Multiple mechanisms for the loss of coking properties caused by mild air oxidation

Larsen, John W.; Lee, Doyoung; Schmidt, Thomas E.; Grint, Alan

doi:10.1016/0016-2361(86)90056-6

Cited by 45 publications

(14 citation statements)

References 7 publications

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“…Table IV compares the data from the equilibrium swelling with pyridine at 35.0 1.0"C for 32 days and at 60.0 & 1.O"C for 16 days of PSOC-207 samples which: (i) had not been pretreated; (ii) had been previously extracted with pyridine; (iii) had been oxidized with air at 60-80°C; and (iv) had been oxygen-methylated via the Liotta technique. It must be noted that the oxygen-methylation used here leaves a residue of R,N+ in the coal which b a y affect the swelling behavior.,, The swelling behavior of oxidized coal has been discussed by Larsen et al 25 as well.…”

Section: Equilibrium Swelling Studiesmentioning

confidence: 98%

Macromolecular structure of coals. IV. Equilibrium swelling studies of coal networks subjected to various treatments

Lucht

Peppas

1987

J. Appl. Polym. Sci.

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SynopsisThe macromolecular network structure of the organic phase of bituminous coals was investigated with equilibrium swelling experiments at 35" and 60°C. It was determined that an oxygen-methylation technique led to cleavage of hydrogen bonds and significant increase of swelling. Pyridine preextraction led to significant differences in swelling due to partial incorporation in the network structure.

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Section: Equilibrium Swelling Studiesmentioning

confidence: 98%

Macromolecular structure of coals. IV. Equilibrium swelling studies of coal networks subjected to various treatments

Lucht

Peppas

1987

J. Appl. Polym. Sci.

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“…[16][17][18] However, using hot air as the drying medium may cause the oxidation of the organic structure of coal, [19,20] and affects its technological properties. [21][22][23][24] There has been a growing interest of application of microwave processing in dewatering [25] and desulfurization [26] of coals. Compared to the conventional heating, microwave heating techniques have many advantages [27] : rapid heating, selective material heating, non-contact heating, higher level of safety and automation, and so on.…”

Section: Introductionmentioning

confidence: 99%

Comparison of drying methods on physical and chemical properties of Shengli lignite

Shang

Chen

et al. 2015

Drying Technology

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The physicochemical properties of Shengli lignite dewatered by three methods in hot air, microwave and vacuum conditions were investigated. The effects of drying methods on the coal pore structure, surface morphology, surface carbon-containing groups and moisture re-adsorption performance of dewatered lignite were studied by Brunner-Emmet-Teller method (BET), mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and dynamic water vapor sorption analyzer (DVS). The results indicate that a large quantity of semi-opened micropores and open ended mesopores which shaped like slit or cylinder exist in lignite. The specific surface area and total pore volume value of dewatered lignite decrease as Downloaded by [Texas A & M International University] at 09:14 23 August 2015 2 follows: microwave dried lignite (MD) > vacuum dried lignite (VD) > hot air dried lignite (HAD), which consistent with MIP results. SEM images exhibit that lignite dried by different methods are characterized with various surface morphology. The XPS results reveal that VD has the highest content of C-C/C-H and the lowest content of C-O, while HAD has a higher content of C-O and a higher surface oxidation degree (α) than MD.Besides, the moisture re-adsorption capability of the dewatered lignite follows the sequence as MD > VD > HAD.

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“…Cokemaking is an important technological process that is adversely affected by coal oxidation [3]. This is directly reflected in a reduction in carbonization rate, coke yield, and coke quality [4][5][6][7][8], effects which reduce the productivity of the coke plant and undermine the economic feasibility of coke production. In the carbonization process the coal softens, melts and then resolidifies to form coke when heated in the absence of air.…”

Section: Introductionmentioning

confidence: 99%

The effect of bituminous additives on the carbonization of oxidized coals

Vega

Fernández

Díaz-Faes

et al. 2017

Fuel Processing Technology

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Two bituminous coals of different rank and coking characteristics were oxidized at low temperature for two months. Bituminous additives obtained in-situ in the coking plant were used to improve the thermoplastic properties of the oxidized coals. The Gieseler fluidity test was applied to evaluate their coking properties. A thermogravimetric analysis (TGA) of the fresh, oxidized coals and their blends with the bituminous additives was carried in order to evaluate the interaction between the blend components.In addition, carbonization tests of the fresh and oxidized coals and the blends with the additives were carried out in a movable wall oven of 17 kg capacity and the quality of the cokes tested by means of standardized methods generally used by the steel industry.The additives increased coal fluidity but the original fluidity values could not be recovered. From TGA it was concluded that the blend components behave independently of one another during co-carbonization. The oxidation of coal leads to an increase in the dangerousness of the low volatile coal which was related to the porous texture of the cokes. In addition, it was found that the decrease in the quality of the coke produced from low rank oxidized coal can be partially recovered by using bituminous additives.

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Multiple mechanisms for the loss of coking properties caused by mild air oxidation

Cited by 45 publications

References 7 publications

Macromolecular structure of coals. IV. Equilibrium swelling studies of coal networks subjected to various treatments

Macromolecular structure of coals. IV. Equilibrium swelling studies of coal networks subjected to various treatments

Comparison of drying methods on physical and chemical properties of Shengli lignite

The effect of bituminous additives on the carbonization of oxidized coals

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