Characteristics of seepage of microemulsions in coal

Yan, Song; Wang, Gang; Wang, Qiannan; Wang, Wenrui

doi:10.1016/j.molliq.2020.112742

Cited by 11 publications

(5 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, because they are not strongly oxidative, they will not experience notable chemical reactions with the coal surface. However, they will destroy and transform the functional group structure of coal samples. − Because the acidification reaction of acetic acid is an exothermic reaction, they will reduce the molecular force of the solutions, generate moist heat, and promote the oxidation of the solutions, thereby promoting the acidification of acetic acid to various degrees. The anionic surfactant (SDBS) can reduce the molecular force of solution, significantly increase the hydrophilicity of coal samples, increase the water absorption and expansion capacity of minerals in pores, weaken the dissolution and migration capacity of minerals in pores, and finally slightly reduce the porosity.…”

Section: Discussionmentioning

confidence: 99%

“…After the minerals in coal are acidified and corroded, new precipitates are generated, which changes the compressive strength of coal. In terms of (2) modification of ionic liquids − and surfactants, − ionic liquids (including imidazole, sodium salicylate–imidazole, and ammonium carbamate) can dissolve the reducing groups in coal, generate many ether, carboxyl, and aromatic benzene ring structures, improve the cohesive energy of coal molecules, and change the functional groups and pore structure of coal. Surfactant solutions (such as cetyltrimethyl ammonium chloride and sodium dodecyl sulfate), which have good dispersion, can dissolve montmorillonite, increase the number of oxygen-containing functional groups in coal, ease the blockage of minerals in pores, and reduce the occupation of pore channels by clear water, thereby improving the porosity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chemical Modification Effect of Compound Solutions of Surfactants with Acetic Acid on Coal Pores

Xie

Chen

et al. 2021

ACS Omega

View full text Add to dashboard Cite

Coal seam pores are the major places for coalbed methane storage, diffusion, and seepage, and changes in the pore structure cause changes in the porosity. The porosity of coal seams can be effectively improved by applying strongly corrosive and oxidative chemical reagents to coal seam pores, but these reagents may pose threats to coal workers, corrode mining equipment, and pollute the environment. In this study, coal samples were treated with solutions compounded by acetic acid and anionic, cationic, and non-ionic surfactants. The variations of pores in coal samples after the compound modification of surfactants and acetic acid were investigated. Experimental methods of SEM, MIP, LTNA, PAC, and FTIR and fractal theory are applied in this work. The results reveal that the compound modification of surfactants and acetic acid conduces to the transformation of pore shape and affects a wider pore size range. The anionic and cationic surfactants can increase the hydrophilicity and can promote the connection of larger pores. The non-ionic surfactant reduces the hydrophilicity and capillary effect yet increases the porosity. Thus, it promotes the connection of pores and makes the pore surface smooth and the pore structure simple. Comparing the three kinds of surfactants, non-ionic surfactants are more conducive to coal seam pore reconstruction.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chemical Modification Effect of Compound Solutions of Surfactants with Acetic Acid on Coal Pores

Xie

Chen

et al. 2021

ACS Omega

View full text Add to dashboard Cite

show abstract

“…Where, γSG, γLG and γSL are the solid-gas, liquid-gas, solid-liquid interfacial tensions (N/m), respectively, and θ (0-180°) is the contact angle at the solution interface [40]. 0° indicates that the solution is completely wet, when the spread on coal surface is complete.…”

Section: Theory and Experimentsmentioning

confidence: 99%

Experimental Investigation of the Wetting Ability of Microemulsion to Different Coal Samples

Sang¹,

Yan²,

Wang³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

To improve water injection effect, microemulsions (MEs) were used to wet coal seam compared with water and sodium dodecyl sulfate solution (SDS). Wetting effects were characterized by contact angle, X-ray diffraction, Fourier infrared spectroscopy. The results showed that the microemulsion has better spreadability on coal surface and has stronger wettability for coals of different ranks and different particle sizes than traditional wetting agents. The W/O type microemulsion is more affinity to coal than the O/W type and the bicontinuous type.Oxygen and hydrogen contents contributed to wetting. Different wetting agents have the greatest impact on the oxygen-containing functional group absorption zone of coal, but have little impact on the change of clay mineral composition.As the content of quartz increased, the content of montmorillonite was decreased, and the hydrophilicity of coal was increased. This research proposes new ideas for solving coal dust problems and reducing coal mine disasters.

show abstract

“…The pore-fracture systems in coal are storage and migration channels of coalbed methane (CBM), and they are likely to be filled with minerals to become closed or semi-closed pores and fractures, which influences the diffusion and migration of CBM [6][7][8][9][10]. Acid fracturing is one of the most effective methods to solve mineral blocking of pores and fractures in coal seams [11][12][13]. Previous research has shown that, when using acid solutions as fracturing fluids, they can dissolve minerals in coal reservoirs, enlarge the volume and specific surface area of mesopores in coal, and simplify pore structures [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Influences of Different Acid Solutions on Pore Structures and Fractal Features of Coal

Zhang,

Ni,

Liu

et al. 2024

Fractal Fract

View full text Add to dashboard Cite

The effect of different acids on the pore structure and fractal characteristics of micropores and mesopores was determined with the help of low-temperature liquid nitrogen adsorption, X-ray diffraction, and the Frenkel–Halsey–Hill (FHH) model by using Yuwu coal as a sample and placing it in acidic environments, such as HF, HCl, HNO3, and CH3COOH. The results show that the acidization effects of HF and CH3COOH are separately dominated by the micropore and mesopore formation effects, while HCl and HNO3 mainly play their roles in expanding mesopores. After acidization, the surface fractal dimensions D1 and D1′ of micropores and mesopores in coal are always negatively correlated with the total specific surface area SBET, specific surface area Smic of micropores, and specific surface area Smes of mesopores. After being acidized by HF, D2 is negatively correlated with the total volume Vtot and the corresponding micropore volume Vmic, while acidization with HCl and HNO3 leads to the opposite result. After being acidized by CH3COOH, D2 has a negative correlation with Vtot and a positive correlation with Vmic. The structural fractal dimensions D2′ of mesopores in samples acidized by HF and CH3COOH are positively correlated with both the volume Vtot and mesopore volume Vmes, while it is the opposite for samples acidized by HNO3. D2′ of coal samples acidized by HCl is negatively correlated with Vtot while positively correlated with Vmes.

show abstract

Characteristics of seepage of microemulsions in coal

Cited by 11 publications

References 38 publications

Chemical Modification Effect of Compound Solutions of Surfactants with Acetic Acid on Coal Pores

Chemical Modification Effect of Compound Solutions of Surfactants with Acetic Acid on Coal Pores

Experimental Investigation of the Wetting Ability of Microemulsion to Different Coal Samples

Influences of Different Acid Solutions on Pore Structures and Fractal Features of Coal

Contact Info

Product

Resources

About