Removal Of Organic Sulfur Research Articles

Study of Coal Microbiocenosis for Development of Biotechnological Method for its Desulfurization

A presence of microscopic fungi, heterotrophic bacteria, as well as neutrophilic and acidophilic chemolitotrophic bacteria was determined in coal microbiocenosis. The largest and most active towards pyrite sulfur removal is the Acidithiobacillus genus. Heterotrophic bacteria have the biggest potential when it comes to removal of organic sulfur. Preceding treatment of coal with “silicate” bacteria from the Bacillus genus will allow to use coal microbiocenosis for its biodesulfurisation at its full potential.

A novel method for removing organic sulfur from high-sulfur coal: Migration of organic sulfur during microwave treatment with NaOH-H2O2

A novel technology of removing organic sulfur from coal was proposed by microwave irradiation combined with NaOH-H2O2. The organic sulfur removal degree and the transformation of sulfur-containing compounds in coal was also analyzed using Inductively coupled plasma (ICP) and Fourier transform infrared (FTIR) during desulfurization. The changes of bond order, bond length, Fukui indices and electrostatic potential charge of sulfur-containing bond were further calculated to support the experimental results. The results show that organic sulfur is mainly transformed into SO32− and SO42− under solvent-assisted microwave irradiation. For three typical organic sulfur functional groups, the disulfide bond (S–S) is the easiest to remove, while the sulfuryl (S=O) is the hardest to remove, which could be explained by the strength of the sulfur-containing bond and the reactivity of S atoms in different functional groups. The order of bond lengths of the sulfur-containing bond is S–S > –SH > S=O. Furthermore, the reactivity of S atoms is much higher than that of C atoms in coal matrix, indicating that this method can be used as an effective process on the removal of organic sulfur without destruction of coal matrix.

The evolution characteristics of organic sulfur structure in various Chinese high organic sulfur coals

Understanding the organic sulfur structure and its evolution characteristics is crucial to the desulfurization of coal, as they are the dominant factors determining the removal of organic sulfur from coal. To learn the organic sulfur structure characteristics, a series of high-organic-sulfur coals from China with different ranks were studied by coal petrology, structural chemistry, and organic geochemistry theory in this paper. Coal petrological analysis shows some of the high-organic-sulfur coals with high TPI values and low GI values indicating that they have experienced unusual conditions when the coal was forming. Through the FTIR analysis, the organic sulfur structural parameters shows the relative abundance of aliphatic sulfur (thiol, thioether and sulfone) in these coals decreased with the increasing coal rank and the relative abundance of aromatic sulfur in coal generally showed an increasing trend with increasing coalification, divided into three different evolutionary stages (0.37%–1.40%, 1.40%–1.99% and 1.99%–3.93% of Rm). Comprehensive analysis shows that EID and TPI had a significant correlation with the organic sulfur structural parameters, which means regardless of the coal rank the impact of the environment on the structure of organic sulfur is independent. These results give a new insight into organic sulfur characteristics in coal and its evolution characteristics with coal rank, which are potentially useful for the efficient remove the organic sulfur from coal.

Biological assisted organic sulfur removal from low rank indigenous coal using airlift bioreactor.

Combustion of coal create many harmful gases which effect on human health as well as on environment. The sulfur in coal limits its own use, and bio-desulfurization (BDS) shows enormous development potential and the prospects for the application of coal desulfurization. Present study highlights the bioprocess strategies for reduction of sulfur content from coal before combustion. The bioprocess involved the use of Airlift Bioreactor along with Rhodococcus sp. ATCC55309 as biocatalyst. Different nutritional and operational parameters involved to promote sulfur reduction at maximum level. The parameters were investigated are different carbon source, temperature, pH, Agitation speed, and pulp density. The impact of these parameters shows that sulfur removal can be enhanced though optimized conditions. The amount of total sulfur and organic sulfur present in coal were reduced by 33 ± 1.7% and 71 ± 1.5%, respectively, compared to untreated coal at controlled condition of various parameters are 20% (w/v) pulp density, 30°C, 170rpm, glucose as carbon source and pH 7. Whereas organic sulfur degrades from coal using Rhodococcus sp. ATCC55309 about 0.36mM DBT (Di-benzothiophene) within 8days via 4S-pathway. The maximum conversion of DBT compound into 2-HBP(2-hydroxybiphenyl) by utilizing 30°C, 170rpm, 20 pulp density and glucose as carbon source.

Microorganisms in Coal Desulfurization (Review)

The information on the use of microorganisms and mixed consortia in the biological desulfurization of coal is summarized. The ecological problems that accompany the burning of high-sulfur coals are shown, and the prospects of environmentally friendly and resource-saving biotechnological approaches to coal desulfurization are considered. Analysis of available literature indicates the enormous role of microorganisms of various taxonomic groups in the removal of inorganic and organic sulfur in coals. Mesophilic and moderately thermophilic acidophilic chemolithotrophic bacteria (ACB) of the genus Acidithiobacillus—A. ferrooxidans, A. thiooxidans, A. caldus, as well as some heterotrophic bacteria Bacillus subtilis and paenibacillus polymyxa—play the dominant role in the removal of inorganic sulfur. Mixed cultures and associations of mesophilic and thermophilic bacteria isolated from coal mines or from the coal surface structure are considered an effective tool in the biosulfurization of pyrite sulfur. The prospects of microbial desulfurization of organic coal sulfur with the use of heterotrophic microorganisms of the genera Pseudomonas, Sulfolobus, Rhodococcus, the fungi Agrocybe aegerita and Alterneria sp., the bacterial–fungal consortia Sulfolobus solfataricus and Phanerochaeta chrysosporium ME446, and the laccase enzyme of the basidiomycetes Trametes versicolor ATCC 20080 are examined.

Experimental Study on Organic Sulfur Removal in Bituminous Coal by a 1-Carboxymethyl-3-methyl Imidazolium Bisulfate Ionic Liquid and Hydrogen Peroxide Solution.

In order to improve the total sulfur removal rate in coal combustion, an acidic ionic liquid (IL) 1-carboxymethyl-3-methylimidazolium hydrogen sulfate ([HOOCCH2mim][HSO4]) as the extractant combined with the oxidant 30% hydrogen peroxide (H2O2) was applied to reduce the total sulfur content, and its microscopic mechanism of desulfurization was analyzed. The experimental results show that the desulfurization rate of the [HOOCCH2mim][HSO4]–H2O2 (1:10) solution was 45.12% and the organic sulfur removal rate was 16.26%, which were significantly higher than those of only H2O2 or pure [HOOCCH2mim][HSO4]. Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy analyses showed that the mercaptan −SH and disulfide −S–S– in coal decreased after being treated with IL–H2O2. In particular, the results of FTIR spectroscopy indicated that the relative proportion of −S–S–and −SH treated with IL–H2O2 (1:10) decreased by 31.9 and 27.2%, respectively, compared with that of a pure IL. This is due to H2O2 oxidation; −SH and −S–S– were oxidized to sulfoxide and then the sulfoxide transferred from the coal phase to the IL phase, which improved organic sulfur removal from coal. Therefore, the combination of an ionic liquid and H2O2 could increase the total desulfurization rate. In addition, the thermogravimetric analysis of coal is divided into four different stages; the weight loss during the combustion stage and the residues show that the IL–H2O2 could improve the coal combustion because of good previous swelling and destruction of bridge bonds and hydrogen bonding of coal. Besides, the fewer residues in IL–H2O2-treated coals also indicate that a less amount of inorganic substance is left in coal after IL–H2O2 desulfurization, which is consistent with the desulfurization results.

Elektron Transfer Yöntemiyle Kömürden Organik Sülfürün Desülfürizasyonuna Klasik ve Mikrodalga Isıtmanın Etkisi

A novel experiment was carried out for the removal of organic sulphur by electron transfer process. In these experiments, the effect of conventional and microwave heating were investigated on desulfurization of organic sulphur. The aim of the study was formed soluble metal-organic sulfur bonds using Pd+2, Sn2+ and Sb3+ metal ions of variable valence state. In this way, it was tried to create a mechanism that cleavage the C-S bonds. Desulfurization is occur by breaking the aliphatic sulfur bonds of metal ions with high negative oxidation potential. As a result of the studies, the 24.30% of total sulfur was removed with Pd2+ ion. In microwave heating, it was determined that higher organic sulfur was removed in less leaching times.

Effect of pre-desulfurization process on the sulfur forms and their transformations during pyrolysis of Yanzhou high sulfur coal

To achieve the utilization of high sulfur coals efficiently and economically, the effects of different pre-desulfurization processes including flotation, acid washing, ultrasonication and stepwise treatment on sulfur removal and changes of sulfur forms in a high sulfur coal, sulfur transformation behavior during pyrolysis and sulfur distribution in char were investigated. Flotation removed almost all the sulfate and partial pyrite from the raw coal, while ultrasonication was more effective in removing some low molecular-weight organic sulfur together with weakening the C-S bond in some sulfur species. The process of HCl-HF-HNO3 and stepwise treatment reduced the ash content and sulfur content to a larger extent, with ultrasonication after flotation and acid treatment having the highest sulfur removal from raw coal. The sulfur forms on coal surface were more modified after different pre-desulfurization processes, together with different sulfur transformations during pyrolysis. The accumulated amount of sulfur-containing gases during pyrolysis of coals after stepwise treatment, in particular of coals treated by the combination of flotation, acid washing and ultrasonication, generated the highest amount of sulfur-containing gases. For the utilization of high sulfur coals, in particular, of high organic-sulfur coals, the above-mentioned treatment of combination of traditional flotation technique and organic sulfur removal process should be considered, which could remove the inorganic sulfur and organic sulfur simultaneously, and release the most sulfur-containing gases during pyrolysis. Besides, it would be helpful to choose the utilization methods based on the sulfur species in raw coal, and the effect of pre-desulfurization process on sulfur transformation behavior.

Evaluation on the microwave-assisted chemical desulfurization for organic sulfur removal

Coal desulfurization is imperative to create clean coal and reducing harmful emissions during the combustion process. However, organic sulfur in coal is more difficult to remove than inorganic sulfur. Therefore, in this paper, a method of coal sample desulfurization using citric acid with microwave assisted was proposed, and experimental investigation was carried out. The influences of the particle size, reaction temperature, irradiation time, microwave power, and concentration of citric acid on desulfurization effect were studied and the corresponding optimal value was determined. The desulfurization effect was improved; the remove efficiencies of the total sulfur, organic sulfur and inorganic sulfur were 34.25%, 59.86% and 20.23%, respectively. In addition, XRD and FTIR were used to test and compare the coal samples before and after the experiment, and it was found that pyrite was transformed into H2S, S and the Fe2+ which was combined with citric acid to form a complex; The carbon-sulfur bond of sulfonate and the iron-sulfur bond of ferrous sulfide are both broken; Clean coal has a smoother surface. In general, microwave-assisted citric acid could potentially remove organic sulfur without any significant interference of the calorific value on coal. And compared with other desulfurizers, citric acid has the advantages of good desulfurization effect (especially organic sulfur), non-toxic, low corrosion and low cost, etc. The current research work may provide new routes and meaningful guidelines to pre-combustion desulfurization of coal.

Combustion behaviour and chemical structure changes of enzyme-treated coal

As one of the technologies for the improvement in coal quality, biological enzyme technology has received much attention. The enzyme product named 3EC was shown to enhance the power plant performance in our previous full-scale test. In this work, its effect on coal was explored. The results indicated that the enzyme product was beneficial in the removal of organic sulphur from coal, and the catalytic action of 3EC on the cleavage of C–C and C–S bonds was proven based on data from the dibenzothiophene decomposition test. Thus, when it was used to treat coal, the CH3-to-CH2 ratio changed from 0.81 to 0.32 with an increase in treatment time, which indicated that some chemical structures in the enzyme-treated coal changed. Because of these structural changes, the combustion behaviour of coal improved, indicated by the increase in the comprehensive combustion index from 2.958 × 106 to 3.113 × 106 %2 min−2 K−3 and the decrease in activation energy from 32.76 to 30.43 kJ mol−1. In addition, the optimum enzyme treatment time should be 4 days to ensure enough reaction time between the enzyme and the coal.

Experimental and Computational Study of Organic Sulfur Removal Proficiency of (Ni, Cu, Co)‐Doped ZIF‐8 Adsorbents

AbstractThe synthesis and characterization of a series of metal‐doped ZIF‐8 (metal=Ni, Co and Cu) has been introduced to gain the highly efficient adsorption of dibenzothiophene (DBT) in liquid phase. Under 150 ml DBT/iso‐octane, 100–1700 ppm, and 25–85 °C, the excellent efficiency and reusability in DBT removal was achieved and fitted better with the pseudo‐first order reaction. The maximum adsorption of 191.84 mg S/g for Ni/ZIF‐8 and two steps for intraparticle diffusion study contrary to Cu‐ and Co‐ZIF‐8 suggested the presence of Ni‐HMeIM clusters in ZIF‐8 cavities. Comparing the performance of prepared adsorbents, the order of qmax and PC was the same, i. e. PC Ni/ZIF‐8> PC Cu/ZIF‐8>PC Co/ZIF‐8>PC ZIF‐8 and qmax (Ni/ZIF‐8)> qmax (Cu/ZIF‐8)> qmax (Co/ZIF‐8)> qmax (ZIF‐8) for both 10% and 100% BT. The prepared adsorbents had the FoMs ranging from 0.05‐0.07 that compared to other adsorbents showed the beneficial use for large scale desulfurization process. The endothermic behavior and a homogeneous adsorption was then indicated through thermodynamic and equilibrium studies.

Comparing product distribution and desulfurization during direct pyrolysis and hydropyrolysis of Longkou oil shale kerogen using reactive MD simulations

The product distribution and organic sulfur removal during direct pyrolysis and hydropyrolysis of oil shale kerogen were investigated via reactive molecular dynamics (RMD) simulations with reactive force field (ReaxFF). Two structural models for direct pyrolysis and hydropyrolysis of kerogen were constructed about kerogen extracted from Longkou oil shale to investigate the impact of H2 at different temperatures on the product distribution and reaction processes of oil shale. The experimental results show that hydropyrolysis could increase light shale oil (the most important product in shale oil industry), and improve the removal rate of organic sulfur simultaneously. It was found that comparing to the direct pyrolysis, hydropyrolysis can provide more H free radicals to participate in the reaction and therefore promoting the pyrolytic reaction of kerogen. In addition, hydropyrolysis greatly promoted the desulfurization due to the contribution to the production of H2O molecules, and the transfer of sulfur to the gas products requires the participation of H2O molecules. This work is an intensive study on hydropyrolysis mechanism at different temperatures at the atomic level. These conclusions could be helpful for the clean utilization technology of oil shale industry.

Desulfurization of Giral lignite of Rajasthan (Western India) using Burkholderia sp. GR 8–02

ABSTRACT Present investigation entails the results of desulfurization of high sulfur Giral (Rajasthan-India) lignite with the help of Burkholderia sp. GR 8–02. Total sulfur varies from 3.73% to 7.91%, where inorganic sulfur is 2.17–3.82%, pyritic and Sulfate sulfur is 0.90–2.42% and 0.47–2.84%, respectively. Chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS) were used in order to understand desulfurization. Bacterial treatment caused a significant reduction in total sulfur content ranging from 23.59% to 37.55%. Organic sulfur removal ranges from 11.06% to 20.54% while pyritic and Sulfate sulfur removal vary from 10.40–43.39% and 50.89–96.97%, respectively. In addition to desulfurization of lignite, the reduction in the ash yield and the volatile matter was also observed whereas there was a relative increase in the fixed carbon and elemental carbon content. Further, an increase in the gross calorific value from 3189 kcal/kg to 3482 kcal/kg was noticed.

Modification of zeolite by metal and adsorption desulfurization of organic sulfide in natural gas

The metal modified zeolite was prepared by impregnation combined with roasting and the adsorption performance of organic sulfur in natural sulfur was evaluated. The zeolite type, ion concentration, calcination temperature, anion and cationic species all have effect on the desulfurization performance. Anions have a great influence on the performance of the zeolite modified by copper ions. Ag/13X had the highest adsorption capacity to methyl sulfide and the adsorption capacity increased by 1.6 times than that of the unmodified 13X zeolite. The order of adsorption capacity to sulfide by Cu/13X is ethyl mercaptan > methyl sulfide > dimethyl disulfide. And the adsorption capacity to the mixed sulfide is greater than that of the single sulfide, but less than the sum of the single sulfides. After regeneration by calcination, the adsorption capacity is basically recovered. Metal-modified zeolites are well suited for the deep removal of organic sulfur from natural gas.

Desulfurization of high sulfur fine coal using a novel combined beneficiation process

The throughputof high-ash and high-sulfur fine-grain coal (0–6 mm) increases year by year. The seriousproblemof direct combustion is the formation of acid rain and smog. Therefore, the pre-combustion desulfurization and ash reduction can reduce environmental pollution. A combined process of dry separation and microwave desulfurization for the cleaning of the 0–6 mm fine coal was applied. The effectsofgas velocity, vibration amplitude and frequency on the removal ofinorganic sulfurwere analyzed systematically. At the same time, the effects of additives, microwave power, irradiation time and temperature on the removal of organic sulfur in the microwave desulfurization reactorwere investigated. The results show that the compounddry separator cansorts the 0–6 mm fine coal under the optimal operating parameters (A = 3 mm, f = 22.5 Hz, v = 0.68 m3/s). After the separation, the yield, ash and sulfur contents of the pre-separatedclean coalis 63.6%, 12.4% and 4.12%, respectively.The compounddry separatorcan effectively remove mineral impurities such as inorganic sulfur. The ash is reducedapparently.However,the organic sulphide cannot be removedby the separator. Asthe pre-separatedclean coal has high sulfur content thatis mainly organic sulfide, the microwave desulfurization reactoris used to remove this part of organic sulfur. The results show that the NaOH solution additive is more beneficial to improve the microwave desulfurization. The desulfurization rate increase with the increasing of temperature and radiationtime and the irradiation time has amore obviouseffect. After the microwave desulfurization the yield, sulfur and ash contents of the clean coal are60.8%, 0.98% and 9.74%, respectively. As a result, the microwave desulfurization processcan effectively remove the organic sulfur compounds.

Oxidative desulfurization of dibenzothiophene with molecular oxygen using cobalt and copper salen complexes encapsulated in NaY zeolite

Abstract The objective of the research is to develop a new method for removal of organic sulfur in liquid fuels. Cobalt and copper salen (salen=N, N’-bis(salicylidene)ethylenediamine) complexes were simultaneously encapsulated in zeolite NaY by using the flexible ligand method, and employed as catalysts in the oxidation of dibenzothiophene (DBT) with molecular oxygen as the oxidant. The material was substantiated by UV–Vis spectroscopy, thermo-gravimetric and differential-thermal analyses, X-ray powder diffraction as well as scanning electron microscope. Effect of various parameters including reaction temperature, initial concentration of DBT, molar ratio of Cu to Co and recycle of the material were investigated. The prepared bimetal material showed much higher activity than single metal salen complexes CusalenY and CosalenY due to the synergetic effect of Cu2+ and Co2+. The desulfurization process was mainly governed by the activation of molecular oxygen using (Cu-Co)salenY. The results prove the feasibility of the proposed desulfurization process for industrial application.

Comparative transcriptomic analysis revealed the key pathways responsible for organic sulfur removal by thermophilic bacterium Geobacillus thermoglucosidasius W-2

Biodesulfurization is a promising method to desulfurize sulfur-containing compounds in oil with its unique advantages, such as environment-friendly treatments and moderate reaction conditions. In this study, a thermophilic bacterium Geobacillus thermoglucosidasius W-2 was reported to show nearly 40% and 55% desulfurization rates on heavy oil with 2.81% and 0.46% initial total sulfur content, respectively. Subsequently, comparative transcriptome analysis indicated that several possible key desulfurization-related genes of this strain were found to be differentially up-regulated induced by benzothiophene and dibenzothiophene, respectively. These desulfurization-related genes were considered to conduct key step to convert organic sulfur to inorganic sulfur. Moreover, the characterization of thermophilic alkanesulfonate monooxygenase systems SsuD1/SsuE1 and SsuD2/SsuE2 revealed that the enzymes exhibit considerable thermal and pH stability and wide substrates applicability. These enzymes probably endowed the strain W-2 with the ability to desulfurize oil and eliminate the sulfur-containing surfactants. Thus, this study provides novel alkanesulfonate monooxygenase systems that have the application potential for heavy oil biodesulfurization, oil demulsification and other biocatalytic processes.

Effect of steam on the transformation of sulfur during demineralized coal pyrolysis

This study focused on the effect of steam on the transformation of sulfur during pyrolysis of demineralized coal in a horizontal tube furnace within the range of temperatures from 300 to 800 °C. The main sulfur-containing products in the resulting pyrolysis gases including H2S, SO2, and COS were quantitatively measured using ion chromatography combined with Fourier-transform infrared spectroscopy gas analyzer. The transformation of pyrite in char was assessed based on X-ray diffraction, while the organic sulfur was determined using both an infrared sulfur analyzer and X-ray photoelectron spectroscopy. The experimental results indicated that sulfur in the demineralized coal was primarily converted to H2S during pyrolysis under both argon and steam/argon atmospheres. During steam/argon pyrolysis, the steam promoted the formation of H2S while inhibiting the formation of SO2, thus increasing and decreasing the yields of these two compounds, respectively. In the argon atmosphere, the pyrite decomposed completely into pyrrhotite at 500 °C and was then converted to troilite at 600 °C. In the steam/argon atmosphere, different iron-containing compounds (Fe1−xS, Fe3O4, and FeO) were formed during the demineralized coal pyrolysis. The promotion of the pyrite transformation by steam was especially pronounced at temperatures above 500 °C. The organic sulfur removal was found to increase likely because the addition of steam above 500 °C promoted the decomposition of thiophenic sulfur.

Removal of Organic Sulfur in Hydrocarbon Liquid Model Fuel by Ni-Loaded Carbon Prepared from Lignite

The removal of dibenzothiophene (DBT) in a hydrocarbon liquid model fuel (MF) by Ni-loaded carbon (Ni/C) prepared from lignite has been studied with a flow-type fixed-bed reactor. The performance o...

Desulfurization of coal using four ionic liquids with [HSO4

Sulfur dioxide produced from Coal-fire power plant are the main sources of air pollution and PM2.5 (the aerodynamic diameter less than or equal to 2.5 μm) which may result in multiple short term and long term health impacts. In this investigation, four ionic liquids, i.e. 1-butyl-3-methyl imidazolium bisulfate([C4C1im][HSO4]), 1-carboxymethyl-3-methylimidazolium bisulfate([HOOCCH2mim][HSO4]), N-butylpyridinium bisulfate([C4Py][HSO4]) and 1-carboxymethyl-3-methylpyridinium bisulfate([HOOCCH2Py][HSO4]), were used to remove sulfur from coal combining with 30% hydrogen peroxide (H2O2) based on chemically oxidative desulfurization. The experimental results of FTIR and XPS indicate that ionic liquids could enhance the oxidation of organic sulfur in H2O2, where [HOOCCH2mim][HSO4]-H2O2 solution can remove 16.76% of organic sulfur, much better than the single 30% H2O2 aqueous solution. Generally, imidazolium ionic liquids are more favorable for organic sulfur removal compared to pyridinium ones. Carboxyl group tethered on imidazolium cation could improve the oxidability of H2O2 due to the formation of peroxycarboxylic acid group. The stronger intramolecular H-bonding interaction of pyridinium ionic liquids is the structural reason for their relatively weak sulfur removal ability.