Experimental Investigation of Pore Structure Damage in Pulverized Coal: Implications for Methane Adsorption and Diffusion Characteristics

2016 ◽  
Vol 30 (12) ◽  
pp. 10383-10395 ◽  
Author(s):  
Kan Jin ◽  
Yuanping Cheng ◽  
Qingquan Liu ◽  
Wei Zhao ◽  
Liang Wang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Pore Structure ◽  
Methane Adsorption ◽  
Pulverized Coal ◽  
Structure Damage ◽  
Diffusion Characteristics ◽  
And Diffusion

The Effect of Leaching on the Pore Structure of Cement-Based Grouts for Use in Nuclear Fuel Waste Disposal

1990 ◽  
Vol 212 ◽  
Author(s):  
M. Onofrei ◽  
M. N. Gray ◽  
D. Breton ◽  
G. Ballivy
Keyword(s):  
Pore Structure ◽  
Total Porosity ◽  
Cementitious Materials ◽  
X Ray ◽  
Diffusion Characteristics ◽  
Deep Geological Disposal ◽  
Porosity And Permeability ◽  
Nuclear Fuel Waste ◽  
And Diffusion

ABSTRACTResearch on the longevity of cement-based grout materials for sealing a deep geological disposal vault is an important aspect of the Canadian and other nuclear waste management programs. These studies include assessments of the chemical durability of cement grouts, and the effects of leaching and phase transformation on the long-term hydraulic and diffusion characteristics of grouts.This paper presents the results of laboratory studies carried out to assess the effects of leaching of cement phases on the pore structure of hardened grouts. Measurements of mercury intrusion and scanning electron microscopy with energy dispersive x-ray analysis, have been used to investigate the changes in pore structure of both a reference grout (90% Type 50 cement, 10% silica fume, water-to-cementitious materials ratio between 0.4 and 0.7) and ALOFIX-MC (a fine cement product of Japan), as a function of leaching time.The work discussed here reveals that the porosity of hardened grout does change during leaching, but within limits that depend on grout composition and initial porosity. The results confirm that the materials have the potential to self-seal and maintain their performance for longer periods than those currently predicted by longevity models.Our studies of the porosity and permeability of grouts suggest that pore size distribution rather than total porosity is the more important parameter in determining longevity.

scholarly journals Methane Adsorption Rate and Diffusion Characteristics in Marine Shale Samples from Yangtze Platform, South China

Energies ◽  
2017 ◽  
Vol 10 (5) ◽  
pp. 626 ◽  
Author(s):  
Wei Dang ◽  
Jinchuan Zhang ◽  
Xiaoliang Wei ◽  
Xuan Tang ◽  
Chenghu Wang ◽  
...  
Keyword(s):  
South China ◽  
Methane Adsorption ◽  
Adsorption Rate ◽  
Yangtze Platform ◽  
Marine Shale ◽  
Diffusion Characteristics ◽  
And Diffusion

Organic Heterojunctions for Photovoltaic Applications: C60 Growth on Pentacene

2010 ◽  
Vol 1263 ◽  
Author(s):  
Rebecca Ann Cantrell ◽  
Paulette Clancy
Keyword(s):  
Atomic Scale ◽  
Short Axis ◽  
Energy Functions ◽  
Potential Energy Functions ◽  
The North ◽  
Diffusion Characteristics ◽  
Static Energy ◽  
Semi Empirical ◽  
Organic Heterojunctions ◽  
And Diffusion

AbstractUsing atomic-scale Molecular Dynamics (MD) and energy minimization techniques in conjunction with semi-empirical MM3 potential energy functions, we consider the adsorption of a C60 molecule on a series of hypothetical pentacene structures that vary only in the tilt of the angle that the short axis of the pentacene molecules makes with the underlying surface (the long axis lying essentially flat, as on a metal substrate). Important relationships were discovered between the angle adopted by the short axis of pentacene on the surface, φ1, and the adsorption and diffusion characteristics of C60. Static energy calculations show that there is a transition of the deepest energy minima from between the pentacene rows at low values of φ1 to within the rows at high values of φ1, where φ1 is the angle the pentacene short axis makes with the surface. MD confirms this trend by the predominant residence locations at the extreme φ1 values. Furthermore, MD results suggest that the C60 traverses the pentacene surface in the east-west direction for lower φ1 values (φ1 ≤ 40°) and in the north-south direction for higher φ1 values (φ1 ≥ 70°). Taking both static and dynamic results together, the most favorable tilt angles for mono-directional nanowire growth should occur between 70° and 80° off-normal.

scholarly journals Changes in Pore Structure of Coal Caused by CS2 Treatment and Its Methane Adsorption Response

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Run Chen ◽  
Yong Qin ◽  
Pengfei Zhang ◽  
Youyang Wang
Keyword(s):  
Pore Structure ◽  
Adsorption Capacity ◽  
Gas Adsorption ◽  
Recovery Process ◽  
Micropore Volume ◽  
Methane Adsorption ◽  
Coal Bed ◽  
Methane Recovery ◽  
Before And After ◽  
Key Issues

The pore structure and gas adsorption are two key issues that affect the coal bed methane recovery process significantly. To change pore structure and gas adsorption, 5 coals with different ranks were treated by CS2 for 3 h using a Soxhlet extractor under ultrasonic oscillation conditions; the evolutions of pore structure and methane adsorption were examined using a high-pressure mercury intrusion porosimeter (MIP) with an AutoPore IV 9310 series mercury instrument. The results show that the cumulative pore volume and specific surface area (SSA) were increased after CS2 treatment, and the incremental micropore volume and SSA were increased and decreased before and after Ro,max=1.3%, respectively; the incremental big pore (greater than 10 nm in diameter) volumes were increased and SSA was decreased for all coals, and pore connectivity was improved. Methane adsorption capacity on coal before and after Ro,max=1.3% also was increased and decreased, respectively. There is a positive correlation between the changes in the micropore SSA and the Langmuir volume. It confirms that the changes in pore structure and methane adsorption capacity due to CS2 treatment are controlled by the rank, and the change in methane adsorption is impacted by the change of micropore SSA and suggests that the changes in pore structure are better for gas migration; the alteration in methane adsorption capacity is worse and better for methane recovery before and after Ro,max=1.3%. A conceptual mechanism of pore structure is proposed to explain methane adsorption capacity on CS2 treated coal around the Ro,max=1.3%.

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