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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Energy Engineering
Journal Basic Information
Journal DOI :
The Korea Society for Energy Engineering
Editor in Chief :
Volume & Issues
Volume 13, Issue 4 - Nov 2004
Volume 13, Issue 3 - Sep 2004
Volume 13, Issue 2 - Jun 2004
Volume 13, Issue 1 - Feb 2004
Selecting the target year
Hydrogen Production by Gasification Technologies
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 1~11
Gasification is the essential technology that can meet the interim hydrogen demand of large quantity before entering the hydrogen economy. Although the hydrogen production that is based upon the pure renewable energy like wind and solar power will eventually prevail, the interim mass production of hydrogen for the next ten to twenty years will come from the technologies that can demonstrate the economic feasibility in production cost with a high potential in minimizing CO
generation and in improving plant efficiency. Particularly, feedstock such as natural gas, coal, petroleum residual oil, wastes, and biomass appears to be utilized in Korea as hydrogen source, at least during the short and medium period of time, owing to the advantage in production cost. Because one of the main reasons behind the recent hydrogen issue is the reduction requirement of CO
that would be controlled according to the climate change protocol, hydrogen production technologies must be developed to yield the minimal CO
Effects of Contact Resistance on temperature Rise in a MCCB
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 12~19
A Molded Case Circuit Breaker (MCCB) is an electric control device to interrupt the abnormal currents which result from the over-loads or short-circuits. Its malfunction will result in severe accidents. In the development of the MCCB, higher current-rating and improved thermal performance become more and more important in providing the safe function and reliability for the modern devices requiring small scale and high performance. It is also very important to consider the factors of temperature rise in the design of MCCB. The major reasons of temperature rise in the MCCB result from the resistances, which are come from the connection and contact surfaces. These resistances are influenced by current, time, configuration of contact surfaces and applied voltage. In order to predict the temperature distribution inside MCCB, we have simulated the model with some assumptions and simplifications, using commercial code ICEPAK. To verify the results of temperature field analysis, the numerical results are compared with experimental ones for the same model. The results show a good agreement with actual temperature rise obtained by experiments.
The Effect of Low Boiling Point Oxygenates on the Diesel Engine Performance and Emissions
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 20~27
In the study, the effect of low boiling point oxygenates in high viscous fuels on the exhaust emissions has been investigated for a single cylinder DI diesel engine. It was tested to estimated change of engine performance and exhaust emission characteristics for the base fuels and low boiling point oxygenates blended fuel which have six kinds of fuels and various mixed rates. The results of the study may be con eluded as follows By blending of various low boiling point oxygenated agents to lower grade fuels, significant improvements were simultaneously obtained in smoke, CO, PM, SOF and BSEC. Especially, these trends were remarkably obtained by retarding injection timing, by decreasing boiling point and increasing blending contents of additives in case of oxygenated agents rather than non-oxygenated agents. Also, it was revealed that when 20 vol.％ DMM added to high viscosity fuels and injection timing was retarded, Nox-smoke trade off relationship was much better than that of ordinary diesel fuel. Thus, lower grade fuels with high viscosity could be expected to be used efficiently and cleanly in diesel operation by blending low boiling point oxygenates.
Heat Transfer Enhancement by Trapezoid Rods in Impinging Jet System
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 28~33
The objective of the study was to investigate the characteristics of heat transfer and flow in 2-dimensional impinging air jet system, in which trapezoid rods have been set up in front of impinging plate in order to increase heat transfer. Experiments were carried out first using without the rods to establish the baseline heat transfer performance. And this result compared with the experimentation with rods. When rods are installed in front of the impinging plate, the acceleration of the flow and the eddies due to the rods seem to contribute to the heat transfer enhancement. Heat transfer performance was best under the condition of C=1 n and as the pitch is 30 mm. In this case, maximum rate of heat transfer augmentation is about 1.62 times greater compared to that without trapezoid rods.
An Experimental Study on the Energy Separation in the Ratio of Nozzle Area of a tow Pressure Vortex Tube
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 34~39
The process of energy separation in a low pressure vortex tube with compressed air as a working medium is studied in detail. Experimental data of the temperature of the cold and hot air leaving the vortex tube are presented. The variation of the maximum wall temperature along the inner surface of a vortex tube and the temperature distribution in a vortex tube provide useful information about the location of the stagnation point of the flow field at the axis of the vortex tube Analysis of the results enabled to find the optimum ratio of nozzle area and the optimum shape of an orifice. From this optimum geometric setup of a low pressure and big vortex tube the effectiveness of energy separation was better than a high pressure and small vortex tube.
Investigation Analysis for Transfer & induction of Energy Conservation Technology
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 40~50
Treatise that see executed investigation analysis about energy conservation technology, which skill move and skill class of introduction subject, transferㆍintroduction skill form, present condition of technology transferㆍintroduction and necessity etc. to energy conservation technology by program of Korea energy basis plan (1997∼2006) etc. Enforced company which questionnaire object achieves from the end 107 assignment practical used of energy conservation technology development propulsion assignment of Korea energy management corporation (KEMCO) to 1998-200 years and 416 companies related energy saving technology constructed to Korea Institute of Energy Research (KIER) database by post investigation and visit investigation. Question investigation result, transferㆍintroduction fields of energy conservation technology are industry sector, the enterprise size appeared with the fact that the small and medium enteifrise is many most. Also, technology transferㆍintroduction section is plan technique, form with technical cooperative form, amount of money 50,000,000 won under, appeared above 1 years in disturbance duration. In hereafter, technology transferㆍintroduction plan it appeared with the fact that the plan technique is many most.
Development of Backup Calculation System for a Nuclear Steam Supply System Thermal-Hydraulic Model ARTS (Advanced Real-time Thermal Hydraulic Simulation) of the W/H Type NPP
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 51~59
The NSSS (Nuclear Steam Supply System) thermal-hydraulic programs adopted in the domestic full-scope power plant simulators were provided in early 1980s by foreign vendors. Because of limited compulsational capability at that time, they usually used very simplified physical models for a real-time simulation of NSSS thermal-hydraulic transients, which entails inaccurate results and, thus, the possibility of so-called "negative training", especially for complicated two-phase flows in the reactor coolant system. In resolve the problem, KEPRI developed a realistic NSSS T/H program ARTS which was based on the RETRAN-3D code for the improvement of the Nuclear Power Plant full-scope simulator. The ARTS (based on the RETRAN-3D code) guarantees the real-time calculations of almost all transients and ensures the robustness of simulations. However, there is some possibility of failing to calculate in the case of large break loss of coolant accident (LBLOCA) and low-pressure low-flow transient. In this case, the backup calculation system cover automatically the ARTS. The backup calculation system was expected to provide substantially more accurate predictions in the analysis of the system transients involving LBLOCA. The results were reasonable in terms of accuracy, real-time simulation, robustness and education of operators, complying with FSAR and the AMSI/ANS-3.5-1998 simulator software performance criteria.
The On-Line Application Algorithm of SCOPE Using Time-varying Sensitivities
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 60~67
The recent movement to deregulated and competitive electricity market reacquires new concepts against existing central dispatch in the system operation and pinning. As power systems tend to be operated more closely to their ultimate ratings, the role of SCOPF (Security Constrained Optimal Power flow) is changed and the importance for real-time security inhancement will be more increased i]1 the new and com partitive electricity market. This paper deals with the application of the SCOPF which makes possible the On-Line application. The security margin of power system truly is changed according to the conditions or configuration of power systems, therefore, the sensitivity factor reiated to the security is recalculated and the application should be updated in accordance with the state of power system. The goal of this paper is to obtain proper security through the effluent usage of the sensitivity and to apply this a1gorithm to system operation. The proposed mechanism has been tested on a sample system and the results show more secure conditions against critical contingencies.
Design of LQR Controller of DSIATCOM for Compensating Voltage Sag Using PSCAD/EMTDC
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 68~74
This paper presents the design of DSTATCOM (Distribution Static Synchronous Compensator) controller. The results are verified by using PSCAD/EMTDC package. The state equation derived by decomposition analysis of DSTATCOM current component is applied to load model and the combined model which considered constraint condition. In case of single line to ground fault, the conventional method of Pl control is compared with LQR control technique. LQR control is shown to be superior in terms of response profile and composition of voltage sag.
The Study on Attrition Resistance of ZnO/natural-zeolite/Fe
Desulfurization Sorbents with CaO for Hot Gas Clean-up
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 75~81
ZZFCa sorbents for hot gas desulfurization in IGCC were prepared by adding calcium oxide to ZZF sorbent in order to improve its attrition resistance in this study. ASTM attrition test for the sorbent was performed at several different weight percentages of CaO to investigate the attrition characteristics of ZBFCa sorbents as a function of CaO content. Attrition index of ZZF without CaO was 28.3% and its collected attrition index was 10.8％. ZZFCa-3 containing 3 wt% CaO showed the lowest attrition index (AI=17.3％, CAI=8.8％) in the test. From the results of SEM morphologies and particle size distribution measurements, ZZFCa-3 maintained a fine shape and a desirable average particle size even after attrition test. In the experiments of sulfidation/regeneration for ZZFCa-3 sorbent concentration of hydrogen sulfide in coal gas was lowered from 10000 ppm to below 1 ppm. Sulfur removing capacity was about 28.8 g S/100 g sorbent. Neither formation of CaSO
was observed in XRD measurement nor SO
slippage was observed during sulfidation process.
Recyclability Analysis of Slags Obtained at Gasification and Incineration-Melting Conditions
Journal of Energy Engineering, volume 13, issue 1, 2004, Pages 82~91
In order to utilize inorganic components in coal and wastewater sludge as an environmentally stable material, slag-forming is considered as one of the suitable methods better than producing as an ash. Coal slag that was produced by gasification as well as the slag made from wastewater sludge by incineration or melting process have been analyzed with the viewpoint of recyclability. Slags produced by water quenching exhibited a cracked shape that has a size of few millimeters with sharp edges. Slags contain the unburned carbon content below 0.15％ and expose mostly amorphous structural characteristics. Analysis results in the extraction of heavy metal compounds demonstrate that both slags from coal and wastewater sludge could be utilized as a safe recycle material even with a Japanese environmental regulation that is ten times more stringent than the current Korean standard. Slags from coal and wastewater sludge show significant differences in contents of each heavy metal compound. Since the future trend of environmental regulation shifts to the control of total content for each heavy metal compound, proper mixing of slags that contain different heavy metal contents might be an option for manufacturing recycle materials.