인위적 CO₂ 누출에 따른 토양 CO₂ 플럭스와 농도의 시공간적 모니터링 = Spatio-Temporal Monitoring of Soil CO₂Fluxes and Concentrations after Artificial CO₂Release

다국어 초록 (Multilingual Abstract)

CCS (Carbon Capture and Storage) is a technical process to capture CO₂ from industrial and energy-based sources, to transfer and sequestrate impressed CO₂ in geological formations, oceans, or mineral carbonates. However, potential CO₂ leakage exists and causes environmental problems. Thus, this study was conducted to analyze the spatial and temporal variations of CO₂ fluxes and concentrations after artificial CO₂ release. The Environmental Impact Evaluation Test Facility (EIT) was built in Eumseong, Korea in 2015. Approximately 34kg CO₂ /day/zone were injected at Zones 2, 3, and 4 among the total of 5 zones from October 26 to 30, 2015. CO₂ fluxes were measured every 30 minutes at the surface at 0m, 1.5m, 2.5m, and 10m from the CO₂ releasing well using LI-8100A until November 13, 2015, and CO₂ concentrations were measured once a day at 15cm, 30cm, and 60cm depths at every 0m, 1.5m, 2.5m, 5m, and 10m from the well using GA5000 until November 28, 2015. CO₂ flux at 0m from the well started increasing on the fifth day after CO₂ release started, and continued to increase until November 13 even though the artificial CO₂ release stopped. CO₂ fluxes measured at 2.5m, 5.0m, and 10m from the well were not significantly different with each other. On the other hand, soil CO₂ concentration was shown as 38.4% at 60cm depth at 0m from the well in Zone 3 on the next day after CO₂ release started. Soil CO₂ was horizontally spreaded over time, and detected up to 5m away from the well in all zones until CO₂ release stopped. Also, soil CO₂ concentrations at 30cm and 60cm depths at 0m from the well were measured similarly as 50.6±25.4% and 55.3±25.6%, respectively, followed by 30cm depth (31.3±17.2%) which was significantly lower than those measured at the other depths on the final day of CO₂ release period. Soil CO₂concentrations at all depths in all zones were gradually decreased for about 1 month after CO₂ release stopped, but still higher than those of the first day after CO₂ release stared. In conclusion, the closer the distance from the well and the deeper the depth, the higher CO₂ fluxes and concentrations occurred. Also, long-term monitoring should be required because the leaked CO₂ gas can remains in the soil for a long time even if the leakage stopped.