CH4 and CO2 Adsorption Characteristics of Low-Rank Coals Containing Water: An Experimental and Comparative Study

Ma, Ruying; Yao, Yanbin; Meng, Weiyi; Dai, Xiaogan; Li, Anhang

doi:10.1007/s11053-022-10026-x

Cited by 13 publications

(5 citation statements)

References 44 publications

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“…[ 28–30 ] Coals that are rich in vitrinite content tend to have higher surface areas [ 31 ] for adsorption due to the dominance of meso‐ and micro‐pores in high vitrinite coals compared to other maceral compositions. [ 32–34 ] This observation was applicable as well for the medium rank coals. Table 1 summarizes the characterization information for the coals studied.…”

Section: Resultsmentioning

confidence: 58%

In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO₂ sequestration potential

Premlall,

Kipyegon

2023

Can J Chem Eng

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This study aimed to investigate the sorption behaviour of South African coal seams with relation to the effect of temperature during CO2 sequestration. The excess adsorption isotherms of CO2 adsorption were undertaken using a high‐pressure volumetric system for four coals of different coal rank (denoted by Somkele [SK], anthracite KZN [AN], Tshikondeni [TD], and Syferfontein [SF]). The volumetric pressure step method was conducted at increments of system temperature of 35, 45, 55, and 65°C for pure CO2 adsorption at incremental pressures up to 93 bar. The results showed that high temperatures have a very significant negative effect on the amount of CO2 adsorbed on the coal samples. The high‐rank coal samples (SK and AN) demonstrated elevated CO2 adsorption capacity across all tested temperatures due to their high vitrinite content. The medium‐rank coals (TD and SF) exhibited comparatively lower CO2 adsorption capacity, attributed to the presence of adsorption hindrances such as higher ash content and volatile and mineral matter. The isosteric heat of adsorption revealed an increasing trend with coverage for all coal samples, with higher rank coals displaying greater slopes. The determined range of the isosteric heat of adsorption, spanning from 10 to 59 kJ/mol, indicated that the adsorption process is primarily of a physisorption nature. Three theoretical models (Langmuir, Freundlich, and Temkin) were evaluated and fitted to the sorption experimental data. The Temkin model exhibited superior fitting compared to the Langmuir and Freundlich isotherms. The Temkin isotherm parameters suggest that the adsorption of CO2 onto coal is a physisorption process.

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Section: Resultsmentioning

confidence: 58%

In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO₂ sequestration potential

Premlall,

Kipyegon

2023

Can J Chem Eng

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“…The coal samples were vacuum-dried at 50 °C for 4 h and then degassed for 48 h to remove the moisture and impurities until the change in two sequential weights did not exceed 2% of the sample mass. 15 Before the experiment and after each adsorption experiment at different temperatures, the gas tightness of the device and the dead volume were measured by injecting helium. The adsorption system was then evacuated for the CH 4 isothermal adsorption experiments at 20, 40, 60, 80, and 100 °C, respectively.…”

Section: Experimental Methods 221 Ch 4 Isothermalmentioning

confidence: 99%

“…The adsorption was measured using a 3H-2000 PH High-Pressure Gas Sorption Analyzer (Beishide Company) and was done at the China University of Mining and Technology (Beijing). The coal samples were vacuum-dried at 50 °C for 4 h and then degassed for 48 h to remove the moisture and impurities until the change in two sequential weights did not exceed 2% of the sample mass . Before the experiment and after each adsorption experiment at different temperatures, the gas tightness of the device and the dead volume were measured by injecting helium.…”

Section: Methodsmentioning

confidence: 99%

Factors Influencing the Methane Adsorption Capacity of Coal and Adsorption Heat Variations

Wang,

Li,

Wang

et al. 2023

Energy Fuels

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Adsorption capacity is a key parameter to evaluate the underground storage capacity of natural gas and the reliability of CO2 sequestration. To explore the effects of temperature and pore structure and properties on adsorption capacity, the quantitative characterization of the effect of temperature on the adsorption capacity of coal and on changes in the heat of adsorption of coal samples during the adsorption process, nine coal samples with thermal maturities ranging from 0.47% to 5.16% vitrinite reflectance (R o) were analyzed by isothermal adsorption experiments at from 20 to 100 °C in 20 °C steps, and the pore structure was analyzed by low-temperature N2 and CO2 adsorption. Moreover, the isosteric heat based on a fixed amount of adsorption and the ultimate heat of CH4 adsorption in different rank coals were also analyzed. The results show that the adsorption capacity of all coals decreases with increasing temperatures, with the maximum volume adsorbed being 11.77–33.34 cm3/g at 20 °C and 9.87–28.99 cm3/g at 100 °C. The change in adsorption ranges from 1.90 to 14.18 cm3/g per 20 °C change, with the coals from 0.71% R o to 3.65% R o showing the least variability: 2.49 cm3/g for every 20 °C change. Coals are dominated by 0.3–0.8 nm micropores, and the isosteric heat of adsorption variation is influenced by the coal surface roughness and intermolecular forces during adsorption. With increasing coal rank, the ultimate heat of adsorption for coal follows the same trend as the adsorption capacity and is positively correlated with the volume and surface area of micropores. The adsorption capacity can be well predicted by the isosteric heat of adsorption only at temperatures ≥ 60 °C. The results can be beneficial for understanding the gas storage in deep reservoirs and promoting the efficient production of deep coalbed methane.

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“…In physical experimental measurement techniques, depending on the pore size, methods primarily include low-temperature nitrogen adsorption, low-temperature carbon dioxide adsorption, high-pressure mercury 2 of 16 intrusion, and nuclear magnetic resonance (NMR) technologies [7]. Each technique targets pores within different size ranges; for example, low-temperature gas adsorption is suitable for detecting mesopores and micropores [8], while high-pressure mercury intrusion is more apt for characterizing macropores [9]. Although these methods have their strengths, limitations exist, such as the potential for high-pressure mercury intrusion to damage samples [10], whereas low-temperature gas adsorption can avoid sample destruction, thereby increasing sample usability [11].…”

Section: Progress In the Study Of Pore Characteristics And Gas Conten...mentioning

confidence: 99%

Characteristics of Micro–Nano-Pores in Shallow Shale Gas Reservoirs and Their Controlling Factors on Gas Content

Liu,

Xian,

Huang

2024

Energies

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This investigation ventures into the nuanced porosity traits of shallow shale gas reservoirs, pinpointing the critical determinants of their gas content with a nuanced touch. By harnessing sophisticated microscopy and analytical methods, we embarked on an exploration into the porosity architecture of shale, identifying the distinct pore spaces that harbor shale gas and applying gas adsorption techniques to evaluate its storage potential. Noteworthy is our utilization of diverse adsorption mechanisms and models to accurately fit methane adsorption data while carefully considering the influence of marine shallow shale’s pore structure peculiarities, total organic carbon (TOC) content, and clay mineral content on its adsorption prowess. We introduce a refined model for appraising gas adsorption volumes, an innovative stride toward bolstering the precise estimation of reserves in marine dam shallow shale gas and shedding light on accurate gas adsorption volume calculations in analogous shallow shale gas scenarios. This manuscript offers profound insights into the sophisticated interplay between shale porosity and gas storage, enriching our understanding and enabling more accurate future resource estimations.

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CH4 and CO2 Adsorption Characteristics of Low-Rank Coals Containing Water: An Experimental and Comparative Study

Cited by 13 publications

References 44 publications

In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO₂ sequestration potential

In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO₂ sequestration potential

Factors Influencing the Methane Adsorption Capacity of Coal and Adsorption Heat Variations

Characteristics of Micro–Nano-Pores in Shallow Shale Gas Reservoirs and Their Controlling Factors on Gas Content

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CH4 and CO2 Adsorption Characteristics of Low-Rank Coals Containing Water: An Experimental and Comparative Study

Cited by 13 publications

References 44 publications

In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO2 sequestration potential

In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO2 sequestration potential

Factors Influencing the Methane Adsorption Capacity of Coal and Adsorption Heat Variations

Characteristics of Micro–Nano-Pores in Shallow Shale Gas Reservoirs and Their Controlling Factors on Gas Content

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In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO₂ sequestration potential

In‐situ temperature‐depth profile evaluation of South African unmineable coal seams to determine CO₂ sequestration potential