Sulfur transformation in coal during supercritical water gasification

Meng, Nan; Jiang, Dandan; Liu, Yang; Gao, Zhiyuan; Cao, Yaqin; Zhang, Jinli; Gu, Junjie; Han, You

doi:10.1016/j.fuel.2016.08.097

Cited by 56 publications

(22 citation statements)

References 50 publications

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“…Meng et al studied sulfur transformation in coal during SCW process at temperature 350 to 550 °C and affirmed H 2 S was the main gaseous sulfur product. 20 However, the temperature was relatively lower than 700 °C for coal complete gasification, 21 and the sulfur transformation characteristics above 550 °C were not explored.…”

Section: Introductionmentioning

confidence: 99%

Sulfur Transformation Characteristics and Mechanisms during Hydrogen Production by Coal Gasification in Supercritical Water

Liu

Guo

et al. 2017

Energy Fuels

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Coal supercritical water gasification (SCWG) is famous for generating clean gas without SO x pollutant. Study of sulfur transformation characteristics can provide the basis of sulfur removal during hydrogen production by coal gasification in supercritical water (SCW) at the source. In this work, two coals produced from Linfen and Zhangjiamao in China (hereinafter to be referred as L-coal and Z-coal), were chosen as experimental feedstocks to investigate sulfur transformation characteristics during hydrogen production by coal gasification in SCW (550−750 °C, 20 min, 25 MPa). Sulfur transformation pathway and sulfur forms in the products were complex but detected comprehensively. H 2 S was the only gaseous product instead of SO x , whereas SO 4 2− was the main liquid−sulfur product. Inorganic and organic sulfur compounds were used to investigate sulfur transformation mechanisms. H 2 S had three sources as follows. First, among inorganic sulfur of raw coal, FeS 2 (Pyrite) was chemically stable in SCW lacking of hydrogen. When FeS 2 was in hydrogen atmosphere, H 2 S was generated and FeS 2 was converted to Fe 1−x S and Fe 3 O 4 under SCW. Second, H 2 S came from unstable sulfate minerals such as FeSO 4 which may decompose and be converted to Fe 3 O 4 . Third, organic sulfur, especially thiophene sulfur transformed to H 2 S. The two sulfur products H 2 S and SO 4 2− depend on H or OH free radical in SCW. More H free radical provided a reducing environment of SCW to generate H 2 S at higher temperatures, whereas more OH radical provided an oxidizing environment of SCW to generate SO 4 2− at lower temperatures, but the final trend was generating H 2 S when coal gasified completely at a higher temperature. The results of this study may provide an experimental basis of solving the SO x emission from coal at the source and demonstrate a promising clean utilization way of coal.

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Section: Introductionmentioning

confidence: 99%

Sulfur Transformation Characteristics and Mechanisms during Hydrogen Production by Coal Gasification in Supercritical Water

Liu

Guo

et al. 2017

Energy Fuels

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“…H 2 S is a colorless, highly toxic gas with an unpleasant odor. The Chinese "Coal Mine Safety Regulations" states that the H 2 S concentration of coal mine gas is considered abnormal if it concentration is greater than 6.6 ppm 1 – 3 . Such concentrations present a serious threat to life and property in well mines due to the risk of H 2 S outburst 3 – 6 .…”

Section: Introductionmentioning

confidence: 99%

“…The Chinese "Coal Mine Safety Regulations" states that the H 2 S concentration of coal mine gas is considered abnormal if it concentration is greater than 6.6 ppm 1 – 3 . Such concentrations present a serious threat to life and property in well mines due to the risk of H 2 S outburst 3 – 6 . In recent years, more than 10 people have died in H 2 S disasters in mines in Xinjiang, Sichuan, Hunan, Chongqing and elsewhere in China, and H 2 S poisoning incidents have led to shutdowns in Shandong, Shanxi and Henan provinces 4 – 7 , 22 .…”

Section: Introductionmentioning

confidence: 99%

Genesis, controls and risk prediction of H2S in coal mine gas

Xie

Wang

et al. 2021

Sci Rep

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Abnormal H2S concentration in coal mine gas is a serious threat to normal mining activities, which has caused serious loss of life and property in many coal mines. This study explores the genesis and influencing factors of abnormal H2S concentration in coal mine gas, taking the Xishan coal mine in the Fukang mining area as a case study. The H2S formation by bacterial sulfate reduction (BSR) is simulated with a bacterial culture experiment and that by thermochemical sulfate reduction (TSR) is simulated with a thermal reduction experiment. The potential for a magmatic genesis is assessed using data regarding the tectonic evolution and history of magma intrusion in the study area. The factors influencing H2S formation and enrichment are then analyzed by a comprehensive consideration of the characteristics of coal, the gas composition, the coal seam groundwater geochemistry and other geological factors in the study area. The results show that the study area meets the necessary conditions for the BSR process to operate and that there is widespread BSR derived H2S. TSR genesis H2S mainly forms in coal fire areas and their vicinity, while there is little contribution from magmatically formed H2S. The concentration of H2S is negatively correlated with the buried depth of the coal seam, the concentrations of CH4, N2 and CO2, and the ash yield; and it is positively correlated with the volatiles yield and total sulfur content. In addition, in areas with abnormally high H2S concentration, the concentration of SO42− is obviously lower, HCO3− + CO32− concentration is higher, and the HCO3−/SO42− value is larger than that in non-anomalous areas. Geologically, H2S enrichment is found to be controlled by lithology, tectonism, and hydrogeological conditions. Moreover, the results of predictive modeling show that areas prone to abnormal H2S concentration are generally spatially correlated with coal fire areas. In this study, the genetic types of H2S and the factors controlling their formation and retention are discussed, producing research results that have guiding significance for the prediction and prevention of the coal mine disasters that arises from abnormal H2S concentration.

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“…The hypothesis postulated that mild acid resulting from the FW during Co-HTC enhances the sulfur removal from coal waste. There are three main forms of sulfur, namely, sulfate sulfur, pyritic sulfur, and organic sulfur, which can be found in coal as well as biomass [5,6].…”

Section: Introductionmentioning

confidence: 99%

Transformation of Sulfur during Co-Hydrothermal Carbonization of Coal Waste and Food Waste

Saha

Mazumder

et al. 2021

Energies

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Co-hydrothermal carbonization (Co-HTC) is an emerging technology for processing multiple waste streams together to improve their fuel properties in the solid product, known as hydrochar, compared to the hydrothermal carbonization (HTC) of those individual streams. Sulfur is considered one of the most toxic contaminants in solid fuel and the combustion of this sulfur results in the emission of SOx. It was reported in the literature that, besides the fuel properties, Co-HTC reduced the total sulfur content in the hydrochar phase significantly. However, the transformation of different forms of sulfur has not yet been studied. Therefore, this study investigated the transformation of different forms of sulfur under the Co-HTC treatment. In the study, the Co-HTC of food waste (FW) and two types of coal wastes (middle bottom (CW1) and 4 top (CW2)) were conducted at 180 °C, 230 °C and 280 °C for 30 min. Different forms of sulfur were measured by using elemental analysis (total sulfur), and a wet chemical method (sulfate sulfur and pyritic sulfur). The organic sulfur was measured by the difference method. The results showed that a maximum of 49% and 65% decrease in total sulfur was achieved for CW1FW and CW2FW, respectively, at 230 °C. Similar to the total sulfur, the organic sulfur was also decreased about 85% and 75% for CW1FW and CW2FW, respectively. Based on these results, a sulfur transformation mechanism under Co-HTC treatment was proposed.

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Sulfur transformation in coal during supercritical water gasification

Cited by 56 publications

References 50 publications

Sulfur Transformation Characteristics and Mechanisms during Hydrogen Production by Coal Gasification in Supercritical Water

Sulfur Transformation Characteristics and Mechanisms during Hydrogen Production by Coal Gasification in Supercritical Water

Genesis, controls and risk prediction of H2S in coal mine gas

Transformation of Sulfur during Co-Hydrothermal Carbonization of Coal Waste and Food Waste

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