Methane Adsorption Interpreting with Adsorption Potential and Its Controlling Factors in Various Rank Coals

Water content, metamorphism (coal rank) particle size, and especially pore structure, strongly influence the adsorption capacity of coal to methane. To understand the mechanism of methane adsorption in different rank coals, and its controlling factors, isothermal adsorption experiments with different coal ranks, moisture contents and particle sizes at the temperature of 303.15 K were conducted. In addition, the pore structures of coals were investigated through N2 adsorption/desorption experiments at the low-temperature of 77 K for selected coals from the Junggar Basin of NW China, Qinshui Basin and Ordos Basin of north China. Moreover, the adsorption potential of methane on the surface of the coal matrix was calculated, the controlling factors of which were discussed. The obtained methane isothermal adsorption result shows that the Langmuir volume (VL) of coal is independent of the particle size, and decreases with the increase of moisture content, which decreases first and then increases when the coal rank increases. Combined with the pore structure by the N2 adsorption at 77 K, VL increases with the increase of pore surface area and pore volume of coal pores. Besides, the adsorption potential of all selected coals decreased with the increase of the methane adsorption volume, showing a negative relationship. The interesting phenomena was found that the surface adsorption potential of the coal matrix decreases with the increase of moisture content, and increases with the decrease of particle size at the same pressure. With the same adsorption amount, the adsorption potential on the surface of coal matrix decreases first, and then increases with the increase of coal rank, reaching a minimum at Ro,m of 1.38%, and enlarging with the increase of pore surface area and the pore volume of coal pores. These findings may have significant implications for discovering CBM accumulation areas and enhancing CBM recovery.

Download Full-text

TEKNOLOGI PEMBUATAN ADSORBEN DARI LIMBAH EKSTRAKSI BIOSILIKA SEKAM PADI

Pasundan Food Technology Journal ◽

10.23969/pftj.v7i3.3001 ◽

2020 ◽

Vol 7 (3) ◽

pp. 116-125

Author(s):

Prima Luna ◽

Hoerudin ◽

Sri Usmiati ◽

Sunarmani

Keyword(s):

Particle Size ◽

Activated Carbon ◽

Mass Production ◽

Raw Material ◽

Pore Surface ◽

Lignocellulosic Waste ◽

Impregnation Process ◽

Pore Surface Area ◽

By Products ◽

Calcination Treatment

Adsorbent from lignocellulosic waste constitutes an alternative in industry due to the large amount and easy to get. The unique characteristics of activated carbon from lignocellulosic waste as well as more economically with regard to mass production were the reasons for the development of by-products of this rice husk biosilica waste. This research aimed to produce adsorbent from waste of nanobiosilica powder extraction. Calcination or treatment without impregnation) and with impregnation were applied in this study. Calcination was carried out by heating the residual waste at 600 ° C; 700 ° C; and 800 ° C; however the impregnation process was carried out by immersing the residual waste with catalysts ZnCl2, H3PO4, and KOH with ratio 1: 1 and 1: 2 for 24 hours. Subsequently, carbonisation was carried out at 600 ° C; 700 ° C; and 800 ° C for 1 and 3 hours with variations in mesh sizes of 10, 20, 80, and 100 mesh. The results showed that the waste of nanobiosilica extraction still contained high SiO2 (89.86%) so that it could be used as raw material for adsorber to apply in water purification applications. The calcination treatment showed the highest absorption as well as the area of the pore surface. The best particle size was 100 mesh and calcined at 800 ° C in which has a pore surface area meet the requirement of commercial activated charcoal, which is 15.83 m² / g.

Download Full-text

Mesoporous Au–TiO2 Nanoparticle Assemblies as Efficient Catalysts for the Chemoselective Reduction of Nitro Compounds

MRS Proceedings ◽

10.1557/opl.2014.327 ◽

2014 ◽

Vol 1641 ◽

Author(s):

Ioannis Tamiolakis ◽

Ioannis N. Lykakis ◽

Gerasimos S. Armatas

Keyword(s):

Particle Size ◽

Gold Particle ◽

Nitro Compounds ◽

Nitroaromatic Compounds ◽

Pore Surface ◽

Nanoparticle Assemblies ◽

Gold Particle Size ◽

Pore Surface Area ◽

Hydrogenation Reactions ◽

Amine Groups

ABSTRACTHere, we propose novel mesoporous Au-loaded TiO2 nanoparticle assemblies (Au-MTA) as highly effective catalysts for the reduction of nitroaromatic compounds into the corresponding aryl amine products. The obtained materials possess a continuous network of interconnected gold and anatase TiO2 (ca. 9 nm in size) nanoparticles with controllable gold particle size (i.e. ranging from ∼3.2 to ∼9.4 nm) and exhibit large and accessible pore surface area (ca. 100–160 m2/g), as evidenced by SAXS, XRD, TEM and N2 physisorption measurements. Interestingly, the Au-MTA mesophases have exhibited remarkable activity and selectivity for the reduction of nitro into amine groups using NaBH4 as reducing agent. Indeed, the Au loading and particle size have a key effect on hydrogenation reactions, affecting significantly the yield and product composition.

Download Full-text

Nano-Scale Pore Structure and Fractal Dimension of Longmaxi Shale in the Upper Yangtze Region, South China: A Case Study of the Laifeng–Xianfeng Block Using HIM and N2 Adsorption

Minerals ◽

10.3390/min9060356 ◽

2019 ◽

Vol 9 (6) ◽

pp. 356 ◽

Cited By ~ 16

Author(s):

Cheng Huang ◽

Yiwen Ju ◽

Hongjian Zhu ◽

Yu Qi ◽

Kun Yu ◽

...

Keyword(s):

Fractal Dimension ◽

Pore Structure ◽

Surface Area ◽

South China ◽

Pore Volume ◽

Pore Surface ◽

N2 Adsorption ◽

Longmaxi Shale ◽

Pore Surface Area ◽

Shale Reservoirs

This paper tries to determine the key evaluation parameters of shale reservoirs in the complex tectonic provinces outside the Sichuan Basin in South China, and also to target the sweet spots of shale reservoirs accurately. The pore-structure characteristics of the Lower Silurian Longmaxi shale gas reservoirs in Well LD1 of the Laifeng–Xianfeng Block, Upper Yangtze region, were evaluated. N2 adsorption and helium ion microscope (HIM) were used to investigate the pore features including pore volume, pore surface area, and pore size distribution. The calculated results show good hydrocarbon storage capacity and development potential of the shale samples. Meanwhile, the reservoir space and migration pathways may be affected by the small pore size. As the main carrier of pores in shale, organic matter contributes significantly to the pore volume and surface area. Samples with higher total organic carbon (TOC) content generally have higher porosity. Based on the Frenkel–Halsey–Hill equation (FHH model), two different fractal dimensions, D1 and D2, were observed through the N2 adsorption experiment. By analyzing the data, we found that large pores usually have large values of fractal dimension, owing to their complex pore structure and rough surface. In addition, there exists a good positive correlation between fractal dimension and pore volume as well as pore surface area. The fractal dimension can be taken as a visual indicator that represents the degree of development of the pore structure in shale.

Download Full-text

Effect of coal rank, oxygen level and particle size on oxidation reactivity of typical Chinese coals

Thermochimica Acta ◽

10.1016/j.tca.2020.178838 ◽

2021 ◽

Vol 696 ◽

pp. 178838

Author(s):

Xing Liu ◽

Houzhang Tan ◽

Xuebin Wang ◽

Zhao Wang ◽

Jiaye Zhang ◽

...

Keyword(s):

Particle Size ◽

Coal Rank ◽

Oxygen Level ◽

Oxidation Reactivity

Download Full-text

Geometric pore surface area and fractal dimension of catalyzed electrodes in polymer electrolyte membrane fuel cells

International Journal of Energy Research ◽

10.1002/er.4260 ◽

2018 ◽

Vol 43 (7) ◽

pp. 3011-3019 ◽

Cited By ~ 3

Author(s):

Jian Zhao ◽

Samaneh Shahgaldi ◽

Adnan Ozden ◽

Ibrahim E. Alaefour ◽

Xianguo Li ◽

...

Keyword(s):

Fractal Dimension ◽

Fuel Cells ◽

Polymer Electrolyte ◽

Surface Area ◽

Polymer Electrolyte Membrane ◽

Pore Surface ◽

Electrolyte Membrane ◽

Pore Surface Area

Download Full-text

98/03687 Application of the mono/multilayer and adsorption potential theories to coal methane adsorption isotherms at elevated temperature and pressure

Fuel and Energy Abstracts ◽

10.1016/s0140-6701(98)93682-7 ◽

1998 ◽

Vol 39 (5) ◽

pp. 346

Keyword(s):

Elevated Temperature ◽

Adsorption Isotherms ◽

Methane Adsorption ◽

Adsorption Potential ◽

Temperature And Pressure

Download Full-text

Variation of Petrophysical Properties and Adsorption Capacity in Different Rank Coals: An Experimental Study of Coals from the Junggar, Ordos and Qinshui Basins in China

Energies ◽

10.3390/en12060986 ◽

2019 ◽

Vol 12 (6) ◽

pp. 986 ◽

Cited By ~ 5

Author(s):

Yingjin Wang ◽

Dameng Liu ◽

Yidong Cai ◽

Xiawei Li

Keyword(s):

Adsorption Capacity ◽

Vitrinite Reflectance ◽

Inhibitory Effect ◽

Proximate Analysis ◽

Methane Adsorption ◽

Low Rank ◽

Petrophysical Properties ◽

Isothermal Adsorption ◽

Variation Rule ◽

Moisture Absorbent

The petrophysical properties of coal will vary during coalification, and thus affect the methane adsorption capacity. In order to clarify the variation rule and its controlling effect on methane adsorption, various petrophysical tests including proximate analysis, moisture measurement, methane isothermal adsorption, mercury injection, etc. were carried out on 60 coal samples collected from the Junggar, Ordos and Qinshui basins in China. In this work, the boundary values of maximum vitrinite reflectance (Ro,m) for dividing low rank, medium rank and high rank coals are set as 0.65% and 2.0%. The results show that vitrinite is the most abundant maceral, but the maceral contents are controlled by sedimentation without any relation to coal rank. Both the moisture content and porosity results show higher values in the low ranks and stabilized with Ro,m beyond 1%. Ro,m and VL (daf) show quadratic correlation with the peak located in Ro,m = 4.5–5%, with the coefficient (R2) reaching 0.86. PL decrease rapidly before Ro,m = 1.5%, then increase slowly. DAP is established to quantify the inhibitory effect of moisture on methane adsorption capacity, which shows periodic relationship with Ro,m: the inhibitory effect in lignite is the weakest and increases during coalification, then remains constant at Ro,m = 1.8% to 3.5%, and finally increases again. In the high metamorphic stage, clay minerals are more moisture-absorbent than coal, and the inherent moisture negatively correlates with the ratio of vitrinite to inertinite (V/I). During coalification, micro gas pores gradually become dominant, fractures tends to be well oriented and extended, and clay filling becomes more common. These findings can help us better understand the variation of petrophysical properties and adsorption capacity in different rank coals.

Download Full-text

Biogenic Methane Production from Various Coal Rank and Its Controlling Factors Using Ruminant Waste as a Microorganism-Consortium Source

Petrogenesis and Exploration of the Earth’s Interior - Advances in Science, Technology & Innovation ◽

10.1007/978-3-030-01575-6_55 ◽

2019 ◽

pp. 225-227

Author(s):

Ahmad Helman Hamdani ◽

Ellin Harlia ◽

Winantris Sanusi

Keyword(s):

Methane Production ◽

Controlling Factors ◽

Coal Rank ◽

Biogenic Methane

Download Full-text

Effects of Pore Structures of Different Maceral Compositions on Methane Adsorption and Diffusion in Anthracite

Applied Sciences ◽

10.3390/app9235130 ◽

2019 ◽

Vol 9 (23) ◽

pp. 5130 ◽

Cited By ~ 4

Author(s):

Jincheng Zhao ◽

Yong Qin ◽

Jian Shen ◽

Binyang Zhou ◽

Chao Li ◽

...

Keyword(s):

Coalbed Methane ◽

Pore Diameter ◽

Fractal Theory ◽

Effective Diffusion ◽

Low Pressure ◽

Methane Adsorption ◽

Isothermal Adsorption ◽

Diffusion Capacity ◽

Pore Structures ◽

Study Results

The pore structure of coal reservoirs is the main factor influencing the adsorption–diffusion rates of coalbed methane. Mercury intrusion porosimetry (MIP), low-pressure nitrogen adsorption (LP-NA), low-pressure carbon dioxide adsorption (LP-CA), and isothermal adsorption experiments with different macerals were performed to characterize the comprehensive pore distribution and methane adsorption–diffusion of coal. On the basis of the fractal theory, the pore structures determined through MIP and LP-NA can be combined at a pore diameter of 100 nm to achieve a comprehensive pore structural splicing of MIP, LP-NA, and LP-CA. Macro–mesopores and micro-transitional pores had average fractal dimensions of 2.48 and 2.18, respectively. The Langmuir volume (VL) and effective diffusion coefficients (De) varied from 31.55 to 38.63 cm3/g and from 1.42 to 2.88 × 10−5 s−1, respectively. The study results showed that for super-micropores, a higher vitrinite content led to a larger specific surface area (SSA) and stronger adsorption capacity but also to a weaker diffusion capacity. The larger the average pore diameter (APD) of micro-transitional pores, the stronger the diffusion capacity. The diffusion capacity may be controlled by the APD of micro-transitional pores.

Download Full-text