• Title/Summary/Keyword: 열 안정성

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Optimization Strategies for Amine Regeneration Process with Heat-Stable Salt Removal Unit (열 안정성 염 제거장치를 고려한 아민 재생 공정 최적화 전략)

  • Lee, Jesung;Lim, Jonghun;Cho, Hyungtae;Kim, Junghwan
    • Applied Chemistry for Engineering
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    • v.31 no.5
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    • pp.575-580
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    • 2020
  • In this study, we simulated an amine regeneration process with heat-stable salts removal unit. We derived the optimal operating conditions considering the flow rate of waste, the removal rate of heat-stable salts, and the loss rate of MDEA (methyl diethanolamine). In the amine regeneration process that absorbs and removes acid gas, heat-stable salt impairs the absorption efficiency of process equipment and amine solution. An ion exchange resin method is to remove heat-stable salts through neutralization by using a strong base solution such as NaOH. The acid gas removal process was established using the Radfrac model, and the equilibrium constant of the reaction was calculated using Gibbs free energy. The removed amine solution is separated and flows to the heat-stable salts remover which is modeled by using the Rstoic model with neutralization reaction. Actual operation data and simulation results were compared and verified, and also a case study was conducted by adjusting the inflow mass of removal unit followed by suggesting optimal conditions.

Thermal-mechanical sensitivity analysis for the near-field of HLW repository (고준위 폐기물 처분장 near-field에 대한 열-역학적 민감도 분석)

  • 권상기;최종원;강철형
    • Tunnel and Underground Space
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    • v.13 no.2
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    • pp.138-152
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    • 2003
  • Three-dimensional computer modeling using FLAC3D had been carried out fur evaluating the thermal-mechanical stability of a high-level radioactive waste repository excavated in several hundred deep location. For effective modeling, a FISH program was made and the geological conditions and rock properties achieved from the drilling sites in Kosung and Yusung areas were used. Sensitivity analysis fer the stresses and temperatures from the modeling designed utilizing fractional factorial design was carried out. From the sensitivity analysis, the important design parameters and their interactions could be determined. From this study, it was found that deposition hole spacing is the most important parameter on the thermal and mechanical stability. The second and third most important parameters were disposal tunnel and buffer thickness.

A study on Thermo-Structural Analysis of Supersonic Nozzle (초음속 노즐의 열구조 연성 해석에 관한 연구)

  • Kim, Kyung-Sik;Lim, Seol;Kim, Dae-Seung;Cho, Seung-Hwan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.488-491
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    • 2011
  • The thermo-structural analysis of the solid-fuel propulsion Nozzle is studied to estimate the thermo-structural safety of the metal nozzle. The thermal load is determined to be significantly large, Because the metal nozzle in a short combustion time is directly exposed to high pressure and temperature of combustion gas. Through a analysis result, the influence of a thermal load is estimated and henceforward a design data of thruster is used.

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Effect of Palm Oil Blending on the Thermal and Oxidative Stability of Soybean Oil (대두유의 열산화 안정성에 미치는 팜유 배합의 영향)

  • Han, Yoon-Sook;Yoon, Jae-Young;Lee, Su-Rae
    • Korean Journal of Food Science and Technology
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    • v.23 no.4
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    • pp.465-470
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    • 1991
  • In order to investigate the thermal and oxidative stability of different frying oils including soybean oil, palm oil, two blended oils of soybean-palm (5 : 5 and 7 : 3) and shortening, physico-chemical properties such as acid value, peroxide value, TBA value, degree of coloring, refractive index and specific gravity of the frying oils were measured during the preparation of French fried potatoes by repeated frying. The instability of soybean oil against thermal and oxidative degradation could be lessened by using blended oils in which the ratio of palm oil to soybean oil is more than 50%.

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A Study on the Design of Varistor Prevented from Thermal Runaway to Improve Safety (안정성 개선을 위해 열폭주 방지 기능을 내장한 배리스터 설계에 관한 연구)

  • Jung, Tae-Hun;Shin, Hee-Sang;Cho, Sung-Min;Lee, Hee-Tae;Lee, Jun-Kyu;Kim, Jae-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.2
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    • pp.69-76
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    • 2010
  • Recently, the natural environment changes drastically and the frequency of occurrence for lightning has gradually been increased. Such lightning delivers high volume of energy along the power line and communication line to the equipment in use. The high volume of energy arising from the lightning surge develops in fast velocity to destroy the facilities in power source and many other facilities in operation in sequential destruction with vast energy. This paper examines the characteristics of ZnO varistor to prevent from thermal runaway. We carry out performance evaluation of electrical characteristics on ZnO varistor. we will develop ZnO varistor Prevented from thermal explosion using test result of this paper.

Effect of Heat Processing on Thermal Stability of Kudzu (Pueraria thumbergiana Bentham) Root Isoflavones (가열처리가 칡 이소플라본의 열 안정성에 미치는 영향)

  • Choi, Sung-Won;Kim, Kyung-Seon;Hur, Nam-Yun;Kim, Kyung-Seon;Ahn, Soon-Cheol;Park, Cheon-Seok;Kim, Byung-Yong;Baik, Moo-Yeol;Kim, Dae-Ok
    • Journal of Life Science
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    • v.18 no.10
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    • pp.1447-1454
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    • 2008
  • Effect of heat processing on thermal stability of kudzu root isoflavone was investigated for future use such as various processed foods and functional foods. Kudzu root extracts were heated at 80, 100, 121, 140, 165, and $180^{\circ}C$ for up to 90 minutes before and after concentration, respectively. Changes in the amount of isoflavones were monitored using HPLC and thermal stability was investigated using Arrhenius equation. The amount of both daidzin and genistin decreased slightly during heating at 80, 100 and $121^{\circ}C$ but decreased significantly above $140^{\circ}C$. This indicated that daidzin and genistin are stable at temperatures near the boiling point of water. The degradation of both daidzin and genistin occurred in two steps and each step showed typical first order kinetic. The degradation rates were faster in the first step than the second step in both daidzin and genistin. Additionally, the degradation was accelerated when they heated after concentration compared to the sample heated before concentration. These results suggested that degradation of kudzu root isoflavone was highly dependent on both their concentration and heating temperature. This study provides the basic information on thermal stability of kudzu root isoflavones, which can be used for future processing of functional foods.

Heat Treatment Effects on the Thermal Stability and Mechanical Property of Spider Silks from Nephila clavata and Bassaniana decorata (무당거미와 나무껍질게거미줄의 열 안정성 및 기계적 성질에 관한 열처리 효과)

  • Chang, So-Yeon;Lee, Ji-Hye;Lee, Ju-Ha
    • Korean journal of applied entomology
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    • v.48 no.1
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    • pp.109-115
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    • 2009
  • The thermal stability and mechanical properties of Nephila clavata and Bassaniana decorata spider silks were measured and compared with those of aramid and polyester fibers. The thermal stability of the spider silk was lower than those of the commercial aramid and polyester fibers. However, the mechanical properties of the spider silk were far superior to that of the polyester fiber. The effect of the water content of the spider silk on its thermal stability and mechanical property was examined by conducting the silk to heat treatment at $100^{\circ}C$ under vacuum for various times. The results indicated that spider silk subjected to heat treatment for 1.5 hr had excellent thermal stability and mechanical property.

Stationary test of Annual precipitation in Korea using Data Screening (Data screening을 이용한 우리나라 연강수량 자료의 시계열 특성 분석)

  • Lim, Ga Kyun;Kang, Dong Ho;Jung, Se Jin;Kim, Byung Sik
    • Proceedings of the Korea Water Resources Association Conference
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    • 2019.05a
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    • pp.231-231
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    • 2019
  • 수문자료는 수문과정을 이해하고 그 특성을 파악하여 장래 예견되는 자연재해로부터 인간의 생명과 재산을 보호하는데 있어서 매우 중요하다. 특히 수자원 계획 수립 및 대규모 수공구조물 설계 시 수문학적 설계기준이 되는 강수량 및 유출량과 같은 설계 수문량을 정확하게 산정하기 위해서는 장기간의 과거자료가 필요하다. 그러나 한국의 경우 수문자료 관측을 위한 관측소가 대부분 근래에 설치되어 자료의 기록기간이 짧은 실정이며, 수문자료의 질적인 면에서의 신뢰성이 의심되는 경우가 많아 수문 시계열 자료의 특성을 파악하는 것이 더욱 중요하다. 한국의 경우 수문 시계열 자료가 정상성이나 독립성을 지니고 있다고 가정하고 수문분석을 실시하는 경우가 많기 때문에 정상성을 가정한 수문분석으로 인해 왜곡된 결과를 얻을 수 있는 가능성이 있다. 본 논문에서는 한국의 기상청 63개의 기상관측소 중 45년 이상의 장기간의 관측 자료를 가지고 있는 37개의 기상관측소의 연강수량 자료를 대상으로 Data Screening 방법을 이용하여 정상성 분석을 실시하였다. 분석결과 37개소의 기상관측소 연 강수량의 시계열 자료 중 4개 관측소의 연강수량 자료에서 경향성을 보였으며 평균과 분산의 시간변동성을 의미하는 안정성은 22개 관측소 연강수량 자료에서 불안정성을 나타내었다. 또한 4개 관측소 연강수량 자료에서 지속성을 나타내었다. 본 논문에서는 경향성이 없고 평균과 분산의 안정성이 존재하며 지속성을 보이지 않는다는 조건을 동시에 만족하는 연 강수량 시계열 자료만을 정상성이 있다고 판단하였으며 분석 결과, 37개 관측소 중 23개 관측소(약 62%) 연 강수량자료가 비정상성을 나타냄을 확인할 수 있다.

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그래핀 나노유체의 유동 비등 열전달에 대한 연구

  • Kim, Ji-U;Yang, Yong-U;Kim, Nam-Jin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.382.2-382.2
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    • 2016
  • 현재 전 세계적으로 에너지 소비가 급격히 증가하고 있다. 하지만 급격한 에너지 소비에 따른 자원 및 에너지 공급의 불확실성은 점점 높아지고 있다. 특히, 우리나라는 공급 에너지의 96.4%를 해외 수입에 의존하고 있기 때문에 에너지 안보에 매우 취약한 구조를 갖고 있다. 그리고 열전달 시스템에서 임계 열유속은 열전달 시스템의 한계를 나타낸다. 따라서 임계 열유속의 향상은 열전달 시스템의 안전성의 향상을 위한 필수적인 요소이다. 이에 따라 다양한 산업에서 열전달 시스템을 통하여 막대한 양의 에너지가 소비됨에 따라 우수한 열전달 특성을 가진 나노유체를 사용하여 열전달 시스템의 효율 및 안정성을 높이고자 하는 많은 연구가 진행되고 있다. 따라서 본 연구에서는 유동 비등에서 그래핀 나노 유체 사용에 따른 열전달 특성을 분석하였다. 유동 비등에서 0.01 vol%의 산화 처리된 그래핀 나노유체를 사용하였을 경우 유속이 증가함에 따라 임계 열유속은 증가하였으며 유속이 증가함에 따라 비등 열전달 계수도 증가함을 확인하였다. 그리고 임계 열유속은 순수 물보다 최대 66.32% 증가하였으며, 비등 열전달 계수는 풀비등에서 보다 최대 28.14% 증가함을 확인하였다.

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