NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 31, No. 2, 2013 … 419 Korean Journal of Chemical Engineering,
Vol.30, No.4, 771-786, 2013
Natural gas hydrate as a potential energy resource: From occurrence to production Seol J, Lee H
Abstract - Natural gas hydrate reservoirs have been strongly suggested as a potential energy resource. However, this potential is expected to be limited by geological factors, reservoir properties, and phase-equilibria considerations. Accordingly, sufficient understanding and accurate analyses for the complex surroundings in a natural gas hydrate system have to occur before methane recovery. In this paper, we discuss the formation and structure patterns of global natural gas hydrate, including the origins of hydrocarbon, crystal structures, and unique structure transition. We also summarize two important anomalies related to methane occupancy and chlorinity which were revealed very recently. Furthermore, we review the geological and chemical surroundings of the shallow hydrate deposits, the so-called brine patch discovered in the Cascadia Margin and Ulleung Basin, which are significantly related to tectonic conduits for methane gas and positive chlorinity.
Korean Journal of Chemical Engineering, Vol.30, No.4, 949-954, 2013
Synthesis and characterization of CdSe nanocrystals in the presence of butylamine as a capping agent
Truong NTN, Kim WK, Park C
Abstract - TOPO-capped cadmium selenide (CdSe) nanocrystals of sizes between 3 and 8 nm have been synthesized, and the surface-capping molecule, trioctylphosphine oxide, was replaced by butylamine. The effects of changing the surface ligands of the synthesized CdSe nanocrystals on the structural, optical, and electrical properties were investigated. The shift toward shorter wavelength (higher energy) in the visible range of the optical absorption band edge was observed by UV- Vis spectroscopy, and a blue-shift of the photoluminescence peaks was observed with luminescent quenching. Surface modification was found to cause an increase in the surface energy of nanocrystals, resulting in the improvement in charge carrier separation and cell performance in applications towards bulk hetero-junction solar cells.
Korean Journal of Chemical Engineering, Vol.30, No.5, 977-987, 2013
Biological conversion of methane to methanol Park D, Lee J
Abstract - The conversion of methane to methanol is important to economic utilization of natural/shale gas. Methanol is a valuable liquid fuel and raw material for various synthetic hydrocarbon products. Its industrial production is currently based on a two-step process that is energy-intensive and environmentally unfriendly, requiring high pressure and temperature.
The biological oxidation of methane to methanol, based on methane monooxygenase activity of methanotrophic bacteria, is desirable because the oxidation is highly selective under mild conditions, but conversion rate and yield and stability of catalytic activity should be improved up to an industrially viable level. Since methanotrophic bacteria produce methanol as only a precursor of formaldehyde that is then used to synthesize various essential metabolites, the direct use of bacteria seems unsuitable for selective production of a large amount of methanol. There are two types of methane monooxygenase:
soluble (sMMO) and particulate (pMMO) enzyme. sMMO consisting of three components (reductase, hydroxylase, and regulatory protein) features an ( α β γ )2 dimer architecture with a di-iron active site in hydroxlase. pMMO, a trimer (pmoA, pmoB, and pmoC) in an α 3 β 3 γ 3 polypeptide arrangement is a copper enzyme with a di-copper active site located in the soluble domain of pmoB subunit. Since the membrane transports electrons well and delivers effectively methane with increased solubility in the lipid bilayer, pMMO seems more rationally designed enzyme in nature than sMMO. The engineering/evolution/modification of MMO enzymes using various biological and chemical techniques could lead to an
Editor’s Choice
420 … NICE, 제31권 제2호, 2013
optimal way to reach the ultimate goal of technically and economically feasible and environmentally friendly oxidation of methane. For this, multidisciplinary efforts from chemical engineering, protein engineering, and bioprocess research sectors should be systematically combined.
Korean Journal of Chemical Engineering, Vol.30, No.5, 1013-1022, 2013
Effect of organoclay on non-linear rheological properties of poly(lactic acid)/poly(caprolactone) blends
Salehiyan R, Hyun K
Abstract - The nonlinear viscoelastic properties of PLA/PCL blends with and without clay (montmorillonite, MMT) under large amplitude oscillatory shear (LAOS) flow were investigated. The G’and G’ ’as a function of strain amplitude, Lissajous plots and FT-rheology methods were used to interpret nonlinear behavior of PLA/PCL blends with and without MMT. Additionally, scanning electron microscopy (SEM) images of PLA/PCL with MMT blends were taken to investigate the effects of clay on the internal structure of the PLA/PCL blends. A relationship between morphological changes and linear and nonlinear rheological properties was observed. SEM image analysis revealed that clay acted as a compatibilizer and then reduced the size of droplets in the PCL domain of the PLA matrix. As a result, nonlinear properties sensitively reflect morphological changes with increasing MMT amount. The nonlinear rheological properties of PLA/
PCL/MMT/metallocene-LLDPE (mLLDPE) were also investigated when mLLDPE was used as an impact modifier to improve mechanical properties, and the nonlinear rheological properties of PLA/PCL/MMT and PLA/PCL/MMT/mLLDPE were also compared.
Korean Journal of Chemical Engineering, Vol.30, No.6, 1229-1234, 2013
Esterification of sludge palm oil using trifluoromethanesulfonic acid for preparation of biodiesel fuel
Adeeb Hayyan, Mohd Ali Hashim, Mohamed Elwathig Saeed Mirghani, Maan Hayyan, and Inas Muen AlNashef
Abstract - Trifluoromethanesulfonic acid (TFMSA) was used to reduce the high free fatty acids (FFA) content in sludge palm oil (SPO). The FFA content of SPO was converted to fatty acid methyl ester (FAME) via esterification reaction. The treated sludge palm oil was used as a raw material for biodiesel production by transesterification process. Several working parameters were optimized, such as dosage of catalyst, molar ratio, reaction temperature and time. Less than 2% of the FFA content was the targeted value. The results showed that the FFA content of SPO was reduced from 16% to less than 2%
using the optimum conditions. The yield of the final product after the alkaline transesterification was 84% with 0.07% FFA and the ester content was 96.7%. All other properties met the international standard specifications for biodiesel quality such as EN 14214 and ASTM D6751.
Korean Journal of Chemical Engineering, Vol.30, No.6, 1171-1180, 2013
Improvement in CO
2absorption and reduction of absorbent loss in aqueous NH
3/triethanolamine/2-amino-2-methyl-1-propanol blends
Min-Kyoung Kang, Soo-Bin Jeon, Min-Ho Lee, and Kwang-Joong Oh
Abstract - Changes in the CO
2absorption rates and capacities of the absorbent 2-amino-2-methyl-1-propanol (AMP),
blended with NH
3and other additives, were investigated toward performance improvement. The NH
3-blended absorbent
removed CO
2more efficiently than the AMP absorbent alone. However, absorbent loss through NH
3evaporation was
observed under these conditions. A second absorbent, the tertiary amine triethanolamine (TEA), which has a low vapor
pressure, was selected and blended with the NH
3/AMP system to reduce NH
3evaporation. Its effects on NH
3loss and the
absorption rate and capacity of the NH3/AMP system were investigated, and the optimum blending ratios were determined.
NEWS & INFORMATION FOR CHEMICAL ENGINEERS, Vol. 31, No. 2, 2013 … 421 In addition, the absorbent blend at the optimum blending ratio was compared to AMP alone and the commercially available absorbent monoethanolamine at the same weight ratio. The thermal stabilities of the absorbents,
under conditions used in the CO
2absorption process, were compared by thermogravimetric analysis.
Korean Chemical Engineering Research, Vol.51, No.2, 171-180, 2013
금속유기구조체를 이용한 이산화탄소 흡착 연구
CO
2Adsorption in Metal-organic Frameworks
김
김 준 준, 김 김희 희영 영, 안 안화 화승 승
Abstract - 금속유기구조체(metal-organic frameworks, MOF)는 넓은 비표면적, 규칙적인 구조 및 높게 분산된 금 속 성분 등 뛰어난 물리화학적 특성으로 인해 활발한 연구가 이뤄지고 있는 다공성 물질이며, 특히 가스의 흡 착, 분리 매체로서 뛰어난 성능이 보고되고 있다. MOF를 이용한 온실가스 이산화탄소의 흡착 연구는 상온 고 압 영역에서 이산화탄소 저장공정과 상온 저압 영역에서 이산화탄소 흡착 공정의 두 범주로 나눌 수 있으며, MOF 의 넓은 비표면적 외에도 (1) MOF의 빈 배위결합 자리, (2) MOF의 기능화, (3) MOF의 상호 침투 효과, 및 (4) 이온 교환 효과를 이용한 연구 결과가 보고되고 있다. MOF 물질들은 비교적 낮은 수분 및 열에 대한 안정성 이 문제로 제기되고 있으며, 제올라이트 유사 구조체(zeolitic imidazolate frameworks, ZIF) 또는 유기 골격 구조체 (covalent organic frameworks, COF) 물질의 이산화탄소 흡착 특성이 거론되고 있다. 본 소고에서는 MOF를 이용 한 이산화탄소 흡착에 대한 최근의 연구 결과를 본 연구실의 실험 결과를 중심으로 간략히 소개하고자 한다.
Korean Chemical Engineering Research, Vol.51, No.2, 221-225, 2013
화학공정 산업에서의 지속가능성과 공정시스템 공학
