• Title/Summary/Keyword: equilibrium temperature

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Application of High-temperature 3-phase Equilibrium Distribution to Dry Scrubber for the Simultaneous Removal of $SO_2$ and Vinyl Chloride (건식세정기에서의 오염물 동시제거를 위한 고온3계평형 모델의 적용과 예비설계에의 응용)

  • 구자공;백경렬
    • Journal of Korean Society for Atmospheric Environment
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    • v.6 no.1
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    • pp.85-96
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    • 1990
  • Simultaneous removal efficiencies of hydrophilic and hydrophobic gaseous pollutants are experimentally determined, and the macroscopic removal mechanism of pollutants in a dry scrubber is analyzed using the extended model of three phase equilibrium distribution of pollutant at high temperatures that can describe the different morphological conditions of adsorbent and water at varying relative humidities. For the simplicity, the inside of spray dryer is divided into three regions of ; (1) absorption, (2) three-phase equilibrium, and (3) adsorption, and the removal efficiencies of each pollutants at three regions are observed at different experimental conditions to estimate the effects of important parameters of dry scrubber. The laboratory experiments simulate the three regions of spray dryer with the temperature control and thus evaporation rate of water from the slurry particle. $SO_2$ as a hydrophilic gaseous pollutant and vinyl chloride as a hydrophobic toxic gas are selected for the future field application to soid waste incineration, and the two types of slurry are made of the two sorbents ; 10 wt.% $Ca(OH)_2$, and 10 wt.% NaOH. Result of temperature effect shows the height of absorption plus three-phase region is decreased as the operation temperature is increased, which results in the lower removal efficiency of $SO_2$ but higher removal for vinyl chloride in the adsorption region of dry scrubber. The removal efficiency of $SO_2$ is higher by NaOH slurry than by $Ca(OH)_2$ slurry due to the hygroscopic nature of NaOH, while the removal of vinyl chloride is higher in $Ca(OH)_2$ case. From the analysis of redults using three-phase equilibrium distribution model, the effective two-phase partition coefficients can be obtained, and the possible extention in the application of the three-phase equilibrium model in a dry scrubber design has been demonstrated.

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Comparison of Equilibrium Moisture Contents for Conventional Kiln Dried- and High Temperature Dried Softwood Lumber by Moisture Content Determination (관행열기건조(慣行熱氣乾操)와 고온건조(高溫乾燥) 침엽수재(針葉樹材)의 함수율(含水率) 측정법(測定法)에 의한 평형함수율(平衡含水率) 비교(比較))

  • Jung, Hee-Suk;Smith, William B.
    • Journal of the Korean Wood Science and Technology
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    • v.22 no.4
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    • pp.37-42
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    • 1994
  • The adsorption of water vapor and equilibrium moisture content(EMC) of the specimens for four softwood species dried by conventional- and high temperature method and equilibrated to 15% of the target EMC condition at 25$^{\circ}C$ were determined by oven drying method and with moisture meters. The amount of adsorption for high temperature dried red pine was significantly higher than that of conventional kiln dried wood, while those of eastern white pine, eastern hemlock and Norway spruce were not significantly different between drying methods. EMCs of these four species determined by oven drying method and with capacitive admittance moisture meter were not significantly different between drying methods. EMC of high temperature dried red pine determined with resistance moisture meter was significantly higher than that of conventional kiln dried wood. But EMCs of other species did not show significant difference between drying methods. EMCs of conventional and high-temperature dried wood determined with electronic moisture meters, especially in the case of the capacitive-admittance moisture meter measurement, were lower than that determined by oven drying method.

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The Prediction of Vapor-Liquid Equilibrium Data for Ethanol/3-methyl-1-butanol System at Constant Temperature (정온하에서 Ethanol/3-methyl-1-butanol계의 기-액평형치 추산)

  • Lee, Joon-Man;Park, Young-Hae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.4
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    • pp.2055-2061
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    • 2013
  • Recently, an understanding of new sources of liquid hydrocarbons such as bio-ethanol is economically very important. Successful design of distillation columns in a separation process depend on the availability of accurate vapor-liquid equilibrium data. For the binary system of Ethanol/3-methyl-l-butanol mixture, isothermal Vapor-liquid equilibrium data were measured at temperature of 50, 55, 60, 65, 70, 75 and $80^{\circ}C$. An empirical relation to predict Vapor-liquid equilibrium data was obtained from the above measured data. The predicted values are compared with the measured ones to be in a good agreement within accuracy of ${\pm}0.0005$, ${\pm}0.0022$.

Investigation of Vapor-Liquid Equilibrium and Miscibility for R-410A/POE Oil Mixtures (R-410A/POE 오일 혼합물의 기-액상평형과 상용성에 관한 연구)

  • 김창년;송준석;이은호;박영무;유재석;김기현
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.6
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    • pp.589-598
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    • 2000
  • The vapor-liquid equilibrium and miscibility measurement apparatus was developed and used to obtain data for refrigerant/oil mixture. The vapor-liquid equilibrium and miscibility data for R-410a/POE32 and R-410A/POE46 oil mixtures are obtained over the temperature range from -20 to $60^{\circ}C\;with\;10^{\circ}C$ intervals and the oil concentration range from 0 to 90 wt%. Using the experimental data, an empirical model is developed to predict the temperature-pressure-concentration relations for R-410A/POE oil mixtures at equilibrium. In the R-410A/POE32 oil mixture, the average root-mean-square deviation between measured data and calculated results from the empirical model is 2.00% and in the R-410a/POE46 oil mixture, that is 3.69%. Flory-Huggins theory is also used to predict refrigerant/oil mixture behavior. Miscibility for R-410A/POE32 oil mixture was observed all over the experimental conditions. Immiscibility for R-410A/POE46 oil mixture was observed at the low oil concentrations(10~30 wt%).

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Salinity Effect on the Equilibria and Kinetics of the Formation of CO2 and R-134a Gas Hydrates in Seawater

  • Johanna, Lianna;Kim, A Ram;Jeong, Guk;Lee, Jea-Keun;Lee, Tae Yun;Lim, Jun-Heok;Won, Yong Sun
    • Korean Journal of Materials Research
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    • v.26 no.7
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    • pp.382-387
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    • 2016
  • Gas hydrates are crystalline solids in which gas molecules (guests) are trapped in water cavities (hosts) that are composed of hydrogen-bonded water molecules. During the formation of gas hydrates in seawater, the equilibria and kinetics are then affected by salinity. In this study, the effects of salinity on the equilibria of $CO_2$ and R134-a gas hydrates has been investigated by tracing the changes of operating temperature and pressure. Increasing the salinity by 1.75% led to a drop in the equilibrium temperature of about $2^{\circ}C$ for $CO_2$ gas hydrate and $0.38^{\circ}C$ for R-134a gas hydrate at constant equilibrium pressure; in other words, there were rises in the equilibrium pressure of about 1 bar and 0.25 bar at constant equilibrium temperature, respectively. The kinetics of gas hydrate formation have also been investigated by time-resolved in-situ Raman spectroscopy; the results demonstrate that the increase of salinity delayed the formation of both $CO_2$ and R134-a gas hydrates. Therefore, various ions in seawater can play roles of inhibitors for gas hydrate formation in terms of both equilibrium and kinetics.

Temperature and Concentration Dependencies of Chemical Equilibrium for Reductive Dissolution of Magnetite Using Oxalic Acid

  • Lee, Byung-Chul;Oh, Wonzin
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.19 no.2
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    • pp.187-196
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    • 2021
  • Chemical equilibrium calculations for multicomponent aqueous systems involving the reductive dissolution of magnetite (Fe3O4) with oxalic acid (H2C2O4) were performed using the HSC Chemistry® version 9. They were conducted with an aqueous solution model based on the Pitzer's approach of one molality aqueous solution. The change in the amounts and activity coefficients of species and ions involved in the reactions as well as the solution pH at equilibrium was calculated while changing the amounts of raw materials (Fe3O4 and H2C2O4) and the system temperature from 25℃ to 125℃. In particular, the conditions under which Fe3O4 is completely dissolved at high temperatures were determined by varying the raw amount of H2C2O4 and the temperature for a given raw amount of Fe3O4 fed into the aqueous solution. When the raw amount of H2C2O4 added was small for a given raw amount of Fe3O4, no undissolved Fe3O4 was present in the solution and the pH of the solution increased significantly. The formation of ferrous oxalate complex (FeC2O4) was observed. The equilibrium amount of FeC2O4 decreased as the raw amount of H2C2O4 increased.

"A survey of Elementary School Children,s Concept of Temperature" (국민학교 아동의 온도개념 형성에 관한 조사)

  • Kim, Hyun-Jae;Kim, Han-Ho
    • Journal of The Korean Association For Science Education
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    • v.10 no.1
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    • pp.95-118
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    • 1990
  • This students ideas in science are diverse and unique It is realized that children's preconceptions and misconceptions established before lessoning hgve a crucial in fluence on the following education. so it is meaningful to analyse the children's concept of temperature for the better teaching strategy in this study. This survey of the Elementary school children's concept is designed for the subtopics of temperature as the relation between heat and temperature, He relation between volume(size) and temperature, the temperature of change of state on water, the temperature of substances in the condition of thermal equilibrium. Using Clinical method, this research was executed to 306 children at elementary school. The network method or the analyse of questionnaires were used to analyse the children's response. Findings of this survey are as follow. Students are already familiar with such concept as this increase of temperature by geating, but they think every substance is not the case. Many students appears to believe that the temperature of an object(substance) is related to its size(vloume) Qualitative tasks are difficult than qualitative ones. This trend appear highly in the low grade students. Don't know the temperature of change of state on water and it's stability They think that the temperature is determined by the heating time(period) and the temperature of heating source. Students think, in general that temperature of substance in the condition of thermal equilibrium is different.

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Simulation of Natural Air Drying of Barley -Comparison of Experimental and Simulated Results- (보리의 상온 통풍건조 시뮬레이션(I) -실험치와 예측치의 비교-)

  • Keum, D.H.;Yi, S.D.
    • Journal of Biosystems Engineering
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    • v.15 no.1
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    • pp.44-51
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    • 1990
  • Four models in current use for cereal grain drying, equilibrium model, Morey model, partial differential equation model and simplified partial differential equation model, were modified to be suitable for natural air drying of barley. The predicted by the four models and experimental results were compared. Three models except equilibrium model predicted moisture comtent and grain temperature very well. But equilibrium model overpredicted moisture content and grain temperature of bottom layer. The degree of prediction of the four models for relative humidities of exhaust air didn't differ much from one another and equally the four models predicted relative humidity statisfatorily. Morey model took much shorter computing time than any other models. Therefore, considering the degree of prediction and computing time Morey model was the most suitable for natural air drying of barley.

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Equilibrium Conditions of Methane Hydrate added Help Gases (보조가스가 첨가된 메탄 하이드레이트 상평형 조건에 대한 연구)

  • Kim, Nam-Jin;Lim, Sang-Hoon;Chun, Won-Gee
    • Journal of the Korean Solar Energy Society
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    • v.27 no.4
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    • pp.51-58
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    • 2007
  • Gas hydrate is a special kind of inclusion compound that can be formed by capturing gas molecules to water lattice in high pressure and low temperature conditions. When referred to standard conditions, $1m^3$ solid hydrates contain up to $172Nm^3$ of methane gas, depending on the pressure and temperature of production. Such large volumes make natural gas hydrates can be used to store and transport natural gas. In this study, three-phase equilibrium conditions for forming methane hydrate were theoretically obtained in aqueous single electrolyte solution containing 3wt% NaCl. The results show that the predictions match the previous experimental values very well, and it was found that NaCl acts as an inhibitor.

Magnetic Anisotropy Energy Distribution and Magnetization of CoPt Nanoparticles Encaged in Protein Shell

  • Lee, T.H.;Suh, B.J.;Jang, Z.H.
    • Journal of Magnetics
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    • v.22 no.1
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    • pp.1-6
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    • 2017
  • Magnetic properties of CoPt nanoparticles (average size = 2.1 nm) encapsulated in synthesized protein shell have been investigated with SQUID (Superconducting Quantum Interference Device) magnetometer and analyzed by the recently developed non-equilibrium magnetization calculation by our group [T. H. Lee et al., Phys. Rev. B 90, 184411 (2014)]. Field dependence of magnetization measured at 2 K was successfully analyzed with modified Langevin function. In addition, small hysteresis loops having the coercive field of 890 Oe were observed at 2 K. Temperature dependence of magnetization has been measured with zero field cooled (ZFC) and field cooled (FC) protocol with slightly modified sequence in accordance with non-equilibrium magnetization calculation. The analysis on the M vs. T data revealed that the anisotropy energy barrier distribution is found to be very different from the log-normal distribution found in a size distribution. Zero temperature coercive field and Bloch coefficient have also been extracted from the analysis and the validity of those values is checked.