Coal structure and reactivity changes induced by chemical demineralisation

Rubiera, F.; Arenillas, A.; Pevida, C.; García, Roberto; Pís, J.J.; Steel, Karen M.; Patrick, John W.

doi:10.1016/s0378-3820(02)00185-6

Cited by 78 publications

(45 citation statements)

References 12 publications

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“…A marked oxidation was produced in HW-D in comparison with HW-HF, and this was caused by the treatment with 25% HNO 3 , which is a strong oxidising agent. The nitrogen content also experienced a great increase due to nitrification of the sample with incorporation of nitro groups, -NO 2 , as it has been found in previous FTIR studies on these samples [20]. Oxidation also produced a complete loss of fluidity of HW-D, as inferred from its nil Free…”

Section: Methodssupporting

confidence: 57%

Combustion behaviour of ultra clean coal obtained by chemical demineralisation

Rubiera

Arenillas

Arias

et al. 2003

Fuel

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The increasing environmental concern caused by the use of fossil fuels and the concomitant need for improved combustion efficiency is leading to the development of new coal cleaning and utilisation processes. However, the benefits achieved by the removal of most mineral matter from coal either by physical or chemical methods can be annulled if poor coal combustibility characteristics are attained. In this work a high volatile bituminous coal with 6% ash content was subjected to chemical demineralisation via hydrofluoric and nitric acid leaching, the ash content of the clean coal was reduced to 0.3%. The original and treated coals were devolatilised in a drop tube furnace and the structure and morphology of the resultant chars was analysed by optical and scanning electron microscopies. The reactivity characteristics of the chars were studied by isothermal combustion tests in air at different temperatures in a thermogravimetric system.Comparison of the combustion behaviour and pollutant emissions of both coals was conducted in a drop tube furnace operating at 1000 °C. The results of this work indicate that the char obtained from the chemically treated coal presents very different structure, morphology and reactivity behaviour than the char from the original coal. The changes induced by the chemical treatment increased the combustion efficiency determined in the drop tube furnace, in fact higher burnout levels were obtained for the demineralised coal.

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Section: Methodssupporting

confidence: 57%

Combustion behaviour of ultra clean coal obtained by chemical demineralisation

Rubiera

Arenillas

Arias

et al. 2003

Fuel

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“…Each absorption band in the spectra ( Figure 7) was analyzed for the intensity of transmission by Lambert-Beer law [9][10][11][12]. Bands were assigned according to the published articles [9][10][11][12].…”

Section: Ftir Analysismentioning

confidence: 99%

“…Bands were assigned according to the published articles [9][10][11][12]. Figure.7 showed that the entire spectrum had more or less similar broad characteristic absorption bands.…”

Section: Ftir Analysismentioning

confidence: 99%

Chemical Leaching of Low Rank Coal and its Characterization using SEM/EDAX and FTIR

Balachandran

Kunjomana²,

Chandrasekharan³

2009

JMMCE

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“…[8][9][10][11][12]. Moreover, quantitative methods can be applied to TGA curves in order to obtain kinetic parameters of the thermal events.…”

Section: Introductionmentioning

confidence: 99%

Kinetic models comparison for non-isothermal steam gasification of coal–biomass blend chars

Fermoso

Gil

Pevida

et al. 2010

Chemical Engineering Journal

116

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The non-isothermal thermogravimetric method (TGA) was applied to a bituminous coal (PT), two types of biomass, chestnut residues (CH) and olive stones (OS), and coalbiomass blends in order to investigate their thermal reactivity under steam. Fuel chars were obtained by pyrolysis in a fixed-bed reactor at a final temperature of 1373 K for 30 min. The gasification tests were carried out by thermogravimetric analysis from room temperature to 1373 K at heating rates of 5, 10 and 15 K min -1 . After blending, no significant interactions were detected between PT and CH during co-gasification, whereas deviations from the additive behaviour were observed in the PT-OS blend.However, for the two coal-biomass blends, the gasification behaviour resembled that of the individual coal, as this component constituted the larger proportion of the blend. The temperature-programmed reaction (TPR) technique was employed at three different heating rates to analyze noncatalytic gas-solid reactions. Three nth-order representative gas-solid models, the volumetric model (VM), the grain model (GM) and the random pore model (RPM) were applied in order to describe the reactive behaviour of the chars during steam gasification. From these models, the kinetic parameters were determined.The best model for describing the reactivity of the PT, PT-CH and PT-OS samples was the RPM model. VM was the model that best fitted the CH sample, whereas none of the models was suitable for the OS sample.

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Coal structure and reactivity changes induced by chemical demineralisation

Cited by 78 publications

References 12 publications

Combustion behaviour of ultra clean coal obtained by chemical demineralisation

Combustion behaviour of ultra clean coal obtained by chemical demineralisation

Chemical Leaching of Low Rank Coal and its Characterization using SEM/EDAX and FTIR

Kinetic models comparison for non-isothermal steam gasification of coal–biomass blend chars

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