Kinetic and quantitative studies of the formation of SO2 from iron(II) and calcium sulfates by sequential and fractionated pyrolysis

Ericsson, Ingvar; Almén, Per

doi:10.1016/0165-2370(95)00922-1

Cited by 7 publications

(4 citation statements)

References 5 publications

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“…The limitation in isothermal pyrolysis done under constant conditions is that a degradation product released from different mechanisms cannot be separated. In the fractionated pyrolysis the sample is not directly heated to the maximum temperature but heated to successive steps of increasing temperatures [18,19]. This procedure favors the release of volatile species at different temperatures and thus gives a better indication of their origin in terms of thermal stability of the related linkages.…”

Section: Py-gc/ms Experimentsmentioning

confidence: 99%

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Influence of step duration in fractionated Py-GC/MS of lignocellulosic biomass

Martínez

Ohra-aho

Perez³

et al. 2019

Journal of Analytical and Applied Pyrolysis

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Fractionated pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS) appears as an interesting analytical tool for elucidating lignocellulosic biomass structure, as it allows the progressive release of chemical fragments representative of biomass macromolecular composition. In this paper the effect o f fractionated pyrolysis time (from 5 s to 300 s) on the degradation of lignin and carbohydrates from beech wood was studied at temperatures between 250 °C and 500 °C. Fractionated Py-GC/MS showed that the release temperature of the volatile degradation products varied between the volatile species detected. In addition, the step duration time changed the thermal degradation behavior of lignocellulosic components. Shortening the constant step duration time from 300 s to 5 s shifted the maximum weight loss to the higher temperatures. The result was opposite at long step duration times. Time optimization at each pyrolysis temperature (250 °C, 40 s; 300 °C, 30 s; 350 °C, 25 s; 370 °C, 20 s; 400 °C, 15 s; 450 °C, 10 s; 500 °C, 5 s) enhanced the yield of both lignin and carbohydrate volatile pyrolysis degradation products. In addition, two multiple temperature maxima were shown for some lignin and carbohydrate derivatives. This behavior may be due to the two different pathways of formation and macromolecular origins of compounds in beech wood. At optimized conditions lignin derivatives having a 3carbon side chain substituent had a maximum at lower temperature than that of lignin derivatives with a 1carbon side chain substituent. That phenomenon follows the order of primary and secondary pyrolysis reactions. Similar behaviors were observed among the degradation products of hemicelluloses and cellulose. Degradation products of hemicelluloses were mainly released at lower temperatures than those of cellulose derivatives, which illustrates the lower thermal stability of hemicelluloses compared to cellulose.

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Section: Py-gc/ms Experimentsmentioning

confidence: 99%

“…The result shows that the highest yield of volatile species was obtained at optimized conditions (profile 4 ). T hat i s p robably b ecause optimization prevents secondary reactions [18,19]. Shorter pyrolysis time gave lower yields.…”

Section: Effect Of Step Duration On Volatile Species Formationmentioning

confidence: 99%

Influence of step duration in fractionated Py-GC/MS of lignocellulosic biomass

Martínez

Ohra-aho

Perez³

et al. 2019

Journal of Analytical and Applied Pyrolysis

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“…When raising the reaction temperature, the relative ratio of sulfate-S in RS char-S declined from 17.2% to 1.8%. Ericsson and Almén [33] described coal sulfate degradation in inert atmosphere as the following procedure (Eqs. (7) and (8)).…”

Section: Effects On Sulfur Behaviormentioning

confidence: 99%

Product distribution and sulfur behavior in sewage sludge pyrolysis: Synergistic effect of Fenton peroxidation and CaO conditioning

Liu

Qiang

Xing

et al. 2015

Fuel

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“…Therefore, it is important to study sulphate decomposition during coal pyrolysis. Generally, thermal degradation of sulphate in inert atmosphere can be described as follows [59]:…”

Section: Sulphate Transformation During Coal Pyrolysismentioning

confidence: 99%

Sulphur transformation during pyrolysis of an Australian lignite

Zhang

Yani

2011

Proceedings of the Combustion Institute

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Sulphur Transformation during Pyrolysis of an Australian Lignite v moisture, very high ash, low fixed carbon and thus they have low calorific value, except for L1. The lignites contain considerable amount of total sulphur, except for L1. Mineralogy of the lignites showed that the lignites contain extremely high sodium and chlorine. FTIR and solid state 13 C NMR spectroscopy confirmed that oxygenated functional structures are significantly present in the lignites. Transformation of pyrite in the lignite during pyrolysis was studied using samples of a lignite with pyrite-free lignite (L1), a high pyrite lignite (L2), acid-washed lignites (AW L1 and AW L2), a pyrite mineral, and AW L1 blended with various amounts of the pyrite minerals. It was shown that in nitrogen the pyrite mineral (S/Fe = 2) decomposes to troilite (S/Fe =1) at ca 1200K and above this temperature, the troilite further decomposes to form elemental iron (S/Fe <1). However, when blended with the demineralised lignite, the pyrite mineral can be completely decomposed to troilite at 873 K as confirmed by FTIR, SEM-EDS and XRD analyses on the resulting chars. Using TGA-MS, it was revealed that hydrogen sulphide and a small quantity of sulphur dioxide were released during the pyrolysis of the pyrite-lignite blends. However, only sulphur dioxide was detected during the pyrolysis of the lignite with high pyrite content. By assuming that the pyrolysis follows the first-order reactions, kinetic parameters of the pyrolysis of the lignite samples and the pyrite-lignite blends were obtained. The activation energy values of the lignite samples decreased with increasing temperature. The transformation of sulphate during pyrolysis of the lignite was studied using pure sulphates (CaSO 4, FeSO 4 and Fe 2 (SO 4) 3), L1 and L4, and acid washed L1 doped with sulphates (CaSO 4 +L1 and FeSO 4 +L1), respectively. The TGA experiments showed that CaSO 4 decomposes between 1400-1700 K in nitrogen and a 50/50 N 2 /CO 2 mixture, while in air CaSO 4 decomposes between 1500-1700 K. Using a TGA-MS it was found that only a small fraction of CaSO 4 in CaSO 4 +L1 decomposed at 653 K, releasing SO 2 .

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Kinetic and quantitative studies of the formation of SO2 from iron(II) and calcium sulfates by sequential and fractionated pyrolysis

Cited by 7 publications

References 5 publications

Influence of step duration in fractionated Py-GC/MS of lignocellulosic biomass

Influence of step duration in fractionated Py-GC/MS of lignocellulosic biomass

Product distribution and sulfur behavior in sewage sludge pyrolysis: Synergistic effect of Fenton peroxidation and CaO conditioning

Sulphur transformation during pyrolysis of an Australian lignite

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