• Journal of Mechanical Science and Technology
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• v.16 no.8
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• pp.1127-1134
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• 2002

The effects of pressure and temperature on the autoignition of propane and n-butane blends were investigated using a rapid compression machine (RCM) , which is widely used to examine the autoignition characteristics. The RCM was designed to be capable of varying the compression ratio between 5 and 20 and minimize the vortex formation on the cylinder wall using a wedge-shaped crevice. The initial temperature and pressure of the compressed gas were varied in range of 720∼900 K and 1.6∼ 1.8 MPa, respectively, by adjusting the ratio of the specific heat of the mixture by altering the ratio of the non-reactive components (N$_2$, Ar) under a constant effective equivalence ratio (ø$\_$f/= 1.0) The gas temperature after the compression stroke could be obtained from the measured time-pressure record. The results showed a two-stage ignition delay and a Negative Temperature Coefficient (NTC) behavior which were the unique characteristic of the alkane series fuels. As the propane concentration in the blend were increased from 20% and 40% propane, the autoignition delay time increased by approximately 41 % and 55% at 750 K. Numerical reduced kinetic modeling was performed using the Shell model, which introduced some important chemical ideas, represented by the generic species. Several rate coefficients were calibrated based on the experimental results to establish an autoignition model of the propane and n-butane blends. These coefficients can be used to predict the autoignition characteristics in LPG fueled Sl engines.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.328-333
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• 2012

In this study, CFD simulation was performed with commercial CFD code FLUENT for the 3D mixing tank model (1 m in a diameter and 2.5 m in a height) of DME-Propane liquified fuels. Initial condition set-up with existence of DME 146 l at the upper side of mixing tank and Propane 770 l at the lower side of mixing tank. Characteristics of mixture and fluid flow were observed for 34 hours simulation. Two liquid fuel were uniformly mixed within range of 3 mol% after 24 hours, and range of 1 mol% after 34 hours. The simulation result following 4 hours was verified with KOGAS experimental data.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.464-470
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• 2012

To study characteristics of DME and Propane blended fuel in mixing drum as time passed, mixing experiment of two components was performed. After 20 wt% of DME and 80 wt% of Propane were injected into mixing drum sequentially, and the mixture ratio of blended fuel was analyzed at several sampling ports. Consequently, DME and Propane were not easily mixed and DME was sunk to the bottom of the mixing drum by the density difference. The daily rate of DME ingredient increase was 0.2-0.3 wt%, and it took over 500 hours until two of them were mixed uniformly. And after recirculation of blended fuel in mixing drum, DME and Propane were mixed immediately and uniformly.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.146-149
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• 2014

Compared to Butane tank, the propane tank should have a higher compressive strength due to its higher vapor pressure. In this study, a theoretical analysis was performed to evaluate the effect of change in the geometry of bottom plate on the mechanical property of tank, and an experiment was also carried out to observe the propensity of the deformation and failure of the vessel using hydraulic pressurizing device. The compressive strength of the vessel was observed to improve 1.5-2.5 MPa as the curvature of the bottom plate was decreased 62 mm and the thickness of the bottom plate was increased 0.25 mm. This study are expected to provide viable information conducive to achieve on-going development of a small vessel for the pressurized propane gas.

• Membrane Journal
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• v.30 no.6
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• pp.450-459
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• 2020

Membrane-based separations have the potential to reduce energy consumption and environmental impact associated with conventional processes. However, many researches have been done to develop new membrane materials with greater selectivity and permeability. Here, we report highly selective membranes by introducing bulky ethyl substituents into the polyimide. The ethyl group in the ortho position to the imide nitrogen interferes the chain packing and increases chain stiffness and the distance between the polymer chains. The polyimide membranes were synthesized from various aromatic dianhydrides and 4,4'-methylenebis(2,6-diethylaniline) (MDEA). The synthesized membranes with increased gas diffusion length due to bulky substituents showed improved propylene/propane (C3H6/C3H8) selectivity. Single gas permeation showed high C3H6/C3H8 selectivity of 14.5, and C3H6 permeability of 7.0 barrer was found in MDEA-polyimide. Mixed-gas permeation results also demonstrate that MDEA-polyimide can achieve high selectivity in mixed-gas environment. Furthermore, this approach could significantly increase the feasibility of economic propylene separation compared to conventional polymer materials.

• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.126-132
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• 2008

Cutting procedures whose qualifies are determined by various variables largely influences shipbuilding productivity. Particularly, defects in cutting shapes and cutting surface results in delay of the post shipbuilding stages such as welding and assemblage process. Because cutting procedures are influenced by various numbers of requirements according to the plate thickness, cutting precision can be maintained when the cutting conditions are appropriate. Existing cutting procedures utilize fossil fuels such as propane or ethylene as the main fuel component. Especially, when fossil fuel is applied to thick plate cutting, this process gives relatively slow cutting speed and generates large quantities of harmful polluting fumes. Recently, hydrogen-oxygen mixed gas generated by electrically dissociating water into Hydrogen and oxygen components is welcomed as an alternative fuel source. Also recent results report that alternative cutting fuel improves the cutting Dualities and speed. This paper presents that cutting characteristics and optimum cutting condition of hydrogen-oxygen mixed gas.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1285-1288
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• 1993

We tried gas identification by using one semiconductive gas sensor. As a method of gas identification, we used the fuzzy reasoning with fuzzy set of slope of gas pattern which is divided into arbitary interval. As a result, we got a good successful rate for hydrogen 66.6%, propane 79.1%, butane 100%, methane 100%, city gas 79.1% and alcohol 91.6%, respectively.

• Fire Science and Engineering
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• v.29 no.5
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• pp.42-50
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• 2015

Three simulation approaches for turbulence were applied for the computation of propane dispersion in a simplified real-scale urban area with one building:, Large Eddy Simulation (LES), Detached Eddy Simulation (DES), and Unsteady Reynolds Averaged Navier-Stokes (RANS). The computations were performed using FLUENT 14, and the grid system was made with ICEM-CFD. The propane distribution depended on the prediction performance of the three simulation approaches for the eddy structure around the building. LES and DES showed relatively similar results for the eddy structure and propane distribution, while the RANS prediction of the propane distribution was unrealistic. RANS was found to be inappropriate for computation of the gas dispersion process due to poor prediction performance for the unsteady turbulence. Considering the computational results and cost, DES is believed to be the optimal choice for computation of the gas dispersion in a real-scale space.

• Membrane Journal
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• v.24 no.5
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• pp.409-415
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• 2014

This study is aimed to separate propylene and propane using membrane process instead of NCC(Naphtha Cracking Center) $C_3$ splitter. Membrane process is a low energy consumption and eco-friendly process while $C_3$ splitter requires high energy consumption in petrochemical processes. In this study, high performance facilitated transport membrane (FTM) is used for propylene/propane separation. FTM module was prepared on top of porous polyetherimide hollow fiber using PVP/$AgBF_4$/TCNQ. We developed simulation program predicting the membrane separation properties under operation conditions. Separation properties of FTM module for propylene and propane were obtained from the simulation program based on the pure gas permeation data. Based on these results, it is predicted that an one-stage membrane process provides 99.5% of propylene at permeate side from a binary gas mixture of 95/5 vol% $C_3H_6$ / vol% $C_3H_8$ supplied as a feed gas.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.890-893
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• 2012

Gas hydrates are solid crystal structures formed by enclathration of gaseous guest species into 3-dimensional lattice structure of hydrogen-bonded water molecules. These compounds can be potentially used as an energy storage/transportation medium because they can hold a large amount of gas in a small volume of the solid phase. In addition, huge amount of natural gas, buried in seabeds or permafrost region in the form of the solid hydrate, is regarded as a future energy source. In this study, synthesized natural gas, whose composition is 90.0 mol% of methane, 7.0 mol% of ethane, and 3.0 mol% of propane, was used to identify formation behaviors of natural gas hydrates for the purpose of applying the gas hydrate to a storage/transportation medium of natural gas. According to the experimental results obtained by means of the solid-state NMR and high-resolution powder XRD methods, it is found that formed natural gas hydrates have crystal structure of the structure-II hydrate, and that methane occupies both small and large cages, while the others only occupy large ones. In addition, both the NMR spectroscopy and the gas chromatograph showed that there exists preferential occupation among the natural gas components during the hydrate formation. Compositional changes after the hydrate formation revealed that the preferential occupation is in order of propane, ethane, and methane (propane is the most preferential guest species when forming natural gas hydrates).