Editor’s Choice

Editor’s Choice

NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 33, No. 4, 2015 … 537 Korean Journal of Chemical Engineering,

Vol.32, No.7, 1207-1217, 2015

Modeling and simulation of biopolymer networks: Classification of the cytoskeleton models according to multiple scales

Banerjee N, Park J

Abstract - We reviewed numerical/analytical models for describing rheological properties and mechanical behaviors of biopolymer networks with a focus on the cytoskeleton, a major component of a living cell. The cytoskeleton models are classified into three categories: the cell-scale continuum-based model, the structure-based model, and the polymerbased model, according to the length scales of the phenomena of interest. The criteria for classification of the models are modified and extended from those used by Mofrad [M. R. K. Mofrad, Annual Rev. Fluid Mech. 41, 433 (2009)]. The main principles and characteristics of each model are summarized and discussed by comparison with each other. Since the stress- deformation relation of cytoskeleton is dependent on the length scale of stress elements, our model classification helps systematic understanding of biopolymer network modeling.

Korean Journal of Chemical Engineering, Vol.32, No.7, 1229-1242, 2015

Design of a dividing wall column for fractionation of biodiesel

Abstract - This study presents an efficient design method for DWC which can fractionate palm methyl esters (PME, biodiesel) into three more valuable product groups: a mixture of methyl laurate and methyl myristate as light-cut, pure methyl palmitate (≥99.5%) as middle cut, and the mixture of the remaining methyl esters (biodiesel), which has good low- temperature operability to such an extent as to come close to cold filter plugging point (CFPP) 0 ℃, as heavy cut. The first step of the design was to determine numbers of stages for four sub-sections of DWC, liquid split ratio, and initial reflux ratio by the shortcut design, based on the component net flow model and the method of Fenske, Underwood, and Gilliland (FUG method). Secondly, optimal reflux ratio, vapor split ratio, locations of stages for feed and side product were found out by sensitivity analysis in rigorous simulation. The results from the simulation model developed by the method show that the reboiler duty of a single DWC is about 24% less than that of two simple columns in direct sequence and about 25% less than in indirect sequence. These energy saving ratios are almost close to 30%, which is popularly known as a typical value for energy saving of DWC.

Korean Journal of Chemical Engineering, Vol.32, No.7, 1273-1277, 2015

Homogeneous catalytic activity of gold nanoparticles synthesized using turnip (Brassica rapa L.) leaf extract in the reductive degradation of cationic azo dye

Narayanan KB, Park HH

Abstract - A new greener strategy for the synthesis and stabilization of gold nanoparticles using aqueous turnip leaf extract under ambient conditions is reported in this study. The formation of gold nanoparticles was monitored using a UV-Vis spectrophotometer and the maximum absorption peak (λmax) at 535 nm with a visual color change to pinkishred confirmed the gold nanoparticles. Further characterization was conducted using Fourier-transform Infra-red spectrometry (FT-IR), powder X-ray diffractometry (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS) with zeta potential at pH 7.5. The stability of the nanoparticles was due to the capping of nanoparticles with amine groups and ortho-substituted aromatic phytoconstituents, which exhibit higher negative values of zeta potential (ζ). XRD pattern revealed the formation of face-centered cubic (fcc) lattice crystals of gold nanoparticles, while TEM have demonstrated the size of gold nanoparticles ranging from 3 to 58 nm. The as-synthesized gold nanoparticles showed rapid catalytic reduction of methylene blue (MB) dye to leuco MB in the presence of sodium borohydride (NaBH4). The reduction reaction followed pseudo-first order kinetics with a reaction rate constant of 0.372 min.1. This process of nanoparticle synthesis is simple, nontoxic and environmentally benign compared to the chemical synthetic routes.

538 … NICE, 제33권 제4호, 2015

Korean Journal of Chemical Engineering, Vol.32, No.8, 1455-1476, 2015

Reviews on drag reducing polymers

Abstract - Polymers are effective drag reducers owing to their ability to suppress the formation of turbulent eddies at low concentrations. Existing drag reduction methods can be generally classified into additive and non-additive techniques. The polymer additive based method is categorized under additive techniques. Other drag reducing additives are fibers and surfactants. Non-additive techniques are associated with the applications of different types of surfaces: riblets, dimples, oscillating walls, compliant surfaces and microbubbles. This review focuses on experimental and computational fluid dynamics (CFD) modeling studies on polymer-induced drag reduction in turbulent regimes. Other drag reduction methods are briefly addressed and compared to polymer-induced drag reduction. This paper also reports on the effects of polymer additives on the heat transfer performances in laminar regime. Knowledge gaps and potential research areas are identified.

It is envisaged that polymer additives may be a promising solution in addressing the current limitations of nanofluid heat transfer applications.

Korean Journal of Chemical Engineering, Vol.32, No.8, 1477-1485, 2015

Performance simulations of MEA/NH

based large-scale CO

capture in packed columns under different flue gas parameters

Minkai Zhang, Yincheng Guo

Abstract - Based on the rate-based process simulation, performances of MEA and NH3 based large-scale CO2 capture in packed columns under different flue gas parameters were investigated. Simulation results show that the CO2 regeneration energy for the MEA based process is lower than that for the NH3 based process, which is mainly because the flow rate of the MEA solution is significantly lower than that of the aqueous ammonia. The MEA leakage concentration is far lower than the NH3 leakage concentration, and this indicates that the NH3 abatement system should be added for dealing with the NH3 slip in the NH3 based CO2 capture process. With the flow rate of the flue gas increasing, the liquid gas ratios for both processes decrease, which gives rise to the decrease of the CO2 removal efficiencies for the two processes. Since the liquid gas ratios are very high, the temperature of the flue gas has little effects on the MEA and NH3 based CO2 capture processes.

The comparative studies on the effects of the flue gas parameters can provide technical guidance for the pretreatment of the flue gas before CO2 capture.

Korean Journal of Chemical Engineering, Vol.32, No.8, 1688-1693, 2015

Properties of chitosan/magnetite nanoparticles composites for efficient dye adsorption and antibacterial agent

Abstract - Chitosan (CS)/iron oxide (Fe3O4) composites were prepared using a chemical precipitation method. The CS/

Fe3O4 composite was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, and zeta-potential measurements. The composite was used to remove methyl orange (MO) dye from an aqueous solution. The factors affecting the adsorption capacity, such as adsorption time, absorbent dosage and solution pH were investigated. The results suggested that the composite was an effective adsorbent for the removal of MO dye from its aqueous solution. Kinetics studies showed that the adsorption process was consistent with a pseudo-second-order model.

The adsorbent efficiency was unaltered, even after five cycles of reuse, and the adsorbent could be recollected easily using a magnet. In addition, the composite exhibited a superior antibacterial efficacy against Escherichiacoli; 82% within 24 h, as measured by the colony forming units.

NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 33, No. 4, 2015 … 539 Korean Chemical Engineering Research,

Vol.53, No.3, 302-308, 2015

3-메틸펜테인과 에틸렌 글리콜 모노프로필 에테르 및 에틸렌 글리콜 아이소프로필 에테르 혼합물에 대한 2성분계 등온 기-액 상 평형

Isothermal Vapor-liquid Equilibria for the Binary Mixtures of 3-Methylpentane with Ethylene Glycol Monopropyl Ether and Ethylene Glycol Isopropyl Ether

형성훈, 장성현, 김화용

Abstract - 본 연구에서는 3-Methylpentane을 포함하는 Ethylene glycol monopropyl ether (C3E1) 및 Ethylene glycol isopropylether (iC3E1) 계면활성제 혼합물에 대한 2성분계 기-액 상 평형을 서로 다른 온도 조건(303.15, 318.15, 333.15K)에서 측정 및 비교하였다. C3E1은 분자 내 수소결합과 분자 간 수소결합이 동시에 나타나는 자가 회합 성 물질이므로 상 평형 예측을 어렵게 하는 경향이 있다. 본 연구의 목적은 C3E1 혼합물과 그 이성질체인 iC3E1 혼합물의 상 평형을 각각 측정 및 비교함으로써, 자가 회합 성 물질의 이성질체가 상 평형에 어떠한 영향을 미치는지 알아보는 것이다. 측정된 시스템은 PR-WS-NRTL, PR-WS-UNIQUAC, 그리고 PR-WS-WILSON 모델을 이용하여 각각 계산하고 각 모델의 성능을 비교하였다. 계산에 사용된 모델은 대부분 좋은 결과를 보여주었으며, 특히 PR-WS-NRTL 모델이 가장 좋은 결과를 나타냈다. 또한 측정 시스템 간의 상 평형 차이가 크게 발생하지 않은 것으로 보아 자가 회합 성 물질의 이성질체가 상 평형에 끼치는 영향은 크지 않음을 알 수 있었다.

Korean Chemical Engineering Research, Vol.53, No.3, 339-349, 2015

Dealumination에 의한 NaY zeolite의 개질과 VOCs 흡착특성에 관한 연구 A Study on Dealumination of NaY Zeolite and its VOCs Adsorption Properties

강신춘, 이화열, 박융호

Abstract - 본 연구에서는 활성탄을 대체하는 소재로서 재생이 용이하고 열적 안정성이 높은 DAY (Dealuminated Y-type) 제올라이트를 제조하였다. 원료물질로는 NaY 제올라이트를 이용하였으며, 이온교환, 소성, 수증기처리, 산처리의 단계를 거쳐 DAY 제올라이트를 제조하였다. 이때 결정성을 유지하면서 높은 Si/Al ratio를 얻기 위하여 소성 온도, 시간 및수증기 처리 시간에 변화를 주었다. 또한 제조한 DAY 제올라이트, 원료 물질인 NaY 제올라이트 및 상용 제올라이트 인 HISIV 1000에 대하여 상대습도 50%의 공기 흐름 중에서 VOCs 들에 대한 흡착 실험을 하였다. 520 oC에서 4시간 소성 및 7시간의 수증기처리를 통해 제조한 DAY 제올라이트는 결정성이 유지되었고, Si/Al ratio는 80.4이였다.

수분흡착특성은 NaY 제올라이트의 10% 정도로 소수성을 나타내었다. 상용 DAY 제올라이트인 HISIV 1000과 비교한 결과 극성이 강한 MEK에 대해서는 0.8배 정도의 흡착용량을 보였으나, 무극성이거나 극성이 약한 toluene과 EA에 대해서 각각 1.6배, 1.3배 정도 높은 흡착 용량을 보였다.

Korean Chemical Engineering Research, Vol.53, No.3, 391-396, 2015

다양한 합성 방법으로 제조된 BiFe

MoP

산화물 촉매 상에서 n-부텐의 산화탈수소화 반응 Oxidative Dehydrogenation of n-Butenes over BiFe

MoP

Oxide Catalysts Prepared

with Various Synthesis Method

Abstract - n-부텐의 산화탈수소화에서 제조방법이 촉매의 반응활성에 미치는 영향을 조사하기 위하여 BiFe0.65MoP0.1 산화물 촉매를 모델 촉매로 선정하여 공침법, 시트르산법, 수열합성법, 주형법 등의 방법으로 촉매를 제조하였다.

제조한 촉매의 물리·화학적 특성을 알아보고 반응 활성과 연관시키기 위하여 X-선 회절분석(XRD), 질소 흡착·탈착분석(N2 sorption), 암모니아/1-부텐-승온탈착분석(NH₃/1-butene-TPD) 등의 특성분석을 수행하였다.

공침법으로 제조한 촉매의 활성이 가장 높게 관찰되었으며, 14시간 동안의 산화탈수소화 반응 기준으로 n-부텐의 전환율은 79.5%, 1,3-부타디엔의 선택도는 85.1%, 1,3-부타디엔 수율은 67.7%의 수치를 보였다. 암모니아 승온탈착 실험으로부터 촉매의 반응 활성은 촉매의 산 특성과 밀접하게 관련이 있으며, 공침법으로 제조한 산화물 촉매가 다른 합성방법으로 제조한 촉매와 비교하여 가장 큰 산량을 갖는 것으로 관찰되었다. 또한, 1-부텐의 승온탈착 분석결과, 촉매의 활성은 흡착된 1-부텐과 촉매의 표면반응에 기인한 중간체의 흡.탈착 특성, 즉 약하게 흡착된 중간체(<200 ℃)의 상대적인 양과 강하게 흡착된 중간체의 탈착 온도(>200 ℃)와 밀접하게 관련이 있었다.