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Updated: Jul 27, 2025

Achieving Moderate Pressures in Sealed Vessels Using Dry Ice As a Solid CO2 Source
Published on: August 17, 2018
Effects of Supercritical CO
Xicong Ma1, Yi Du1,2, Changqing Fu3
1National and Local Joint Engineering Research Center for Carbon Capture Utilization and Sequestration & State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China.
Supercritical CO2 and water alter coal's pore structure by creating new pores and fractures. Mineral dissolution, particularly calcite, significantly impacts pore volume, surface area, and complexity across different pore sizes.
Area of Science:
- Geochemistry
- Materials Science
- Coal Science
Background:
- Coal pore structure is crucial for energy storage and carbon sequestration.
- Understanding mineral-coal interactions under supercritical conditions is vital for optimizing these processes.
Purpose of the Study:
- To investigate the impact of supercritical CO2 (ScCO2)-H2O-coal interactions on coal pore structure.
- To analyze mineral-induced changes in coal porosity and surface area.
Main Methods:
- Autoclave experiments simulating ScCO2-H2O-coal interactions.
- Mercury Intrusion Capillary Pressure (MICP), nitrogen and CO2 adsorption, and FESEM analyses.
- Application of fractal theory to quantify pore complexity.
Main Results:
- ScCO2-H2O treatment significantly increased coal pore volume and specific surface area, forming new pores and fractures.
- Complete calcite dissolution led to larger pores (>150 nm) with uniform morphologies and decreased fractal dimensions.
- Incomplete calcite dissolution resulted in more complex pore structures (2-150 nm) with increased fractal dimensions.
- Micropores (<2 nm) became more uniform with decreased fractal dimensions after the reaction.
Conclusions:
- Water presence enhances ScCO2 interaction with coal, potentially improving CO2 injectivity.
- Mineral dissolution, especially calcite, is a key driver of coal pore structure evolution under ScCO2-H2O conditions.
- Fractal dimensions effectively characterize the complexity changes in coal pores due to mineral alterations.
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