The spontaneous combustion behavior of some low rank coals and a range of dried products

Yi, Fei; Aziz, Ainul Azzah Abd; Nasir, S; Jackson, W. Roy; Marshall, Marc; Hulston, Janine; Chaffee, Alan L.

doi:10.1016/j.fuel.2009.03.017

Cited by 57 publications

(30 citation statements)

References 15 publications

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“…Considering the spontaneous combustion temperatures of Loy Yang lignite [433 K to 443 K (160°C to 170°C)], [11] the samples were dried by superheated steam at 383 K, 403 K, 423 K, and 443 K (110°C, 130°C, 150°C, and 170°C, hereafter referred to as test temperature, T a ). Before setting the sample, a test section was heated to T a under a flow of nitrogen, then TC for the center 350-VOLUME 1E, DECEMBER 2014the fluid was replaced with superheated steam.…”

Section: Methodsmentioning

confidence: 99%

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Size Dependence of the Drying Characteristics of Single Lignite Particles in Superheated Steam

Kiriyama

Sasaki

Hashimoto

et al. 2014

Metallurgical and Materials Transactions E

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lignite particles 10, 5, and 2.5 mm in diameter were dried with superheated steam at temperatures ranging from 383 K to 443 K (110°C to 170°C) under atmospheric pressure. The drying rates were obtained by measuring their weights with an electronic balance, while temperatures of the particles were monitored. The following typical drying characteristics were observed: (i) Temperature of lignite rose to 373 K (100°C) accompanied by condensation of steam on the surface. (ii) A constant drying rate period was then observed, while temperature of the overall particle was maintained at 373 K (100°C). (iii) A decreasing drying rate period began accompanied by a rise in surface temperature, and eventually the overall particle reached the temperature of the superheated steam. Based on these results, the evaporation rate of water was expressed as a function of particle diameter. A numerical model for simulating the drying process of lignite, which was developed for a large particle in a previous study, was modified to make it applicable to small particles. The model is applicable for simulations of drying behaviors of lignite with size distribution in various dryers when an appropriate heat transfer coefficient is given.

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Section: Methodsmentioning

confidence: 99%

“…[11] from thermal conductivity and volume fraction of water, coal, and steam (Table II). There is no heat transfer from the center layer (n ¼ 51).…”

Section: Heat Transfer Inside the Lignite Particlementioning

confidence: 99%

Size Dependence of the Drying Characteristics of Single Lignite Particles in Superheated Steam

Kiriyama

Sasaki

Hashimoto

et al. 2014

Metallurgical and Materials Transactions E

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“…In this process, water is absorbed in plant remains and clay minerals to form coal. When the coal is spontaneously combusted in coal-fired thermal power-plant, this absorbed water is then immediately released, hence producing porous particles in fly ashes [31]. Hollow spherical particles seen in the fly ashes can be identified as cenospheres, which have been investigated by [32,33].…”

Section: Morphological Propertiesmentioning

confidence: 99%

Determining the Role of Individual Fly Ash Particles in Influencing the Variation in the Overall Physical, Morphological, and Chemical Properties of Fly Ash

et al. 2016

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Abstract. The properties of fly ashes vary because of the differences in the properties of their individual particles, and the determination of variation in these properties is of interest to the industries which use pulverized raw fly ash in applications, such as in cementitious materials and in the recovery of certain rare elements from raw fly ash. To investigate the differences in individual particles, four pulverized raw fly ashes from thermal power plants of the Czech Republic were used in this research. It was observed from FE-SEM that all four fly ashes consist of glassy hollow spherical, solid spherical, porous spherical, bright spherical, porous slaggy and compact slaggy particles. Box and whisker diagrams were plotted from the data of EDX individual particle analyses, which showed that the data of percentages for the Si, Al, and Fe elements is more scattered as compared to other elements. It was further observed from ternary phase diagrams and pseudo coloured images, that nature of fly ash particles changes from alumino silicate glassy to alumino silicate calcite metallic to pure ferro-metallic, where glassy particles showed high percentages and pure calcite particles were absent in fly ashes. Furthermore, a comparison between the XRF, the EDX total area analyses, showed that the EDX individual particle analysis gives more realistic and reliable data with median, mean, and the standard deviation for percentages of each element present in the fly ashes.

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“…In order to inhibit the low temperature oxidation and reduce the spontaneous combustion tendency, various work have been reported. [16][17][18] Alkali treatment is one of the effective means to suppress spontaneous combustion, which can reduce the contents of organic matters in coal, especially oxygen functional group. Wang et al 17 reported that coal oxidation at low temperatures (i.e.…”

Section: Introductionmentioning

confidence: 99%

Effects of alkali-oxygen oxidation temperature on the structures and combustion properties of Shengli lignite

Wang

et al. 2017

RSC Adv.

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The spontaneous combustion behavior of some low rank coals and a range of dried products

Cited by 57 publications

References 15 publications

Size Dependence of the Drying Characteristics of Single Lignite Particles in Superheated Steam

Size Dependence of the Drying Characteristics of Single Lignite Particles in Superheated Steam

Determining the Role of Individual Fly Ash Particles in Influencing the Variation in the Overall Physical, Morphological, and Chemical Properties of Fly Ash

Effects of alkali-oxygen oxidation temperature on the structures and combustion properties of Shengli lignite

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