Orientational transition in adsorbed methane films

1984 ◽  
Vol 29 (9) ◽  
pp. 5190-5192 ◽  
Author(s):  
John Bruno ◽  
M. R. Giri
1998 ◽  
Vol 41 (5) ◽  
pp. 507-512 ◽  
Author(s):  
V Berejnov ◽  
J.-C Bacri ◽  
V Cabuil ◽  
R Perzynski ◽  
Yu Raikher

2014 ◽  
Vol 962-965 ◽  
pp. 1118-1122
Author(s):  
Hua Ping Yang ◽  
Ming Li

The methane molecule model, the coal molecule model and the absorption model of coal and methane have been thoroughly investigated using the DFT method,Van der Walls force radius as boundary conditions as well. The investigations focuses on optimizing the three types of model structure. Meanwhile, adsorption equilibrium geometries with 6-311G++ basic sets have been established. Through the model analysis of the changes in the structure and Millikan charge from free state to the adsorption states, the results indicate that the adsorption process of methane gas on the coal in the Van der Walls force mainly dispersion forces and induction force, methane molecules are polarized in the adsorption process, the electric dipole moment.


Methane ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 24-37
Author(s):  
Muhammad Alfiza Farhan ◽  
Yuichi Sugai ◽  
Nuhindro Priagung Widodo ◽  
Syafrizal Syafrizal

The leakage of methane from the subsurface on the coalfield or natural gas field invariably becomes an important issue nowadays. In notable addition, materials such as activated carbon, zeolites, and Porapak have been successfully identified as adsorbents. Those adsorbents could adsorb methane at atmospheric pressure and room temperature. Therefore, in this scholarly study, a new method using adsorbents to detect points of methane leakage that can cover a wide-scale area was developed. In the beginning, the most capable adsorbent should be determined by quantifying adsorbed methane amount. Furthermore, checking the possibility of adsorption in the column diffusion and desorption method of adsorbents is equally necessary. The most capable adsorbent was activated carbon (AC), which can adsorb 1.187 × 10−3 mg-CH4/g-AC. Hereinafter, activated carbon successfully can adsorb methane through column diffusion, which simulates the situation of on-site measurement. The specific amount of adsorbed methane when the initial concentrations of CH4 in a bag were 200 ppm, 100 ppm, and 50 ppm was found to be 0.818 × 10−3 mg-CH4/g-AC, 0.397 × 10−3 mg-CH4/g-AC, 0.161 × 10−3 mg-CH4/g-AC, respectively. Desorption of activated carbon analysis shows that methane concentration increases during an hour in the temperature bath under 80 °C. In conclusion, soil methane leakage points can be detected using activated carbon by identifying the observed methane concentration increase.


2020 ◽  
Vol 53 (15) ◽  
pp. 154004
Author(s):  
Da-Xiao Yang ◽  
Zi-Long Wang ◽  
Ming-Xia Shi ◽  
Kai Sun ◽  
Min-Long Tao ◽  
...  

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3445 ◽  
Author(s):  
Donghyeon Kim ◽  
Youngjin Seo ◽  
Juhyun Kim ◽  
Jeongmin Han ◽  
Youngsoo Lee

Coalbed methane (CBM) content is generally estimated using the isotherm theory between pressure and adsorbed amounts of methane. It usually determines the maximum content of adsorbed methane or storage capacity. However, CBM content obtained via laboratory experiment is not consistent with that in the in-situ state because samples are usually ground, which changes the specific surface area. In this study, the effect of the specific surface area relative to CBM content was investigated, and diffusion coefficients were estimated using equilibrium time analysis. The differences in adsorbed content with sample particle size allowed the determination of a specific surface area where gases can adsorb. Also, there was an equilibrium time difference between fine and lump coal, because more time is needed for the gas to diffuse through the coal matrix and adsorb onto the surface in lump coal. Based on this, we constructed a laboratory-scale simulation model, which matched with experimental results. Consequently, the diffusion coefficient, which is usually calculated through canister testing, can be easily obtained. These results stress that lump coal experiments and associated simulations are necessary for more reliable CBM production analysis.


Sign in / Sign up

Export Citation Format

Share Document