Evaluation of a hot oil immersion drying method for the upgrading of crushed low-rank coal

Ohm, Tae-In; Chae, Jong-Seong; Lim, Jae-Ho; Moon, Sung‐Hyun

doi:10.1007/s12206-012-0210-4

Cited by 30 publications

(11 citation statements)

References 10 publications

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“…Coal plays an important role in fulfilling the energy needs of our society. Lignite is a typical low-rank coal with very large deposits, which is easy to burn and has highly volatile components [ 1 , 2 ]. However, lignite has low heating values primarily because of its high oxygen and moisture contents, and it forms a great deal of coal slime in mining because lignite is weathered and fragmented easily.…”

Section: Introductionmentioning

confidence: 99%

Adsorption Behavior of Surfactant on Lignite Surface: A Comparative Experimental and Molecular Dynamics Simulation Study

He¹,

Zhang²,

Cao³

et al. 2018

IJMS

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Experimental and computational simulation methods are used to investigate the adsorption behavior of the surfactant nonylphenol ethoxylate (NPEO10), which contains 10 ethylene oxide groups, on the lignite surface. The adsorption of NPEO10 on lignite follow a Langmuir-type isotherm. The thermodynamic parameters of the adsorption process show that the whole process is spontaneous. X-ray photoelectron spectroscopic (XPS) analysis indicates that a significant fraction of the oxygen-containing functional groups on the lignitic surface were covered by NPEO10. Molecular dynamics (MD) simulations show that the NPEO10 molecules were found to adsorb at the water-coal interface. Moreover, polar interactions are the main effect in the adsorption process. The density distributions of coal, NPEO10, and water molecules along the Z axis show that the remaining hydrophobic portions of the surfactant extend into the solution, creating a more hydrophobic coal surface that repels water molecules. The negative interaction energy calculated from the density profiles of the head and tail groups along the three spatial directions between the surfactant and the lignitic surface suggest that the adsorption process is spontaneous. The self-diffusion coefficients show that the presence of NPEO10 causes higher water mobility by improving the hydrophobicity of lignite.

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Section: Introductionmentioning

confidence: 99%

Adsorption Behavior of Surfactant on Lignite Surface: A Comparative Experimental and Molecular Dynamics Simulation Study

He¹,

Zhang²,

Cao³

et al. 2018

IJMS

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“…With these considerations, various properties and combustion characteristics of low-rank coal, especially brown coal (or lignite) for coal-fired power generation, have been examined. , The studies on brown coal mostly focused on improving the physical properties of raw materials using blended coal combustion or biomass addition. ,, However, the combustion of coal blends may exhibit different combustion characteristics from those of the raw coal. It has been recognized that the conventional predictable properties associated with fuel composition such as proximate, ultimate analysis and heating value remain additive, while many characteristics associated with combustion are reported to be nonadditive. , So, it may be challenging to determine the interaction between the blended coal components that yield acceptable combustion results.…”

Section: Introductionmentioning

confidence: 99%

“…6 With these considerations, various properties and combustion characteristics of low-rank coal, especially brown coal (or lignite) for coal-fired power generation, have been examined. 7,8 The studies on brown coal mostly focused on improving the physical properties of raw materials using blended coal combustion or biomass addition. 2,9,10 However, the combustion of coal blends may exhibit different combustion characteristics from those of the raw coal.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Char Characteristics and Combustibility of Low-Rank-Coal Blends with Different Reflectance Distributions

2019

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Petrographic analysis can provide valuable information about pulverized coal used in coal-fired power plants. In this study, petrographic analysis was used to determine the effect of blending on the combustion of low-rank coal from Mongolia and two bituminous coals from Russia. After blending these coals based on their calorific values and combusting them in a drop tube furnace, the unburned combustibles in the char were analyzed. The coal rank, determined from the mean random vitrinite reflectance, was closely correlated with the proportion of each single coal in the blend. Char component analysis showed that the generated char particles were not affected by the coal rank but had a strong relationship with the microlithotype of the raw coal. In contrast, for single coals, the unburned combustibles at equal temperatures were affected by the coal rank. Morphological analysis of the char types revealed that the geometric tendency of each coal was in agreement with the char formed at different temperatures. However, combustion results for the blended samples exhibited somewhat complicated tendencies. The unburned combustibles showed interactions between coals relating to their petrographic properties, such as vitrinite reflectance and char components.

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“…Among them, lignites (a low-rank coal) are particularly difficult to conserve. Some authors have reported their spontaneous combustion (Ohm, 2012). This particular reactivity is associated with their high moisture content and high porosity, as well as with the presence of reactive C sites such as carbonyl that are activated due to the catalyzing action of mineral impurities (Takarada et al, 1985;Ohm, 2012;Kabir et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Neutron imaging investigation of fossil woods: non-destructive characterization of microstructure and detection of in situ changes as occurring in museum cabinets

et al. 2017

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Abstract. This paper discusses the applicability of neutron imaging techniques for probing the internal microstructure of several fossil woods upon wetting and drying, two phenomena occurring in museum cabinets and endangering the fossil woods. Investigations were carried out using lignites (fossil woods) from two French localities (Rivecourt, Parisian Basin, Oise -Paleogene; Angeac, Aquitanian Basin, Charente -Cretaceous), which present different macroscopic behavior upon drying. Thanks to the high sensitivity of neutrons to hydrogen content, it was possible to track water diffusion through 3 mm thick samples and to follow in situ changes related to either supply or withdrawal of water without any special preparation and in a relevant time range (from 1 min to a few hours). Classical image analysis allows discriminating between the behavior of the two fossil woods with regard to their interaction with water. Further analysis based on a Fourier transform of projection images provides additional information regarding the existence of large pores in one of the samples. Differences in pore network and internal structures have important mechanical consequences as one of the samples retains its integrity upon drying, whereas the other one shatters into pieces. A better understanding of the underlying processes will clearly require multi-scale analyses, using additional techniques that could probe the materials at a lower scale. Such a combination of multi-scale analyses should provide valuable information for a better conservation of wood remnants, which is crucial for both paleobotanical research and museum exhibits.

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Evaluation of a hot oil immersion drying method for the upgrading of crushed low-rank coal

Cited by 30 publications

References 10 publications

Adsorption Behavior of Surfactant on Lignite Surface: A Comparative Experimental and Molecular Dynamics Simulation Study

Adsorption Behavior of Surfactant on Lignite Surface: A Comparative Experimental and Molecular Dynamics Simulation Study

Evaluation of Char Characteristics and Combustibility of Low-Rank-Coal Blends with Different Reflectance Distributions

Neutron imaging investigation of fossil woods: non-destructive characterization of microstructure and detection of in situ changes as occurring in museum cabinets

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