• Title/Summary/Keyword: 초임계 환경

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Numerical Study for Kerosene Surrogate Model in Supercritical Swirl Injector (초임계 스월 인젝터에서의 케로신 Surrogate 모델에 대한 수치적 연구)

  • Kim, Kuk-Jin;Heo, Jun-Young;Sung, Hong-Gye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.19-23
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    • 2010
  • Injection characteristics of a kerosene swirl injector of liquid rocket engine operating at supercritical environment have been investigated. Kerosene surrogate models are proposed to model the kerosene properties. Turbulent numerical model is based on large eddy simulation and contains Soave modification of Redlich-Kwong equation of state and Chung's model. Numerical analysis results at supercritical environment are compared with the one at transcritical condition. Differences of density and viscosity are analyzed at both liquid film and core gas in the swirl injector.

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초임계 이산화탄소를 이용한 방사성 오염물의 청정제염기술

  • Park, Gwang-Heon;Kim, Hak-Won
    • Journal of the KSME
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    • v.55 no.7
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    • pp.42-45
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    • 2015
  • 초임계 이산화탄소는 환경친화적 유체로서 많은 장점을 갖고 있고, 기화시켜 재사용할 경우 2차 폐기물의 발생이 없는 우수한 용매이다. 이 글에서는 초임계 이산화탄소를 이용하여 방사성 오염물을 제염(除染, decontamination)하는 기술을 소개하고자 한다.

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Comparison of Antioxidant, Wrinkle Improvement, and Whitening Efficacies of Extracts from Pinus koraiensis Cone Scale Using Extraction Methods (추출방법에 따른 잣나무(Pinus koraiensis) 구과피 추출물의 항산화, 주름개선 및 미백 효능 비교)

  • Chae, Jungwoo;Kim, Jeongyou;Jo, Huiseon;Lee, Jin-young
    • Journal of Korean Society of Forest Science
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    • v.110 no.3
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    • pp.431-439
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    • 2021
  • The present study evaluated the antioxidant activity, skin wrinkle reduction, and whitening activity of Pinus koraiensiscone scale extracts made with three different solvents (ethanol, supercritical fluid, and a mixture of both). Total polyphenol content was 11.03 mg/g GAE in the supercritical fluid extractand 33.79 mg/g GAE in the 70% ethanol extract. Electron donating ability of 1,000 ㎍/mL extract was 13.60% in the supercritical fluid extract, 91.37% in 70% ethanol extract, and 71.62% in mixed solvent extract. SOD-like activities in 100 ㎍/mL extract using supercritical fluid, 70% ethanol, and mixed solvents were 16.49%, 21.84%, and 10.7%, respectively. The ABTS+ radical scavenging activities of 1,000 ㎍/mL extract were 38.19%, 80.23%, and 78.72%for supercritical fluid extract, 70% ethanol extract, and mixed solvent extract, respectively. Tyrosinase inhibitory activities in 1,000 ㎍/mL extract were 24.54%, 36.55%, and 15.23% for supercritical fluid extract, 70% ethanol extract, and mixed solvent extract, respectively. Elastase inhibitory activities in 1,000 ㎍/mL extract were 15.62%, 22.56%, and 26.64% for supercritical fluid extract, 70% ethanol extract, and mixed solvent extract, respectively. Skin astringent activity (81.23% with 5000 ㎍/mL extract) was only detected in the 70% ethanol extract. Supercritical fluid and mixed solvent extracts showed no such activity. Our analysis of Pinus koraiensiscone scale extracts show that the highest aggregate activity was found in the 70% ethanol extract, followed by mixed solvent and supercritical fluid extracts. Therefore, our results oppose the hypothesis stating supercritical extract has the highest total polyphenol content and antioxidant activity.

Numerical Simulation of Supercritical $CO_2$ Flow in a Geological Storage Reservoir of Ocean (해양 지중저장층내 초임계 $CO_2$ 유동에 대한 전산모사)

  • Choi, Hang-Seok
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.4
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    • pp.251-257
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    • 2011
  • In the present study, a 3-dimensional (3D) numerical model was developed to mimic the micro porous structure of a geological $CO_2$ storage reservoir. Especially, 3D modeling technique assigning random pore size to a 3D micro porous structure was devised. Numerical method using CFD (computational fluid dynamics) was applied for the 3D micro porous structure to calculate supercritical $CO_2$ flow field. The three different configurations of 3D micro porous model were designed and their flow fields were calculated. For the physical conditions of $CO_2$ flow, temperature and pressure were set up equivalent to geological underground condition where $CO_2$ fluid was stored. From the results, the characteristics of the supercritical $CO_2$ flow fields were scrutinized and the influence of the micro pore configuration on the flow field was investigated. In particular, the pressure difference and consequent $CO_2$ permeability were calculated and compared with increasing $CO_2$ flow rate.

Synthesis of Photoresist Using Environmental-benign Supercritical $CO_2$ Processes (환경친화적인 초임계 이산화 탄소 공정을 이용한 포토레지스트의 합성)

  • 허완수;이상원;박혜진;김장엽;홍유석;유기풍
    • Polymer(Korea)
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    • v.28 no.6
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    • pp.445-454
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    • 2004
  • The requirement for a much finer line width circuits on semiconductors needs new developers such as supercritical fluid to prevent the collapse of the photoresist micro-patterns. The copolymers contain t-butyl methacrylate having an acid-cleavable t-butyl group and supercritical fluid $CO_2$ soluble perfluorinated decyl methacrylate segments. The supercritical fluid $CO_2$-philic properties of the photoresist changed to supercritical fluid $CO_2$-phobic properties after the deprotection reaction by exposure, which made the exposed resist insoluble in the supercritical fluid $CO_2$ developer. The synthesized copolymers containing more than 30% of perfluorinated decyl methacrylate were found to be soluble in supercritical fluid $CO_2$. The variation of film thickness before and after exposure was largest when the mole ratio of perfluorinated decyl methacrylate in the copolymer was 30%.

Supercritical Dyeing Technology (초임계 염색 기술)

  • Kim, Taewan;Park, Geonhwan;Kong, Wonbae;Lee, Youn-Woo
    • Clean Technology
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    • v.24 no.1
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    • pp.1-8
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    • 2018
  • As the social demands for environmental pollution increase and regulations on the dyeing process wastewater are strengthened, supercritical dyeing process has been attracting attention as an alternative technology to reduce wastewater and energy consumption. In the supercritical dyeing process where carbon dioxide is used as a solvent instead of water as a solvent, there is no wastewater generated. The unfixed dyes can be reused later which makes the process environment-friendly. Also, after dyeing process, dried textiles can be obtained without additional drying process, which makes the process energy efficient. In this article, we have summarized the development of the supercritical dyeing process along with the research in Korea today and compared the principle of supercritical dyeing process with conventional dyeing process. To further explain the principle, studies of the distribution factor and mass transfer of dyes in supercritical carbon dioxide and fibers, as well as solubility between supercritical $CO_2$ and dyes are discussed. The dynamic behavior of dyes in supercritical dyeing apparatus and summary of the supercritical dyeing facilities developed around the world are also discussed. Finally, we suggest the direction of research and development for optimization of supercritical dyeing process and application to synthetic fibers and natural fibers except for polyester.

Visualization of Supercritical Mixed Hydrocarbon-Fuel Droplet (혼합 탄화수소계 초임계 상태 연료의 액적 거동 가시화)

  • Song, Juyeon;Song, Wooseok;Koo, Jaye
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.9
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    • pp.711-716
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    • 2020
  • Injection visualization of heated mixed simulant droplets based on hydrocarbon fuel was performed under supercritical state environment. Mixed simulant consisted of Decane and Methylcyclohexane with different critical pressure and critical temperature. Flows injected into the supercritical state environment created droplet by Rayleigh breakup mechanism, and the Oh number and Re number were determined to confirm the breakup area. The temperature of the mixed simulant varied from Tr=0.49 to Tr=1.34. The flow rate was maintained at 0.7 to 0.8 g/s. Droplet became shorter in breakup length as heated and into a lumped form. Second droplet was formed and when Tr=1.34, the phase was not visible in the supercritical state with local unsteady flow.

초임계압 유동층보일러 2대, 1,000MW 증기터빈 조합 신개념 발전 플랜트 소개

  • Kim, Hyeon-Cheol
    • Journal of the KSME
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    • v.56 no.10
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    • pp.44-48
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    • 2016
  • 에너지 생태계의 급변하는 환경속에 고효율, 대용량, 연료 유연성을 확보하기 위한 새로운 도전이 펼쳐지고 있다. 이 글에서는 세계 최대, 최초 초임계 순환유동층 보일러 2대와 1,000MW 증기터빈을 조합한 신개념 설계의 2개 호기(2,000MW) 건설, 한국남부발전(주) 삼척그린파워를 중심으로 내용을 기술하고자 한다.

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Supercritical Fluids and Preparation of Porous Materials (초임계 유체 및 다공성 소재 제조 기술)

  • Lee, Jun-Young;An, Joon-Hyun;Kim, Jung-Hyun
    • Applied Chemistry for Engineering
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    • v.16 no.2
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    • pp.169-179
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    • 2005
  • Porous materials are useful in a wide range of applications including bio/electronic products. The preparation and processing of these materials are mainly progressed by using an organic solvent, which gives rise to air pollution by its emissions. Alternatively, supercritical fluids are well suited to the production of functional porous materials due to a number of specific physical, chemical, and toxicological advantages. In this review, we will introduce the preparation and processing techniques for the formation of the nano/macro pore structure and their morphology, which can be controled by using supercritical fluids.

초임계 이산화탄소를 응용한 개질 제강 슬래그의 Cs 및 Co 이온의 제거 특성

  • 김민길;원휘준;현재혁;김계남;오원진;정종헌
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2004.06a
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    • pp.122-123
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    • 2004
  • 산업체에서 폐기물로 발생되는 제강 슬래그를 사용전 초임계 이산화탄소를 이용해 고온 고압에서 전처리를 통해 얻어진 제강 슬래그를 이용하여 토양 제염 후 발생하는 방사성 폐액 중에 포함되어 있는 성분 가운데 방사성이 높은 성분인 Cs 이온과 Co 이온을 제거하는데 활용함으로서 폐기물의 재활용에 의한 방사성 이온 제거 방안을 모색해 보고자 하였으며 이에 대한 연구는 환경보호 차원뿐만 아니라 폐기물 자원 회수라는 측면에서도 그 중요성이 크다고 할 수 있다.(중략)

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