Effect of Residual Water in Sediments on the CO 2 -CH 4 Replacement Process
CO 2 replacement is a promising method of gas hydrate recovery. However, the influence of residual water in the replacement process and selections of a suitable mining area remain uncertain. To better understand this method, we examined the influence of the particle size and initial hydrate saturati...
| Published in: | Energies |
|---|---|
| Main Authors: | , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
MDPI AG
2023
|
| Subjects: | |
| Online Access: | https://doi.org/10.3390/en16073154 https://doaj.org/article/3fb8976fb5994bb98bd273ce2b903d38 |
| Summary: | CO 2 replacement is a promising method of gas hydrate recovery. However, the influence of residual water in the replacement process and selections of a suitable mining area remain uncertain. To better understand this method, we examined the influence of the particle size and initial hydrate saturation on the replacement process while using the same amount of residual free water. The results showed that during the replacement process, two stages of rapid reaction and slow reaction occurred, which were manifested by the speed of pressure change in the reactor. The CO 2 sequestration ratio decreased with the increase in sediment particle size and increased with the increase in initial hydrate saturation. During the replacement process, two reactions occurred: CH 4 was replaced by CO 2 and CO 2 hydrate was formed, and the replacement amount and recovery efficiency of CH 4 increased with a decrease in sediment particle size. When the sediment particle size was less than 166 μm, the CH 4 recovery efficiency was significantly affected by the particle size. The replacement amount of CH 4 increased with the increase in initial hydrate saturation, and the recovery efficiency decreased. This study provides a basis for selecting suitable hydrate-accumulation areas for on-site mining. |
|---|