Sulfur-containing Gases Research Articles

A novel process of low-temperature fractionation combined with extractive distillation for H2S removal from natural gas

H2S is a common component of natural gas. In order to meet the quality standards for U.S. commodity natural gas that contains less than 5.7 mg/m3 of H2S, it is necessary to process the natural gas to remove H2S. Since H2S will form azeotropes with ethane and propane in natural gas, it is impossible to achieve complete separation of H2S by ordinary distillation columns. Therefore, a novel low-temperature fractionation combined with extractive distillation process is proposed and designed, which can achieve the removal of H2S from sulfur-containing natural gas and obtain sweet gas(almost pure methane), ethane product and H2S gas. The process consists of three steps: demethanization with low temperature, deethanization with extractive distillation and H2S recovery. Extensive simulation and analysis have confirmed that extractive distillation using high molecular weight, high boiling point benzene homologs (toluene, o-Xylene, p-Xylene, m-Xylene) as extractant is a good method to separate ethane-H2S azeotrope. Furthermore, the effects of parameters such as the number of column stages, the reflux ratio, the location of feed stream inlet stage, the type of extractants, the inlet stage location of extractant, the molar flow rate of extractant on the product purity and the column duty have been studied, and the optimal applicable ranges of different parameters are finally determined. The simulation results show that o-Xylene is the best extractant for the separation of ethane and H2S. Under the economic optimization, the minimum total annual cost for the demethanizer is $952,611 per year and the minimum total annual cost for the deethanizer is $2,026,364 per year.

Sulfur Evolution and Capture Behavior by a Solid Waste of Red Mud during Chemical Looping Combustion of Petroleum Coke

The sulfur evolution behavior during the chemical looping combustion (CLC) process of petroleum coke was investigated in a fluidized bed reactor with a low-cost solid waste of red mud as the oxygen carrier. Effects of temperature, oxygen carrier, and potassium catalyst addition on sulfur release were investigated, and H2S oxidization kinetics with the red mud and the effect of elements in the red mud on sulfur conversion were evaluated in detail. The red mud oxygen carrier had a promoting effect on H2S generation and thus enhanced sulfur conversion. The addition of potassium remarkably accelerated carbon conversion due to its catalytic effect. Meanwhile, it promoted H2 generation and then enhanced the generation of H2S. The addition of potassium into the process could weaken the release of gaseous sulfur but had no obvious negative influence on the reactivity of the red mud oxygen carrier. The experiment H2S interaction with the red mud suggested that the conversion of H2S to SO2 decreased with increasing temperature. The red mud has a low ability to oxidize H2S to SO2 but a high reactivity to capture sulfur-containing gases. Solid sulfur-containing products such as CaSO4 and Fe3S4 as well as K2S2 in the case of K addition into the process were detected.

Tuning the selective sensing properties of transition metal dichalcogenides (MoX2: X= Se, Te) toward sulfurrich gases

There is an urgent need for an efficient sensor to mitigate the effects of toxic pollutants possessing severe impacts on humans and the environment. Motivated by this, we investigated the selected transition metal dichalcogenides (MoX2: X = Se, Te) monolayers toward the toxic sulfur-containing gases, such as H2S and SO2. We employed density functional theory simulations in combination with nonequilibrium Green's function formalism to study the optimized geometries, binding strength, electronic structures, charge transfer mechanism, and transport (current–voltage) characteristics of MoX2 with and without H2S and SO2. Weak binding energies (<-0.30 eV) of H2S/SO2 on pristine MoX2 were enhanced by selectively substituting the latter with elements like As, Ge, and Sb at lower doping concentrations of around 2%. We find that the doped MoX2 strongly adsorbs H2S/SO2 yielding significant changes in their electronic properties, which were the fundamentals for the efficient sensing mechanism and were studied through the density of states and work function calculations. For the practical sensing applications, we considered the statistical thermodynamic analysis to investigate the sensing properties of pristine and doped MoX2 monolayers under varied conditions of the temperatures and pressures. We are confident that our findings would pave the way for synthesizing sensitive and selective transition metal dichalcogenides-based nanosensor toward H2S/SO2.

Experimental study on dynamic release and transformation of sulfur during pyrolysis of Shanxi high-sulfur anthracites based on MFBRA and XPS

Pyrolytic desulfurization of two Shanxi high-sulfur anthracites was investigated experimentally under hydrogen atmospheres using a micro fluidized bed reaction analyzer (MFBRA), the dynamic release behavior of sulfur-containing gas during pyrolysis was characterized by a rapid online gas analyzer, and the transformation between sulfur-containing components in the resultant char was analyzed based on morphological and XPS characterizations. The results show that the dynamic release of sulfur-containing gas features two intensity peaks at 530–560 °C and 812–830 °C, respectively, indicating that the sulfur release proceeds by two subsequent processes: the reduction reaction of pyrite and the organic sulfur decomposition. The migration from inorganic to organic sulfur occurs predominately at lower temperatures, while the transformation between different forms of organic sulfur components is dominant at higher temperatures. Overall, the anthracite coal with a higher organic sulfur content has a higher sulfur removal efficiency in the hydrogen atmosphere. The research results provide the essential data supporting the development of highly efficient pyrolysis desulfurization technology for clean and efficient utilization of high sulfur anthracite coal resources.

Atmospheric Corrosion of Silver and Silver Nanoparticles

Even though it is a noble metal, silver will corrode in ambient atmospheres, predominantly by reacting with sulfur-containing gases such as hydrogen sulfide (H2S) and carbonyl sulfide (OCS) to form the silver sulfide (Ag2S) acanthite. Other aspects of the environment, such as relative humidity and the presence of oxidizing species, also play a critical role. With the emergence of silver nanoparticles for a range of technological and medical applications, there has been a revival of interest in the corrosion behavior of this important metal. This article reviews the current understanding of the atmospheric corrosion of silver in both the bulk and nanoparticle forms. Gaps in our current understanding and areas for future investigation are identified.

DFT exploration of adsorptive performances of borophene to small sulfur-containing gases.

Density functional theory (DFT) calculations were applied to study the ability of B36 to adsorb H2S, SO2, SO3, CH3SH, (CH3)2S, and C4H4S gases. Several exchange-correlation including B97D, PBE, B3LYP, M062X, and WB97XD were utilized to evaluate adsorption energies. The initial results showed that boundary boron atoms are the most appropriate interaction sites. The adsorption energies, electron density, electron localized function, and differential charge density plots confirmed the formation of chemical covalent bonds only between SOx and B36. The results of thermochemistry analysis revealed the exothermic nature of the adsorption of sulfur-containing gases on B36; the highest values of ∆H298 were found for SO3/B36 and SO2/B36 systems. The electronic absorption spectra and DOS of B36 did not exhibit significant variations after gases adsorption, while the modeled CD spectra showed a remarkable change in the case of the SOx/B36 system. Accordingly, B36 is not suggested for detecting the studied gases. The effect of imposing mono vacancy defect and external electric field to the adsorption of titled gases on the sorbent showed, while the former did not affect the adsorption energies significantly the later improved the adsorption of gas molecules on the B36 system. The results of the current study could provide deeper molecular insight on the removal of SOx gases by B36 system.

Marine gas-phase sulfur emissions during an induced phytoplankton bloom

Abstract. The oxidation of dimethyl sulfide (DMS; CH3SCH3), emitted from the surface ocean, contributes to the formation of Aitken mode particles and their growth to cloud condensation nuclei (CCN) sizes in remote marine environments. It is not clear whether other less commonly measured marine-derived, sulfur-containing gases share similar dynamics to DMS and contribute to secondary marine aerosol formation. Here, we present measurements of gas-phase volatile organosulfur molecules taken with a Vocus proton-transfer-reaction high-resolution time-of-flight mass spectrometer during a mesocosm phytoplankton bloom experiment using coastal seawater. We show that DMS, methanethiol (MeSH; CH3SH), and benzothiazole (C7H5NS) account for on average over 90 % of total gas-phase sulfur emissions, with non-DMS sulfur sources representing 36.8 ± 7.7 % of sulfur emissions during the first 9 d of the experiment in the pre-bloom phase prior to major biological growth, before declining to 14.5 ± 6.0 % in the latter half of the experiment when DMS dominates during the bloom and decay phases. The molar ratio of DMS to MeSH during the pre-bloom phase (DMS : MeSH = 4.60 ± 0.93) was consistent with the range of previously calculated ambient DMS-to-MeSH sea-to-air flux ratios. As the experiment progressed, the DMS to MeSH emission ratio increased significantly, reaching 31.8 ± 18.7 during the bloom and decay. Measurements of dimethylsulfoniopropionate (DMSP), heterotrophic bacteria, and enzyme activity in the seawater suggest the DMS : MeSH ratio is a sensitive indicator of the bacterial sulfur demand and the composition and magnitude of available sulfur sources in seawater. The evolving DMS : MeSH ratio and the emission of a new aerosol precursor gas, benzothiazole, have important implications for secondary sulfate formation pathways in coastal marine environments.

Comparative analysis of the main occupations working conditions in the copper production by pyrometallurgical and hydrometallurgical methods in Russia

Introduction. The primary materials for copper production are sulfide copper-nickel and oxidized ores with a copper percentage of 1.5-4%, traditionally processed by the pyrometallurgical method. For processing depleted copper-containing raw materials (less than 1%), the pyrometallurgical approach is not commonly suitable. The introduced hydrometallurgical way differs by including in one production process, combined underground leaching of ore, extraction of copper from solution, and the following electrolysis. At the same time, insufficient attention is paid to the hydrometallurgical method of processing depleted copper raw materials from a hygienic standpoint in our country. Materials and methods. Based on the results of our research carried out at copper-smelting plants using pyro- and hydrometallurgical methods of processing raw materials, a comparative analysis was carried out for such indicators as the pollutants content in the workplaces’ air at different stages of production, predicted values of occupational cancer risks, toxicity indicators, and the health and essential physiological functions of workers. Results. Working under increased heat intensity in hot shops, exposure to sulfur-containing gases and industrial aerosols leads to significant changes in hemodynamics and thermoregulation stress in workers. In the hydrometallurgical production of copper, the only occupational hazard exceeding hygienic standards is sulfuric acid vapours, and changes in physiological parameters and thermoregulation are insignificant. The predicted values of occupational cancer risk for hydrometallurgical machines operators exceed the acceptable level after 9-10 years of working experience. For smelters, an unacceptable level of risk is achieved with up to 5 years of working experience. Conclusion. For the first time in the country, a hygienic assessment of the hydrometallurgical method of processing depleted copper raw materials was proved to be the only appropriate method of improving working conditions in copper production.

Modeling the Solubility of Sulfur in Sour Gas Mixtures Using Improved Support Vector Machine Methods.

The study of sulfur solubility is of great significance to the safe development of sulfur-containing gas reservoirs. However, due to measurement difficulties, experimental research data on sulfur solubility thus far are limited. Under the research background of small samples and poor information, a weighted least-squares support vector machine (WLSSVM)-based machine learning model suitable for a wide temperature and pressure range is proposed to improve the prediction accuracy of sulfur solubility in sour gas. First, we use the comprehensive gray relational analysis method to extract important factors affecting sulfur solubility as the model input parameters. Then, we use the whale optimization algorithm (WOA) and gray wolf optimizer (GWO) intelligence algorithms to find the optimal solution of the penalty factor and kernel coefficient and bring them into three common kernel functions. The optimal kernel function is calculated, and the final WOA-WLSSVM and GWO-WLSSVM models are established. Finally, four evaluation indicators and an outlier diagnostic method are introduced to test the proposed model’s performance. The empirical results show that the WOA-WLSSVM model has better performance and reliability; the average absolute relative deviation is as low as 3.45%, determination coefficient (R2) is as high as 0.9987, and the prediction accuracy is much higher than that of other models.

The longtime global climatic consequences modeling of the Chicxulub asteroid impact event

Studies indicate the mass death of a significant number of biological groups on Earth, in particular - dinosaurs, at the end of the Cretaceous period 66 million years ago. Currently, there are two main theories: large-scale volcanic eruptions and the asteroid impact that formed the Chicxulub crater (Mexico). The production of sulfur-containing gases from the Earth’s surface layers vapors during impact is considered a main source of climatic effects, as they form stratospheric sulfate aerosols that block sunlight and thus cool the Earth’s atmosphere and interfere with photosynthesis. It is presented an application of the 3-D coupled global hydrodynamic climate model of intermediate complexity, including ocean model, sea ice evolution model and energy - moisture balance atmosphere model to study this asteroid impact effects on the Earth’s climate. The model continents and ocean depths distribution corresponds to Cretaceous period. A series of calculations with different residence times and deposition times of the stratosphere aerosol have been carried out. It was found that, depending on the stratosphere aerosol time parameters, the global annual average surface air temperature decreased by 18°C - 27°C, remained below zero for 4 - 30 years, and a recovery time of more than 30 years was observed.

Experimental study on mineral variation in coal under microwave irradiation and its influence on coal microstructure

Microwave technology is regarded as a promising new method for coalbed methane production. An investigation was carried out using a self-developed controllable microwave device to study the mineral variation in coal under microwave irradiation and its influence on coal microstructure. The mineral phase change, mass loss, P-wave velocity, and microstructure evolution of coal under different microwave conditions were studied using an energy dispersion spectrometer, ultrasonic detector, and scanning electron microscope. The results show that the mass loss of coal increases from slightly to significantly with microwave irradiation time, while with the increase of microwave power, it shows a trend of increasing steadily to slightly decrease. The mineral variation process includes water-soluble minerals migrating with water evaporation, sulfide minerals releasing sulfur-containing gas and the fuming of fine-grained volatile substances. Mineral variation is one of the main reasons for the damage of coal microstructure. In this process, the coal body is damaged by water vapor pressure, sulfur-containing gas and pyrolysis gas release and the fume of fine-grained materials, resulting in new pores and weak structural planes. Besides, increasing the microwave power to the power threshold and then prolonging the microwave time has significantly affected microstructure damage.

Removal of elemental mercury from flue gas using the magnetic attapulgite by Mn-Cu oxides modification.

Mercury pollution has become one of the most concerned environmental issues in the world because of its high toxicity, non-degradability, and bioaccumulation. Attapulgite adsorbents modified by magnetic manganese-copper (MnxCuy-MATP) were fabricated by co-precipitation and ultrasonic impregnation method, aiming at removing Hg0 from coal-fired flue gas. BET, SEM, XRD, VSM, and XPS were used to systematically explore the physical and chemical properties of the adsorbents, the effects of manganese and copper additions, reaction temperature, and various components in the flue gas on the efficiency of Hg0 removal were investigated. Mn8Cu5-MATP exhibited the optimal properties, and excessive copper loadings led to the aggregation of the active components. The efficiency of mercury removal can be effectively improved by NO and HCl regardless of the absence and presence of O2, because the NO+, NO3, NO2, and Cl* produced during the reaction can promote the adsorption and oxidation of Hg0. SO2 and H2O inhibited the oxidation of Hg0 because of the competitive adsorption at the active sites, while a large amount of sulfite and sulfate were formed to block the pores. However, the introduction of copper caused the sample to obtain SO2 resistance, which resulted in a mercury removal efficiency of 84.3% even under 1500 ppm SO2. In addition, after 5 cycles of adsorption and regeneration, Mn8Cu5-MATP can still maintain excellent Hg0 removal ability. The fabricated adsorbent can save the actual production cost and effectively improve the mercury removal efficiency in sulfur-containing flue gas.

Metal-Free Phosphated Mesoporous SiO2 as Catalyst for the Low-Temperature Conversion of SO2 to H2S in Hydrogen.

Highly active metal-free mesoporous phosphated silica was synthesized by a two-step process and used as a SO2 hydrogenation catalyst. With the assistance of a microwave, MCM-41 was obtained within a 10 min heating process at 180 °C, then a low ratio of P precursor was incorporated into the mesoporous silica matrix by a phosphorization step, which was accomplished in oleylamine with trioctylphosphine at 350 °C for 2 h. For benchmarking, the SiO2 sample without P precursor insertion and the sample with P precursor insertion into the calcined SiO2 were also prepared. From the microstructural analysis, it was found that the presence of CTAB surfactant was important for the incorporation of active P species, thus forming a highly dispersed, ultrafine (uf) phosphate silica, (Si-P) catalyst. The above approach led to the promising catalytic performance of uf-P@meso-SiO2 in the selective hydrogenation of SO2 to H2S; the latter reaction is very important in sulfur-containing gas purification. In particular, uf-P@meso-SiO2 exhibited activity at the temperature range between 150 and 280 °C, especially SO2 conversion of 94% and H2S selectivity of 52% at 220 °C. The importance of the CTAB surfactant can be found in stabilizing the high dispersion of ultrafine P-related species (phosphates). Intrinsic characteristics of the materials were studied using XRD, FTIR, EDX, N2 adsorption/desorption, TEM, and XPS to reveal the structure of the above catalysts.

Structural difference of gas coal separation components and its effect on sulfur transformation during pyrolysis of high sulfur coal

Two gas coals were respectively separated into four components with different vitrinite content using ZnCl2 solution. The carbon structure, composition of coal macerals and minerals, and plastic layer behavior of separating components were characterized by nuclear magnetic resonance spectrometer (13C NMR), coal petrographic analyzer, X-ray fluorescence spectrometry (XRF) and Gieseler fluidity. Combining with X-ray photoelectron spectroscopy (XPS), effect of different gas coal separation components on sulfur transformation behavior during pyrolysis of high-sulfur coal and distribution of sulfur forms in coke was investigated. The results show that with increase of vitrinite content in gas coal, the relative ratio of aliphatic carbon in coal increases, and the release amount of volatiles increases during pyrolysis; hydrogen free radicals in volatiles promote decomposition of sulfur, stabilize sulfur free radicals in time and release as sulfur-containing gases, and thus sulfur content in coke is reduced. Low density components in gas coal have the largest maximum fluidity and widest plastic range, and stability of plastic layer is the best during co-pyrolysis with high sulfur coal. The basic minerals in gas coal are mainly enriched in high density components, which leads to increase of sulfide sulfur and sulfate sulfur in the coke. For utilization of gas coal in coal-blending pyrolysis, enrichment of vitrinite and selection of coals with easier removal of alkaline minerals are beneficial for reducing sulfur in coke.

Pyrolysis Characteristics and Kinetics Analysis of Oil Sludge with CaO Additive

In the process of exploitation, transportation and refining of high-sulfur crude oil, a large number of oil sludge (OS) with high sulfur content is produced. Pyrolysis has been proved to be an effective method for OS disposal, but for solid waste with high sulfur content, lots of sulfur-containing gases will be released during thermal disposal. The addition of calcium oxide [1] in pyrolysis process is an economical and effective way to capture sulfur-containing gases. In order to understand the pyrolysis process of OS with CaO, a thermogravimetric analyzer was used to conduct pyrolysis experiments of OS with different Ca/S molar ratios (0, 1, 2, and 3) at different heating rates (10, 20, 30 and 40 °C/min). The results showed that with the increase of CaO addition the derivative thermogravimetric curves (DTG curves) showed a gentle trend. In addition, new weight loss peaks were occurred at 700∼900°C and after 1100°C, which were the decomposition of calcium carbonate and calcium sulfate, respectively. The kinetic parameters were solved by Friedman, FWO, and Starink methods, and the results were similar, with an average activation energies (E) value of 214 kJ/mol. The change trend of the activation energy followed by an increase and then a decrease corresponding to the change of energy demand for the reaction. The calculated average values of ΔH, ΔG and ΔS were about 207 kJ/mol, 447 kJ/mol and -0.3250 kJ/mol respectively. When the conversion rate was 0.5, the thermodynamic parameters reached their maximum values.

Numerical study on the effective utilization of high sulfur petroleum coke for syngas production via chemical looping gasification

This study aims at investigating the syngas production and sulfur conversion mechanisms during the chemical looping gasification (CLG) process with the industrial by-product petroleum coke (petcoke) as fuel, which is beneficial to the waste-to-energy process. The chemical kinetics including petroleum coke decomposition, char gasification, oxygen carrier reduction and the sulfur species reaction model are incorporated into the dynamic model to simulate a CLG fluidized bed reactor with iron-based oxygen carriers. Results suggest that the model is able to well predict the time-varying concentrations of the syngas products and sulfur-containing gases. The near-zero COS emission from the reactor outlet confirms the previous experimental results and contributes additional evidence that the presence of steam enhances the conversion of COS to H2S. The effects of temperature, steam and N2 flow rates on the petcoke CLG performance are also evaluated. The results indicate that higher temperature and steam flow rate lead to an improvement in the conversion of carbon and sulfur in petroleum coke. However, further increasing the gas flow rates may result in a more intense fluidization state, which might significantly facilitate the OC reduction reactions with flammable gases, thus increasing the CO2 and SO2 production in the petcoke CLG process.

Study of heterogeneous reaction of dimethyl sulfide on atmospheric-like particulate TiO2

Dimethyl sulfide (DMS) related to solar radiation and greenhouse effect is one of the most important volatile sulfides and its' oxidation products are also important contributors to acid rain. It is of great importance to study the consumption and reactions of DMS in the atmosphere. In this work, atmospheric-like particulate TiO2 was selected to study the reaction mechanism of DMS on TiO2 with the purpose to explore the possible heterogeneous oxidation of DMS. The results showed that the heterogeneous reaction of DMS with TiO2 occurred under the condition of illumination, which is a first-order-like reaction with the rate constant K = 2.83 × 10−4/s, the initial reaction uptake coefficient and the steady reaction uptake coefficient indicated the occupation of products and by-products on the surface of TiO2. The heterogeneous reaction mechanism of DMS studied by aerosol time-of-flight mass spectrometry (ATOFMS) suggested that DMS underwent a series of complex chemical reactions with sulfate and various sulfur-containing gas products, in which hydroxyl radicals might play an important role.

Mercury Speciation in Various Coals Based on Sequential Chemical Extraction and Thermal Analysis Methods

Coal combustion is an anthropogenic source of mercury (Hg) emissions to the atmosphere. The strong toxicity and bioaccumulation potential have prompted attention to the control of mercury emissions. Pyrolysis has been regarded as an efficient Hg removal technology before coal combustion and other utilization processes. In this work, the Hg speciation in coal and its thermal stability were investigated by combined sequential chemical extraction and temperature programmed decomposition methods; the effect of coal rank on Hg speciation distribution and Hg release characteristics were clarified based on the weight loss of coal; the amount of Hg released; and the emission of sulfur-containing gases during coal pyrolysis. Five species of mercury were determined in this study: exchangeable Hg (F1), carbonate + sulfate + oxide bound Hg (F2), silicate + aluminosilicate bound Hg (F3), sulfide bound Hg (F4), and residual Hg (F5), which are quite distinct in different rank coals. Generally, Hg enriched in carbonates, sulfates, and oxides might migrate to sulfides with the transformation of minerals during the coalification process. The order of thermal stability of different Hg speciation in coal is F1 &lt; F5 &lt; F2 &lt; F4 &lt; F3. Meanwhile, the release of Hg is accompanied with sulfur gases during coal pyrolysis, which is heavily dependent on the coal rank.

Sulfur release and transformation during the pyrolysis of lignite with different particle sizes

The release and transformation behavior of sulfur during the pyrolysis of lignite with different particle sizes were investigated. Results showed that reducing the particle size of lignite could promote the transfer of more sulfur into gaseous phase and then improved the desulfurization extent of char. With the reducing particle size of lignite, the release amount of H2S, COS and SO2 increased. The temperature at which pyrite was completely converted to pyrrhotite and troilite decreased. At 800 ℃, reducing the particle size intensified the capture of sulfur-containing gases by the coal matrix and alkaline minerals, resulting in the content of inorganic sulfides in char increased from 0.7 % to 0.86 %. At temperatures of 400–600 ℃, the retention of organic sulfides, sulfoxide sulfur and sulfone sulfur in char decreased with the reducing particle size. At temperatures of 700–800 ℃, the retention of thiophene-S, sulfoxide sulfur and sulfone sulfur in small particles was lower than that of large particles, while organic sulfides tended to be enriched in small particles.

Characteristics of fine particle formation during combustion of Xinjiang high-chlorine-sodium coal

Shaerhu (SEH) coal in Xinjiang province of China, with a reserve of 90 billion tons, is one of the most representative high-chlorine-alkaline coal. However, the chlorine content in coal exceeding 1% easily leads to severe problems of ash deposition and hot corrosion on tubes, which are closely related to the evolution of fine particles. In this study, the formation of fine particle from the combustion of two types of SEH coal (#1 and #2) are investigated in the temperature range of 900–1300 °C. Their results are compared with Xinjiang Tianchi (TC) coal (high-sodium but low-chlorine). In order to demonstrate the formation mechanism of fine particles, the particle size distribution, elemental composition and morphology of fine particles, as well as chlorine- and sulfur-containing gas products, are characterized. The results show that the particle size distribution of PM10 present a bimodal distribution. Fine-mode particles (PM0.4) from SEH#1 coal combustion mainly consist of NaCl since the molar ratio of Na/Cl is about 1.0, while fine-mode particles from TC coal combustion could be Na2SO4 and CaSO4. Coarse-mode particles (PM0.4-10) mainly consist of silicon, aluminum, calcium and magnesium, whose compositions are not significantly affected by combustion temperature, and calcium accounts for the largest proportion in coarse-mode particles. As the temperature increased to 1150 °C, the chlorine and sulfur in SEH coal were fundamentally associated to solid ashes, while for TC coal extra sulfur existed as the gaseous form of SO2.