• 공업화학
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• 제19권1호
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• pp.59-65
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• 2008

비이온 계면활성제 $C_{12}E_8$ 마이셀에 의한 이성분 탄화수소 오일 혼합물 시스템의 가용화도(equilibrium solubilization capacity)를 $23^{\circ}C$에서 기체 크로마토그래피(GC)를 이용하여 측정하였다. 단일 성분의 탄화수소 오일 가용화도는 탄화수소 오일의 탄소수(ACN)가 증가함에 따라 거의 선형적으로 감소하였다. 한편 탄화수소 오일의 이성분 시스템은 사용한 두 탄화수소 오일의 탄소수(alkane carbon number, ACN) 차이에 따라 선택적 가용화 혹은 비선택적 가용화 경향을 나타내었다. 본 연구에서 가용화도 실험을 수행한 n-octane/n-nonane, n-nonane/n-decane과 n-decane/n-undecane 혼합물 시스템과 같이 이성분 탄화수소 혼합물의 탄소수 차이가 1인 경우에는 비선택적(non-selective) 가용화 경향을 나타내었다. 반면에 n-octane/n-decane과 n-octane/n-undecane 혼합물 시스템과 같이 탄소수 차이가 1보다 큰 경우에는 선택적(selective) 가용화 경향을 나타내었다.

• 한국환경과학회지
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• 제11권4호
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• pp.375-382
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• 2002

The total hydrocarbon distribution of oil products obtained from the pyrolysis of four kinds of mixtures of polyethylene-polystyrene waste has been studied by multidimensional chromatography(high performance liquid chromatography followed by capillary gas chromatography)/mass spectrometry. Saturated, unsaturated and aromatic hydrocarbons in oil products were selectively pre-separated according to structural groups by HPLC and the weight fraction of each group was estimated by analysis of each component using GC-FID response factors. The hydrocarbon distribution of aliphatic fraction consists of $C_{5}$ to $C_{25}$ saturated and unsaturated hydrocarbons. And that of aromatics fraction consists of benzene, toluene, xylene, styrene, propenyl benzene, naphthalene, and some of derivatives. Pyrolysis temperature did not affect the ratio of total weight fraction of aliphatic over aromatic hydrocarbon distribution in case of PS only and PE-PS mixtures (1:1 and 1:4 wt. ratio) as a feed while affected the ratio of total wt. fraction in case of PE only. The optimal temperature for the maximum oil production was $600^{\circ}C$ for pyrolysis of PS and 1:1 and 1:4 mixtures of PE and PS. The optimal condition for aromatic recovery was $600^{\circ}C$ with 1:1 mixture of PE and PS. In this condition, aromatic was produced up to 90% of total oil product. The maximum yield of toluene, xylene, styrene, and propenyl benzene were 8.6, 8.9, 51.0 and 7.4% of feed for pyrolysis PS at $700^{\circ}C$, respectively. However, only 1.3% naphthalene was recovered at $700^{\circ}C$ with 1:1 PE:PS(by wt.).

• 공업화학
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• 제8권3호
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• pp.357-364
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• 1997

본 연구에서는 비이온성 계면활성제를 사용하여 오염 토양 내의 탄화수소 유기물을 정화하는 데 있어서 필수적인 최적의 비이온성 계면활성제에 대한 조건을 도출하고자 하였다. 이를 위하여 비이온성 계면활성제, 물, 탄화수소로 이루어진 3성분계에 대하여 특정 탄화수소 유기물이 계면활성제에 의하여 최대로 가용화될 수 있는 조건을 계면활성제 친수성 기의 변화에 따라 측정하고 비이온성 계면활성제 용액과 탄화수소 사이의 계면장력을 측정하였다. 이런 결과들을 바탕으로 실제 회분식 sur-factant washing 실험을 수행한 결과 탄화수소의 유기물은 PIT(Phase Inversion Temperature)에서 생성되는 middle-phase microemulsion에 최대로 가용화될 수 있었으며, 비이온성 계면활성제 $C_{12}E_5(C_{12}H_{25}O(CH_2CH_2O)_5H)$를 사용했을 경우 $C_{12}E_5$, 물, n-hexadecane으로 이루어진 3성분 계의 PIT에 해당하는 $52^{\circ}C$에서 n-hexadecane이 73.4% 제거되었으며, 반면에 PIT보다 낮은 $25^{\circ}C$와 PIT보다 높은 $60^{\circ}C$에서의 n-hexadecane 제거율은 각각 57.1%, 57.0%를 나타내었다. 이와 같이 PIT조건에서 n-hexadecane이 최대로 가용화되는 것은 계의 소수성-친수성이 균형을 이룸으로 인하여 유기물이 가용화되는 속도가 매우 빠를 뿐 아니라 middle-phase microemulsion과 excess oil phase 사이에 존재하는 $10^{-2}{\sim}10^{-3}dyne/cm$의 매우 낮은 계면장력때문인 것을 알 수 있었다.

• 한국자동차공학회논문집
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• 제8권2호
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• pp.57-63
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• 2000

This paper deals with a study on combustion and emission characteristics of a direct injection diesel engine dual fueled with natural gas. Dual fuelling systems tend to emit high unburned fuel especially at low load, resulting in a decreased thermal efficiency. This is because natural gas-air mixtures are too lean for flame to propagate under low load conditions. Suction air quantity and injection timing controls are very useful to improve emissions and thermal efficiency at low load.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권1호
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• pp.17-23
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• 2019

Clean soil environment is of crucial importance to sustain lives of ecosystem and humans. With rapid industrialization, there has been a great increase of soil contamination by accidental releases of petroleum products. In general, soil remediation is an expensive and time-consuming process as compared to cleanup of water and air. Moreover, determining the source and responsible parties of soil pollution often turns into legal conflicts and that further delay the cleanup process of contaminated sites. In practice, total petroleum hydrocarbon (TPH) analysis has been employed to determine the petroleum species and to track down the responsible polluters. However, this approach often suffers from differentiating similar TPH species. In this study, we analyzed TPH chromatogram patterns of 24 domestic petroleum products in specific carbon ranges (${\sim}C_{10}$, $C_{10}-C_{12}$, $C_{12}-C_{36}$, and $C_{36}{\sim}$) and the fractional changes of THP ratio in the mixture products of gasoline, kerosene and diesel. The proposed TPH analysis method in this study could serve as a useful tool to better analyze the petroleum species in soils contaminated with complex oil mixtures, and ultimately be used to identify the polluters of soil.

• Korea-Australia Rheology Journal
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• 제17권3호
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• pp.125-130
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• 2005

Coalescence process of binary immiscible fluid mixtures having bimodal size distributions, prepared by mixing two pre-sheared samples at different shear rates, ${\gamma}_{pre1}\;and\;{\gamma}_{pre2}$, under shear flow at a final shear rate, ${\gamma}_f$, are examined by transient shear stress measurements and microscopic observations in comparison with the results for simply pre-sheared samples having narrow size distributions (unimodal distribution samples). Component fluids are a silicone oil (PDMS) and a hydrocarbon-formaldehyde resin (Genelite) and their viscosities are 14.1 and 21.0 $pa{\cdot}sec$ at room temperature $(ca.\;20^{\circ}C)$, respectively. The weight ratio of PDMS: Genelite was 7:3. Three cases, $({\gamma}_{pre1}=7.2sec^{-1},\;{\gamma}_{pre2}=12.0sec^{-1}\;and\;{\gamma}_f=2.4sec^{-1}),\;({\gamma}_{pre1}=0.8sec^{-1},\;{\gamma}_{pre2}=4.0sec^{-1}\;and\;{\gamma}_f=2.4sec^{-1}),\;and\;({\gamma}_{pre1}=7.2sec^{-1},\;{\gamma}_{pre2}=12.0^sec^{-1}\;and\;{\gamma}_f=7.2sec^{-1})$ the first case, transient shear stress did not show any significant difference but domains larger than the initial state are observed at short times. In the latter cases, there exist undershoot of shear stress, reflecting existence of deformed large domains, which is confirmed by the direct observation. It is concluded that coalescence between large and small domains more frequently occur than coalescence between the domains with similar size in the bimodal distribution samples.