogen sulfide content in the water column with a decrease in the dissolved oxygen content are obtained. [ABSTRACT FROM AUTHOR]

One of the major environmental problems that is currently being raised is the olfactory discomfort. At present, the odor parameter is not regulated in national legislation, rather than in the Odor Immission Directive - OID- edition of 21 September 2004. The lack of a legal framework in terms of odor immissions constitutes an impediment for health of affected population and might have repercussions also on the economic development of the areas. Odors are one of the most emerging issues related to odor immissions from industrial plants and household waste dumps. This discomfort represents a complex problem to solve because of the subjective characteristics of olfactory perception and the difficulty of identifying the source of emissions. The objective of this study is to compare different techniques in assessing odor concentrations in the ambient air, namely olfactometry measurements using the human nose (measures effects of odor perceived by an observer) and analytical measurements (describes odors in terms of their chemical composition and attempts to quantify the odorants present). Both methods have drawbacks because sensory measurements may be too subjective in interpreting the results, and analytical measurements are complicated because of the large number of odorants often present at concentrations close to detection limits of measuring equipment. This paper highlights the relationship between any activity that can be a source of odor (industrial, agricultural, household, etc.) and the release of odors. Such a relationship is important and critical in the reduction of odors, in order to understand that any activity that results in smelling gases can affect, over time, both the quality of environment and health of population. Moreover, the paper presents some hydrogen sulphide (H2S) and ammonia (NH3) measurements performed in residential areas in Hunedoara County, compounds clearly identified as major odors specific to urban areas because of their high olfactory impact. [ABSTRACT FROM AUTHOR]