• Title/Summary/Keyword: High temperature gas separation

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Preparation of Microporous Glasses by the Phase-Separation Technique and Their Salt-Rejection Characteristics (상분리법에 의한 다공질유리의 제조 및 탈염특성)

  • 현상훈;김계태
    • Journal of the Korean Ceramic Society
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    • v.23 no.5
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    • pp.93-101
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    • 1986
  • Microporous glasses were prepared from the 50 $SiO_2-44$ $B_2O_3-6$ $Na_2O$(wt%) parent glass by the phase eparation technique and were characterized by SEM, BET, and Gas Adsorption methods to investigate the possiblity of their use as salt-rejection membranes for reverse osmosis. The conditions of the phase separation for the possible glass membranes were optimized for the given parent glass. The temperature and duration of heat-treatment were desired to be lower(853K) and shorter (1/2~1 hr) respectively. The specific surface areas of porous glasses prepared in this study were about 80~120$m^2$/g and their pore size distribution had a unimodal shape(peak pore radius less than 15$\AA$) It was suggested that the porous glass obtained in this work could be effective for salt-rejection in point of pore size distributions but the way to increase its surface area for the high flux must be studied.

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Separation Permeation Characteristics of N2-O2 Gas in Air at Cell Membrane Model of Skin which Irradiated by High Energy Electron (고에너지 전자선을 조사한 피부의 세포막모델에서 공기 중의 O2-N2 혼합기체의 분리투과 특성)

  • Ko, In-Ho;Yeo, Jin-Dong
    • Journal of the Korean Society of Radiology
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    • v.13 no.2
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    • pp.261-270
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    • 2019
  • The separation permeation characteristics of $N_2-O_2$ gas in air at cell membrane model of skin which irradiated by high energy electron(linac 6 MeV) were investigated. The cell membrane model of skin used in this experiment was a sulfonated polydimethyl siloxane(PDMS) non-porous membrane. The pressure range of $N_2$ and $O_2$ gas were appeared from $1kg_f/cm^2$ to $6kg_f/cm^2$. In this experiment(temperature $36.5^{\circ}C$), the permeation change of $N_2$ and $O_2$ gas in non-porous membrane by non-irradiation were found to be $1.19{\times}10^{-4}-2.43{\times}10^{-4}$, $1.72{\times}10^{-4}-2.6{\times}10^{-4}cm^3(STP)/cm^2{\cdot}sec{\cdot}cmHg$, respectively. That of $N_2$ and $O_2$ gas in non-porous membrane by irradiation were found to be $0.19{\times}10^{-4}-0.56{\times}10^{-4}$, $0.41{\times}10^{-4}-0.76{\times}10^{-4}cm^3(STP)/cm^2{\cdot}sec{\cdot}cmHg$, respectively. The irradiated membrane was significantly decreased about 4-10 times than membrane which was not irradiated. And ideal separation factor of $N_2$ and $O_2$ gas by non-irradiation was found to be from 1.32 to 0.42 and that of $N_2$ and $O_2$ gas by irradiation was found to be from 0.237 to 0.125. The irradiated membrane was significantly decreased about 4-5 times than membrane which was not irradiated. When the operation change(cut) and pressure ratio(Pr) by non-irradiation were about 0, One was increased to the oxygen enrichment and the other was decreased to the oxygen enrichment. The irradiated membrane was significantly decreased about 4-19 times than membrane which was not irradiated. As the pressure of $N_2$ and $O_2$ gas was increased, the selectivity was decreased. As separation permeation characteristics of $N_2-O_2$ gas in cell membrane model of skin were abnormal, cell damages were appeared at cell.

A Comparative Study on the Formation of Methane Hydrate Using Natural Zeolite and Synthetic Zeolite 5A (천연 제올라이트와 합성 제올라이트 5A를 이용한 메탄 하이드레이트의 생성에 대한 비교 연구)

  • Park, Sung-Seek;Park, Yun-Beom;Kim, Nam-Jin
    • New & Renewable Energy
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    • v.8 no.2
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    • pp.24-32
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    • 2012
  • Natural gas hydrates have a high potential as the 21st century new energy resource, because it have a large amount of deposits in many deep-water and permafrost regions of the world widely. Natural gas hydrate is formed by physical binding between water molecule and gas mainly composed of methane, which is captured in the cavities of water molecules under the specific temperature and pressure. $1m^3$ methane hydrate can be decomposed to the methane gas of $172m^3$ and water of $0.8m^3$ at standard condition. Therefore, there are a lot of practical applications such as separation processes, natural gas storage transportation and carbon dioxide sequestration. For the industrial utilization of methane hydrate, it is very important to rapidly manufacture hydrate. However, when methane hydrate is artificially formed, its reaction time may be too long and the gas consumption in water becomes relatively low, because the reaction rate between water and gas is low. So in this study, hydrate formation was experimented by adding natural zeolite and Synthetic zeolite 5A in distilled water, respectively. The results show that when the Synthetic zeolite 5A of 0.01 wt% was, the amount of gas consumed during the formation of methane hydrate was higher than that in the natural zeolite. Also, the natural zeolite and Synthetic zeolite 5A decreased the hydrate formation time to a greater extent than the distilled water at the same subcooling temperature.

Performances of Anaerobic Sequencing Batch Reactor for Digestion of Municipal Sludge at the Conditions of Critical Solid-liquid Separation (혐기성 연속 회분식 공정에 의한 도시하수슬러지 소화시 고액분리 특성에 따른 처리효율평가)

  • Hur, Joon-Moo;Park, Jong-An
    • Journal of Environmental Health Sciences
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    • v.28 no.5
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    • pp.77-85
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    • 2002
  • The objective of this study was to evaluate the performances of the ASBR under critical conditions of solid-liquid separation, caused by extremely high solids concentration, for wider application of the ASBR to various wastes. The ASBRs and completely-mixed daily-fed control runs were operated using a municipal mixed sludge at 35$^{\circ}C$ and 55$^{\circ}C$. Conversion of completely-mixed daily-fed reactor to sequencing batch mode and changes in HRT of all ASBRs were easily achieved without adverse effect, regardless of digestion temperature. Solids accumulation was remarkable in the ASBRs, and directly affected by settleable solids concentration of the feed sludge. Noticeable difference in solids-liquid separation was that flotation thickening occurred in the mesophilic ASBRs, while gravity thickening was a predominant solid-liquid separation process in the thermophilic ASBRS. Solids profiles at the end of thickening step dramatically changed at solid-liquid interface, and slight difference in solids concentrations was observed within thickened sludge bed. Organics removals based on subnatant or supernatant after thickening always exceeded 80% in all reactors. Thickened sludge volume and gas production of the ASBRs affected mutually. Gas production increased as thickened sludge accumulated, and continuous gas evolution during thickening could cause thickened sludge to expand or resuspend. Thickened sludge volume exceeding a predetermined withdrawal level resulted in loss of organic solids as well as biomass during withdrawal step, leading to decrease in gas production ind SRT. Such an adverse mutual effect was significant in gravity thickening, while it was not sensitive in flotation thickening. Changes in organic loading had no significant effect on organic removals and gas production after build-up of solids in the ASBRs.

Separation Characteristics of $CH_4/CO_2$ Mixed Gas by Polyamide Composite Membrane (Polyamide 복합막을 이용한 메탄/이산화탄소 혼합기체의 분리 특성)

  • Lee, Jae-Hwa;Lee, Geon-Ho;Choi, Kyung-Seok;Poudel, Jeeban;Kim, Soo-Ryong;Oh, Sea-Cheon
    • Journal of the Korean Applied Science and Technology
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    • v.29 no.3
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    • pp.478-485
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    • 2012
  • Polymers are widely used as membrane material for performing the separation of various gaseous mixtures due to their attractive permselective properties and high processability. The separation characteristics of $CH_4$ and $CO_2$ mixed gas using polyamide composite membrane has been studied in this work. The sample gas was prepared by mixing pure methane and carbon dioxide. Permeation tests were carried out at different operation conditions. Feed flow rates were varied between 800~1000 $cm^3/min$, and the stage cuts were varied between 50~60%. The gas inlet pressure and the temperature were varied as 6 bar and $30{\sim}70^{\circ}C$, respectively. The effects of the above mentioned parameters were investigated to estimate the permeability of $CH_4$ and $CO_2$, and the selectivity of $CO_2$ was also calculated for all conditions. The Arrhenius plots were also performed to obtaine the activation energies of $CH_4$ and $CO_2$ permeabilities.

Synthesis of SiC from the Wire Cutting Slurry of Silicon Wafer and Graphite Rod of Spent Zinc-Carbon Battery (폐 반도체 슬러리 및 폐 망간전지 흑연봉으로부터 탄화규소 합성)

  • Sohn Yong-Un;Chung In-Wha;Sohn Jeong-Soo;Kim Byoung-Gyu
    • Resources Recycling
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    • v.12 no.3
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    • pp.25-30
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    • 2003
  • The synthesis of SiC used for the parts of the gas turbine and the heat exchanger, was carried out. In this study, wire cutting slurry of silicon wafer and the graphite rod of spent zinc-carbon battery were applied to the starting materials for the synthesis. The powders of Si or Si+SiC were obtained from the waste material by filtration, gravity separation and magnetic separation. Graphite powder was produced by dismantling, grinding and gravity separation from spent zinc-carbon battery. The synthesis of SiC could be completed from the mixture powders of Si and C or Si+SiC and C at the condition of equivalent ratio of Si and C, atmosphere of Ar or vacuum, temperature of above 1$600^{\circ}C$ and 2 hours reactions. The purity of synthesized Si-C was above 99%.

Variation of Single Gas ($SF_6$, $N_2$, $O_2$, $CF_4$) Permeance through Hollow Fiber Polymeric Membranes Depending on Temperature and Pressure (중공사 고분자 분리막을 통한 단일기체($SF_6$, $N_2$, $O_2$, $CF_4$) 투과플럭스의 온도와 압력에 따른 변화특성)

  • Lee, Min-Woo;Lee, Soon-Jae;Kim, Han-Byul;Kim, Sung-Hyun;Lee, Sang-Hyup
    • Membrane Journal
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    • v.22 no.1
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    • pp.23-34
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    • 2012
  • In this study, we investigated the permeation property of single gases ($N_2$, $O_2$, $SF_6$, $CF_4$ through hollow fiber polymeric membrane (PSF, PC, PI) as a function of pressure and temperature to decide operating condition for $SF_6$ gas separation process. The results showed the gas permeation varied differentlydepending on the properties of gases and membrane. When permeance of each gases was represented as a function of temperature and pressure in 3 dimensional space, the surface of permeance was shown approximately flat. Thus, we established permeance models with forms of first-and second-order polynomial. These two models showed high goodness of fit. This indicates that the two polynomial models have enough applicability to predict the gas separation process.

Annealing Characteristic of Phosphorus Implanted Silicon Films using an Ion Mass Doping Method (Ion Mass Doping 법을 이용한 Phosphorus 주입된 실리콘 박막의 Annealing 특성)

  • 강창용;최덕균;주승기
    • Journal of the Korean institute of surface engineering
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    • v.27 no.4
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    • pp.234-240
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    • 1994
  • A large area impurity doping method for poly-Si TFT LCD has been developed. The advantage of this method is the doping of impurities into Si over a large area without mass separation and beam scanning. Phosphorus diluted in hydrogen was discharged by RF(13.56MHz) power and ions from discharged gas were accelerated by DC acceleration voltage and were implanted into deposited Si films. The annealing characteristic of this method was similar to that of the ion implantation method in the low doping concentration. Three mechanisms were evolved in the annealing characteristics of phosphorus doped Si films. Point defects annihilation and the retrogradation of dopant atoms at grain boundaries as a result of grain growth played a major role at low and high annealing temperature, respectively. However, due to the dopant segregation, the reverse annealing range existed at intermediate annealing temperature.

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Highly Efficient Biogas Upgrading Process Using Polysulfone Hollow Fiber Membrane at Low Temperature (폴리술폰 중공사막을 이용한 바이오가스 고순도화 고효율 저온 분리 공정)

  • Kim, Se Jong;Han, Sang Hoon;Yim, Jin Hyuk;Lee, Chung Seop;Chang, Won Seok;Kim, Gill Jung;Ha, Seong Yong
    • Membrane Journal
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    • v.32 no.2
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    • pp.140-149
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    • 2022
  • In this study, the conditions of low temperature and high pressure of biogas upgrading process using polysulfone membrane have been designed and tested to achieve the high recovery and efficiency corresponding to those of the highly selective polymeric materials. Polysulfone hollow fiber membrane with 4-component dope solution was spun via non-solvent induced phase separation. The hollow fiber membrane was mounted into a 1.5 inch housing. The effective area was 1.6 m2, and its performance was examined in various operation temperatures and pressures. CO2 and CH4 permeances were 412 and 12.7 GPU at 20℃, and 280 and 3.6 GPU at -20℃, respectively, while the CO2/CH4 selectivity increased from 32.4 to 77.8. Single gas test was followed by the mixed gas experiments using single-stage and double stage where the membrane area ratio varied from 1:1 to 1:3. At the single-stage, CH4 purity increased and the recovery decreased as the stage-cut increased. At the double stage, the area ratio of 1:3 showed the higher CH4 recovery as decreasing the operation temperature at the same purity of CH4 97%. Finally, polysulfone hollow fiber membranes have yielded of both CH4 purity and recovery of 97% at -20℃ and 16 barg.

Combustion Characteristics of Cylindrical Premixed Combustor using Liquid Fuel by Self Evaporation (자열증발된 액체연료를 적용한 원통형 예혼합 연소기의 연소특성)

  • Lee, Pil Hyong;Song, Ki Jong;Hwang, Sang Soon
    • Journal of the Korean Society of Combustion
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    • v.21 no.3
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    • pp.7-15
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    • 2016
  • The fuel in conventional liquid fuel combustor is atomized by spray method for high efficiency and low emissions. To improve the overall fuel efficiency and lower pollutant emissions in liquid fuel combustion systems, the effective spatial and temporal separation of droplet evaporation from normal spray process is needed. In this paper, the recuperation of high temperature burnt gas for fuel evaporation was proposed to develop a cylindrical premixed combustor. The recuperation process using U shaped tube is effective to evaporate the liquid fuel. The results show that the flame mode is changed into red radiation flame, blue flame and lift off flame with decreasing equivalence ratio as gas fuel combustion mode. In particular, the blue flame is found to be very stable at heating load 9.2 kW and equivalence ratio 0.731. NOx was measured blow 105 ppm ($O_2$ zero base) from equivalence ratio 0.705 to 0.835. CO which is a very important emission index in liquid fuel combustor was observed below 5 ppm ($O_2$ zero base) under the same equivalence region.