COS Concentration Research Articles

Investigation of oxy-fuel combustion for methane and acid gas in a diffusion flame

Co-combustion of methane (CH4) and acid gas (AG) is required to sustain the temperature in Claus reaction furnace. In this study, oxy-fuel combustion of methane and acid gas has been experimentally studied in a diffusion flame. Three equivalence ratios (ER = 1.0, 1.5, 2.0) and CH4-addition ratios (CH4/AG = 0.3, 0.5, 0.7) were examined and the flame was interpreted by analyzing the distributions of the temperature and species concentration along central axial. CH4-AG diffusion flame could be classified into three sections namely initial reaction, oxidation and complex reaction sections. Competitive oxidation of CH4 and H2S was noted in the first section wherein H2S was preferred and both were mainly proceeding decomposition and partial oxidation. SO2 was formed at oxidation section together with obvious presence of H2 and CO. However, H2 and CO were inclined to be sustained under fuel rich condition in the complex reaction section. Reducing ER and increasing CH4/AG contributed to higher temperature, H2S and CH4 oxidation and CO2 reactivity. Hence a growing trend for CH4 and AG to convert into H2, CO and SO2 could be witnessed. And this factor enhanced the generation of CS2 and COS in the flame inner core by interactions of CH4 and CO2 with sulfur species. COS was formed through the interactions of CO and CO2 with sulfur species. The CS2 production directly relied on reaction of CH4 with sulfur species. The concentration of COS was greater than CS2 since CS2 was probably inhibited due to the presence of H2. COS and CS2 could be consumed by further oxidation or other complex reactions.

Carbonyl Sulfide Sulfur Isotope Fractionation During Uptake by C3 and C4 Plants

AbstractCarbonyl sulfide (COS) is a major long‐lived sulfur‐containing gas in the atmosphere. Similar to CO2, COS main sink is the uptake by terrestrial plants. Therefore, COS is used as a proxy for CO2 uptake by terrestrial plants (gross primary production [GPP]). Currently, COS budget estimates have large uncertainties. Sulfur isotopes measurements are used in an isotopic mass‐balance to constrain the COS budget. Here we conducted plant‐chamber experiments for determining the isotopic fractionation during COS uptake by C3 and C4 plants, and that associated with enzymatic fractionation inside plant leaves. We also conducted COS diffusion in nitrogen experiment to determine the fractionation associated with COS diffusion through plant stomata. We then measured the δ34S values of COS from these experiments by a gas chromatograph/multicollector inductively coupled plasma mass spectrometer. Applying these measured δ34S values, we calculated fractionations (εplant) of −1.6 ± 0.1‰ and −5.4 ± 0.5‰ during COS uptake for C3 plants and C4 plants respectively. A fractionation of −5.2 ± 0.5‰ for COS diffusion through plant stomata was calculated as well. We estimate the total diffusive component of plant uptake fractionation (including boundary layer, stomata, and gas‐liquid interface diffusions) as −1.6 ± 0.1‰. Using plant chamber measurements under high CO2 and COS concentrations we calculated the enzymatic component of the plant uptake fractionation as −15 ± 2‰. Based on the diffusive and enzymatic components of plant uptake fractionation, we calculate COS concentrations inside plant leaves. Using the C3 and C4 fractionation results, a value of −2.3 ± 0.5‰ is estimated as the global plant uptake fractionation, which can be incorporated into improved COS‐based‐GPP estimates in the future.

Purification of Low-Concentration Carbonyl Sulfide by Red Mud-Based Adsorbent.

Bauxite residue, also known as red mud (RM), is a kind of industrial solid waste with high alkali content, complex composition and difficult utilization. In this study, a new type of RM-based adsorbent was prepared by using polyethylene glycol modified RM and was used to remove low concentration of COS in flue gas. The optimum preparation conditions of adsorbent and the optimum technological parameters of COS adsorption purification were investigated. Under the optimal conditions, the adsorption efficiency of the new adsorbent exceeds 95%, and the COS adsorption capacity reaches 63.56mg/m3. The characterization results showed that the main active components of the adsorbent were active alkali, FeOOH and Fe3O4, and the main products were Na2S2O3, Na2SO4, FeS and FeS2.

Influence of dissolved organic matter on carbonyl sulfide and carbon disulfide formation from dimethyl sulfide during sunlight photolysis.

Carbonyl sulfide (COS) and carbon disulfide (CS2 ) are important atmospheric gases photochemically generated from organic sulfur precursors in sunlit natural waters. This study examined these processes by evaluating COS and CS2 photoproduction from dimethyl sulfide (DMS) in the presence of dissolved organic matter (DOM). DOM was added because it photochemically produces various reactive intermediates (3 CDOM*, • OH, 1 O2 , and H2 O2 ) potentially involved in these reaction pathways. DMS-amended synthetic waters at pH 8 were varied in terms of their DOM type and concentration, spiked with the 3 CDOM* quenching agent, phenol, in certain cases, and subsequently irradiated over varying exposure times. Results indicated that various DOM types ranging from freshwater to open-ocean DOM increased COS but did not alter CS2 , which remained at nondetect levels. DOM type influenced COS only at higher concentrations (20 mg/L), whereas increasing DOM concentrations proportionally increased COS concentrations for all DOM types. Phenol addition lowered COS formation for reasons that remained unclear because phenol likely quenched 3 CDOM* and DMS-derived sulfur-based radicals. Further comparisons with DMS-spiked natural waters and cysteine (CYS)-spiked synthetic and natural waters assessed previously indicated that COS formation from both precursors in natural waters was always greater than in waters containing DOM alone. PRACTITIONER POINTS: DMS- and DOM-spiked synthetic waters formed COS but did not form CS2 during sunlight photolysis. In DMS-spiked synthetic solutions, DOM type has a limited influence on COS formation whereas DOM concentration has a stronger influence on COS formation. COS formation in the DMS-spiked synthetic waters was fairly proportional to the DOC concentration but was generally lower than COS formation in DMS-spiked natural waters.

High-Pressure Densities and Excess Molar Volumes for the Binary Mixture of Carbon Dioxide and Hydrogen Sulfide at T = 343–397 K

A few studies have been carried out on the volumetric properties of binary systems of H2S + CO2, which are rich in CO2; however, no volumetric studies for acid gas fluids rich in H2S have been found in the open literature. Herein we report new high-precision density measurements for three compositions (x(CO2) = 0.09822, 0.26989, and 0.49556) for the CO2 + H2S binary system at T = 343–398 K and pressures up to p = 25 MPa. The measured mixture densities were compared to data from Stouffer et al. ( J. Chem. Eng. Data 2001, 46, 1309−1318. DOI: 10.1021/je000182c.) and Nazeri et al. ( Fluid Phase Equilib. 2016, 423, 156−171. DOI: 10.1016/j.fluid.2016.04.024.The measured density data showed agreement within ca. ±2% at high pressures and up to 4% in the vicinity of the critical point or high compressibility region. Additionally, we used our mixtures and interpolated pure fluid densities to calculate the excess molar volumes, to further ascertain the accuracy of the mixing coefficients provided by Kunz and Wagner ( J. Chem. Eng. Data 2012, 57, 3032−3091. DOI: 10.1021/je300655b.). The comparison of the calculated and experimental molar volumes showed good agreement to within ±2 cm3·mol–1, especially in the high-pressure region. Within the study, we considered the COS formation from the reaction of CO2 + H2S, which was a potential explanation for measurement failure in previous studies. The measured equilibrium concentrations of COS were low and showed that the reaction of CO2 + H2S to form COS was not facile at the measured conditions.

Steam-oxygen gasification of sewage sludge: Reduction of tar, H2S and COS with limestone as bed additive

Biogenic residue conversion to fuel and chemicals via fluidized bed gasification and synthesis is a promising pathway allowing biogenic residues to replace fossil carbon sources. This study focuses on sewage sludge gasification with the application of limestone as bed additive for tar, H2S and COS reduction. Experiments were conducted in a 20 kW fuel input bubbling fluidized bed facility with steam and oxygen as gasification agents. The syngas composition, considering the concentrations of H2, CO, CO2, CH4, CxHy, H2S, COS, NH3 and tar species, was determined for different limestone to fuel ratios. The results show that the produced syngas has high H2 and CO concentrations of up to 0.37 m3 m−3 and 0.18 m3 m−3 respectively and is thus suitable for synthesis. Tar species from sewage sludge gasification are characterized by various methods and differ from those from wood gasification. It was found that a small additive ratio of ~0.06 kg kg−1 (limestone to fuel ratio) is sufficient to reduce heavy tar species up to 75%, and with higher additive ratios, light tar species can also be partially reduced. Moreover, H2S and COS capture is demonstrated, with H2S and COS concentrations decreasing by 40%–65% with increasing limestone additive ratio. The ammonia (NH3) concentration was not affected by the additive. This study concludes that limestone addition is an effective and low cost measure to mitigate tar related facility problems and to reduce the downstream tar and sulfur cleaning efforts.

Performance Assessment of a Sulphur Recovery Unit

A refinery plant in the middle east started its official production in 2020. All the refinery plant acidic gas is fed to the Sulphur recovery unit plant to produce sulphur and prevent any acidic emissions against environmental regulations. The Sulphur recovery unit was simulated via special package named SULSIM. The results were validated, then the simulation was used in case studies to understand some important parameters of Sulphur recovery plants. The effect of decreasing the combustion air inlet temperature, the effect of decreasing the Claus reactor 1 inlet temperature and the effect of decreasing the thermal reactor feed were studied. Decreasing combustion air outlet temperature on the thermal reactor decreases the thermal reactor burning temperature, increases the concentration of COS and CS 2 by-products. Decreasing Catalytic reactor 1 inlet temperature decreases the hydrolysis reactions of COS and CS 2 but increases the Sulphur conversion efficiency. Decreasing AAG feed to the thermal reactor decreases the waste heat boiler duty.

Release of nitrogen, sulfur and chlorine species from coal in carbon dioxide atmosphere

In oxyfuel combustion, the release of minority species, such as sulfur, nitrogen and chlorine compounds from the fuel plays an essential role, since significant corrosion and emission issues arise from these species. In the present study, the release of nitrogen, sulfur and chlorine species from a US-American bituminous coal with high sulfur content was studied in CO2 atmosphere in an entrained flow reactor. With the entrained flow reactor, particle heating rates comparable to those observed in a full-scale furnace can be achieved. The experiments were performed at different reactor temperatures in CO2 atmosphere. Gas samples were extracted from the reactor, and the concentration of various gas species, including NO, N2O, NH3, HCN, H2S, SO2, COS and HCl, was determined. It was found that the formation and release of the considered minority species changes with temperature and fuel residence time. A rapid decrease of the N2O concentration and an increase of the NO concentration was observed with increasing temperature. The release of NH3 from the fuel increased with increasing temperature, whereas the release of HCN decreased. Furthermore, compared to pyrolysis in nitrogen atmosphere, the release of sulfur and chlorine species increased significantly. Finally, COS was detected in significant amounts in CO2 atmosphere, but not in inert N2 atmosphere.

Simulation Study of the Formation of Corrosive Gases in Coal Combustion in an Entrained Flow Reactor

Gaseous sulfur species play a major role in high temperature corrosion of pulverized coal fired furnaces. The prediction of sulfur species concentrations by 3D-Computational Fluid Dynamics (CFD) simulation allows the identification of furnace wall regions that are exposed to corrosive gases, so that countermeasures against corrosion can be applied. In the present work, a model for the release of sulfur and chlorine species during coal combustion is presented. The model is based on the mineral matter transformation of sulfur and chlorine bearing minerals under coal combustion conditions. The model is appended to a detailed reaction mechanism for gaseous sulfur and chlorine species and hydrocarbon related reactions, as well as a global three-step mechanism for coal devolatilization, char combustion, and char gasification. Experiments in an entrained flow were carried out to validate the developed model. Three-dimensional numerical simulations of an entrained flow reactor were performed by CFD using the developed model. Calculated concentrations of SO2, H2S, COS, and HCl showed good agreement with the measurements. Hence, the developed model can be regarded as a reliable method for the prediction of corrosive sulfur and chlorine species in coal fired furnaces. Further improvement is needed in the prediction of some minor trace species.

Experimental study on sulfur-containing products in pressurised oxy-fuel pyrolysis of pulverised coal

Although the contribution of the pressurised oxy-fuel combustion technology for improving energy conversion efficiency and reducing SOx emissions is well recognised, the mechanism of sulfur transformation in the initial pyrolysis step has not yet been elucidated because of the complexity of the pyrolysis process. Clarifying such scientific fundamentals and overcoming technological challenges can effectively advance the implementation of pressurised oxy-fuel combustion technology and realise cleaner production. Herein, the transformation mechanisms of sulfur among solid, liquid, and gaseous states during the pressurised oxy-fuel pyrolysis of pulverised coal were experimentally investigated. The analysis of the gaseous products indicated that the concentration of H2S, the most abundant gaseous product, decreased from 840.3 to 32.1 ppm as the operating pressure increased from 0.1 to 3.1 MPa. Similar trends were observed for CH3SH and SO2. Conversely, COS concentration first increased from 61.4 to 143.4 ppm, after which it decreased to 30.4 ppm, a level similar to H2S concentration. The decreasing sulfur concentration in the volatiles is attributable to the oxidation of low-valence sulfur to form high-valence sulfur and the subsequent absorption by alkali metals in the char residue. The sulfur concentration in liquid tar, which was determined by the competitive reactions of the cracking of heavy hydrocarbons and the polymerisation of light volatiles, first decreased from 6.25 to 3.17 mg/L, followed by an increase to 5.03 mg/L as the operating pressure increased. To further investigate the sulfur transformation, the physicochemical, morphological, and structural properties of pyrolysed char were characterised. The crystal phase, microstructure, average particle size, specific surface area, and surface elemental content of the char affected the distribution and conversion of organic and inorganic sulfur in the char residue. The total sulfur content in the char residue typically increased with operating pressure. Moreover, the effect of operating temperature on the sulfur-containing products was investigated. Based on the experimental results, a binary correlation fitting was applied to predict the various trends in different sulfur-containing gaseous products of pressurised oxy-fuel pyrolysis.

Theoretical study on COS oxidation mechanism

COS is the most abundant sulfur containing compound in the atmosphere that could cause serious adverse effects on human health and environment. Understanding the oxidation mechanism of COS is with great significance in controlling and utilization reduced sulfur (CS2 and COS). In this study, density function theory (DFT) and multi-reference configuration interaction with Davidson correction (MRCI+Q) methods were adopted to investigate the oxidation mechanism of COS. All energies were refined at CCSD(T)/CBS level and subsequently used to deduce the kinetic parameters. The critical mechanism was validated by experiments results. It was found that the oxidation of COS is initiated through three channels. In COS+COS channel, S2(a1∆g) is first produced and then oxidized to SO(X3Σ). In COS+O2 channel, COS combines O2(X3Σg) to yield SO(X3Σ, a1∆) and CO2(X1Σg). In COS dissociation channel, atomic sulfur S(3P, 1D) will be primarily generated and subsequently oxidized to SO(X3Σ) and O(3P). Oxidation of SO(X3Σ) could either result in O(3P) formation. At higher COS concentration, O(3P) formed through three initiation channels will react with COS to produce S(3P) and SO(X3Σ), both of which will be oxidized finally to SO2(X1A1) to reproduce O(3P). Reaction of COS+O(3P) is the dominating consumption reaction of COS. The major products of COS oxidation are CO(a1∆) and CO2(X1Σg) and SO2(X1A1). The ratio of CO/CO2 in products is mainly affected by the branching fraction of COS+O(3P). Based on the rate coefficient calculated at CCSD(T)/CBS level, a comprehensive kinetic model was developed to predict the COS oxidation process. The modeling results are in agreement with experiment data.

Syngas cleaning for coal to methanol demo plant – H2S and COS removal

Syngas cleaning, especially the removal of COS and H2S, is a crucial step in the production of valuable chemicals from coal. As a part of the Tuncbilek Coal to Methanol project, a gas cleaning demo plant has been built. The aim of this paper is to disseminate the experience gained from these demo plant experiments concerning the performance of the gasifier and syngas cleaning demo-plant, especially about the removal of sulfur compounds. Additionally, some practical recommendations regarding the design and operation of such demo plants are given. The design-basis for the demo plant was a gas stream of 450 m3/h (at STP) containing 4,000 ppmv H2S and 2,000 ppmv COS. The performance target was to reduce H2S and COS concentrations to less than one ppmv each. The gas cleaning process consisted of a particulate filter, COS hydrolysis reactors, caustic scrubbers, H2S guard beds and heat exchangers. Two demo plant runs were conducted, and Tuncbilek lignite was gasified in the 6 ton/day (coal feeding capacity) entrained flow gasifier. The gasifier produced syngases with lower heating values of 7.64 and 8.86 MJ/m3 (at STP), and cold gas efficiencies of 71 and 81% were achieved. The H2S and COS content of the successful run were 3,300 ppmv and 550 ppmv, respectively. At the exit of the gas cleaning demo plant, a concentration of 0.12 ppmv for H2S and 0.72 ppmv for COS were measured. Consequently, it was concluded that the performance of the gas cleaning demo plant was satisfactory for methanol production.

The conformational stability of terminal helices of [formula omitted]-repressor protein in aqueous dodine and choline-O-sulfate solutions

In this article, we have ventured into the denaturation of fast folding λ6-85-repressor protein at a millimolar concentration of dodine and henceforth, evaluated the candidature of choline-O-sulfate as a protecting osmolyte against it, employing classical molecular dynamics simulations. Our simulation results show that, the terminal helices of λ-repressor protein get unfolded in presence of ∼15 mM dodine while 0.5 M and higher concentration of COS can prevent this deleterious effect of dodine. Careful analyses of a set of simulations with increasing COS concentration reveals that a higher concentration of COS can provide remarkable stability to the protein, even slightly better than its native state in water. Different interaction parameters show that in aqueous dodine, both the dodinium and acetate ions interact strongly with the terminal helices to disrupt the structure whereas in presence of COS, due to the preferential interaction of COS with the protein molecule, dodine molecules get excluded from the protein surface. In addition, the favorable interaction of COS with dodinium head group, the dodinium ions become less available to the vicinity of protein surface which also plays an indirect but decisive role to prevent the unfolding of the terminal helical domains of the λ-repressor protein.

Facile batch synthesis of porous vaterite microspheres for high efficient and fast removal of toxic heavy metal ions

The contamination of water by heavy metals has become one of the greatest threats to global ecological systems. Vaterite, in spite of the excellent performance to remove toxic metal ions, is difficult to be prepared with a large scale production, which limits its further industrial application. To this end, we developed a green and rapid approach to prepare in batch uniform porous vaterite/chitosan oligosaccharide (COS) hybrid microspheres (V-COS) at room temperature. Especially in the presence of 5gL−1 COS, high vaterite content (nearly 100%) and large scale production of CaCO3 microspheres were obtained within only 2min without any other organic solvent. SEM images showed that an individual hybrid microsphere was composed of many nanoparticles, and TEM results demonstrated that these nanoparticles consisted of multiple nanocrystals. It was found that the concentration of COS and high shearing stirring were the key issues for the high production of V-COS. Based on the results the formation mechanism of V-COS was proposed. Their application for removal of lead and cadmium ions from aqueous solutions was investigated. The high and fast adsorption capacity for Pb2+ and Cd2+ ions were achieved with the adsorption amount up to 1884 and 156mg/g within 6min, respectively, which were much higher than that of rhombohedron CaCO3 obtained without stirring (R-COS). The porous vaterite hybrid microspheres obtained with such large scale production has never been reported before, and this will lay foundation for its further wide applications.

Peak growing season gross uptake of carbon in North America is largest in the Midwest USA

Gross primary production (GPP) is a first-order uncertainty in climate predictions. Large-scale CO2 observations can provide information about the carbon cycle, but are not directly useful for GPP. Recently carbonyl sulfide (COS or OCS) has been proposed as a potential tracer for regional and global GPP. Here we present the first regional assessment of GPP using COS. We focus on the North American growing season—a global hotspot for COS air-monitoring and GPP uncertainty. Regional variability in simulated vertical COS concentration gradients was driven by variation in GPP rather than other modelled COS sources and sinks. Consequently we are able to show that growing season GPP in the Midwest USA significantly exceeds that of any other region of North America. These results are inconsistent with some ecosystem models, but are supportive of new ecosystem models from CMIP6. This approach provides valuable insight into the accuracy of various ecosystem land models. Using carbonyl sulfide as a tracer, gross primary production in the Midwest USA is shown to significantly exceed that of any other region of North America. This approach provides a valuable means of assessing the regional accuracy of ecosystem land models.

The Effect of Temperature and Carbonyl Sulphide on Carbon Deposition on 20Cr25Ni Stainless Steel

In this paper, the results of a systematic study of the effect of temperature and COS concentration on the formation of carbon deposits on a 20Cr25Ni austenitic stainless steel under a depositing gas of 1000 vppm ethene in 1%CO/CO2 have been presented. Carbon deposits were found over the temperature range of 550–725 °C after 4 h exposure. COS additions to the ethene-bearing gas inhibited the deposition process, but the effect was concentration and temperature dependent. The results have been interpreted in terms of the oxidation process and the adsorption of sulphur on the catalytic Ni-rich particles.

Study of oxidation for gas mixture of H 2 S and CH 4 in a non-premixed flame under oxygen deficient condition

Oxidation process of gas mixture of hydrogen sulfide (H2S) and methane (CH4) in a non-premixed flame and formation of COS and CS2 has been studied under oxygen deficient condition. Premixed fuel consisting of H2S and CH4 with constant molar ratios (1:1) was injected and air was varied from the stoichiometric to the fuel rich condition (equivalence ratio, Φ = 2) to determine the influence of Φ upon the oxidation manner. The flame could be divided into three sections namely initial oxidation, intense combustion and post-flame section. Oxidation competition between H2S and CH4 was observed at the first section wherein H2S conversion, mainly via partial oxidation, was superior to that of CH4. Initial CH4 conversion involved partial oxidation and interaction with sulfur species which contributed to productions of COS and CS2. Formation of SO2 was witnessed at the second section together with significant increase in concentrations of CO, H2 and C2H2. However, the productions of these combustibles were favored by higher temperature and fuel rich condition and likely to be maintained under anoxic environment in the post-flame section. The CS2 and COS concentration profiles suggested a tight relationship between its conversion path and the O2 level downstream.

Fischer–tropsch diesel production and evaluation as alternative automotive fuel in pilot-scale integrated biomass-to-liquid process

Fischer–Tropsch (F-T) diesel produced from biomass through gasification is a promising alternative fuel. In this study, a biomass-to-liquid (BTL) system involving a dual fluidized bed gasifier (DFBG), a methanol absorption tower, and an F-T synthesis process was investigated for producing clean biodiesel as an automotive fuel. A DFBG, which is an efficient indirect gasifier, can produce syngas with high caloric value while minimizing the amount of nitrogen in the product gas. In order to meet the strict requirements of syngas for F-T synthesis, any contaminants in the syngas must be minimized and its composition must be carefully controlled. In this work, the syngas mainly comprised 35vol% of H2 and 21.3vol% of CO. The concentrations of H2S and COS in the syngas were less than 1 ppmV owing to the use of chilled methanol cleaning process. Furthermore, long-term operation of a fully integrated BTL system was successfully conducted for over 500h. The results showed that the BTL diesel can be used as an alternative automotive diesel fuel.

Conversion of COS by corona plasma and the effect of simultaneous removal of COS and dust

In the study, the conversion of COS and dust removal efficiency by corona plasma was investigated in a wire-cylinder corona plasma reaction. The compositions of gases were determined by Fourier Transform Infrared (FTIR). Chemical compositions of the solid deposition collected were analyzed by X-ray diffraction (XRD) and X-ray fluorescence (XRF). COS was converted to CO, CO2, S, SO2, and SO42− by corona plasma and high specific input energy (SIE) could result in high conversion of COS. With corona plasma, direct electron collision between S and C was the key and major way to convert COS. The conversion of COS decreased with content of O2 for more energy being shared when generating more O3 under high O2 content. Low relative humidity was superior to discharge and then gain higher COS conversion. The introducing of dust can promote conversion of COS weakly and reduce SO2 yield obviously for SO2 could further react with some compounds in the dust. With O2 content of 0.5%, relative humidity of 23%, dust content of 5600±5%mg/m3 and SIE of 691J/L, COS conversion reached to 91.4% with the inlet COS concentration of 1620ppm. At the same time, dust removal efficiency was over 99.9% by the reactor. COS and dust can be removed simultaneously by corona plasma and existing of dust can promote COS conversion to some extent.

The mechanism of coal gas desulfurization by iron oxide sorbents

This study aims to understand the roles of hydrogen and carbon monoxide during the desulfurization process in a coal gasification system that H2S of the syngas was removed by Fe2O3/SiO2 sorbents. The Fe2O3/SiO2 sorbents were prepared by incipient wetness impregnation. Through the breakthrough experiments and Fourier transform infrared spectroscopy analyses, the overall desulfurization mechanism of the Fe2O3/SiO2 sorbents was proposed in this study. The results show that the major reaction route is that Fe2O3 reacts with H2S to form FeS, and the existence of CO and H2 in the simulated gas significantly affects equilibrium concentrations of H2S and COS. The formation of COS occurs when the feeding gas is blended with CO and H2S, or CO2 and H2S. The pathways in the formation of products from the desulfurization process by the reaction of Fe2O3 with H2S have been successfully established.