Influence of coke particle size on pore structural determination by optical microscopy

Nyathi, Mhlwazi S.; Mastalerz, María; Kruse, Richard

doi:10.1016/j.coal.2013.08.004

Cited by 23 publications

(14 citation statements)

References 17 publications

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“…Figure 6 shows porous structures from Commercial Coke 1; it was found to have an average porosity of 48 %, which is similar to values previously reported for commercial coke materials [42]. Figure 7 shows the porosity of a single image of Coke A prepared at relatively low power input (3kW for 15 mins with a total input of 3,400kWh/t ).…”

Section: Coke Porositysupporting

confidence: 65%

Factors affecting the microwave coking of coals and the implications on microwave cavity design

Binner

Mediero-Munoyerro

Huddle

et al. 2014

Fuel Processing Technology

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The work carried out in this paper assessed how processing conditions and feedstock affect the quality of the coke produced during microwave coke making. The aim was to gather information that would support the development of an optimised microwave coke making oven. Experiments were carried out in a non-optimised 2450 MHz cylindrical cavity. The effect of treatment time (15 -120 min), power input (750 W -4.5 kW) and overall power input (1,700 -27,200 kWh/t) on a range of coals (semi-bituminous -anthracite) was investigated. Intrinsic reactivity, random reflectance, strength index and dielectric properties of the produced cokes were compared with those of two commercial cokes to assess the degree of coking produced in the microwave system.Overall energy input and coal rank were found to be the major factors determining the degree of coking following microwave treatment. The dependency on coal rank was attributed to the larger amount of volatiles that had to be removed from the lower ranked coals, and the increasing dielectric loss of the organic component of the coal with rank due to increased structural ordering. Longer treatment times at lower powers or shorter treatment times at higher powers are expected to produce the same degree of coking.It was concluded that microwave coke making represents a potential step-change in the coking industry by reducing treatment times by an order of magnitude, introducing flexibility and potentially decreasing the sensitivity to quality requirement in the feedstock. The main challenges to development are the energy requirements (which will need to be significantly reduced in an optimised process) and penetration depth (which will require an innovative reactor design to

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Section: Coke Porositysupporting

confidence: 65%

Factors affecting the microwave coking of coals and the implications on microwave cavity design

Binner

Mediero-Munoyerro

Huddle

et al. 2014

Fuel Processing Technology

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“…The pores in the coke are generally in an extensive size range. Large pores on the surface of a coke can be observed using the microscope image method [ 69 , 70 ] and X-ray CT imaging technique [ 71 , 72 , 73 ]. X-ray CT imaging is a non-destructive detection method.…”

Section: Characterization Of Coke Structuresmentioning

confidence: 99%

“…Nyathi et al [ 69 ] analyzed the pore structure in different sizes of coke by optical microscope. One hundred images were taken systematically for each sample.…”

Section: Characterization Of Coke Structuresmentioning

confidence: 99%

A Comprehensive Review of Characterization Methods for Metallurgical Coke Structures

Zheng

Zhang

et al. 2021

Materials

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The structure of coke affects its reactivity and strength, which directly influences its performance in the blast furnace. This review divides coke structures into chemical structure, physical structure, and optical texture according to their relevant characteristics. The focuses of this review are the current characterization methods and research status of the coke structures. The chemical structures (element composition and functional group) can be characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS), and nuclear magnetic resonance imaging technology (13C NMR). The physical structures (pore structure and micro-crystallite structure) can be characterized by image method, X-ray CT imaging technique, mercury intrusion method, nitrogen gas adsorption method, X-ray diffraction method (XRD), and high-resolution transmission electron microscopy (HRTEM). The optical textures are usually divided and counted by a polarizing microscope. In the end, this review provides an idea of the construction of a coke molecular structural model, based on the above characterization. With the coke model, the evolution principles of the coke can be calculated and simulated. Hence, the coke performance can be predicted and optimized.

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“…The microstructure of coke particles can be considered to consist of their optical texture and porosity. Several image analysis techniques were used to determine the size, shape, and orientation of the optical domains in calcined petroleum cokes (Nyathi et al 2013;Qiao and Eser 1997).…”

Section: Introductionmentioning

confidence: 99%

Influence of coke structure on coke quality using image analysis method

Ghosh

Sahoo

Chakraborty

et al. 2018

Int J Coal Sci Technol

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The quality of coke affects the performance of the blast furnace, factors affecting coke quality include coal properties, coal charge granulometry and carbonization conditions. The coke properties include the size analysis, cold strength (Micum Indices-M 40 , M 10) and hot strength (Coke Reactivity Index-CRI, Coke Strength after Reaction-CSR) properties and structural properties such as coke structure and texture. Structural properties comprise the porosity, pore-cell wall thickness and pore sizes, while textures consist of the carbon forms in the coke. In present work, advanced method such as image analysis method was used to interpret coke microstructure. Conventional methods such as determination of coke porosity by measurement of real and apparent density and mercury porosimetry have a number of limitations. Coke size, magnification, number of image frames captured, process of pellet preparations and coke properties such as M 40 , M 10 , CRI and CSR (low, medium and high values) were taken as variables for experimental purposes. The coke structure parameters such as porosity, length, perimeter, breadth, roundness, pore-wall thickness and pore size distribution of the pores were determined by image analysis method. This method provided average porosity in addition to pore-wall thickness and pore-size distribution. The pore wall thickness measurement by image analysis method provided significant correlations with M 40 , CRI and CSR values. This explained the usability of image analysis for coke structure measurement.

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Influence of coke particle size on pore structural determination by optical microscopy

Cited by 23 publications

References 17 publications

Factors affecting the microwave coking of coals and the implications on microwave cavity design

Factors affecting the microwave coking of coals and the implications on microwave cavity design

A Comprehensive Review of Characterization Methods for Metallurgical Coke Structures

Influence of coke structure on coke quality using image analysis method

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