Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O Treatment
The dissolution of supercritical carbon dioxide (ScCO<sub>2</sub>) in water forms a ScCO<sub>2</sub>–H<sub>2</sub>O system, which exerts a transformative influence on the physicochemical characteristics of coal and significantly impacts the CO<sub>2</sub&...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-09-01
|
| Series: | Minerals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-163X/13/10/1262 |
| _version_ | 1797572883997786112 |
|---|---|
| author | Run Chen Yajun Zhang Kunpeng Hu Guanglong Tu Tianzheng Dou |
| author_facet | Run Chen Yajun Zhang Kunpeng Hu Guanglong Tu Tianzheng Dou |
| author_sort | Run Chen |
| collection | DOAJ |
| description | The dissolution of supercritical carbon dioxide (ScCO<sub>2</sub>) in water forms a ScCO<sub>2</sub>–H<sub>2</sub>O system, which exerts a transformative influence on the physicochemical characteristics of coal and significantly impacts the CO<sub>2</sub>-driven enhanced coalbed methane (CO<sub>2</sub>-ECBM) recovery process. Herein, the effect of ScCO<sub>2</sub>–H<sub>2</sub>O treatment on the physicochemical properties of coal was simulated in a high-pressure reactor. The migration of major elements, change in the pore structure, and change in the CH<sub>4</sub> adsorption capacity of coal after the ScCO<sub>2</sub>–H<sub>2</sub>O treatment were detected using plasma emission spectroscopy, the low-temperature liquid nitrogen adsorption method, and the CH<sub>4</sub> adsorption method, respectively. The results show that (1) the ScCO<sub>2</sub>–H<sub>2</sub>O treatment led to mineral reactions causing a significant migration of constant elements in the coal. The migration of Ca ions was the most significant, with an increase in their concentration in treated water from 0 to 16–970 mg·L<sup>−1</sup>, followed by Na, Mg, and K. Al migrated the least, from 0 to 0.004–2.555 mg·L<sup>−1</sup>. (2) The ScCO<sub>2</sub>–H<sub>2</sub>O treatment increased the pore volume and pore-specific surface area (SSA) of the coal via the dissolution and precipitation of minerals in the coal pores. The total pore volume increased from 0.000795–0.011543 to 0.001274–0.014644 cm<sup>3</sup>·g<sup>−1</sup>, and the total pore SSA increased from 0.084–3.332 to 0.400–6.061 m<sup>2</sup>·g<sup>−1</sup>. (3) Changes in the CH<sub>4</sub> adsorption capacity were affected by the combined effects of a mineral reaction and pore structure change. The dissolved precipitates of the minerals in the coal pores after the ScCO<sub>2</sub>–H<sub>2</sub>O treatment caused elemental migration, which not only decreased the mineral content in the coal pores but also increased the total pore volume and total pore SSA, thus improving the CH<sub>4</sub> adsorption capacity of the coal. This study provides theoretical support for CO<sub>2</sub> sequestration and ECBM recovery. |
| first_indexed | 2024-03-10T21:02:04Z |
| format | Article |
| id | doaj.art-e20843c5eefd4063ad94346f84ea6f26 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T21:02:04Z |
| publishDate | 2023-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-e20843c5eefd4063ad94346f84ea6f262023-11-19T17:29:52ZengMDPI AGMinerals2075-163X2023-09-011310126210.3390/min13101262Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O TreatmentRun Chen0Yajun Zhang1Kunpeng Hu2Guanglong Tu3Tianzheng Dou4Jiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, Carbon Neutrality Institute, China University of Mining and Technology, Xuzhou 221008, ChinaJiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, Carbon Neutrality Institute, China University of Mining and Technology, Xuzhou 221008, ChinaJiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, Carbon Neutrality Institute, China University of Mining and Technology, Xuzhou 221008, ChinaJiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, Carbon Neutrality Institute, China University of Mining and Technology, Xuzhou 221008, ChinaJiangsu Key Laboratory of Coal-Based Greenhouse Gas Control and Utilization, Carbon Neutrality Institute, China University of Mining and Technology, Xuzhou 221008, ChinaThe dissolution of supercritical carbon dioxide (ScCO<sub>2</sub>) in water forms a ScCO<sub>2</sub>–H<sub>2</sub>O system, which exerts a transformative influence on the physicochemical characteristics of coal and significantly impacts the CO<sub>2</sub>-driven enhanced coalbed methane (CO<sub>2</sub>-ECBM) recovery process. Herein, the effect of ScCO<sub>2</sub>–H<sub>2</sub>O treatment on the physicochemical properties of coal was simulated in a high-pressure reactor. The migration of major elements, change in the pore structure, and change in the CH<sub>4</sub> adsorption capacity of coal after the ScCO<sub>2</sub>–H<sub>2</sub>O treatment were detected using plasma emission spectroscopy, the low-temperature liquid nitrogen adsorption method, and the CH<sub>4</sub> adsorption method, respectively. The results show that (1) the ScCO<sub>2</sub>–H<sub>2</sub>O treatment led to mineral reactions causing a significant migration of constant elements in the coal. The migration of Ca ions was the most significant, with an increase in their concentration in treated water from 0 to 16–970 mg·L<sup>−1</sup>, followed by Na, Mg, and K. Al migrated the least, from 0 to 0.004–2.555 mg·L<sup>−1</sup>. (2) The ScCO<sub>2</sub>–H<sub>2</sub>O treatment increased the pore volume and pore-specific surface area (SSA) of the coal via the dissolution and precipitation of minerals in the coal pores. The total pore volume increased from 0.000795–0.011543 to 0.001274–0.014644 cm<sup>3</sup>·g<sup>−1</sup>, and the total pore SSA increased from 0.084–3.332 to 0.400–6.061 m<sup>2</sup>·g<sup>−1</sup>. (3) Changes in the CH<sub>4</sub> adsorption capacity were affected by the combined effects of a mineral reaction and pore structure change. The dissolved precipitates of the minerals in the coal pores after the ScCO<sub>2</sub>–H<sub>2</sub>O treatment caused elemental migration, which not only decreased the mineral content in the coal pores but also increased the total pore volume and total pore SSA, thus improving the CH<sub>4</sub> adsorption capacity of the coal. This study provides theoretical support for CO<sub>2</sub> sequestration and ECBM recovery.https://www.mdpi.com/2075-163X/13/10/1262elemental migrationpore structureCH<sub>4</sub> adsorptionCO<sub>2</sub> sequestrationcoal |
| spellingShingle | Run Chen Yajun Zhang Kunpeng Hu Guanglong Tu Tianzheng Dou Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O Treatment Minerals elemental migration pore structure CH<sub>4</sub> adsorption CO<sub>2</sub> sequestration coal |
| title | Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O Treatment |
| title_full | Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O Treatment |
| title_fullStr | Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O Treatment |
| title_full_unstemmed | Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O Treatment |
| title_short | Changes in Physicochemical Properties of Coal and Their Mechanism Due to Supercritical CO<sub>2</sub>–H<sub>2</sub>O Treatment |
| title_sort | changes in physicochemical properties of coal and their mechanism due to supercritical co sub 2 sub h sub 2 sub o treatment |
| topic | elemental migration pore structure CH<sub>4</sub> adsorption CO<sub>2</sub> sequestration coal |
| url | https://www.mdpi.com/2075-163X/13/10/1262 |
| work_keys_str_mv | AT runchen changesinphysicochemicalpropertiesofcoalandtheirmechanismduetosupercriticalcosub2subhsub2subotreatment AT yajunzhang changesinphysicochemicalpropertiesofcoalandtheirmechanismduetosupercriticalcosub2subhsub2subotreatment AT kunpenghu changesinphysicochemicalpropertiesofcoalandtheirmechanismduetosupercriticalcosub2subhsub2subotreatment AT guanglongtu changesinphysicochemicalpropertiesofcoalandtheirmechanismduetosupercriticalcosub2subhsub2subotreatment AT tianzhengdou changesinphysicochemicalpropertiesofcoalandtheirmechanismduetosupercriticalcosub2subhsub2subotreatment |