An investigation into the changes of structure and reactivity during desulphurization of a bituminous coal

Majchrowicz, Bernard B.; Franco, D.; Yperman, Jan; Reggers, Guy; Gelan, Jan; Martens, Henri; Mullens, J.; Poucke, L. C. Van

doi:10.1016/0016-2361(91)90135-w

Cited by 23 publications

(5 citation statements)

References 5 publications

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“…In comparison, e.g. in a Belgian bituminous coal, about 90% of the sulfur is present in condensed thiophenic structures, while almost no aliphatic thioethers are detected (19,20). These findings are in agreement with the hypothesis of a correlation between rank and sulfur functionality (21) suggesting that, with increasing rank, the relative amount of thiophenic sulfur becomes more important.…”

Section: Discussionsupporting

confidence: 85%

Automated potentiometric determination of sulfur functional groups in fossil fuels

Majchrowicz¹,

Yperman²,

Mullens³

et al. 1991

Anal. Chem.

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A fully extended description is given of an automated setup to monltor H,S continuously in a sensltlve, qualitative, and quantltatlve way. H,S Is led by a stream of N, Into an alkallne solution and is contlnuousty determlned as S2-by a potentiometric detectlon system. The H,S detection system has been applied to the temperature-programmed reduction (TPR) of fossil fuel samples. The TPR procedure conslsts of the nonIsothermal heating of a sample in a reducing atmosphere, In order to liberate the different sulfur functional groups as H,S at dlscrete temperature ranges.

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Section: Discussionsupporting

confidence: 85%

Automated potentiometric determination of sulfur functional groups in fossil fuels

Majchrowicz¹,

Yperman²,

Mullens³

et al. 1991

Anal. Chem.

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“…Thus in order to have effective chemical desulphurization of NE region coals of India and also to utilize high sulphur assam coal as a blend (5-10%) for coke making in steel industry as well as thermal power stations with lesser SO 2 evolution, a knowledge of all the sulphur functional groups present in coal is a must. Temperature Programmed Reduction method have been reported by Attar and Dupuis [3],Majchrowicz [4] in the past and recently by E.Jorjani et al [5] for this purpose.Juntgen and Juntgen [6] and Van Heek [7]proposed a thermokinetic method involving linear temperature time program for measuring the rate and amount of sulphur evolution as a function of temperature for evaluating various sulphur functional groups .The capability for direct speciation and approximate quantification (+10%) of organic sulphur forms has also been demonstrated using XANES and XPS [8][9][10][11].XPS and XANES have also been used to establish the trend of increasing aromatic sulphur content with increasing rank [12].These studies basically establish the potential connections between the reactions of sulphur during coal metamorphism and laboratory pyrolysis as were examined by Kelemen [13] while studying the thermal reactivity of sulphur forms in coal using XANES,TPD and XPS.Thus these suggests that sulphur forms are transformed during the study by these methods and hence can not give an estimate of sulphur functional group unambiguously.Moreover,a comparison of reductive method with X-ray based instrumental techniques -XANES,XPS etc .reported by William H. Calkins [14] showed comparable trends in organic sulphur forms in coal.However, complete assignment of sulphur functional group could not be done owing to certain draw backs most importantly due to ambiguity about complete sulphur evolution from each functional group in the form of H 2 S as found in the earlier work of Juntgen and Juntgen [6], VanHeek [7], Dupuis [3],& Majchrowicz [4] and as per the work reported by Srivastava SK et al [15,16,17].…”

Section: Introductionmentioning

confidence: 94%

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2013

IOSR-JAC

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Studies for determination of sulphur functional groups present in Ledo coal of Assam State of NorthEastern Region of India were carried out using Temperature Programmed Reduction (TPR) method. TPR studies were carried out in presence of Resorcinol and hydrogen gas to arrive at the final result. TPR studies on model sulphur compounds viz. L-Cysteine, synthetic rubber, Thiokol, having hydroxyl terminal groups, thioplast, pyrite with sand, and Garlic were carried out in order to assign various sulphur functional groups present in Ledo coal. Six numbers of hydrogen sulphide evolutions from Ledo coal were observed in the temperature range of 190 -220 0 C, 260 -290 0 C, 360 -390 0 C, 460 -490 0 C, 510 -540 0 C and 590 -620 0 C corresponding to mercaptan/ disulphide (0.30), Thiol (1.70), AromaticThioether (0.50), Thiophene (0.90), pyrite + part of complex thiophene (0.60), part of complex thiophene (0.30), The thioketonic sulphur in Ledo coal is estimated to be 1.59 using controlled nitric acid oxidation experiments.

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“…Temperature-programmed reduction (TPR) is based on the principle that different organic sulfur forms present in fossil fuels have different characteristic reduction temperatures at which they will be converted to H 2 S under a hydrogen atmosphere. Initial studies − yielded poor sulfur balances, with virtually all the thiophenic sulfur remaining in the char due to the low hydrogen pressures used. Additionally, little account was taken of the reduction of pyrite to pyrrhotite and retrogressive reactions including the conversion of sulfides into thiophenes.…”

Section: Introductionmentioning

confidence: 99%

Speciation of the Organic Sulfur Forms in a Recent Sediment and Type I and II-S Kerogens by High-Pressure Temperature-Programmed Reduction

Brown¹,

Sirkecioglu²,

Snape³

et al. 1997

Energy Fuels

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Temperature-programmed reduction (TPR) with a well-swept fixed-bed reactor operating at 15 MPa of hydrogen pressure has facilitated the speciation of the organic sulfur forms in coals and petroleum source rocks through complete hydrodesulfurization with typically 75−80% of the sulfur being released as hydrogen sulfide with the remaining 20−25% occurring as primarily thiophenic compounds in the oils obtained in high yield. In this study, the technique has been applied to kerogens isolated from a series of unconsolidated Peru margin sediments, and for comparison, to type I and II-S kerogens (Göynük oil shale and Monterey Fm, respectively) from immature organic-rich rocks. Visual resolution in the hydrogen sulfide TPR evolution profiles has been achieved between mono- and di/polysulfidic forms with the latter being reduced below 250 °C. Indeed, di/polysulfides account for high proportions of the reduced sulfur in surficial sediment samples collected from close to the top of the sediment. In contrast, monosulfides are the dominant sulfur form in the sample analyzed from deeper in the Peru margin sediment where thiophenes account for up to ca. 35% of the organic sulfur. This distribution is remarkably similar to those found for both the type I and II-S kerogens investigated, indicating that the major changes in organic sulfur forms occur during the early stages of diagenesis.

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An investigation into the changes of structure and reactivity during desulphurization of a bituminous coal

Cited by 23 publications

References 5 publications

Automated potentiometric determination of sulfur functional groups in fossil fuels

Automated potentiometric determination of sulfur functional groups in fossil fuels

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Speciation of the Organic Sulfur Forms in a Recent Sediment and Type I and II-S Kerogens by High-Pressure Temperature-Programmed Reduction

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