The influence of temperature on adsorption capacity of Malaysian coal

Azmi, Azlin Suhaida; Yusup, Suzana; Muhamad, Suhana

doi:10.1016/j.cep.2005.10.006

Cited by 36 publications

(18 citation statements)

References 3 publications

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“…They have applied different approaches to describe how sorption capacity, sorption rate, gas diffusion, and permeability are affected. Several groups reported that the sorption of gas on coals at a given pressure increases with decreasing temperature (Azmi et al 2006;Menon 1968;White et al 2005;Zhou et al 2001), but the temperature effect on the maximum sorption capacity was controversial (Sakurovs et al 2010), nor was the temperature effect quantified. Major challenges for ECBM lie in the fact that the density of the adsorbed phase within varying pores is unknown and fundamental understanding of the sorption mechanism is insufficient.…”

Section: Introductionmentioning

confidence: 99%

Molecular simulation studies of hydrocarbon and carbon dioxide adsorption on coal

et al. 2015

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Sorption isotherms of hydrocarbon and carbon dioxide (CO 2 ) provide crucial information for designing processes to sequester CO 2 and recover natural gas from unmineable coal beds. Methane (CH 4 ), ethane (C 2 H 6 ), and CO 2 adsorption isotherms on dry coal and the temperature effect on their maximum sorption capacity have been studied by performing combined Monte Carlo (MC) and molecular dynamics (MD) simulations at temperatures of 308 and 370 K (35 and 97°C) and at pressures up to 10 MPa. Simulation results demonstrate that absolute sorption (expressed as a mass basis) divided by bulk gas density has negligible temperature effect on CH 4 , C 2 H 6 , and CO 2 sorption on dry coal when pressure is over 6 MPa. CO 2 is more closely packed due to stronger interaction with coal and the stronger interaction between CO 2 molecules compared, respectively, with the interactions between hydrocarbons and coal and between hydrocarbons. The results of this work suggest that the ''a'' constant (proportional to T c 2 /P c ) in the Peng-Robinson equation of state is an important factor affecting the sorption behavior of hydrocarbons. CO 2 injection pressures of lower than 8 MPa may be desirable for CH 4 recovery and CO 2 sequestration. This study provides a quantitative understanding of the effects of temperature on coal sorption capacity for CH 4 , C 2 H 6 , and CO 2 from a microscopic perspective.

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Section: Introductionmentioning

confidence: 99%

Molecular simulation studies of hydrocarbon and carbon dioxide adsorption on coal

et al. 2015

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“…Many methods such as hydraulic fracturing, high-pressure water jet and blasting vibration (Shen et al, 2012;Li et al, 2009;Shimizu et al, 2011;Li and Xing 2015), have been tested and applied to achieve these goals. The desorption rate and permeability of CSG can also be significantly increased by physical stimulation through changing the thermal field, stress field, electrical and magnetic field (Pan et al, 2012;Azmi et al, 2006;Hol et al, 2011;Charriére et al,2010;Liu et al, 2006) and their coupling effects. Acoustic wave field stimulation method is relatively new and successfully applied in oil recovery and ultrasonic assisted desorption for removal of aromatic pollutants (Ye et al, 2008;Mohammadian et al, 2013;Alhomadhi et al, …”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of acoustic stimulation induced mechanical vibration enhancing coal permeability

Jiang

Xing

2016

Journal of Natural Gas Science and Engineering

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Mechanical vibration is a major effect generated by acoustic stimulation inside a coal sample for enhancing its permeability. The numerical simulation based on the staggered-grid finite differential method (FDM) is applied to simulate 3D wave propagation in a fractured coal. Two parameters, shear wave energy (SE) and variable width of cleat (DW), are introduced and implemented in the numerical model to explicitly visualise and evaluate the acoustic stimulation effects. The polarized wave induced wave dynamics in a coal sample with a cleat/fracture is numerically simulated and analysed. Especially, the energy trapping and dynamic variation of fracture width in coal for the cleat/fracture with three different filled media (i.e. air, water and weak mineral) are numerically analysed and compared with each other subjected to different incident wave angles, and the optimal stimulation parameters are obtained through such sensitivity analysis. Simulation results show that the coal property (i.e. cleat and its filled media) and incident wave angles are crucial for acoustic stimulation to produce physical damages around coal cleats and enhance the permeability of fractured coal samples.

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“…The desorption rate and permeability of CSG can also be significantly increased by physical stimulation through changing the thermal field (Azmi et al, 2006;Charrié re and Pokryszka, 2010;Pan et al, 2012), stress field (Hol et al, 2011), electrical and magnetic field (Liu et al, 2006) and their coupling effects. Acoustic wave stimulation method is relatively new and successfully applied in oil recovery and ultrasonic assisted desorption for removal of aromatic pollutants (Ye et al, 2008;Naderi and Babadagli, 2010;Alhomadhi et al, 2014;Mohammadian et al, 2013).…”

Section: Backgroundsmentioning

confidence: 99%

“…Many methods such as hydraulic fracturing (Li and Xing, 2015), hydraulic slotting (Shen et al, 2012) and blasting vibration (Li et al, 2009), have been tested and applied to achieve these goals. The desorption rate and permeability of CSG can also be significantly increased by physical stimulation through changing the thermal field (Azmi et al,2006), stress field (Hol et al, 2011), electrical and magnetic field (Liu et al, 2006) and their coupling effects. Acoustic wave field stimulation method is relatively new and successfully applied in oil recovery and ultrasonic assisted desorption for removal of aromatic pollutants (Ye et al, 2008;Nader and Babadagli, 2010;Mohammadian et al, 2013;Alhomadhi et al, 2014).…”

Section: Overviewmentioning

confidence: 99%

“…Unlikely conventional natural gas, which mostly stored in reservoirs in free state, more than 90% amount of CSG exist in pores and micro-fractures/cleats (Azmi et al, 2006; Charrié re and Pokryszka., 2010) of coal in adsorption state (Hol et al, 2011;Gandossi, 2013); the structure of CSG's reservoir is relatively fragile comparing with the conventional reservoirs, which are usually constructed of sandstone or limestone. Meanwhile, due to the low permeability of coal reservoirs, the extraction rate of a single CSG well is very low even in gas-rich areas.…”

Section: Backgroundsmentioning

confidence: 99%

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Numerical simulation of acoustic stimulation for enhancing coal seam gas reservoir permeability

Jiang¹

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Acoustic stimulation method has been recognized as one of the most effective methods for enhancing coal permeability and improving the production amount of gas. Laboratory data has proved that the geometrical parameters (width and length) of coal cleats, which are the crucial pathway for gas migration, could be highly increased by acoustic field stimulation. The main reason for this positive effect is that acoustic energy could induce the mechanical vibration effect around coal cleats. However, the basic mechanism of this effect is still poorly understood due to the limitation of experimental facilities; the progress and details about this effect cannot be directly observed. It is imperative to conduct proper numerical simulation for the technology to improve the understanding of mechanical vibration. And only based on the conclusion of simulation results, the engineering parameters for optimal stimulation effect could be found. This thesis addresses this key issue and demonstrates how exactly the mechanical vibration is induced and affect the original coal cleat system. This thesis focuses on conducting numerical simulation for acoustic wave induced mechanical vibration around the coal cleats. The primary contributions are summarized as follows:(1) The numerical simulation based on the staggered-grid finite differential method (FDM) is applied to simulate 3D wave propagation in a single coal cleat model. Two parameters, shear wave energy (SE) and variable width of cleat (DW), are introduced and implemented in the numerical model to explicitly evaluate the acoustic stimulation effects. The results indicate that these parameters could accurately represent the variations of acoustic energy and geometrical parameters of the coal cleat model.(2) The polarized wave induced wave dynamics in a coal sample with a single cleat model is numerically simulated and analyzed; the energy trapping and dynamic variation of fracture width in coal for the cleat model with three different filled media (i.e. air, water and weak mineral) are numerically analyzed and compared with each other subjected to different incident wave angles, and the optimal stimulation parameters are obtained through such sensitivity analysis. Simulation results show that the mechanical vibration is induced by the energy trapping effect; coal property (i.e. cleat and its filled media) and incident wave angles are crucial for acoustic stimulation to produce physical damages around coal cleats and enhance the permeability of fractured coal samples. II (3)The numerical simulation is further applied to simulate the viscoelastic wave propagation in 3D coal sample with a coal cleat system. Two kinds of coal cleat system model, orthogonal cleat sets (OCS) and T-junction cleat sets (TCS), are adopted to investigate the influence of coal cleats special structure for mechanical vibration. A stochastic model building process, which includes Monte Carlo method and von-Ká rmá n function, is proposed to better represent the structure of coal cleat system and hete...

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The influence of temperature on adsorption capacity of Malaysian coal

Cited by 36 publications

References 3 publications

Molecular simulation studies of hydrocarbon and carbon dioxide adsorption on coal

Molecular simulation studies of hydrocarbon and carbon dioxide adsorption on coal

Numerical modelling of acoustic stimulation induced mechanical vibration enhancing coal permeability

Numerical simulation of acoustic stimulation for enhancing coal seam gas reservoir permeability

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