Molecular simulation of CO2/CH4/H2O competitive adsorption and diffusion in brown coal

Zhou, Wenning; Wang, Haobo; Zhang, Zhe; Chen, Hongxia; Liu, Xunliang

doi:10.1039/c8ra10243k

Cited by 77 publications

(70 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23,25 In addition, CO 2 is much easier for coal to physically adsorb than O 2 and N 2 . 26,27 Therefore, adsorption of CO 2 occupies some of the active sites on the coal surface, inhibiting the ability of O 2 and coal to interact.…”

Section: Features On Tg-dsc Testsmentioning

confidence: 99%

Inhibiting effect of CO₂ on the oxidative combustion thermodynamics of coal

Ren

Deng

et al. 2019

RSC Adv.

View full text Add to dashboard Cite

A thermal analysis experiment was conducted in O 2 /N 2 /CO 2 and O 2 /N 2 atmospheres (O 2 concentrations were 21, 14, 8, and CO 2 concentrations were 0, 39, 46, 52) to investigate the thermal behavior of coal oxidation and combustion. Results demonstrated that an elevated CO 2 concentration or decreased O 2 concentration had a delaying effect on the thermogravimetric analysis and differential scanning calorimetry (DSC) curves; moreover, the characteristic temperatures were substantially augmented.When the O 2 concentration was 21 vol%, the total heat released by coals A (highly volatile bituminous coal) and B (anthracite coal) decreased by 5.8% and 4.1%, respectively, after CO 2 addition. The comprehensive combustion performance index was also lowered. The DSC curve can be divided into two exothermic peaks, and the ratio of the peak 1 to peak 2 areas decreased with the addition of CO 2, which indicated that CO 2 inhibited the oxidation of the active functional groups of coal structures.Apparent activation energy in O 2 /CO 2 /N 2 was less than that in O 2 /N 2 .

show abstract

Section: Features On Tg-dsc Testsmentioning

confidence: 99%

Inhibiting effect of CO₂ on the oxidative combustion thermodynamics of coal

Ren

Deng

et al. 2019

RSC Adv.

View full text Add to dashboard Cite

show abstract

“…Recently, the enhanced coalbed methane (ECBM) recovery has been proposed as a more effective methane recovery method. This method injects different gases (pure N 2 , pure CO 2 , or N 2 /CO 2 mixtures) into coal seams to reduce the partial pressure of methane and accelerate methane desorption …”

Section: Introductionmentioning

confidence: 99%

“…This method injects different gases (pure N 2 , pure CO 2 , or N 2 /CO 2 mixtures) into coal seams to reduce the partial pressure of methane and accelerate methane desorption. [8][9][10] Field tests of CO 2 -ECBM recovery have been carried out around the world. In October 2000, the CO 2 -ECBM pilot was conducted with four injector wells in the San Juan Basin, United States.…”

mentioning

confidence: 99%

Numerical study on enhancing coalbed methane recovery by injecting N₂/CO₂ mixtures and its geological significance

Fan

Wang

Deng

et al. 2019

Energy Science & Engineering

View full text Add to dashboard Cite

As an effective carbon utilization technology, the injection of N2/CO2 mixtures into coal seams has significant potential for improving coalbed methane recovery. Considering the technical barrier that injection of pure CO2 decreases the well injectivity index and pure N2 injection leads to the rapid methane recovery, a method of injecting N2‐enriched gas mixtures with a constant component is proposed. In this study, a thermo‐hydro‐mechanical (THM) coupling numerical model for enhanced coalbed methane (CBM) recovery by injecting N2/CO2 mixtures is established. This model includes complex interactions of coal deformation, competitive adsorption, ternary gas seepage, and heat transfer. The THM coupling model is first validated, and then applied to investigate the evolution of mixed gas concentrations, reservoir permeability, reservoir temperature, CH4 production, and N2/CO2 storage during N2/CO2 enhanced CBM recovery. The results show that the displacement radius and concentration of the mixed gas in the coal seam increased with gas injection pressure increase. The concentration of CH4 gradually decreased with time, and the early decline is faster than the later stage. The sweep of the N2 flow accelerates CH4 desorption and migration, promoting a reduction in reservoir temperature near the production well. Reservoir permeability evolution results from the combined effects of ternary gases (CH4, CO2, N2) competitive adsorption, gas pressure, and geostress on the coal seam within the THM fields. At the methane natural depletion stage (within 250 days), the permeability of coal reservoir first decreases and then increases. With the arrival of the N2/CO2 mixture, the permeability decreases dramatically. From the perspective of cumulative CH4 production, the optimal composition is dominated by the synergistic effect of maximizing breakthrough time and minimizing coal matrix swelling. For 30% CO2‐70% N2, the CH4 recovery ratio reached 71.76%, representing an increase of 16.67% compared to natural depletion.

show abstract

“…Investigation about the adsorption performances of CH 4 and CO 2 on coal could provide useful information to understand the adsorption mechanisms of CH 4 and CO 2 and verify the feasibility of the technology of CO 2 -ECBM. To date, many studies have addressed the adsorption behaviors of CH 4 and CO 2 on different rank coals by the means of laboratory experiment and numerical simulation analysis [2,[8][9][10][11][12][13][14][15][16][17]. Their results indicate that the adsorption amount and adsorption rate of CO 2 on coal are larger than those of CH 4 [2,13,16].…”

Section: Introductionmentioning

confidence: 99%

Adsorption Equilibrium and Thermodynamic Analysis of CO₂ and CH₄ on Qinshui Basin Anthracite

Sun

et al. 2019

Geofluids

View full text Add to dashboard Cite

Adsorption isotherms of CH4 and CO2 on Qinshui Basin anthracite were obtained at the temperatures of 283 K, 303 K, and 323 K using the gravimetric method. The feasibility of the displacement of CH4 by injecting CO2 on this anthracite was verified by calculating the selectivity factor of CO2 over CH4 (αCO2/CH4), adsorption affinities, and thermodynamic properties of CH4 and CO2. Results show that the values of αCO2/CH4 are more than 4.0. Henry’s constant (KH) of CH4 is smaller than that of CO2, and CH4 has a weaker affinity with coal surface. As temperature improves, KH of CO2 and CH4 decrease. Gibbs free energy change (ΔG) and surface potential (Ω) of CO2 are more negative than those of CH4, indicating that CO2 adsorption on anthracite is more spontaneous and favorable. The absolute values of Ω and ΔG of CH4 and CO2 increase with pressure rises. Isosteric heat of adsorption (Qst) of CH4 is lower than that of CO2. With increasing loading, Qst and entropy loss (ΔS) of CH4 decrease, while Qst and ΔS of CO2 increase. The higher ΔS of CO2 reveals that the adsorbed CO2 molecules constitute a more stable rearrangement than CH4 molecules. High temperature reduces ΔS of CH4 and CO2.

show abstract

Molecular simulation of CO₂/CH₄/H₂O competitive adsorption and diffusion in brown coal

Abstract: Competitive adsorption and diffusion behaviours of CO2/CH4/H2O in brown coal were explored by GCMC and MD simulations.

Cited by 77 publications

References 54 publications

Inhibiting effect of CO₂ on the oxidative combustion thermodynamics of coal

Inhibiting effect of CO₂ on the oxidative combustion thermodynamics of coal

Numerical study on enhancing coalbed methane recovery by injecting N₂/CO₂ mixtures and its geological significance

Adsorption Equilibrium and Thermodynamic Analysis of CO₂ and CH₄ on Qinshui Basin Anthracite

Contact Info

Product

Resources

About

Molecular simulation of CO2/CH4/H2O competitive adsorption and diffusion in brown coal

Abstract: Competitive adsorption and diffusion behaviours of CO2/CH4/H2O in brown coal were explored by GCMC and MD simulations.

Cited by 77 publications

References 54 publications

Inhibiting effect of CO2 on the oxidative combustion thermodynamics of coal

Inhibiting effect of CO2 on the oxidative combustion thermodynamics of coal

Numerical study on enhancing coalbed methane recovery by injecting N2/CO2 mixtures and its geological significance

Adsorption Equilibrium and Thermodynamic Analysis of CO2 and CH4 on Qinshui Basin Anthracite

Contact Info

Product

Resources

About

Molecular simulation of CO₂/CH₄/H₂O competitive adsorption and diffusion in brown coal

Inhibiting effect of CO₂ on the oxidative combustion thermodynamics of coal

Inhibiting effect of CO₂ on the oxidative combustion thermodynamics of coal

Numerical study on enhancing coalbed methane recovery by injecting N₂/CO₂ mixtures and its geological significance

Adsorption Equilibrium and Thermodynamic Analysis of CO₂ and CH₄ on Qinshui Basin Anthracite