Structural order and dielectric properties of coal chars

Xu, Liang; Liu, Haiyu; Jin, Yan; Fan, Baoguo; Qiao, Xiaolei; Jing, Bo

doi:10.1016/j.fuel.2014.08.002

Cited by 61 publications

(18 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The temperature rise trend is gentle due to the evaporation of water and the absorption of a large amount of heat at 100–200 °C. Then, the heating rate increases rapidly after water evaporation, which is due to the structure change of semicoke, 27 i.e., significant enhancement of dielectric property resulting in a dielectric response enhancement of semicoke to microwave. 5 The heating rate of coal samples increases significantly under the synergism of each catalyst.…”

Section: Results and Discussionmentioning

confidence: 99%

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

et al. 2020

View full text Add to dashboard Cite

Combined with the advantages of microwave pyrolysis and catalytic pyrolysis, the microwave pyrolysis experiment of low-rank coal under the synergism of catalyst was carried out. The dielectric response of coal samples and metal compound catalysts to microwave was analyzed quantitatively. The microwave pyrolysis behavior and product distribution of low-rank coal were studied. The effects of microwave heating and catalyst properties on the properties of pyrolysis products were analyzed in depth. Results show that the heating effect of dielectric loss and ionic conduction loss of metal compound catalysts could further promote the rapid temperature rise of coal samples. The catalysts could effectively improve the product distribution and properties in the process of microwave pyrolysis of low-rank coal. Compared with the control group, the output of syngas (H 2 + CO) increases by a maximum of 1.72 times, and the content of asphaltene in tar reduces by a maximum of 0.66 times. The introduction of K 2 CO 3 and CaCl 2 is conducive to the formation of a more developed pore structure and the increase of the specific surface area of semicoke. The co-action of the developed pore structure of semicoke and properties of residual catalysts could significantly improve the CO 2 gasification activity of semicoke.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Therefore, the AC polarization is a key factor affecting its heating rate in the microwave field. It is known that the level of dielectric properties reflects the ability of a substance to polarize. , In order to investigate the effect of dielectric properties on the heating rate of the microwave plasma reaction, Mn/AC, Fe/AC, Cu/AC, and AC (test their dielectric loss separately for 50.38, 38.43, 36.65, and 18.99 as shown in Figure ) were irradiated by microwave under pure nitrogen and the temperature results are shown in Figure at 200 W.…”

Section: Results and Discussionmentioning

confidence: 99%

Microwave Plasma-Assisted Catalytic Reduction of NO by Active Coke over Transition-Metal Oxides

et al. 2020

Self Cite

View full text Add to dashboard Cite

Microwave discharge plasma using catalyst-assisted active coke (Fe/AC, Mn/AC, Cu/AC) provides high performances for NO reduction at lower power (200 W) in this study. Results show that the effect of plasma and catalysis not only enhances the ability of plasma to remove NO, but also reduces the energy consumption of reaction; especially, Fe/AC increased the removal efficiency by nearly 64.8% compared with original coke. Plasma intensity was enhanced with the polarization increased by catalysts, giving better denitration performance. All the metal oxides studied catalyze the NO–carbon reaction, and the metal oxides had the tendency to be reduced. What is more, the catalysts increase the polarization of active coke, accelerating the rate of the temperature rise in the microwave field and increase the content of oxygen-containing functional groups, thereby promoting the C–NO reaction.

show abstract

“…Tao et al analyzed the effect of sulfur content on the dielectric properties of coal [29]. Xu et al studied the influence of the crystallite structure on the dielectric properties of coal chars [30]. Liu studied the effect of coal rank on the dielectric properties through structural differences in various coal chars [31].…”

Section: Plos Onementioning

confidence: 99%

Propagation of ground penetrating radar waves in Chinese coals

et al. 2020

View full text Add to dashboard Cite

This paper reports an experimental study on the electrical properties of five coal samples taken from various Chinese coal mines. The dielectric permittivity and specific resistivity of grinded coal samples subjected to electromagnetic (EM) fields in a wide frequency spectrum were determined. Based on the experimental data, a set of approximating equations of the change in electric properties the 100-1000 MHz frequency region was obtained. These equations, along with EM equations for EM speed and attenuation, were used for modeling and studying radar-wave propagation in a coal seam and radar-wave reflection from the body of miners trapped in collapsed tunnels. The modeling concept assumes that a radar transducer with the dominating frequency of 500 MHz is lowered through a vertical or inclined rescue borehole to the depth of the coal seam. It is assumed that only the miner is present in the part of the tunnel that did not collapse. Thus, in the path of the radar wave from the transducer to the human body, only one geological interface reflecting the radar signals is present (coal-air) and one is connected with human body. The human (acting as the reflector) can be located at various distances from the tunnel face; this factor was included in the analyzed geometrical model. Based on the modeling results of different thickness coal seams (2, 3, 4, 5, 6, 7, 8m), conclude that a radar wave reflected from a human body can be reliably measured, when the distance between the human and the transducer is not exceed 8m.

show abstract

Structural order and dielectric properties of coal chars

Cited by 61 publications

References 44 publications

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

Microwave Plasma-Assisted Catalytic Reduction of NO by Active Coke over Transition-Metal Oxides

Propagation of ground penetrating radar waves in Chinese coals

Contact Info

Product

Resources

About

Structural order and dielectric properties of coal chars

Cited by 61 publications

References 44 publications

Microwave-Assisted Pyrolysis of Low-Rank Coal with K2CO3, CaCl2, and FeSO4 Catalysts

Microwave-Assisted Pyrolysis of Low-Rank Coal with K2CO3, CaCl2, and FeSO4 Catalysts

Microwave Plasma-Assisted Catalytic Reduction of NO by Active Coke over Transition-Metal Oxides

Propagation of ground penetrating radar waves in Chinese coals

Contact Info

Product

Resources

About

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts

Microwave-Assisted Pyrolysis of Low-Rank Coal with K₂CO₃, CaCl₂, and FeSO₄ Catalysts