• 상하수도학회지
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• 제24권3호
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• pp.267-276
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• 2010

Many plants have been improved to adapt the target of the biological treatment processes changed from organics to nutrients since the water quality criteria of effluent was reinforced and included T-N and T-P for the municipal wastewater treatment plant. To meet the criteria of T-N and T-P, the conventional biological reactor such as aeration tank in activated sludge system is changed to the BNR (biological nutrient removal) processes, which are typically divided into three units as anaerobic, anoxic and oxic tank. Therefore, the solid separation process should be redesigned to fit the BNR processes in case of the application of the DAF (dissolved air flotation) process as an alternatives because the solid-liquid separation characteristics of microbial flocs produced in the BNR processes are also different from that of activated sludge system as well. The results of this study revealed that the microbial floc of the anaerobic tank was the hardest to be separated among the three steps of the unit tanks for the BNR processes. On the contrary, the oxic tank was best for the removal efficiency of nutrients as well as suspended solid. In addition, the removal efficiency of nutrients was much improved under the chemical coagulation treatment though coagulation was not indispensable with a respect to the solid separation. On the other hand, in spited that the separation time for the microbial floc from the BNR processes were similar to the typical particles like clay flocs, over $2.32{\times}10^3$ ppm of air volume concentration was required to keep back the break-up of the bubble-floc agglomerates.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2003년도 추계학술대회 논문집
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• pp.390-391
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• 2003

Cyclone is one of the most widely used gas - solid separation devices in industries. In spite of its many advantages, lower separation efficiency and flat separation curve are usually associated with cyclones. Therefore, the primary goal of cyclone research is to improve its separation capability while retaining its basic features. In this study, granules were filled in the cone of a cyclone in an attempt to increase the cyclone separation efficiency through the combination of granular filtration and centrifugal separation. (omitted)

• 유기물자원화
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• 제21권3호
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• pp.74-81
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• 2013

본 연구는 생활폐기물 처리에서 매립되는 폐기물량을 줄이고 재활용비율을 늘리기 위하여 고안된 풍력선별기 (공기의 흐르는 방향을 이용하여 공기 중에서 비중분리를 수행하는 방법)에 대하여 ANSYS사의 CFX Program을 이용한 수치 해석적 방법을 통해 풍력선별기의 모형을 설계 및 제작하고 시뮬레이션을 통해 풍력에 따른 폐기물의 분리 효율을 고찰하였다. 흡입장치에서 비닐봉지 1000mL를 흡입하도록 설계할 때 입구 풍속은 0.9 m/sec 이상에서 100%효율을 얻을 수 있었고 1.6 m/sec 이상에서 의 플라스틱병 500mL 와 플라스틱병 1500mL의 혼합 폐기물 효율의 100 % 알루미늄 250mL 선별 효율은 2.3 m/sec 이상에서 100% 마지막으로 알루미늄 250mL를 5mm 두께 압축 선별 효율은 2.4 m/sec 이상에서 90% 임을 알 수 있었다.

• 한국환경과학회지
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• 제31권1호
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• pp.1-8
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• 2022

In this study, solid-liquid separation conditions for coagulation and sedimentation experiments using inorganic coagulant (aluminum sulfate and Poly-Aluminum Chloride (PAC)) were optimized with brine wastewater discharged by the epoxy-resin process. When the turbidity and suspended solid (SS) concentration in raw wastewater were 74 NTU and 4.1 mg/L, respectively, their values decreased the lowest in a coagulant dosage of 135.0 - 270.0 mg Al³⁺/L. The epoxy resin was re-dispersed in the upper part of wastewater treated above 405.0 mg Al³⁺/L. The removal efficiencies of turbidity and SS via dosing with aluminum sulfate and PAC were evaluated at initial turbidity and SS of 74 - 630 NTU and 4.1 - 38.5 mg/L, respectively. They increased most in the range from 135.0 - 270.0 mg Al³⁺/L. The solid-liquid separation condition was quantitatively compared to the correlation of SS removal efficiency between the coagulant dosage and SS concentration based on the concentration of aluminum ions. The empirical formula, R = be^aD, shows the relationship between SS removal efficiency (R) and coagulant dosage (D) at 38.5 mg/L; it produced high correlation coefficients (r²) of 0.9871 for aluminum sulfate and 0.9751 for PAC.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권2호
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• pp.117-125
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• 2003

Experimental and theoretical works were performed for the separation of large polyelectrolyte, such as DNA, in a column packed with gel particles under the influence of an electric field. Since DNA quickly orient in the field direction through the pores, this paper presents how intraparticle convection affects the residence time distribution of DNAs in the column. The concept is further illustrated with examples from solid -liquid systems, for example, from chromatography Showing how the column efficiency is improved by the use of a n electric field. Dimensionless transient mass balance equations were derived, taking into consideration both diffusion and electrophoretic convection. The separation criteria are theoretically studied using two different Peclet numbers in the fluid and solid phases. These criteria were experimentally verified using two different DNAs via electrophoretic mobility measurements. which showed how the separation position of the DNAs varies in the column in relation to the Peg/Pef values of an individual DNA. The residence time distribution was solved by an operator theory and the characteristic method to yield the column response.

• Nuclear Engineering and Technology
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• 제50권7호
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• pp.1184-1189
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• 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%.

• 한국양식학회지
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• 제18권3호
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• pp.189-195
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• 2005

By testing the separation performance for a fine settleable solid removal system in an aquaculture system using polystyrene particles as an experimental substitute, the optimal geometric dimensions for a Low-Pressure Hydrocyclone (LPH) were obtained. The design approach far the LPH took into consideration two inflow diameters (Di: 30, 50 mm), three overflow diameters (Do: 60, 70, 100 mm) and four cylinder lengths (Lc: 250, 345, 442, 575 mm), while the cylinder diameter (Dc) at 335 mm, the underflow diameter (Du) at 50 mm and the cone angle (${\theta}$) at $68^{\circ}$ were kept constant. The separation performances of 19 different dimension combinations of LPH were tested, ranging from 300 to 1200 ml/sec of inflow rate using substitute polystyrene particles (0.4-0.7 mm dia., ${\rho}_s=1.05g/cm^3$). These polystyrene particles exhibit a similar density and settling velocity to the fine fecal debris of the common carp. The total separation efficiency for the inflow rate ranged from a high of 97% to a low of 20%. Experimental results obtained by ANCOVA and the Tukey test (${\alpha}=0.05$) showed that the separation performances of the LPH were significantly affected (P<0.05) by the fi, Di, Do and Lc. The maximum separation performance was detected at a dimension combination of 30 mm of inflow diameter (Di), 60 mm of overflow diameter (Do), 442 and 575 mm of cylinder length (Lc). The dimension proportions were 0.09, 1.32-1.72, 0.18 and 0.15 for Di/Dc, Lc/Dc, Do/Dc and Du/Dc respectively.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.484.2-484.2
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• 2014

There are many efforts to improving the power conversion efficiencies (PCEs) of dye-sensitized solar cells (DSCs). Although DSCs have a low production cost, their low PCE and low thermal stability have limited commercial applications. This study describes the preparation of a novel multifunctional polymer gel electrolyte in which a cross-linking polymerization reaction is used to encapsulate $TiO_2$ nanoparticles toward improving the power conversion efficiency and long-term stability of a quasi-solid state DSC. A series of liquid junction dye-sensitized solar cells (DSCs) was fabricated based on polymer membrane encapsulated dye-sensitized $TiO_2$ nanoparticles, prepared using a surface-induced cross-linking polymerization reaction, to investigate the dependence of the solar cell performance on the encapsulating membrane layer thickness. The ion conductivity decreased as the membrane thickness increased; however, the long term-stability of the devices improved with increasing membrane thickness. Nanoparticles encapsulated in a thick membrane (ca. 37 nm), obtained using a 90 min polymerization time, exhibited excellent pore filling among $TiO_2$ particles. This nanoparticle layer was used to fabricate a thin-layered, quasi-solid state DSC. The thick membrane prevented short-circuit paths from forming between the counter and the $TiO_2$ electrode, thereby reducing the minimum necessary electrode separation distance. The quasi-solid state DSC yielded a high power conversion efficiency (7.6/8.1%) and excellent stability during heating at $65^{\circ}C$ over 30 days. These performance characteristics were superior to those obtained from a conventional DSC (7.5/3.5%) prepared using a $TiO_2$ active layer with the same thickness. The reduced electrode separation distance shortened the charge transport pathways, which compensated for the reduced ion conductivity in the polymer gel electrolyte. Excellent pore filling on the $TiO_2$ particles minimized the exposure of the dye to the liquid and reduced dye detachment.

• 유기물자원화
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• 제22권3호
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• pp.23-32
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• 2014

최근 들어 유기성폐기물의 혐기소화를 이용한 처리(에너지화)가 증가하고 있다. 이에 따라서 혐기소화 후 발생하는 혐기소화폐액의 처리방안에 대한 연구도 증가하고 있다. 그러나, 혐기소화폐액의 특성상 문제로 고액분리에 매우 어려움이 있다.이에 본 연구에서는 CST와 TTF를 이용하여 혐기소화폐액에 대한 응집에 따른 고액분리 특성을 파악하였다. 또한 이러한 문제를 해결하기 위하여 실험실수준의 멤브레인 필터프레스를 제작하고, 혐기소화폐액에 적용하였다. 고분자 응집제는 7192PLUS와 1T60가 가장 적합한 것으로 확인되었으며, 최소 7192PLUS (200 mg/L), 1T60 (100 mg/L)이상의 투입이 필요하였다. 탈수효율을 평가하기 위하여 탈수케이크의 함수율과 탈리여액의 입자성 고형물을 이용하였다. 결과적으로, 멤브레인 필터프스를 이용하여 고액분리 시 입자성 고형물의 제거효율은 97.4%로 높게 나타났으며, 탈수케이크의 함수율은 65%이하로 나타났다.

• 해양환경안전학회지
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• 제11권2호
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• pp.109-115
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• 2005

하이드로사이클론은 다양한 산업 방면의 고$\cdot$액 분리를 위해 널리 사용되어왔다. 왜냐하면 하이드로사이클론의 적당한 응용으로 폭넓은 범위의 입자에 적용이 가능하기 때문이다. 불순물을 함유한 해수가 펌프나 열교환기로 흘러가면 그것은 해수 냉각시스템의 효율을 저하시키는 원인이 된다. 본 연구에서는 하이드로사이클론을 이용한 해수 냉각시스템에서 불순물을 분리하는 몇가지 방법을 제시했다. 설계의 영향을 미치는 인자로서 고체농도, 사이클론 입구압력, 하부배출구의 직경과 유량에 따른 하이드로사이클론의 분리효율에 대해 연구를 하였다. 이 연구의 결과는 다음과 같다. 1) 고형물질의 농도가 감소할수록 고$\cdot$액 분리의 효율이 증가하였다. 2) 사이클론 입구압력이 증가함에 따라 분리효율이 증가하였다. 결과적으로 이 연구에서는 하이드로사이클론을 기계류 냉각시스템의 전처리장치로 사용한다면 엔진시스템에서 예상치 못했던 사고를 방지할 수 있을 것이다.