Particle size effect on pore structure characteristics of lignite determined via low-temperature nitrogen adsorption

Pore structure characteristics and the effect of lithotype and maceral on pore for three types of high-volatile bituminous coals from Binchang area were investigated by combined low-temperature nitrogen adsorption/desorption, nuclear magnetic resonance (NMR), scanning electron microscope (SEM) and maceral analysis. The low temperature N2 adsorption/desorption test results show that: micropores are more abundant than transitional pores with high BET surface area; two types of pore structures can be identified by adsorption/desorption isotherms; Pore morphology is mainly represented by well-connected, ink-bottled, cylindrical and parallel plate pores. NMR T2 distributions at full saturated condition are apparent or less obvious trimodal and three types of T2 distributions are identified; Seepage pores are better developed when compared with the middle-high rank coal. Further research found that the three coal lithotypes are featured by remarkably different pore structure characteristics and maceral contents of coal are linearly correlated to some of pore structure parameters.

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Particle size effect in the low temperature reforming of methane by carbon dioxide on silica-supported Ni nanoparticles

Journal of Catalysis ◽

10.1016/j.jcat.2012.09.011 ◽

2013 ◽

Vol 297 ◽

pp. 27-34 ◽

Cited By ~ 163

Author(s):

David Baudouin ◽

Uwe Rodemerck ◽

Frank Krumeich ◽

Aimery de Mallmann ◽

Kaï C. Szeto ◽

...

Keyword(s):

Carbon Dioxide ◽

Particle Size ◽

Low Temperature ◽

Size Effect ◽

Particle Size Effect ◽

Ni Nanoparticles ◽

Supported Ni

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Particle size effect in nanoscale Pt3Co/C electrocatalysts for low-temperature fuel cells

Nanotechnologies in Russia ◽

10.1134/s1995078009030045 ◽

2009 ◽

Vol 4 (3-4) ◽

pp. 170-175 ◽

Cited By ~ 2

Author(s):

I. N. Leont’ev ◽

V. E. Guterman ◽

E. B. Pakhomova ◽

A. V. Guterman ◽

A. S. Mikheikin

Keyword(s):

Particle Size ◽

Fuel Cells ◽

Low Temperature ◽

Size Effect ◽

Particle Size Effect ◽

Low Temperature Fuel Cells

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Fly Ash Particle Size Effect on Pore Structure and Strength of Fly Ash Foamed Geopolymer

Advances in Polymer Technology ◽

10.1155/2019/1098027 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10

Author(s):

Luchang Xiong ◽

Zhijun Wan ◽

Yuan Zhang ◽

Fangtian Wang ◽

Junhui Wang ◽

...

Keyword(s):

Particle Size ◽

Compressive Strength ◽

Fly Ash ◽

Size Effect ◽

Pore Structure ◽

Early Stage ◽

Particle Size Effect ◽

Test Method ◽

Reaction Extent ◽

Micro Holes

The aim of this paper is to study the particle size effect of fly ash (FLA) on pore structure and strength of Fly Ash Foamed Geopolymer (FAFG). Information on the macro-pores such as macro-pore size and distribution of FAFG is captured through binarization processing. Porosity and compressive strength of FAFG are respectively tested by Archimedes density test method and uniaxial compressive strength test method. It can be concluded that the FLA particle size has an effect on the pore structure and strength of FAFG. More specifically, the effect of FLA particle size shows itself macroscopically on the quantity of middle and large macro-pores and the uniformity of macro-pores distribution, and microscopically on the quantity of micro-holes and cracks and calcium silicate (C-S-H) quantity at the early stage of FAFG mixture. All of the properties of FAFG follow some kind of changing rule except at the turning point when FLA particle is of 0.125~0.25 mm in size. To explain clearly the root cause of FLA particle size effect on FAFG, SEM, and XRD are employed to explore the microstructure of FAFG and the component of FLA. It turns out to be the amorphous phase SiO2 content in FLA of different particle sizes which could determine the reaction extent of FAFG mixture.

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Characterization of Pores and Fractures in Soft Coal from the No. 5 Soft Coalbed in the Chenghe Mining Area

Processes ◽

10.3390/pr7010013 ◽

2018 ◽

Vol 7 (1) ◽

pp. 13 ◽

Cited By ~ 4

Author(s):

Pan Wei ◽

Yunpei Liang ◽

Song Zhao ◽

Shoujian Peng ◽

Xuelong Li ◽

...

Keyword(s):

Low Temperature ◽

Pore Structure ◽

Pore Volume ◽

Fractal Dimensions ◽

Nitrogen Adsorption ◽

Mining Area ◽

Hard Coal ◽

Structure Characteristics ◽

Soft Coal

The characteristics of the pore structure and gas migration in soft coalbeds are the premise of evaluating gas discharge in soft coalbeds. To explore the pore structure characteristics of soft coal masses, the No. 5 soft coalbed in the eastern zone of Chenghe Mining Area, was investigated and compared with the No. 5 hard coalbed in the western zone. By using a mercury intrusion method, low-temperature liquid nitrogen adsorption, and scanning electron microscopy (SEM), the pore structure characteristics of the No. 5 coalbed were explored. Moreover, based on fractal theory, the pore structure of coal was characterized. The results showed the pores in soft coal mainly appeared as small pores and micropores in which the small pores accounted for nearly half of the total pore volume. Mesopores and macropores were also distributed throughout the soft coal. The mercury-injection and mercury-ejection curves of soft coal showed significant hysteresis loops, implying that pores in coal samples were mainly open while the mercury-injection curve of hard coal was consistent with its mercury-ejection curve, showing no hysteresis loop while having an even segment, which indicated that closed pores occupied the majority of the pore volume in the coal samples. The curves of low-temperature nitrogen adsorption of soft coal all follow an IV-class isotherm. Moreover, the fractal dimensions of soft coal are respectively larger than the fractal dimensions of hard coal. It can be seen that the characterization of pores and fractures of the soft coal was different from the hard coal in the western distinct of the old mining area. The gas prevention and control measures of soft coal should be formulated according to local conditions.

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A LOW TEMPERATURE PARTICLE SIZE EFFECT ON THE HEAT CAPACITY OF SODIUM CHLORIDE

Canadian Journal of Chemistry ◽

10.1139/v55-027 ◽

1955 ◽

Vol 33 (2) ◽

pp. 240-244 ◽

Cited By ~ 26

Author(s):

D. Patterson ◽

J. A. Morrison ◽

F. W. Thompson

Keyword(s):

Particle Size ◽

Heat Capacity ◽

Sodium Chloride ◽

Low Temperature ◽

Size Effect ◽

Specific Heat ◽

Significant Contribution ◽

Particle Size Effect ◽

Extensive Property ◽

Effect Of Particle Size

An effect of particle size upon the heat capacity of sodium chloride has been found in the temperature range 9° to 21°K. The experiments were done with three NaCl samples of specific surfaces between 38 and 59 sq. meters per gm. The observed effect has the temperature dependence predicted by theory but its magnitude is three to four times larger than expected. It is unlikely that adsorbed gases have made any significant contribution in the experiments. The accuracy with which the specific heat and surface area differences have been determined is not high enough to show definitely whether or not the surface specific heat is an extensive property of the surface.

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