Effects of coal storage in air on physical and chemical properties of coal and on gas adsorption

Mastalerz, María; Solano-Acosta, Wilfrido; Schimmelmann, Arndt; Drobniak, Agnieszka

doi:10.1016/j.coal.2009.07.001

Cited by 59 publications

(29 citation statements)

References 41 publications

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“…Maria and Cai et al (2013a, b) analyzed eight coals with similar coal rank but varying petrographic for CH 4 sorption capacity using a high-pressure adsorption isotherm technique and determined the coal quality and petrographic composition of the coals to study their relationships to the volume of CH 4 that could be sorbed into the coal. Previous studies have concluded the qualitative and partly quantitative relationship between physicochemical properties of coal and their adsorption capacity without giving variation scope of adsorption parameters (Unsworth et al 1989;Yalçin and Durucan 1991;Reich et al 1992;Clarkson and Bustin 1999;Mastalerz et al 2009;Charrière et al 2010;Yao and Liu 2012).…”

Section: Introductionmentioning

confidence: 99%

Effects of coal rank on physicochemical properties of coal and on methane adsorption

Cheng

Jiang

Zhang

et al. 2017

Int J Coal Sci Technol

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For the thorough research on coal metamorphism impact on gas adsorption capacity, this paper collected and summarized parameters of experimental adsorption isotherms, coal maceral, proximate analysis and ultimate analysis obtained from National Engineering Research Center of Coal Gas Control and related literatures at home and abroad, systematically discussed the coal rank effect on its physicochemical properties and methane adsorption capacity, in which the coal rank was shown in Vitrinite reflectance, furthermore, obtained the Semi-quantitative relationship between physicochemical properties of coal and methane adsorption capacity.

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Section: Introductionmentioning

confidence: 99%

Effects of coal rank on physicochemical properties of coal and on methane adsorption

Cheng

Jiang

Zhang

et al. 2017

Int J Coal Sci Technol

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“…For example, Coppens (1936) firstly observed the moisture-related decrease in methane sorption capacity of several Belgian coals in laboratory. Mastalerz et al (2009) monitored the moisture loss in coal during storage and found that methane adsorption capacity was increased by 40 % during a time period of 13 months. It is also found that there is a critical moisture content above which moisture has no impact on the adsorption capacity any more (Day et al 2008).…”

Section: Gas Flow Inmentioning

confidence: 99%

Impact of Water Film Evaporation on Gas Transport Property in Fractured Wet Coal Seams

et al. 2016

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Production data of coalbed methane have shown that coalbed may be wet for a long time after the completion of water flow and water-gas two-phase flow stages. In this period, water flows out in moisture vapor, but the water in matrix does not change so much. The moisture loss is mainly from the water film in fracture network. Experiments also observed that such a moisture loss has a profound impact on the storage and transport of coalbed methane. However, this impact has not been investigated so far. This study investigates this impact through following works: firstly, a new conceptual permeability model is proposed based on water film adhered to the surface of fractures in a dual-porosity porous medium. The effect of water film is further described in gas flow equation by a non-Darcy law with threshold pressure gradient. Thirdly, a coupled multi-physical model is established to consider the interactions among coal deformation, gas flow, gas sorption and moisture loss. This model is validated by the gas production data of a coal seam in the Fruitland formation of San Juan basin. Finally, four scenarios are computed to comprehensively study the impact of moisture loss. These simulations show that the proposed model can well fit the history of gas production data. Non-Darcy flow has different velocity profile from Darcy flow. For the non-Darcy flow, the gas flow velocity increases quickly, then slowly, and finally decreases once gas starts to flow at a point. Moisture evaporation with gas flow mainly occurs in the zone near wellbore. This loss has a delay to the gas flow velocity. It also reveals that this moisture loss in coal seams can significantly improve coal permeability and thus enhance gas production. Therefore, the change of water film has significant impacts on gas production.

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“…35 Moreover, the hysteresis loop of the anthracite sample WLH8 and low-rank coal sample YZG2, which can be classified as the L4 type, is not mentioned in the above classification but appears in many published reports. 2,[57][58][59] Its main characteristic is that the adsorption and desorption curves do not coincide, even in a very low relative pressure range (P/P 0 < 0.35). The low-pressure hysteresis may be related to the change in the volume of the adsorbent, for example, the sorption-swelling effect of the coal.…”

Section: Ln 2 Ga Analysismentioning

confidence: 99%

Investigation of the fractal characteristics of adsorption‐pores and their impact on the methane adsorption capacity of various rank coals via N₂ and H₂O adsorption methods

Chen

Yang

Gao

et al. 2020

Energy Science & Engineering

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Coal seam is a sedimentary body with complex pore system. The gas adsorption property of coal is greatly determined by the adsorption‐pores (<100 nm), and the fractal dimension can be used an index to estimate the impact of the adsorption‐pores on the methane adsorption capacity of various rank coals. In this paper, low‐temperature N2 adsorption and H2O adsorption methods were used to study the adsorption‐pores structure and its fractal features. The results show that the development of adsorption‐pores closely depends on the coalification, and the degree of pore development exhibits a U‐shaped trend with increasing coal rank. Additionally, the pore size distributions of coal samples from N2 adsorption analysis and H2O adsorption analysis are similar, especially for samples LH7 and WLH8. Fractal analysis indicates that D2(N2) (0.5 < P/P0 < 1) can more accurately characterize the fractal features of adsorption‐pores than D2(H2O), which may be a result of the significant coal‐H2O interaction. Moreover, D2(N2) has stronger correlations with the coal pore parameters. With the increase in D2(N2), the Langmuir volume first decreases and then increases, which is probably associated with the competition effect of the pore structure and surface irregularity of coal. When D2(N2) < 2.7‐2.8, the pore structure plays a key role, while for D2(N2) > 2.7‐2.8, the influence of the specific surface area is more prominent. The equilibrium moisture content of the coal samples also has a positive correlation with D2, except for low‐rank coal sample YZG2 due to the presence of a large amount of oxygen‐containing functional groups, which increases its water‐holding capacity.

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Effects of coal storage in air on physical and chemical properties of coal and on gas adsorption

Cited by 59 publications

References 41 publications

Effects of coal rank on physicochemical properties of coal and on methane adsorption

Effects of coal rank on physicochemical properties of coal and on methane adsorption

Impact of Water Film Evaporation on Gas Transport Property in Fractured Wet Coal Seams

Investigation of the fractal characteristics of adsorption‐pores and their impact on the methane adsorption capacity of various rank coals via N₂ and H₂O adsorption methods

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Effects of coal storage in air on physical and chemical properties of coal and on gas adsorption

Cited by 59 publications

References 41 publications

Effects of coal rank on physicochemical properties of coal and on methane adsorption

Effects of coal rank on physicochemical properties of coal and on methane adsorption

Impact of Water Film Evaporation on Gas Transport Property in Fractured Wet Coal Seams

Investigation of the fractal characteristics of adsorption‐pores and their impact on the methane adsorption capacity of various rank coals via N2 and H2O adsorption methods

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Product

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Investigation of the fractal characteristics of adsorption‐pores and their impact on the methane adsorption capacity of various rank coals via N₂ and H₂O adsorption methods