Editor’s Choice

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404 … NICE, 제36권 제3호, 2018

Editor’s Choice

Korean Journal of Chemical Engineering, Vol.35, No.5, 1053-1064, 2018

Risk based 3-dimensional and multifloor plant layout optimization for liquefied natural gas (LNG) liquefaction process

Park KT, Shin DG, Won WY

Abstract - This paper presents a mathematical formulation for solving a 3-dimensional and multifloor plant layout problem with safety considerations. The presented model is formulated as a mixed integer non-linear programming (MINLP) model and quantifies risk by utilizing Dow’s fire and explosion index (Dow’s F&EI)system. The applicability of the model is demonstrated by an illustrative example regarding layout optimization for the C3MR liquefaction processes.

Hydrodynamics and design of gas distributor in large-scale amine absorbers using computational fluid dynamics

Pham HH, Lim YI, Han SG, Lim BS, Ko HS

Abstract - A gas phase three-dimensional (3D) computational fluid dynamics (CFD) model was developed to investigate the hydrodynamics of gas distributors used in an amine absorber with a diameter of 3.2m. A standard gas inlet, tubular injectors with short, medium and long lengths, and a Schoepentoeter were considered as feed systems of the gas distributors. The pressure drop, dead-area ratio and coefficient of distribution at the packing entry were used as the performance indexes of the gas distributors. The down-pipe as a liquid collector exhibited a lower dead-area ratio when compared with that of the down- comer. The tubular gas injector with a short length reduced the dead-area ratio and the gas maldistribution. The Schoepentoeter was associated with the lowest pressure drop, dead-area ratio, and coefficient of distribution among the gas distributors. The uniformity of gas distribution was enhanced by 25% in the Schoepentoeter when compared to that of the tubular gas injector.

Photoreduction of CO

2

into CH

4

using Bi

2

S

3

-TiO

2

double-layered dense films

Kim JY, Do JY, Park NK, Lee SJ, Hong JP, Kang MS

Abstract - Nano-sized bismuth sulfide (Bi2S3) and titanium dioxide (TiO2) with the orthorhombic and anatase tetragonal structures, respectively, were synthesized for application as catalysts for the reduction of carbon dioxide (CO2) to methane (CH4). Four double-layered dense films were fabricated with different coating sequences.TiO2 (bottom layer)/Bi2S3 (top layer), Bi2S3/TiO2, TiO2/Bi2S3 : TiO2 (1 : 1) mix, and Bi2S3 : TiO2 (1 : 1) mix/Bi2S3 : TiO2 (1 : 1) mix.and applied to the photoreduction of CO2 to CH4; the catalytic activity of the fabricated films was compared to that of the pure TiO2/TiO2 and Bi2S3/Bi2S3 doubled-layered films. The TiO2/Bi2S3 double-layered film exhibited superior photocatalytic behavior, and higher CH4 production was obtained with the TiO2/Bi2S3 double-layered film than with the other films. A model of the mechanism underlying the enhanced photoactivity of the TiO2/Bi2S3 double-layered film was proposed, and it was attributed in effective charge separation.

Effect of surface treatment on hair fiber as reinforcement of HDPE composites: Mechanical properties and water absorption kinetics

Srivastava P, Sinha S

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NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 36, No. 3, 2018 … 405

Editor’s Choice

Abstract - The objective of this work was to investigate the effect of surface improvement on human hair fiber (HF) based high-density polyethylene (HDPE) reinforced polymer composites. A universal testing machine was used for the characterization of the mechanical behaviors of different types of HF base reinforced HDPE composites, and studies were conducted for the optimization of male/female fiber percentage (15% HF) in polymer composites. The alkali treatment (AT) and acrylic acid treatment (AAT) of HF reinforced HDPE composites showed a remarkable improvement in tensile strength (upto 15.487MPa and 15.638MPa, respectively), which was significantly changed in comparison to the tensile strength of untreated composites. FTIR and SEM test were used to characterize the fiber surface and HF/HDPE reinforced composites.

Water absorption kinetics was investigated for the study of diffusion mechanism and kinetics of composites materials, which would be useful to boost the applications of the composite in different areas.

Kinetic models of Fischer-Tropsch synthesis reaction over granule-type Pt-promoted Co/Al

2

O

3

catalyst

Koo HM, Park MJ, Moon DJ, Bae JW

Abstract - Kinetic models of CO hydrogenation to paraffinic hydrocarbons through Fischer-Tropsch synthesis (FTS) reaction were studied by using Langmuir-Hinshelwood Hougen-Watson (LHHW) model of 16 different reaction steps with a pseudo steady-state assumption (PSSA) on the prototype Pt-promoted Co/Al2O3 catalyst having a granule size of ~1 mm of spherical γ-Al2O3 support (surface area of 149m²/g). The derived kinetic models from ten sets of experimental data by altering the reaction conditions such as temperatures, pressures, space velocities and H2/CO molar ratios were found to be well fitted with reasonable kinetic parameters and small errors of conversion of CO and hydrocarbon distributions in terms of mean absolute relative residual (MARR) and relative standard deviation error (RSDE). The derived reaction rates and CO activation energy of -86 kJ/mol well correspond to the our previously reported results using power-type catalysts. Based on the LHHW model with PSSA, the possible chemical intermediates on the granule ball-type Co-Pt/Al2O3 surfaces were precisely considered to explain the typical adsorption, initiation, propagation and termination steps of FTS reaction as well as to derive elementary reaction rates with their kinetic parameters and hydrocarbon distributions. The derived kinetic models were further used to verify temperature-profiles in a pilot-scale fixed-bed tubular FTS reactor with a packing depth of 100 cm catalyst, and it confirmed that the temperature gradients were less than 10 °C in a length of reactor by effectively removing the generated heat by an exothermic FTS reaction.

Gd

³⁺

doped Fe

3

O

4

nanoparticles with proper magnetic and supercapacitive characteristics:

A novel synthesis platform and characterization

Aghazadeh M, Karimzadeh I, Maragheh MG, Ganjali MR

Abstract - A novel electrochemical procedure was developed for the facile preparation of Gd-doped iron oxide nanoparticles (GdIO-NPs). A simple galvanostatic deposition (i=10mA cm^-2) was done in an additive-free aqueous solution containing FeCl2·4H2O, Fe(NO3)3·9H2O and GdCl3·6H2O. The XRD, FE-SEM, EDS and TEM characterizations showed that the product is composed of 15% GdIO-NPs with 10 nm in size. VSM analysis proved that the GdIONPs are superparamagnetic.

The cyclic voltammetry and charge-discharge tests showed that the prepared GdIO-NPs are capable to deliver specific capacity as high as 190.1 F g-1 at 0.5A g-1 and capacity retention of 95.1% after 2000 cycling. Based on the results, it was concluded that the developed electrochemical strategy acts as an efficient procedure for the preparation of lanthanide doped MNPs with proper magnetic and supercapacitive characters.

(3)

406 … NICE, 제36권 제3호, 2018

Editor’s Choice

Korean Chemical Engineering Research, Vol.56, No.2, 162-168, 2018

플라스틱 기재 위에 polysilazane을 이용한 UV 경화형 하드코팅 도막 제조

Preparation of UV Cured Hard Coating Films Using Polysilazane on Plastic Substrates

양준호, 조용주, 송기창

Abstract - 유기 및 무기 폴리실라잔을 우레탄 아크릴레이트와 혼합시킴에 따라 UV 경화형 하드 코팅 용액을 제조하였다. 이 용액을 polymethylmethacrylate (PMMA) 시트에 흐름 코팅한 후 UV 경화시킴에 의해 UV 경화형 하드 코팅 도막을 제조하였다. 이 과정 중 폴리실라잔의 종류 및 첨가량을 변화시켜 코팅 도막의 물성에 미치는 영향을 살펴보았다. 그 결과 유기 폴리실라잔의 경우 95°의 수접촉각을 보여 높은 소수성을 나타내었으며, 7H의 연필경도와 92%의 가시광선 투과율을 보였다. 반면에 무기 폴리실라잔을 코팅한 도막은 8H의 높은 연필경도와 기재와의 우수한 접착력 및 82°의 수접촉각을 나타내었다.

일정압력하에서 1-propanol/benzene 계의 기-액 상평형

Isobaric Vapor-Liquid Equilibrium of 1-propanol and Benzene System at Subatmospheric Pressures

노선균, 강춘형

Abstract - 석유화학산업의 대표적인 물질로 쓰이는 벤젠은 각종 화학 제품의 기초 물질이다. 그러나 일반적으로 벤젠은 석유 화학 산업에서 순수 물질로 존재하지 못하고 알코올류와 벤젠 혼합물로 존재하게 된다. 또한 알코올을 한 성분으로 하는 혼합물은 공비 혼합물이 생성되기 때문에 분리 정제를 위해서는 상평형 데이터가 필수적이다. 본 연구에서는 알코올을 대표하는 1-프로판올을 사용하여 1-프로판올/벤젠 계에 대하여 재순환 평형장치를 이용하여 평형 온도/압력 효과에 따른 상평형 연구를 수행하였다. 측정된 기-액 평형 데이터는 UNIQUAC 식과 WILSON 식을 이용하여 상관관계 시키고 Gibbs/Duhem식을 이용하여 열역학적 건전성을 확인하였다. 상평형 실험 결과 RMSE (Root Mean Square Error)와 AAD (Average Absolute Deviation)는 두 모델식에서 0.05 이하의 값을 보여 실험값과 계산 값이 잘 일치함을 알 수 있었다. 또한 Gibbs/Duhem식을 이용하여 열역학적 건전성을 판별한 결과 잔류항 값이 ±0.2 이내에 분포하는 것을 통해 데이터에 대한 건전성을 확인할 수 있었다.

Fuel-Borne Catalyst와 Perovskite로 구성된 복합촉매 시스템에 의한 디젤 탄소입자상 물질의 연소반응: 반응성능과 Perovskite 촉매조성 (La1-x A′xBO3:A′ = K, Sr; 0 ≤ x ≤ 1; B = Fe, Cr, Mn)의 상관관계

Combustion of Diesel Particulate Matters under Mixed Catalyst System of Fuel-Borne Catalyst and Perovskite: Influence of Composition of Perovskite (La1-x A′xBO3: A′ = K, Sr; 0 ≤ x ≤ 1;B = Fe, Cr, Mn) on

Combustion Activity

이대원, 성주영, 이관영

Abstract - 최근 선진국을 중심으로 고연비-저배출 내연기관 (디젤) 자동차 보급의 필요성이 대두되면서 기존 촉매후처리 장치의 저온성능 강화를 위한 기술적 방안들이 시급히 요구되고 있다. 본 논문에서는 디젤엔진 배출 탄소입자상 물질의 연소반응에 있어 연료함유 촉매(Fuel-Borne Catalyst)와 페로브스카이트(Perovskite)의 복합촉매 시스템이 보이는 상용모델촉매 대비 우수한 저온 연소성능과 이의 Perovskite 촉매 조성에 대한 의존성에 관해 논하였다.

Fe/Ce 계열 연료함유 촉매가 A-site 원소(La)에 K이 부분치환되고, B-site 금속이 Fe인 Perovskite 촉매와 복합화될 때 상대적으로 우수한 저온 연소성능 개선효과가 관찰되었다. 이를 관찰하기 위해 연료함유 촉매가 함유되거나 함유하지 않은 탄소 입자상 물질과 다양한 조성의 La 계열 Perovskite 촉매를 혼합한 고정층에 대한 온도상승 산화반응 실험(Temperature-Programmed Oxidation)을 수행하였으며, 이산화탄소 생성과 질소산화물 농도 저하 패턴의 연동특성을 통해 두 촉매의 상호 연계작용을 유추하였다.