Sulfur-containing Gases Research Articles

Transformation of organic sulfur and its functional groups in nantong and laigang coal under microwave irradiation.

The microwave irradiation experiment of Nantong coal (NTC) and Laigang coal (LGC) has been carried out in a microwave oven and the transformation of organic sulfur and its functional groups was investigated via compact sulfur tester and Fourier transform infrared spectra. The dielectric properties of coal sample are also measured by an Agilent N5244A network analyzer. The result shows that a certain amount of organic sulfur in both NTC and LGC is transformed into iron sulfide, sulfate, and sulfur-containing gas after irradiation of microwave. The retention proportion of the three typical sulfur-containing functional groups in coal is ranking as: disulfide bond (S-S) > sulfinyl (SO) > sulfydryl (-SH), and such phenomenon has been explained by the first principle calculation based on the density functional theory. The calculation results of Fukui indices, electrostatic potential, and frontier orbital analysis indicate the reactivity of the SO and SS is lower than that of the -SH. The calculated bond dissociation enthalpies and bond dissociation times indicate the chemical bonds of -SH and S-S need more time to rupture than SO when microwave power is 1000 W. © 2019 Wiley Periodicals, Inc.

Carbothermic Reduction of Metals in the FeS–Cu1.96S–CaO System

The conditions for the direct carbothermic reduction of metals from mixtures of sulfides Cu1.96S and FeS with calcium oxide are studied using thermogravimetric and thermal analyses combined with mass spectrometry of the formed gases. The metal reduction in a mixture of FeS and CaO on heating to 1250°C is shown to occur with the formation of intermediate oxysulfide phases almost without the evolution of sulfur-containing gases. The formation of SO2 is observed in a mixture of Cu1.96S and CaO at temperatures higher than 550°C. The introduction of FeS into the reaction mixture of Cu1.96S and CaO enhances the completeness of metal reduction by carbon, decreases the temperatures of the intense processes, and suppresses sulfur dioxide evolution.

USE OF DUMPED RED MUD OF ALUMINA INDUSTRY AT GRANULATION OF THE MOLTEN SULFUR-CONTAINING BLAST FURNACE SLAG

There is a problem of using waste of alumina production from bauxite red mud. Warehousing of it is fraught with ecological catastrophes. Red muds constantly worsen the environment due to dusting and pollution of natural waters. Red mud is a product of bauxite processing. One ton of alumina accounts for 1 to 2.5 tons of red mud. Currently, it is not being processed, despite the availability of 3,000 publications and patents on this topic. One of them is justified by the ambiguity in the economic effectiveness of its use by consumers. In this paper, the options for economic and environmental efficiency of RM use are presented as substitutes for expensive lime and limestone used for purification of industrial gases emitted to the atmosphere in large quantities with toxic sulfur compounds. Laboratory and industrial tests revealed the sorption properties of red muds. When cleaning gases from sulfur emitted into the atmosphere by furnace gases, thermal power plants, sinter machines, and steelmaking furnaces. In addition, the ecological and technological efficiency of purification of sulfur-containing gases released in the areas of granulation of molten blast-furnace slags is shown.

Theoretical study of the formation mechanism of sulfur-containing gases in the CO2 gasification of lignite

In this work, molecular dynamics based on a reactive force field (ReaxFF) and density functional theory (DFT) are used to investigate the formation mechanisms of H2S, COS and SO2 in the CO2 gasification process of lignite, which is very difficult to be obtained by recent experimental method. The molecular representation of lignite, provided by Wolfrum, is selected as the structural unit to construct the lignite model and the lignite-CO2 model. ReaxFF simulations of the two models are then performed for 1 ns at 3000 K. The evolution of H2S, COS and SO2 shows a good agreement with the reported formation tendency in the coal pyrolysis process. By analyzing ReaxFF simulation trajectories using C++ programs, it is inferred that the thermal decomposition of sulfur-containing moieties is initiated mainly by cleavage of their carbonsulfur bonds, leading to the same alkylthio intermediates. Reaction energies from DFT calculation indicate that CO2 molecules, as well as alkoxy and aldehyde radicals produced by the reactions between CO2 and the carbon structures in lignite, can weaken the carbonsulfur bonds by stabilizing the cleavage products. The formation reactions of HS, RSCO2 and RSO radicals are respectively key steps in the formation of H2S, COS and SO2, which can both be accelerated by CO2. The obtained mechanism can successfully explain the reported experimental phenomena and helps to understand the formation processes of sulfur-containing gas during the CO2 gasification of lignite.

Computational and Experimental Investigations of the Working Process in a Recovery Burner

The authors have presented computational and experimental investigations into the burning of sulfur-containing oil gases of heterogeneous composition and calorific power in a burner whose combustion products are the working medium for the recovery-power-plant′s turbine drive. The equations of the working process have been written in the context of a generalized law of conservation. The results of numerical modeling have been obtained with the ANSYS FLUENT software package. The experimental data have been derived during the burning of the oil gas stored in cylinders directly at a marginal field. A comparison of the calculated and experimental data has shown the adequacy of the computational model. The calculation results allow the conclusion on the correctness of the technical decisions adopted earlier on creation of a domestic recovery gas-turbine plant of the blocked-module type for marginal fields.

A review of recent researches on Bunsen reaction for hydrogen production via S–I water and H2S splitting cycles

Abstract The Bunsen reaction is the center reaction for both the sulfur–iodine water splitting cycle for hydrogen production and the novel hydrogen sulfide splitting cycle for hydrogen and sulfuric acid production from the sulfur-containing gases. This paper reviews the research progress of the Bunsen reaction in recent 10–15 years. Researches were initially focused on the optimization of the operating conditions of the conventional Bunsen reaction requiring excessive water and iodine to improve the products separation efficiency and to avoid the side reactions and iodine vapor deposition. Alternative methods including electrochemical methods, precipitation methods, and non-aqueous solvent methods had their respective advantages, but still faced challenges. In development of the technology of H2S splitting cycle, dissolving iodine in toluene solvent could render the Bunsen reaction to occur with the flowable I2 stream at ambient temperature such that the side reactions and iodine vaporization can be avoided and the corrosion hazard lessened. It also prevented the Bunsen reaction from using excessive iodine and water. The products from the Bunsen reaction including HI, H2SO4, H2O, and toluene could be directly electrolyzed.

Molecular Simulation of Capture of Sulfur-Containing Gases by Porous Aromatic Frameworks

The adsorption of pure SO2 and H2S and their selective adsorption from various gas mixtures by porous aromatic frameworks (PAFs) are investigated using grand canonical Monte Carlo (GCMC) simulations and first-principles density functional theory calculations. The influence of functional groups including −CH3, −CN, −COOH, −COOCH3, −OH, −OCH3, −NH2, and −NO2 on the adsorption of pure SO2 and H2S as well as selective capture of SO2 and H2S from SO2/N2, SO2/CO2, H2S/CO2, and H2S/CH4 mixtures is explored. Our calculations indicate that PAFs exhibit high loadings for pure SO2 and H2S gas adsorption at 298 K up to 40 bar compare to other gases such as CH4 and CO2. Additional functional groups enhance gas uptake at low pressures because of stronger interaction with the gas molecules while reducing gas uptake at high pressures because of a decrease in pore volume. The contributions of electrostatic interactions to gas adsorption loadings are analyzed in GCMC simulations. Ideal adsorbed solution theory calculations...

Comprehensive risk assessment of high sulfur-containing gas well

Well integrity has been a growing concern of oil and gas industry, especially in the years of cheap oil. The failure of well integrity may cause undesirable events or even devastating consequences such as safety hazards or loss of containment. In this paper, a novel calculation model of wellbore integrity comprehensive risk has been presented. Firstly, the risk hazard associated with well barrier failure modes are identified based on the relevant literature. The risk factors of well integrity in production phase are investigated in detail. The risk matrix based on Borda number analytical method and Analytic Hierarchy Process (AHP) is then presented to assess the risks of well integrity in production safety. Finally, the case of XX high sour gas well is empirically investigated to validate the model. The results indicate that 27 risk factors are identified for XX gas well in production. In addition, it is found that the XX gas well is prone to suffer damage in presence of H2S and CO2, furthermore, the Borda number analytical results also show that the most important factor affecting the well integrity is effect of string corrosion, followed by the corrosion of string sealing accessories and the corrosion environment of material applicability. Therefore, the appropriate measures should be taken to reduce the corrosion of string and sealing accessories, thus prolonging the service life of the equipment. The case of XX high sour gas field verifies the feasibility and applicability of the risk matrix method in wellbore integrity risk assessment. The innovative assessment method provides methodological reference and guidance for the application of the limited resources, in addition, it also has practical information for well integrity engineers to improve the performance of safety management, thus ensuring well safety during production.

Prediction of gaseous products from Dachengzi oil shale pyrolysis through combined kinetic and thermodynamic simulations

The characteristics of gas evolution from Dachengzi oil shale pyrolysis under different temperatures were experimentally investigated using a fixed bed reactor and then were evaluated by integrating thermodynamic equilibrium simulation employing HSC Chemistry program and Sandia PSR kinetics simulation in this paper. The experiment results indicate that the non-condensable gases contain much higher CO2, CH4 and H2 and lower CO and C2–C4 hydrocarbons in terms of volume percentages, and mainly consist of CO2 and CH4 as well as some minor gases in terms of mass distribution. CO2, CO and H2 are firstly produced followed by the generation of light hydrocarbons. The HSC calculation results present that some C2 and C2+ hydrocarbons disappear in the predicted gaseous products thermodynamically, and the nitrogen- and sulfur-containing gases mainly are N2 and H2S, respectively. Then, the normalized HSC species are inputted into the Sandia PSR code by three methods, i.e., the CHO input method, the regional input method and the individual input method, considering the potential kinetic constraints. Some C2 and C2+ hydrocarbons appear in the predicted gaseous products based on the three methods. The regional input method demonstrates that more H2 and CO are produced at higher temperature, which agrees with the experimental results. And more C2H4 and C2H2 release at higher temperature depending on the enhanced secondary gas cracking reactions. The peak concentration of every gas product is obtained at higher temperature with lower value compared to the experimental results possibly due to ignoring the effect of the shale ash. The individual input method indicates that C2 and C3 hydrocarbons are generated after the formation of CH4, CO, CO2 and H2. The change trends of CO2, CO and H2 obtained from the experiment and simulation with rising temperature are very similar, but those for CH4 are different, due to most likely certain limitations of a fixed bed reactor as a reaction system. Combining the HSC and PSR calculations, the obtained gas products are closer to the realistic situation.

Gas Chromatography Columns Based on Functionalized Polymer for the Analysis of Catalytic Reaction Products

For the first time in this work, two methods of modification of poly(1-trimethylsilyl-1-propyne) (PTMSP) and the possibilities of its application for the determination of catalytic reaction products are described. Aging of PTMSP is determined by three mechanisms: physical, chemical and mechanical effects. Free volume decreases, texture characteristics change, and partial oxidation of the polymer takes place in the structure of PTMSP. The chromatographic behavior of PTMSP, which was used for 18 months, differs significantly from the properties of the freshly prepared polymer. Thermal stability and chemical inertness are the main requirements for chromatographic materials. Therefore, two methods were used to stabilize the aging process. The first method consisted of preparing a mixed phase by adding disubstituted polyacetylene poly(1-phenyl-1-propyne) (PPP) to PTMSP. The resulting sorbent Chromosorb Р NAW + 10 wt% (97% PTMSP + 3% PPP) is efficient for solving a wide range of chromatographic tasks such as simultaneous analysis of hydrocarbons and sulfur-containing inorganic gases, analysis of chlorine-substituted methanes in CCl4 and thiophene in benzene, separation of hydrocarbons and aromatic compounds. It should be noted, the low selectivity of separation of oxygen-containing components on this sorbent. A second method of PTMSP modification, namely the oxidation treatment with nitrous oxide, is proposed. It was shown that the polymer is oxidized by means of its C=C double bond with the formation of ketone, carbonyl and hydroxyl groups. The increase in number of those groups in the polymer changed the polarity of PTMSP. The change in polarity of polymer led to the selectivity of separations, including oxygen-containing substances. Examples of separations of aliphatic and aromatic hydrocarbons, oxygen- and halogen-containing substances are presented. Chromatographic characteristics of the sorbent Chromosorb P NAW + 10 wt% (97% PTMSP + 3% PPP) and PTMSP oxidized by nitrous oxide are stable in the temperature range from 30 to 220 °C for at least 1.5 years of continuous operation.

Green diesel production through simultaneous deoxygenation of palmitic acid and desulfurization of 4,6-Dimethyl-dibenzothiophene over commercial CoMo/Al2O3

This study investigated the deoxygenation of palmitic acid as a model compound of palm fatty acid distillate (PFAD), in the presence of 4,6- di-methyl-di-benzothiophene as a sulfur-containing light gas oil (LGO). Reactions were performed at the pressure of 25 barg, liquid hourly space velocity (LHSV) of 1.7 h-1, and H2/oil of 630 NL/L over CoMo/Al2O3 as catalyst. The effect of temperature was studied in the range of 275-300 oC. Both deoxygenation and desulfurization led to approximately 100% conversions at 300 oC, while at 275 oC, palmitic acid deoxygenation was recorded at a higher conversion rate compared with that of the desulfurization of 4,6- di-methyl-di-benzothiophene. The presence of 4,6- di-methyl-di-benzothiophene during the deoxygenation of palmitic acid resulted in high conversions (>95%). Pressure drop studies showed that the formation of heavy products caused a gradual pressure drop throughout the reactor over time. The catalyst was deactivated during 10 d. Two different sulfur-containing reagents were used for catalyst reactivation including dimethyl-disulfide in n-C18 and LGO containing 484 ppmw of sulfur. Reactivation with 2 wt.% of dimethyl-disulfide in n-C18 at 320 oC for 36 h led to more favrable performance recovery vs. the sulfur-containing LGO.

Research into biotechnological processes of plant S­nutrition stimulation by the products of phosphogypsum disposal in gas cleaning systems

The rational qualitative and quantitative composition of granules of phosphogypsum that is used as the load for the systems of biochemical cleaning of gas emissions was established. The study of the zones of biotransformation of phosphogypsum component with the use of raster microscopy was performed. The biofilm, formed by sulfur oxidizing bacteria on the surface of granules, and elementary sulfur that is metabolite, deposited during oxidation of hydrogen sulfide, were explored. Physical and chemical properties of biosulfur, produced as a result of biochemical gas cleaning of sulfur-containing gas flows in biofilters with the load from phosphogypsum, were determined. We analyzed the models of metabolic pathways of sulfoxydizing bacteria, providing oxidation of sulfur-containing compounds into the forms that are easily accessible for plants using electronic databases, such as KEGG database, MetaCyc and EzTaxon databases. The biochemical mechanisms of transformation of biosulfur when using it in the process of S-nutrition of plants were determined, which will make it possible to dispose of it in agroecosystems. The combined scheme of the ways of bacterial oxidation of sulfide to sulfate was substantiated. The species structure of ecological and trophic groups of microorganisms, involved in oxidation of sulfur, among which hemolithotrophic bacteria of the genus Thiobacillus are dominant, was assessed.The general technological scheme of the phosphogypsum disposal with the production of biosulfur in the systems of biochemical gas cleaning was developed. Environmental effects from implementation of the proposed technological system were obtained: impurities (hydrogen sulfide, carbon dioxide) were removed from gas emissions; the waste of chemical industry – dump phosphogypsum was disposed of; biosulfur as a product, used to improve S-nutrition in agroecosystems, was produced

Desulfurization of Brown Coal in Water under Supercritical Conditions

A method for the desulfurization of brown coal by treatment in supercritical water (T = 673.15 K, P = 30 MPa) with the subsequent deposition of gaseous sulfur compounds on a copper substrate was proposed. The products were refined fuel with a low heat value of 24 MJ/kg and Cu2S films with a thickness of 0.1 mm. The semiconductor Cu2S films can be used for the preparation of thin-film photoelectric energy converters. The greatest degree of the removal of sulfur from the brown coal was observed after an hour. The main sulfur-containing gas formed upon the autoclave treatment of brown coal in supercritical water was H2S.

Recycling Spent Cr Adsorbents as Catalyst for Eliminating Methylmercaptan.

Waste adsorbents generated from treating Cr(VI)-containing wastewater are hazardous materials and generally landfilled or treated by acid or base desorption, with concomitant high cost and toxic effects. The present work shows that these Cr adsorbents can be reused as highly efficient catalysts for treating sulfur-containing VOCs (CH3SH), not only avoiding the economic and environmental impact from the conventional approaches, but also achieving the efficient treatment of sulfur-containing waste gas. Importantly, these reused Cr adsorbents exhibit enhanced activity and stability compared with the catalysts reported elsewhere, indicating a new avenue of green chemistry. The highly toxic adsorbed Cr(VI) species are reduced to a Cr2O3 crystalline phase by calcination and finally immobilized as a Cr2S3 solid phase while converting and eliminating CH3SH. Still, the presence of Cr(VI) species on the reused Cr adsorbent provides enough reactive sites for reaction, but high concentration of Cr(VI) species causes serious accumulation of coke deposit on the catalyst, leading to fast deactivation of the catalyst.

Effects of Hydrothermal Modification on Sulfur Release of Low-Quality Coals During Thermal Transformation Process

In this paper, the effects of hydrothermal modification on sulfur-containing pollutants, such as sulfur dioxide (SO2) and carbonyl sulfide (COS), during coal pyrolysis and combustion, have been investigated. Three typical Chinese low-quality coals, Zhundong, Yimin, and Zhaotong coal (ZT), have been treated by hydrothermal modification at final modification temperatures of 200 °C, 250 °C, and 300 °C. Coal pyrolysis and combustion experiments using raw coal and modified coals were performed using a tube furnace. Results showed that SO2 and COS emission were suppressed after hydrothermal modification in the pyrolysis process. Lower emission of both SO2 and COS were also achieved when final hydrothermal modification was increased, this was attributed to the loss of aliphatic sulfur, e.g., sulfoxide, sulfone, and thiother, during the modification process. For ZT, hydrothermal modification also caused a delay in the release of sulfur-containing gases. In combustion experiments, hydrothermal modification reduced the SO2 emission for Yimin coal, but for ZT, the SO2 release amount almost doubled, and for Zhundong coal (ZD), it also increased, after hydrothermal modification. Hydrothermal modification also caused a delay in peak SO2 emission during the combustion of ZT; this is attributed to conversion of sulfur containing structures to stable aromatic compounds through hydrothermal modification.

Effect of etoksidol against sulfur-containing gas induced reduction in bone marrow microcirculation in different stages of ontogenesis in rats

Objective: To investigate the state of femoral red bone marrow microvasculature of nonlinear white male rats in the course of an acute experiment. Materials and Methods: The ontogenesis of experimental animals were between 36 and 730 days: Intact ones, those subjected to the action of subtoxic doses of sulfur-bearing gas, and those receiving a protector-drug “Etoksidol”. The data on microcirculation were obtained using laser Doppler flowmetry. The industrial sulfur-containing natural gas of the Astrakhan gas condensate field was used as a toxic agent. It was revealed that the reducing intensity of blood microcirculation in the red bone marrow of intact rats is statistically more significance in the presenile period of ontogenesis compared with the earlier periods. Results: The use of “Etoksidol” along with the influence of sulfur-containing pollutant on the experimental animals of different age groups led to improvement of microcirculation in the bone marrow at all the studied stages of ontogeny. However, such improvement was statistically highly significant (P < 0.01) in the mature age I, very close to significant in the mature age II, and was not statistically significant in the young and presenile age. Conclusions: As a result, the following findings were obtained: The toxic effect greatly reduces the intensity of the microcirculation in the bone marrow, which is most pronounced in younger animals; the experimental results suggest that the drug “Etoksidol,” with an antihypoxic and antioxidant action, has a positive effect on red bone marrow microvasculature.

Effect of Lime Addition to CaSO 4 Oxygen Carrier in Chemical Looping Combustion

Abstract Chemical-looping combustion (CLC), which has the characteristic of greenhouse gas CO2 inherent separation, is a novel combustion technology. In this study, CLC experiments of methane using CaSO4 oxygen carrier with lime addition were carried out in a batched fluidized bed reactor, where the sample was exposed to alternate oxidizing and reducing conditions. The influences of temperature, calcium-to-sulphur ratio and lime particle size on the conversion of CaSO4 and sulfur capture were investigated and a suitable operation condition was determined. Under the optimal operation condition, a multi-cycle test was performed to evaluate the cyclic redox behavior of the lime-promoted CaSO4 sample. X-ray diffraction and a field emission scanning electron microscope were used to characterize the phase and surface morphology of the samples used. The results show that the addition of lime could improve the conversion rate of CaSO4 and the capture efficiency of sulfur-containing gases. The operation conditions of calcium-to-sulfur ratio 0.8, lime particle size of 180-250 μm and operation temperature of 900 °C turned out to be the optimal conditions. Besides, the average desulphurization rate of lime was up to 78.77% during the cyclic test.

Improving Sensing of Sulfur-Containing Gas Molecules with ZnO Monolayers by Implanting Dopants and Defects

Two-dimensional ZnO materials are proposed for use in nanosensors and their ability to adsorb and detect toxic H2S and SO2 gases are compared. Graphene-like, two-dimensional ZnO monolayer (ZnO-ML) materials are considered that are doped with B, C, N, or S atoms or have Zn or O vacancies. In its pristine form, a ZnO-ML binds the two gases weakly, with binding energies of −0.33 eV and −0.67 eV for H2S and SO2, respectively. However, the presence of defects or the substitution of a Zn or O atom with heteroatoms was found to result in significant increases in the adsorption energy, resulting in a binding energy of up to −3.67 for H2S on a ZnO-ML with a Zn vacancy and −5.15 eV for SO2 on a C-doped ZnO-ML. The H2S molecule is observed to undergo dissociative adsorption on these substituted monolayers, which makes the materials unsuitable as reusable H2S sensors. However, SO2 does not dissociate in any of the cases studied. On SO2 adsorption, significant changes in the conductivity of the ZnO-ML that has an O va...

Emerging Roles of Carbonyl Sulfide in Chemical Biology: Sulfide Transporter or Gasotransmitter?

Carbonyl sulfide (COS) is the most prevalent sulfur-containing gas in the Earth's atmosphere, and it plays important roles in the global sulfur cycle. COS has been implicated in origin of life peptide ligation, is the primary energy source for certain bacteria, and has been detected in mammalian systems. Despite this long and intertwined history with terrestrial biology, limited attention has focused on potential roles of COS as a biological mediator. Recent Advances: Although bacterial COS production is well documented, definitive sources of mammalian COS production have not been confirmed. Enzymatic COS consumption in mammals, however, is well documented and occurs primarily by carbonic anhydrase (CA)-mediated conversion to hydrogen sulfide (H2S). COS has been detected in ex vivo mammalian tissue culture, as well as in exhaled breath as a potential biomarker for different disease pathologies, including cystic fibrosis and organ rejection. Recently, chemical tools for COS delivery have emerged and are poised to advance future investigations into the role of COS in different biological contexts. Possible roles of COS as an important biomolecule, gasotransmitter, or sulfide transport intermediate remain to be determined. Key advances in both biological and chemical tools for COS research are needed to further investigate these questions. Further evaluation of the biological roles of COS and disentangling the chemical biology of COS from that of H2S are needed to further elucidate these interactions. Chemical tools for COS delivery and modulation may provide a first avenue of investigative tools to answer many of these questions. Antioxid. Redox Signal. 28, 1516-1532.

Effect of naphtha diluent on greenhouse gases and reduced sulfur compounds emissions from oil sands tailings

The long-term storage of oil sands tailings has resulted in the evolution of greenhouse gases (CH4 and CO2) as a result of residual organics biodegradation. Recent studies have identified black, sulfidic zones below the tailings-water interface, which may be producing toxic sulfur-containing gases. An anaerobic mesocosm study was conducted over an 11-week period to characterize the evolution of CH4, CO2 and reduced sulfur compounds (RSCs) (including H2S) in tailings as it relates to naphtha-containing diluent concentrations (0.2, 0.8, and 1.5% w/v) and microbial activity. Our results showed that RSCs were produced first at 0.12μmol°RSCs/mL MFT (1.5% w/v diluent treatment). RSCs contribution (from highest to lowest) was H2S and 2-methylthiophene>2.5-dimethylthiophene>3-methylthiophene>thiofuran>butyl mercaptan>carbonyl sulfide, where H2S and 2-methylthiophene contributed 81% of the gas produced. CH4 and CO2 production occurred after week 5 at 40.7μmolCH4/mL MFT and 5.9μmolCO2/mL MFT (1.5% w/v diluent treatment). The amount of H2S and CH4 generated is correlated to the amount of diluent present and to microbial activity as shown by corresponding increases in sulfate-reducers' Dissimilatory sulfite reductase (DsrAB) gene and methanogens' methyl-coenzyme M reductase (MCR) gene.