Desulphurization of coal via low temperature atmospheric alkaline oxidation

Liu, Kaicheng; Yang, Jingsi; Jia, Jinping; Wang, Yaling

doi:10.1016/j.chemosphere.2007.10.005

Cited by 40 publications

(17 citation statements)

References 15 publications

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“…It was reported that organic sulphur decomposition begins with the formation of -SH radical [9], the formation of the radicals is favour with increasing in the porosity of the chars. The decrease in the inorganic matter contents in acid washed L3 can also be seen in cm -1 [122] as well as C-S stretching vibration in the range of 570-705 cm -1 [123,128] are very weak in both L3 and AW L3.…”

Section: Chapter 4)mentioning

confidence: 94%

“…region [17,18,87,88]. The present of inorganic sulphate in the sample can also be detected by FTIR [122,123]. Bands observed in the range of 610-680 cm -1 and 1130-1080 cm -1 could be assigned to ion sulphate.…”

Section: Transformation Of Inherent Sulphate During Lignite Pyrolysismentioning

confidence: 95%

“…Oxidised organic sulphur compounds or sulphur-oxy compounds are formed based on the type of organic sulphur and the oxidising conditions, they may present in the form of sulphoxides, sulphone, sulphonic acid, sulphinic acid or sulphenic acid. Whatever the oxidised organic sulphur forms, they have -S=O stretching vibration [123]. Band assignments of sulphur-oxy compounds are presented in Table 7 It can be seen from Figure 7.7 that the bands in the range of 1020-1420 cm -1 in AW L3 char yielded at 673 K are weaker than in AW L3.…”

Section: Chapter 4)mentioning

confidence: 99%

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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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Section: Chapter 4)mentioning

confidence: 94%

Section: Transformation Of Inherent Sulphate During Lignite Pyrolysismentioning

confidence: 95%

Section: Chapter 4)mentioning

confidence: 99%

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Sulphur transformation during pyrolysis of an Australian lignite

Zhang

Yani

2011

Proceedings of the Combustion Institute

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“…As shown in Table 4, the sodium and potassium contents of coal A and coal B were more than coal C. However, for 50A50C and 50B50C, these deviations showed that blending with coal C would inhibit a certain degree of low temperature oxidation. Some kind of minerals like calcium and magnesium contained in coal C would increase the chemical inertness of coal at low temperature [21], promote the formation of a surface film surrounding the fractured surface coal and fill pillar internal fissures. As given in Table 4, calcium and magnesium contents of coal C were more than coal A and coal B.…”

Section: Interaction Between Blended Coals During Low Temperature Oximentioning

confidence: 99%

Study on thermochemical kinetic characteristics and interaction during low temperature oxidation of blended coals

Chen

Lin

et al. 2015

Journal of the Energy Institute

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“…Most of the oxygen that reacts with the organic matrix remains attached as hydroperoxides and their decomposition products. Lui (Liu et al 2008) achieved the removal of 73% organic sulfur, and 83% pyritic sulfur by alkali leaching of Yangzhou (Eastern China) in dissolved oxygen and then further treated with acid re ux. He stated that loss of organic sulfur may be occurred due to removal of thiols compounds present in the coal that are very attractive to oxidation, they are easily converted to the disul des under basic condition.…”

Section: Organic Sulfurmentioning

confidence: 99%

Desulfurization of thar lignite by oxidative alkali leaching under pressure

Usto

Abbasi

Maitlo

et al. 2021

International Journal of Coal Preparation and Utilization

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Pakistan is the world largest lignite bearing country in the world due to the Thar coal reserves. Sulfur contained in this coal need to be removed prior to combustion. Oxidative alkali leaching in dissolved oxygen technique was used to remove the sulfur from Thar coal. This method removed enough all three types of sulfur; about 90% pyretic sulfur, 78% organic sulfur and 50% sulfate sulfur and more than 82S% of total sulfur removal was achieved. Effect of various reaction parameters were observed, it was investigated that reaction time and partial pressure of oxygen has positive effect on the desulfurization, higher the reaction time and oxygen partial pressure higher the degree of desulfurization, also the desulfurization increased with increase in reaction temperature and alkali concentration till some optimum value and then decreases with further increase in value of temperature and concentration of alkali, although desulfurization was observed maximum with minimum particle size. Coal was also characterized with Thermogravimetric Analysis (TGA) and Testo smoke number to investigate the combustion behavior of processed coal. It was observed that combustion properties of processed coal were improved and black smoke in processed coal was reduced.

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Desulphurization of coal via low temperature atmospheric alkaline oxidation

Cited by 40 publications

References 15 publications

Sulphur transformation during pyrolysis of an Australian lignite

Sulphur transformation during pyrolysis of an Australian lignite

Study on thermochemical kinetic characteristics and interaction during low temperature oxidation of blended coals

Desulfurization of thar lignite by oxidative alkali leaching under pressure

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