• 제목/요약/키워드: Geologic CO2 storage

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포항 지역 토양 CO2의 분포 및 거동 특성 연구: CO2 지중저장 부지 자연 배경 조사 및 예비 해석 (Distribution and Behavior of Soil CO2 in Pohang area: Baseline Survey and Preliminary Interpretation in a Candidate Geological CO2 Storage Site)

  • 박진영;성기성;유순영;채기탁;이세인;염병우;박권규;김정찬
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제21권1호
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    • pp.49-60
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    • 2016
  • Distribution and behavior of baseline soil CO2 were investigated in a candidate geologic CO2 storage site in Pohang, with measuring CO2 concentrations and carbon isotopes in the vadose zone as well as CO2 fluxes and concentrations through ground surface. This investigation aimed to assess the baseline CO2 levels and to build the CO2 monitoring system before injecting CO2. The gas in the vadose zone was collected using a peristaltic pump from the depth of 60 cm below ground surface, and stored at gas bags. Then the gas components (CO2, O2, N2, CH4) and δ13CCO2 were analyzed using GC and CRDS (cavity ringdown spectroscopy) respectively in laboratory. CO2 fluxes and CO2 concentrations through ground surface were measured using Li-COR in field. In result, the median of the CO2 concentrations in the vadose zone was about 3,000 ppm, and the δ13CCO2 were in the wide range between −36.9‰ and −10.6‰. The results imply that the fate of CO2 in the vadose zone was affected by soil property and vegetations. CO2 in sandy or loamy soils originated from the respiration of microorganisms and the decomposition of C3 plants. In gravel areas, the CO2 concentrations decreased while the δ13CCO2 increased because of the mixing with the atmospheric gas. In addition, the relation between O2 and CO2, N2, and the relation between N2/O2 and CO2 implied that the gases in the vadose zone dissolved in the infiltrating precipitation or the soil moisture. The median CO2 flux through ground surface was 2.9 g/m2/d which is lower than the reported soil CO2 fluxes in areas with temperate climates. CO2 fluxes measured in sandy and loamy soil areas were higher (median 5.2 g/m2/d) than those in gravel areas (2.6 g/m2/d). The relationships between CO2 fluxes and concentrations suggested that the transport of CO2 from the vadose zone to ground surface was dominated by diffusion in the study area. In gravel areas, the mixing with atmospheric gases was significant. Based on this study result, a soil monitoring procedure has been established for a candidate geologic CO2 storage site. Also, this study result provides ideas for innovating soil monitoring technologies.

고압 유체 시료의 pH 및 알칼리도 측정 방법 : 가상 시료를 활용한 실용성 평가 (Method for Measuring pH and Alkalinity of High-Pressure Fluid Samples : Evaluation through Artificial Samples)

  • 송민석;문수현;채기탁;방준환
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제29권1호
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    • pp.1-9
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    • 2024
  • As part of monitoring technology aimed at verifying the stability of CO2 geologic storage and mitigating concerns about leakage, a method for measuring the pH and alkalinity of high-pressure fluid samples was established to obtain practical technology. pH measurement for high-pressure samples utilized a high-pressure pH electrode, and alkalinity was measured using the Gran titration method for samples collected with a piston cylinder sampler (PCS). Experimental samples, referencing CO2-rich water and CO2 geologic storage studies, were prepared in the laboratory. The PCS controls the piston, preventing CO2 degassing and maintaining fluid pressure, allowing mixing with KOH to fix dissolved CO2. Results showed a 6.1% average error in high-pressure pH measurement. PCS use for sample collection maintained pressure, preventing CO2 degassing. However, PCS-collected sample alkalinity measurements had larger errors than non-PCS measurements, limiting PCS practicality in monitoring field settings. Nevertheless, PCS could find utility in preprocessing for carbon isotope analysis and other applications. This research not only contributes to the field of CCS monitoring but also suggests potential applications in studies related to natural analogs of CCS, CO2-rock interaction experiments, core flooding experiments, and beyond.

지중 저장 이산화탄소의 누출 위험도 평가를 위한 결함수 분석 (Fault Tree Analysis for Risk Assessment of CO2 Leakage from Geologic Storage)

  • 이상일;이상기;황진환
    • 환경영향평가
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    • 제18권6호
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    • pp.359-366
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    • 2009
  • CCS (Carbon Capture and Storage) is considered as the most promising interim solution to deal with the greenhouse gas such as $CO_2$ responsible for global warming. Even though carefully chosen geologic formations are known to contain stored gas for a long time period, there are potential risks of leakage. Up to now, applicable risk assessment procedures for the leakage of $CO_2$ are not available. This study presents a basis for risk analysis applicable to a complex geologic storage system. It starts with the classification of potential leakage pathways. Receptors and the leakage effect on them are identified and quantified. Then, a fault tree is constructed, which yields the minimum cut set (i.e., the most vulnerable leakage pathway) and quantifies the probability of the leakage risk through the cut set. The methodology will provide a tool for risk assessment in a CCS project. The outcomes of the assessment will not only ensure the safety of the CCS system but also offer a reliable and efficient monitoring plan.

이산화탄소 지중저장의 환경 관리를 위한 미국과 유럽연합의 법·제도 현황과 시사점 (Status and Implications of Regulatory Frameworks for Environmental Management of Geologic CO2 Storage in USA and EU)

  • 장은선;윤성택;최병영;정다위;강헌
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제17권6호
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    • pp.9-22
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    • 2012
  • Though geologic storage of $CO_2$ (GS) is considered as an attractive technological option to enormously reduce greenhouse gases emission into the atmosphere, many concerns on potential environmental and health risks associated with $CO_2$ leakage have been raised. In particular, groundwater contamination due to the brine displacement by a pressure build-up and the acidification by leaked $CO_2$ is paid a special attention. Therefore, integrated regulatory frameworks have been established by law in many countries to secure the permanent containment of injected $CO_2$. Regulatory frameworks deal with entire processes of GS, including site selection, monitoring and post-closure environmental management. This review paper provides a summary of regulatory frameworks in USA (U.S. EPA Geologic Sequestration Rule) and EU (Geologic $CO_2$ Sequestration Directive). The regulatory framework to properly address environmental issues should be established for the deployment of CCS projects in Korea.

이산화탄소 지중저장 모델링: 저투수 이질협재층이 이산화탄소 거동에 미치는 영향 (Modeling Geologic Storage of Carbon Dioxide: Effects of Low-permeability Layer on Migration of CO2)

  • 한아름;김태희;권이균;구민호
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제22권3호
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    • pp.42-49
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    • 2017
  • TOUGH2 was used to simulate the migration of $CO_2$ injected into a sandy aquifer. A series of numerical simulations was performed to investigate the effects of a low-permeability layer (LPL) embedded in the aquifer on the injection rate and the pressure distribution of $CO_2$. The results show that the size and location of the LPL greatly affected the spread of $CO_2$. The pressure difference between two points in the aquifer, one each below and above the LPL, increased as the size of the LPL increased, showing a critical value at 200 m, above which the size effect was diminished. The location of the LPL with respect to the injection well also affected the migration of $CO_2$. When the injection well was at the center of the LPL, the injection rate of $CO_2$ decreased by 5.0% compared to the case with no LPL. However, when the injection well was at the edge of the LPL, the injection rate was decreased by only 1.6%. The vertical distance between the injection point and the LPL also affected the injection rate. The closer the LPL was to the injection point, the lower the injection rate was, by up to 8.3%. Conclusively, in planning geologic storage of $CO_2$, the optimal location of the injection well should be determined considering the distribution of the LPL in the aquifer.

pH가 낮은 탄산수의 CO2 탈기에 따른 용존탄소동위원소 변화 (Changes of carbon-13 Isotope of Dissolved Inorganic Carbon Within Low-pH CO2-rich Water during CO2 Degassing)

  • 채기탁;유순영;김찬영;박진영;방하은;이인혜;고동찬;신영재;오진만
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제24권3호
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    • pp.24-35
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    • 2019
  • It is known that ${\delta}^{13}C_{DIC}$ (carbon-13 isotope of dissolved inorganic carbonate (DIC) ions) of water increases when dissolved $CO_2$ degases. However, ${\delta}^{13}C_{DIC}$ could decrease when the pH of water is lower than 5.5 at the early stage of degassing. Laboratory experiments were performed to observe the changes of ${\delta}^{13}C_{DIC}$ as $CO_2$ degassed from three different artificial $CO_2$-rich waters (ACWs) in which the initial pH was 4.9, 5.4, and 6.4, respectively. The pH, alkalinity and ${\delta}^{13}C_{DIC}$ were measured until 240 hours after degassing began and those data were compared with kinetic isotope fractionation calculations. Furthermore, same experiment was conducted with the natural $CO_2$-rich water (pH 4.9) from Daepyeong, Sejong City. As a result of experiments, we could observe the decrease of DIC and increase of pH as the degassing progressed. ACW with an initial pH of 6.4, ${\delta}^{13}C_{DIC}$ kept increasing but, in cases where the initial pH was lower than 5.5, ${\delta}^{13}C_{DIC}$ decreased until 6 hours. After 6 hours ${\delta}^{13}C_{DIC}$ increased within all cases because the $CO_2$ degassing caused pH increase and subsequently the ratio of $HCO_3{^-}$ in solution. In the early stage of $CO_2$ degassing, the laboratory measurements were well matched with the calculations, but after about 48 hours, the experiment results were deviated from the calculations, probably due to the equilibrium interaction with the atmosphere and precipitation of carbonates. The result of this study may be not applicable to all natural environments because the pressure and $CO_2$ concentration in headspace of reaction vessels was not maintained constant as well as the temperature. Nevertheless, this study provides fundamental knowledge on the ${\delta}^{13}C_{DIC}$ evolution during $CO_2$ degassing, and therefore it can be utilized in the studies about carbonated water with low pH and the monitoring of geologic carbon sequestration.

CO2 해양격리시스템의 기술.경제적 가능성평가 (Economic Feasibility Study for CO2 Ocean Sequestration)

  • 박세헌;오위영;권문상
    • Ocean and Polar Research
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    • 제27권4호
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    • pp.451-461
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    • 2005
  • The $CO_2$ storage in geologic and oceanic reservoirs is considered to be one of the carbon management strategies for responding to global climate change. Ocean carbon sequestration is purposeful storage acceleration into the ocean of large amounts of carbon that would accumulate in the atmosphere and naturally enter the ocean over a longer timespan. Some technologies for $CO_2$ ocean sequestrations have been developed as a nation project. However, $CO_2$ ocean sequestrations are attractive because they have the advantage of vast capacity sequestration far away from industrial areas, and offer easier monitoring whereas less economic advantage has been indicated as one of the key barriers compared with $CO_2$ geosphere sequestration, which is produced as a byproduct. In this paper, a conceptual design for $CO_2$ ocean sequestration is introduced, and the preliminary examination is described. As a result, the $CO_2$ price, US$ 24/t shows far away from the economics. The causes come from the expensive $CO_2$ recovery cost and the low $CO_2$ price. The expensive $CO_2$ recovery cost is because too much electricity and water are consumed. In order to look for an economic balance point for $CO_2$ ocean sequestration, NPV=0, it is increases the $CO_2$ price. Finally 60.4$ per ton is found to be the balance price.

다채널 지표토양 CO2 농도 모니터링(SCM) 시스템 개발 및 적용성 평가 연구 (Applicability of the Multi-Channel Surface-soil CO2-concentration Monitoring (SCM) System as a Surface Soil CO2 Monitoring Tool)

  • 성기성;유순영;최병영;박진영;한래희;김정찬;박권규;채기탁
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제20권1호
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    • pp.41-55
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    • 2015
  • Monitoring of $CO_2$ release through the ground surface is essential to confirm the safety of carbon storage projects. We conducted a feasibility study of the multi-channel surface-soil $CO_2$-concentration monitoring (SCM) system as a soil $CO_2$ monitoring tool with a small scale injection test. The background concentrations showed the distinct diurnal variation. The negative relation of $CO_2$ with temperature and the low $CO_2$ concentrations during the day imply that surface-soil $CO_2$ depends on photosynthesis and respiration. After 4.2 kg of $CO_2$ injection (1 m depth for 29 minutes), surface-soil $CO_2$ concentrations increased in the all five chambers, which were located less than 2.8 m of distance from each other. The $CO_2$ concentrations seem to be recovered to the background around 4 hours after the injection ended. To determine the leakage, the data from Chamber 2 and 5 with low increase rates were used for statistical analyses. Coefficient of variation for 30 minutes ($CV_{30min}$.) is efficient to determine a leakage signal, with reflecting the fast change in $CO_2$ concentrations. Consequently, SCM and $CV_{30min}$ could be applied for an efficient monitoring tool to detect $CO_2$ release through the ground surface. Also, this study provides ideas for establishing action steps after leakage detection.

CO2 지중저장 시 단층 안정성 평가 (Case Study on Stability Assessment of Pre-existing Fault at CO2 Geologic Storage)

  • 김현우;천대성;최병희;최헌수;박의섭
    • 터널과지하공간
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    • 제23권1호
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    • pp.13-30
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    • 2013
  • $CO_2$를 지중저장하는 과정에서 유체압력의 증가로 인한 단층 활성화는 저장영역의 기밀성 유지에 중대한 영향을 미치며, 상황에 따라 저장기능의 회복 또는 저장중인 $CO_2$의 처리 문제 등으로 확대될 수 있다. 따라서 현지조사 결과의 불확실성을 최소화하고 이를 토대로 부지 선정과 주입압력 결정 단계에서 실제 조건에 가까운 모델링을 수행하여 저장영역 내 단층의 안정성과 $CO_2$ 누출 가능성을 평가하여야 한다. 본 연구에서는 이와 관련된 기존 연구 결과들을 살펴봄으로써 연구 동향 및 연구 방법에 대한 정보를 제공하고자 하였다. 먼저 인위적으로 지반에 주입된 유체 또는 자연 생성되어 응집되어 있던 $CO_2$에 의해 지진활동이 일어났던 사례들을 조사하였으며, 현지응력의 크기 및 방향, 단층 및 유체압력 분포 자료를 획득하는 방법에 대해 살펴보았다. 그리고 단층 활성화 가능성 평가 및 지진활동 시 진동 크기 추정, 활성화에 따른 $CO_2$ 누출 모델링 관련 연구 사례를 정리하였다.

관정 시멘팅 재료의 물리역학물성 및 시멘트층의 안정성 분석 (Physical and Mechanical Properties of Cements for Borehole and Stability Analysis of Cement Sheath)

  • 김기덕;이희권;김태희;김교원
    • 지질공학
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    • 제26권1호
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    • pp.101-115
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    • 2016
  • 관정의 시멘팅 재료로 사용될 수 있는 두 시멘트 물질(KS-1 보통 포틀랜드, Class G)의 물/고체(고체=시멘트) 중량비와 첨가제인 비산재의 부피함량 변화에 따른 이들 물질들의 물리역학적 물성 변화를 파악하기 위해 실내물리역학실험을 실시하였다. KS-1 보통 포틀랜드 시멘트의 경우 물/고체(고체=시멘트) 중량비를 변화시키며, Class G 시멘트의 경우 물/고체(고체=비산재+시멘트)을 고정한 채 비산재:시멘트의 부피비를 변화시키며 시료를 제작하였다. KS-1 보통 포틀랜드 시멘트의 경우 물/고체 중량비가 증가할수록, Class G 시멘트의 경우 비산재의 함량이 증가할수록, 공극률 증가, 밀도감소, 음파속도(P, S파) 감소. 탄성상수(영율, 포아송비) 감소, 압축 및 인장강도 저하, 열전도도 감소, 비열 증가의 경향을 보였다. 또한 구속압(σ3)의 증가와 비산재 함량의 증가는 재료의 소성파괴거동을 초래하였다. 이 실내실험결과를 이용하여, 여러 주입공 페라미터(케이싱, 시멘트층의 두께, 주입압, 주입공 경사방향 및 경사각, 주입공 심도)등을 변화 시키면서, 시멘트층의 안정성 분석을 실시하였다. 분석결과 낮은 주입압과 경사정 혹은 수평정에서는 시멘트층이 안정하였으나, 다른 조건에서는 시멘트층에서 주로 인장파괴가 관찰 되었다.