Effect of active composite ionic liquids treatment on chemical structure and wettability of coal

Chen, Xi; Gao, Jiahui; Deng, Cunbao; Ge, Shaocheng; Fan, Chaonan; Zhang, Wei

doi:10.1016/j.fuel.2022.126885

Cited by 22 publications

(11 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the contents of pro/hydrophobic functional groups, which have huge influence on the wettability of coal, were picked up as positive/negative evaluation indexes with reference to previous studies. The former includes hydroxyl and oxygen-containing functional groups, and the latter includes aromatic structures and aliphatic functional groups. − The evaluation index system is shown in Figure .…”

Section: Tests and Methodsmentioning

confidence: 99%

Research on the Optimization for Acidification Modification Scheme Considering Coal’s Wettability Based on the AHP–TOPSIS Method

He,

Yuan,

et al. 2023

ACS Omega

View full text Add to dashboard Cite

Acidification technology is an important measure for enhancing the extraction of coalbed methane from seams with low permeability and abundant minerals, and the acidification scheme is the key to the success of acidification treatment. To determine the optimal acidification modification scheme, an improved AHP−TOPSIS method is proposed to decide on the optimal conditions for wettability modification. This method constructs an evaluation index system, taking the wettability of coal as the target layer and the pro/hydrophobic functional groups in coal as the index layer. Meanwhile, it innovatively takes the adsorption energy of each functional group when absorbing a single water molecule as the basis for assigning weights to the evaluation indexes. Then, nine acidification modification schemes are evaluated and selected by the improved AHP−TOPSIS method based on the test results of different schemes to get the optimal one. The optimal scheme selected by the AHP−TOPSIS method is validated by water adsorption tests and isothermal adsorption tests. The results showed that the significance of each evaluation index is ranked as follows: aromatic structures > hydroxyl groups > aliphatic functional groups > oxygen-containing functional groups. The optimal acidification modification scheme is selected by the AHP−TOPSIS method with a HF concentration of 4% and a reaction time of 6 h. The ranking of acidification modification schemes obtained by the AHP−TOPSIS method is in high agreement with the ranking of water adsorption tests. When compared with raw coal, the coal samples treated with the optimal scheme have lower adsorption capacity for gas, which indicates that the aforementioned method could be used to evaluate and select the optimal acidification modification scheme, and the selected optimal scheme has the potential to increase the output of coalbed methane.

show abstract

Section: Tests and Methodsmentioning

confidence: 99%

Research on the Optimization for Acidification Modification Scheme Considering Coal’s Wettability Based on the AHP–TOPSIS Method

He,

Yuan,

et al. 2023

ACS Omega

View full text Add to dashboard Cite

show abstract

“…Functional groups are atoms or atom groups on the edge of the basic unit of the chemical structure, reflecting the organic components in coal. 68 Raw infrared spectral data were imported into OMNIC, and the spectral transmittance was converted to absorbance processed with baseline correction, atmospheric compensation, and noise reduction smoothing. The processed data were then imported into Origin for peak fitting analysis.…”

Section: Effects Ofmentioning

confidence: 99%

Wetting Behavior of CO₂–H₂O–coal with Different Metamorphic Degrees under In Situ Thermophysical Conditions

Li,

Zhu,

Zhang

et al. 2024

Energy Fuels

View full text Add to dashboard Cite

Wettability in CO2–H2O–coal directly determines pore-scale configuration and further affects practice projects on the hectometer scale; however, coal rank and thermophysical condition dependences of wettability and their underlying mechanisms are inadequate. Potential candidate coal beds (hvBb, hvAb, mvb, sa) were considered, and wettability reflected by static/dynamic contact angles was evaluated under in situ reservoir conditions (temperature and pressure) by the captive bubble method. Physicochemical properties with potential effects on wetting behavior were characterized via SEM-EDS, FTIR, and XRD. Static/dynamic contact angles increased with pressure and coal rank, while they decreased with temperature, typically showing intermediate- or CO2-wetting in deep reservoirs. Advancing contact angles depended less on temperature and coal rank than static/receding contact angles. At a low temperature (T = 25 °C), CO2-wetting was stronger and was more significantly affected by coal rank and pressure. The curves of contact angles and CO2 density as a function of pressure almost coincided and increased steeply at pressures between 60 and 90 bar (∼64.3 bar). With increasing metamorphic degrees, defects, oxygen content, and polar oxygen-containing functional groups (hydroxyl, etc.) on the surface decreased, while C/O (the ratio of carbon to oxygen), C, and aromatic hydrocarbons increased. The results of the gray relational model indicate that C/O and hydroxyl are the primary factors affecting wettability in chemical properties. With coal rank, the degree of aromatic ring condensation increased and inorganic minerals (e.g., clay minerals and calcite) reduced; the crystallite structure tended to grow and become graphite-like. Measurement data and an understanding of wetting behavior have implications for project site selection and provide input parameters for field-scale reservoir modeling.

show abstract

“…25 Wang et al found that the wetting time became shorter with decreasing surface tension; lower surface tension was not related to the wetting time. 26 studied the physicochemical properties of coal by compounding sodium salicylate and imidazole ionic liquids and found that the compounding could reduce the cohesive energy of water molecules and improve the wetting effect. 28 Existing research has focused on modifying coal by surfactant compounding and single ionic liquid solutions as wetting agents.…”

Section: Introductionmentioning

confidence: 99%

“…Zhou et al established an analytical mechanism for coal–surfactant wettability evaluation by simulating the effect of surfactants on coal microcrystalline structures and found that ether groups and hydroxyl groups affect the wetting effect . Wang et al found that the wetting time became shorter with decreasing surface tension; lower surface tension was not related to the wetting time . Chen et al investigated the effect of ionic liquids compounding with each other on coal wetting and found that [Bmim][BF 4 ] and [Emim][BF 4 ] compounding had the best effect .…”

Section: Introductionmentioning

confidence: 99%

Study on Surface Activity of Inorganic Salts on [C₁₂MIm]Cl and Wetting Characteristics of Compound Modified Bituminous Coal

Zhang,

Ni,

Jiang

et al. 2024

Energy Fuels

View full text Add to dashboard Cite

The technical problem of the difficult wetting of coal bed water injection urgently needs to be solved, and the wetting of surfactants on the coal body is mainly affected by the concentration. In recent years, research related to surface-active ionic liquids (SAILs) with long-chain alkyl groups has attracted much attention. Salt can enhance the wetting effect of surfactants, but there are few studies on the effect of inorganic salts on the surface activity of [C 12 MIm]Cl and the effect of compound wetting bituminous coal. In this paper, NaCl was selected to be complexed with [C 12 MIm]Cl, and the trends of key functional groups and surface activity changes during coal wetting were quantitatively characterized from a microscopic point of view by functional group and wetting characterization analysis. The results showed that under the treatment of 0.6 mol/L of NaCl + 10 mmol/L of the [C 12 MIm]Cl compound, the surface tension was reduced by 7 N m/m and the minimum contact angle by 15.5°. In the modified coal, the peak area of the �CH 2 group is reduced by 29%, the peak area of the −CH 3 group is increased by 24%, the peak area of the OH•••N group is reduced by 14%, and the wetting effect is enhanced. However, the high concentration of NaCl in the composite solution will weaken the wetting effect on bituminous coal. The research results provide theoretical support for coal seam composite wetting by water injection.

show abstract

Effect of active composite ionic liquids treatment on chemical structure and wettability of coal

Cited by 22 publications

References 44 publications

Research on the Optimization for Acidification Modification Scheme Considering Coal’s Wettability Based on the AHP–TOPSIS Method

Research on the Optimization for Acidification Modification Scheme Considering Coal’s Wettability Based on the AHP–TOPSIS Method

Wetting Behavior of CO₂–H₂O–coal with Different Metamorphic Degrees under In Situ Thermophysical Conditions

Study on Surface Activity of Inorganic Salts on [C₁₂MIm]Cl and Wetting Characteristics of Compound Modified Bituminous Coal

Contact Info

Product

Resources

About

Effect of active composite ionic liquids treatment on chemical structure and wettability of coal

Cited by 22 publications

References 44 publications

Research on the Optimization for Acidification Modification Scheme Considering Coal’s Wettability Based on the AHP–TOPSIS Method

Research on the Optimization for Acidification Modification Scheme Considering Coal’s Wettability Based on the AHP–TOPSIS Method

Wetting Behavior of CO2–H2O–coal with Different Metamorphic Degrees under In Situ Thermophysical Conditions

Study on Surface Activity of Inorganic Salts on [C12MIm]Cl and Wetting Characteristics of Compound Modified Bituminous Coal

Contact Info

Product

Resources

About

Wetting Behavior of CO₂–H₂O–coal with Different Metamorphic Degrees under In Situ Thermophysical Conditions

Study on Surface Activity of Inorganic Salts on [C₁₂MIm]Cl and Wetting Characteristics of Compound Modified Bituminous Coal