Feasibility and Applicability Analysis of CO2-ECBM Technology Based on CO2–H2O–Coal Interactions

Wu, Caifang; Zhao, Kai

doi:10.1021/acs.energyfuels.7b01663

Cited by 20 publications

(11 citation statements)

References 30 publications

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“…Storing carbon dioxide (CO 2 ) into unmineable coal seams and simultaneously recovering CH 4 (CO 2 -ECBM) has become a feasible way to mitigate CO 2 emissions. − As an alternative option to CO 2 -ECBM, a novel technical proposal, that is, directly injecting oxygen-enriched coal-combustion flue gas into coal seams, has been gaining broad interest. , This technology is expected to cut the cost regarding denitration (DeNO x ) and flue gas desulfuration. Next, the multiple interactions between NO x , SO 2 , and coal matrix are expected to stably store oxygen-enriched coal-combustion flue gas within coal reservoirs in the geologic time scale.…”

Section: Introductionmentioning

confidence: 99%

Influence of Water on Nitrous Oxide Adsorption and Desorption on Coals

Liu

et al. 2021

Ind. Eng. Chem. Res.

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Oxygen-enriched coal-combustion flue gas geologic sequestration in unmineable coal seams is a promising option to mitigate gaseous pollutant emissions and recover coalbed methane (CH4). Water (H2O) always exists in practical coal seams and shows significant impact on fluid adsorption, desorption, diffusion, and flow behaviors. Thus, this study mainly addressed the influence of H2O on nitrous oxide (N2O) adsorption and desorption, a typical component that existed in oxygen-enriched coal-combustion flue gas, on different rank coals. Results indicate that the N2O adsorption equilibrium and kinetic behaviors within moist coals can be well-predicted using the Sips model and the simplified bidisperse kinetic model, respectively. The H2O dramatically hinders the adsorption and diffusion capability of N2O within coals, which is attributed to the fact that H2O molecules occupy pore channels, induce coal matrix swelling, and compete with N2O molecules for the same adsorption sites, particularly the oxygen-containing functional groups. The H2O impairs the physisorption and chemisorption of N2O on coals. Furthermore, the H2O enhances the chemical transformation among the four main nitrogen-containing species within coals, that is, pyridine-N, pyrrole/pyridone-N, quaternary-N, and oxide-N. Particularly, the abundant −H groups of H2O molecules inhibit the decomposition of pyrrole/pyridone-N and accelerate the transformation of pyridine-N, while −OH groups of H2O molecules promote the formation of oxide-N. To sum up, the practical N2O geologic sequestration should focus on the effects of in-situ H2O within coal reservoirs.

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Section: Introductionmentioning

confidence: 99%

Influence of Water on Nitrous Oxide Adsorption and Desorption on Coals

Liu

et al. 2021

Ind. Eng. Chem. Res.

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“…The adsorption capacity of coal to carbon dioxide (CO 2 ) is greater than that of CH 4 , and the adsorbed CH 4 in micropores − can be replaced by CO 2 by competitive adsorption, which positively affects CBM recovery. , The very first CO 2 -enhanced CBM (CO 2 -ECBM) studies were conducted by American researchers. The field application of CO 2 -ECBM (Figure ) has demonstrated that CO 2 injection can increase CBM production and that CO 2 can be geologically sequestrated. − Wang et al conducted numerical simulations and demonstrated that, in general, the permeability evolution of reservoirs has a downward trend.…”

Section: Introductionmentioning

confidence: 99%

Influence of Carbon Dioxide on the Adsorption of Methane by Coal Using Low-Field Nuclear Magnetic Resonance

Bai

Zeng

et al. 2020

Energy Fuels

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The adsorption capacity of coal with respect to carbon dioxide (CO2) is greater than that of methane (CH4). Studying the CO2 replacement of CH4 in coal is essential to understanding the mechanism behind CO2-enhanced coalbed methane. In this paper, scanning electron microscopy was used to qualitatively study the influence of CO2 injection pressure on the fracture characteristics of coal. The time effect of the CH4/CO2 adsorption and the effect of the CO2 injection on the CH4 adsorption were quantitatively studied using low-field nuclear magnetic resonance. The results suggest three different CH4 states in the coal samples: CH4 adsorbed on the pore surface, free CH4 in the pore center, and free CH4 between the coal particles. Indeed, the greater the CO2 injection pressure, the more developed the fracturing and network, which, in turn, increases connectivity. As the adsorption time of CH4/CO2 increases, the adsorption rate of CO2/CH4 gradually decreases. In essence, CO2 preferentially replaces the CH4 of the minipores. As the CO2 injection pressure increases, the difference between the CO2 equilibrium pressure and the initial injection pressure increases. Moreover, the CH4 production rate increases, the transverse relaxation time (T 2) spectrum of the adsorption-state area decreases, the T 2 spectrum of the free-state area increases, and the number of adsorption holes gradually decreases, whereas the number of seepage holes increases.

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“…CO 2 displacement can be adopted for CBM recovery [9]. CO 2 -enhanced coalbed methane (CO 2 -ECBM) technology involves the injection of CO 2 into a coal seam rich in CBM, to sequester CH 4 , promotes clean green energy, and is widely used in the production of deep ultra-low permeability coal seams [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Effect of Injected CO2 Temperature and Pressure on CO2-Enhanced Coalbed Methane

et al. 2020

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The injection of CO2 to displace CH4 in coal seams is an effective method to exploit coalbed methane (CBM), for which the CO2 injection temperature and pressure are important influential factors. We performed simulations, using COMSOL Multiphysics to determine the effect of CO2 injection temperature and pressure on CO2-enhanced coalbed methane (CO2-ECBM) recovery, according to adsorption/desorption, seepage, and diffusion of binary gas (CO2 and CH4) in the coal seam, and deriver a thermal–hydraulic–mechanical coupling equation of CO2-ECBM. The simulation results show that, as CO2 injection pressure in CO2-ECBM increases, the molar concentration and displacement time of CH4 in the coal seam significantly decrease. With increasing injection temperature, the binary gas adsorption capacity in the coal seam decreases, and CO2 reserves and CH4 production decrease. High temperatures are therefore not conducive for CH4 production.

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Feasibility and Applicability Analysis of CO₂-ECBM Technology Based on CO₂–H₂O–Coal Interactions

Cited by 20 publications

References 30 publications

Influence of Water on Nitrous Oxide Adsorption and Desorption on Coals

Influence of Water on Nitrous Oxide Adsorption and Desorption on Coals

Influence of Carbon Dioxide on the Adsorption of Methane by Coal Using Low-Field Nuclear Magnetic Resonance

Numerical Simulation of the Effect of Injected CO2 Temperature and Pressure on CO2-Enhanced Coalbed Methane

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