• Journal of Korean Society of Environmental Engineers
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• v.34 no.10
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• pp.671-677
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• 2012

In this study, the characteristics of emulsified fuel and engine emissions were studied with an engine dynamometer. In the results of physical property analysis, the margin of error of net calorific value and gross calorific value was ${\pm}0.5%$, were almost same theoretical calculation and results of physical property analysis test. In emulsified fuel, density and viscosity increased with increasing water contents. Emulsified fuel which is composed of water and Bunker-A was manufactured by using homogenizer and ultrasonic generator in $80^{\circ}C$. Phase separation did not take place in $20^{\circ}C$ and $50^{\circ}C$. In the results of engine dynamometer test, NOx concentration and smoke density were reduced with increasing water contents in using emulsified fuel. Total NOx could be reduced by about 41%, 10%, 32% and 28% at 1,000 rpm, 1,200 rpm, 1,500 rpm and 2,500 rpm respectively. Total smoke density was reduced to 42%, 65%, 70%, 62%, and 82% at 1,000 rpm, 1,200 rpm, 1,500 rpm, 2,000 rpm, and 2,500 rpm respectively.

• Journal of the Korean Institute of Gas
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• v.24 no.5
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• pp.56-64
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• 2020

This study presents the hydrate induction time of PVCap according to subcooling temperature, salt concentration, and MEG concentration in order to analyze the inhibition effect of PVCap in various production environments of offshore gas fields. A high-pressure hydrate generator was made for the hydrate formation experiments. It was verified that the apparatus had sufficient reliability by comparing the results of hydrate equilibrium conditions and induction time from the apparatus with published reference data. As the subcooling temperature increased from 6.1℃ to 12.1℃, the induction time of PVCap concentration of 0.1~1 wt% decreased. When the salt concentration increased from 3 wt% to 7 wt%, the induction time was reduced by up to 78% under the condition of 0.5 wt% PVCap due to polymer structure degradation by salt effect. In the case of HHI (hybrid hydrate inhibitor) made by mixing MEG 10 wt% and PVCap, the change in induction time was not large compared to PVCap 1 wt% due to the under-inhibition effect. On the other hand, the hydrate inhibition efficiency of HHI with MEG 20wt% increased 1.7 times compared to PVCap.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.11
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• pp.1757-1763
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• 2010

Flywheel energy storage system (FESS) is defined as a high speed rotating flywheel system that can save surplus electric power. The FESS is proposed as an efficient energy storage system because it can accumulate a large amount of energy when it is operated at a high rotating speed and no mechanical problems are encountered. The FESS consists of a shaft, flywheel, motor/generator, bearings, and case. It is difficult to simulate rotor dynamics using common structure simulation programs because these programs are based on the 3D model and complex input rotating conditions. Therefore, in this paper, a program for the FESS based on the 2D FEM was developed. The 2D FEM can model easier than 3D, and it can present the multi-layer rotor with different material each other. Stiffness changing of the shaft caused by shrink fitting of the hub can be inputted to get clear solving results. The results obtained using the program were compared with those obtained using the common programs to determine any errors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1103-1109
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• 2021

ECS is a control device so that the warship can perform the mission stably by controlling and monitoring the entire propulsion system. As the recent provisions of the warship, it's propelling system is complicated than past, as the demand performance and mission of the warships are diverse. In accordance with the complicated propulsion system configuration, the demand for automatic control function of the ECS is increasing for convenient and stable propulsion system control for convenient and stable. As a result, verification of ECS stability and reliability is required. In this paper, we develop an interlocking signal simulator for verifying ECS control logic and communication protocol for warship with CODLOG propulsion systems. The simulator developed was implemented to simulate a signal of gas turbine, propulsion motors, diesel generator and 11 kinds of auxiliary equipment. The reliability of ECS was verified through the ECS communication program and the I/O signal static test with the simulator.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1209-1215
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• 2022

The selective catalytic reduction (SCR) is known as a very efficient method to reduce nitrogen oxides (NOx) and the catalyst performs reduction from nitrogen oxides (NOx) to nitrogen (N₂) and water vapor (H2O). The catalyst, which is one of the factors determining the performance of the nitrogen oxide (NOx) ruduction method, is known to increase catalyst efficiency as cell density increases. In this study, the reduction characteristics of nitrogen oxides (NOx) under various engine loads investigated. A 100CPSI(60Cell) catalysts was studied through a laboratory-sized simulating device that can simulate the exhaust gas conditions from the power generation engine installed in the training ship SEGERO. The effect of 100CPSI(60Cell) cell density was compared with that of 25.8CPSI(30Cell) cell density that already had NOx reduction data from the SCR manufacturing. The experimental catalysts were honeycomb type and its compositions and materials of V₂O₅-WO₃-TiO₂ were retained, with only change on cell density. As a result, the NOx concentration reduction rate from 100CPSI(60Cell) catalyst was 88.5%, and IMO specific NOx emission was 0.99g/kwh satisfying the IMO Tier III NOx emission requirement. The NOx concentration reduction rate from 25.8CPSI(30Cell) was 78%, and IMO specific NOx emission was 2.00g/kwh. Comparing the NOx concentration reduction rate and emission of 100CPSI(60Cell) and 25.8CPSI(30Cell) catalysts, notably, the NOx concentration reduction rate of 100CPSI(60Cell) catalyst was 10.5% higher and its IMO specific NOx emission was about twice less than that of the 25.8CPSI(30Cell) catalysts. Therefore, an efficient NOx reduction effect can be expected by increasing the cell density of catalysts. In other words, effects to production cost reduction, efficient arrangement of engine room and cargo space can be estimated from the reduced catalyst volume.