• Geomechanics and Engineering
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• 제9권1호
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• pp.25-37
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• 2015

To predict the surface subsidence of salt rock storage, a new surface subsidence basin model is proposed based on the Logistic function from the phenomenological perspective. Analysis shows that the subsidence curve on the main section of the model is S-shaped, similar to that of the actual surface subsidence basin; the control parameter of the subsidence curve shape can be changed to allow for flexible adjustment of the curve shape. By using this model in combination with the MMF time function that reflects the single point subsidence-time relationship of the surface, a new dynamic prediction model of full section surface subsidence for salt rock storage is established, and the numerical simulation calculation results are used to verify the availability of the new model. The prediction results agree well with the numerical simulation results, and the model reflects the continued development of surface subsidence basin over time, which is expected to provide some insight into the prediction and visualization research on surface subsidence of salt rock storage.

• 한국가스학회지
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• 제28권2호
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• pp.7-16
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• 2024

본 연구에서는 대규모 수소 저장을 위한 암염 공동(salt cavern) 저장 공법의 기술 특성과 현장사례 분석을 수행하였다. 암염 공동 저장 방식은 공동을 구성하는 암염(rock salt)의 낮은 공극률(porosity)과 투과도(permeability)로 인해 누출이 잘 일어나지 않고, 운영을 위한 쿠션 가스(cushion gas)의 양이 적어 타 공법 대비 효과적인 수소 저장이 가능하다. 암염-수소 간 화학적 반응이 거의 일어나지 않으며 다수의 주입/배출 사이클을 수행할 수 있어 피크 쉐이빙(peak shaving) 및 단주기 저장에 효과적이다. 공동은 크게 침출(leaching), 염수제거(debrining), 충진(filling)의 3단계로 형성되며 누출 실험을 통해 공동의 안정성을 평가한다. 현재 영국과 미국 Texas 주의 4개소에서 주변 지역의 산업 수요를 충당하기 위한 현장 적용이 이루어지고 있으며, 독일, 프랑스와 같은 유럽 지역에서 에너지 저장을 위한 암염 공동 운영을 준비하고 있다. 본 연구 결과는 향후 수소 저장 프로젝트 설계를 위한 기초자료로 활용될 수 있을 것으로 기대된다.

• Geomechanics and Engineering
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• 제10권3호
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• pp.325-334
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• 2016

Rock salt is a near-perfect material for gas storage repositories due to its excellent ductility and low permeability. Gas storage in rock salt layers during gas injection and gas production causes the stress redistribution surrounding the cavity. The triaxial cyclic loading and unloading tests for rock salt were performed in this paper. The elastic-plastic deformation behaviour of rock salt under cyclic loading was observed. Rock salt experienced strain hardening during the initial loading, and the irreversible deformation was large under low stress station, meanwhile the residual stress became larger along with the increase of deviatoric stress. Confining pressure had a significant effect on the unloading modulus for the variation of mechanical parameters. Based on the theory of elastic-plastic damage mechanics, the evolution of damage during cyclic loading and unloading under various confining pressure was described.

• Geomechanics and Engineering
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• 제9권4호
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• pp.499-511
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• 2015

The creep property of salt rock significantly influences the long-term stability of the salt rock underground storage. Triaxial creep tests were performed to investigate the creep behavior of salt rock. The test results indicate that the creep of salt rock has a nonlinear characteristic, which is related to stress level and creep time. The higher the stress level, the longer the creep time, the more obvious the nonlinear characteristic will be. The elastic modulus of salt rock decreases with the prolonged creep time, which shows that the creep damage is produced for the gradual expansion of internal cracks, defects, etc., causing degradation of mechanical properties; meanwhile, the creep rate of salt rock also decreases with the prolonged creep time in the primary creep stage, which indicates that the mechanical properties of salt rock are hardened and strengthened. That is to say, damage and hardening exist simultaneously during the creep of salt rock. Both the damage effect and the hardening effect are considered, an improved Maxwell creep model is proposed by connecting an elastic body softened over time with a viscosity body hardened over time in series, and the creep equation of which is deduced. Creep test data of salt rock are used to evaluate the reasonability and applicability of the improved Maxwell model. The fitting curves are in excellent agreement with the creep test data, and compared with the classical Burgers model, the improved Maxwell model is able to precisely predict the long-term creep deformation of salt rock, illustrating our model can perfectly describe the creep property of salt rock.

• 한국식품조리과학회지
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• 제28권4호
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• pp.363-374
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• 2012

Quality characteristics of baechu (Kimchi cabbage) kimchi prepared using various kinds of domestic solar salts (KS5Y, KS2Y, KS1Y, KFS, and KSS) and imported solar salts (AS1Y and CS1Y) were compared with Korean processed salt (KRS) and Mexican rock salt (MR1Y) during 60 days of storage. Sodium contents of MR1Y, AS1Y, and domestic KRS with values of 363,653.40, 358,952.40, and 356,799.90 mg/dL, respectively, were significantly higher than that of KFS with a value of 280,249.80 mg/dL (p < 0.001). Thus, the kimchi using KFS was expected to have 22-23% lower sodium content compared to that of the other kimchis. KFS magnesium content was significantly highest at 4,464.10 mg/dL and calcium was significantly the highest in samples of KS1Y with a value of 711.31 mg/dL. Most of the pHs and acidities in the kimchi samples were in the optimum range due to the relatively low storage temperature of $2^{\circ}C$. The salt concentrations of all kimchis using domestic solar salt during storage was greatly reduced compared to those using the imported salts or KRS. Sensory saltiness of the KS1Y sample group was significantly the lowest value (6.08) at 0 days of storage (p < 0.001) and maintained relatively low saltiness during the entire storage period. The crispness of the KS2Y, KS1Y, and KSS sample groups were significantly higher (10.02, 9.77, and 9.49, respectively), compared to that of KRS (7.64) at 60 days of storage (p < 0.001). The KFS sample group had the higher acceptance values for pickled seafood aroma, sour aroma, saltiness, and overall acceptability compared to those in the other samples.

• Geomechanics and Engineering
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• 제30권1호
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• pp.45-49
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• 2022

In the present study, a physical model was built for the Jintan underground gas storage cavern group according to the similarity theory. In this regard, four ellipsoid caverns were built with scaled in-situ stresses and internal pressure. Then the stability of underground caverns was analyzed. The obtained results demonstrate that loss of internal pressure adversely affects the safety of caverns and attention should be paid during the operation of gas storage.