• 동력기계공학회지
• /
• 제15권2호
• /
• pp.25-30
• /
• 2011

A fresh water generation system is designed for converting brackish water or seawater into fresh water. In this paper fresh water generation by distillation process that evaporates feed water and subsequently condenses vapor as evaporation product to get fresh water was studied and city water was employed as feed water. The system uses the ejector to create a vacuum, under which liquid can be evaporated at lower temperature than it at normal or atmospheric condition, hence less energy consumption. The effect of various operating conditions i.e. temperature of feed water and different orifice diameters were studied experimentally to investigate the characteristic of the system. It was found that these parameters have significant effect in the performance of fresh water generation system with low pressure evaporation.

• 대한기계학회논문집B
• /
• 제33권5호
• /
• pp.373-380
• /
• 2009

The evaporation process of multi-component fuel is different from one of a single component, because the properties of each component affects among the components. In actual engine, the spatial distribution of fuel vapor concentration dominates auto-ignition and initial combustion, and depends on the volatility and diffusivity of each component fuel contained in the multi-component fuel. Then, this study proposes a simplified numerical scheme for analysis of evaporation process of multi-component fuel sprays. Evaporation process is calculated by KIVA-II code based on the simple two-phases region that is approximated by modified saturated liquid-vapor line, which was obtained by connecting the 50% distillation temperature for each component under several pressure fields. Consequently, it can be quantitatively simulated that vapor of low boiling fuel component mostly exists around nozzle and spray tip region, the high boiling duel component, on the other hand, mostly appears near the spray tip.

• 한국기계기술학회지
• /
• 제13권4호
• /
• pp.149-156
• /
• 2011

In case of domestic pyrolysis dry distillation gassification technology, it stays at the stage of its early introduction and development. Moreover, the companies possessed of this technology are limited to Japan and some countries in Europe, and domestic operative performance of this system is nominal, so there exist a lot of difficulties in securing its basic data. In addition, considering its operation and management, there happens a corrosion of metals by the production of corrosive gases in time of combustion of waste, and there arise a problem of occurrence of low temperature corrosion on exterior casing or gas ducts of a combustion chamber due to the high temperature corrosion around the burner of an incinerator, lowering the durability of an incinerator. Therefore, this study looked at the problems arising in time of incineration by understanding the characteristics of the pyrolysis dry distillation gassification incinerating facility, and did research on the improvement plan for durability of an incinerator for more economic, efficient waste incineration.

• Nuclear Engineering and Technology
• /
• 제50권7호
• /
• pp.1184-1189
• /
• 2018

Pyroprocessing uses various molten salts during electrochemical unit processes. Reaction products after the electrochemical processes must contain a significant amount of residual salts to be separated. Vacuum distillation is a common method to separate the residual salts; however, its high operation temperature may cause side reactions. In this study, a simple rotation technique using centrifugal force was suggested to separate the residual salts from the reaction products at relatively low temperature compared to the distillation technique. When a reaction product container with porous wall rotates inside a vessel heated above the melting point of the residual salt, the residual salt in the liquid phase is separated through centrifugal force. It was shown that the $LiNO_3-Al_2O_3$ mixture can be separated by this technique to leave solid $Al_2O_3$ inside the container, with a separation efficiency of 99.4%.

• 대한금속재료학회지
• /
• 제48권2호
• /
• pp.154-162
• /
• 2010

A fundamental study of the distillation behavior of ferromanganese alloy melts was carried out at 1773 K and 0.1333 kPa (=1 Torr). During the distillation of ferromanganese alloy melts under reduced pressure, manganese vaporizes preferentially to phosphorus and other solute elements. High purity manganese metal with a very low content of solute elements can be obtained by distillation of ferromanganese alloy melts. The evaporation of manganese is suppressed as the carbon content of ferromanganese alloy melt increases due to the decrease of activity and vapor pressure of the manganese. When the carbon content of ferromanganese alloy melt is high, melt droplets are ejected from the bath, especially in the early stages of the distillation, and the solute elements in the splashed droplets contaminate the condensed material. The ejection of melt droplets is presumed to be caused by the increase of melting temperature and viscosity of the surface layer of melt due to the enrichment of solute elements such as carbon and iron.

• Membrane and Water Treatment
• /
• 제13권5호
• /
• pp.235-243
• /
• 2022

The paper presents the effect of operating temperatures and flow rates on the distillate flux that can be obtained from a hydrophobic membrane having the characteristics: pore size of 0.15 ㎛; thickness of 130 ㎛; and 85% porosity. That membrane in the present investigation could be the direct contact (DCMD) or the air-gap membrane distillation (AGMD). To model numerically the membrane distillation processes, the two-dimensional computational fluid dynamic (CFD) is used for the DCMD and AGMD cases here. In this work, DCMD and AGMD models have been validated with the experimental data using different flows (Parallel and Counter-current flows) in non-steady-state situations. A good agreement is obtained between the present results and those of the experimental data in the literature. The new approach in the present numerical modeling has allowed examining effects of the nature of materials (Polyvinylidene fluoride (PVDF) polymers, copolymers, and blends) used on thermal properties. Moreover, the effect of the area surface of the membrane (0.021 to 3.15 ㎡) is investigated to explore both the laminar and the turbulent flow regimes. The obtained results found that copolymer P(VDF-TrFE) (80/20) is more effective than the other materials of membrane distillation (MD). The mass flux and thermal efficiency reach 193.5 (g/㎡s), and 83.29 % using turbulent flow and an effective area of 3.1 ㎡, respectively. The increase of feed inlet temperatures and its flow rate, with the reduction of cold temperatures and its flow rate are very effective for increasing distillate water flow in MD applications.

• 상하수도학회지
• /
• 제29권2호
• /
• pp.261-269
• /
• 2015

In this study, we applied a membrane distillation process to investigate a feasibility of treating a wastewater with high concentration of organic matters including nitrogen and phosphorus. The laboratory scale experiment was performed by using a hydrophobic PVDF membrane with the pore size of $0.22{\mu}m$ and porosity of 75%. The installation was direct contact type where the temperature difference between a feed and permeate side was controlled to have a range from 20 to $60^{\circ}C$. We observed a flux variation and a concentration changes of COD, $PO{_4}^{3-}$-P, $NH_4{^+}$-N and conductivity of feed side as well as permeate side with various temperature differences (20 to $60^{\circ}C$), cross flow velocities (0.09 to 0.27 m/s) through the module, and pH (6.6 to 12.0) of the feed that has the initial concentration of COD about 1,000 mg/L, total nitrogen 390 mg/L, total phosphorus 10 mg/L, conductivity of $7,000{\mu}s/cm$. The results showed that the average flux was ranged from 4 to $40L/m^2/hr$ which was almost similar with the flux of NaCl and deionized water used as a feed solution. The lowest flux was obtained at the operating condition with the temperature difference of $20^{\circ}C$ and cross flow velocity of 0.09 m/s while the highest one was measured with $60^{\circ}C$ and 0.27 m/s. Above 99% of COD and $PO{_4}^{3-}$-P in the feed could be rejected regardless of an operating condition. However, the removal rate of ammonium nitrogen was varied from 64 to 99% depending on the pH of feed solution.

• 동의생리병리학회지
• /
• 제16권3호
• /
• pp.532-536
• /
• 2002

Jookrhyuk (Bambusae Caulis in Liqamen) was extracted at low temperature (100℃ - 160℃) and purified by adsorption and distillation and their physicochemical properties were compared. In case of colour among all Jookrhyuk samples the L value appeared to be higher in the purified Jookrhyuk,and the b value appeared to be higher in crude Jookrhyuk. Purified Jookrhyuk showed much lower level of total sugar and tar contents than crude Jookrhyuk. A considerable reduction in concentration of methanol and phenolic compounds was achieved by purification process, whereas the content of acetic acid was increased. Therefore it was suggested that adsoption and distillation could be used as one of effective purification methods of various Joockrhyuk samples.

• 멤브레인
• /
• 제26권1호
• /
• pp.70-75
• /
• 2016

본 연구에서는 하수처리수를 원수로 사용하여 직접 접촉식 막증발법을 적용하여 원수 온도와 원수 유량 변화에 따른 하수처리수의 COD, TN, TP, TOC의 제거율 변화와 여과플럭스의 변화를 측정하였다. 또한 하수처리수에 의한 분리막의 오염 가역성을 평가하기 위해 1차 증류수만을 사용하여 물리세정을 수행한 후 플럭스의 회복률을 측정하였다. 실험결과 원수의 온도 및 유량에 관계없이 원수가 3배 농축될 때까지 여과를 진행하였음에도 불구하고 하수처리수의 주요 오염물질인 COD, TN, TP, TOC에 대한 제거율이 92% 이상으로 높게 나타났다. 또한 비교적 낮은 온도인 $50^{\circ}C$와 $60^{\circ}C$에서 원수의 유량에 따라 최소 13.8 LMH에서 20.3 LMH로 높은 여과플럭스를 나타냈다. 그리고 높은 농축계수까지 여과 실험을 진행했음에도 불구하고 낮은 여과플럭스의 감소를 나타냈으며 1차 증류수를 이용한 짧은 시간 동안의 물리세정만으로 최소 90% 이상의 높은 여과 플럭스 회복율을 나타냈다. 따라서 하수처리수 재이용을 위한 공정으로 막증발법의 적용이 충분히 가능할 것으로 판단된다.

• Journal of Ginseng Research
• /
• 제14권3호
• /
• pp.353-356
• /
• 1990

The isolation of volatile compounds by vacuum-distillation with freeze-drying was tested 1 with fresh ginseng roots. The roots were frozen at-8$0^{\circ}C$; they were dried at-4$0^{\circ}C$ tinder vacuum(40 tory), for 24 hours; and the ice condensed at the silrface of condenser in the freeze-dryer was thauved at room temperature. The ether extract of the resulting aqueous solution was analyzed by gas chromatography (GC) equipped with a flame ionization detector (FID) or a nitrogen-phosphorils detecto(NPD) and by gas : chromatography/mass spectrometry(GC/MS). More than forty peaks were observed in the CG(FID) profile. and more than ten peaks were observed in the GC(NPD) profile. Among them, thirteen components 1including one aldehyde, four hydrocarbons, two esters, folly alcohols, and two vyrazines were identified: six components the molesuiar ions of which were m/z, 204 were estimated to be a series of azulene compounds; and the other components unidentified were estimated to have molecular weights of lower than 254. Therefore, the freeze-drying technicue is thought to be usefu1 for the isolation of volatile compounds of such low molecufilar weights from vegetables, fruits and biological fluids as well as fresh ginseng roots under the tested conditions.