• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.526-530
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• 2004

The portion of plant industry has increased within construction market. In spite of plant industry is dynamic field which leads state-of-the-art and creates a value, phased information management and knowledge intensive business accomplishment are insufficient. Henceforth plant is expected to demand increment of industrial project from hereafter international plant industry market. The continuous plan technique and know-how accumulation are urgent from domestic. 1'his research analyzes the areas in which domestic plant industry is insufficient and then elicits project management key success factors from current operation process. In addition, this research compares domestic plant level with overseas plant level. This study establishes work models for critical work phases based on the analysis of domestic plant technical level.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1038-1040
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• 1992

Booster is used widely as one of the step-up DC/DC power converter in power conversion process for fuel cell power plant which have the electrical characteristic of the high current density and low cell voltage. In view of control system, booster can be unstable when it is operated in broad operation range because the transfer function of booster has zero in right half plane of s-domain. So for reliable operation, controller must make the system stable in whole working range. In this paper, the two control method such as digital PID control and fuzzy control is studied for booster output voltage regulation in fuel cell plant. The design procedure of PID control and fuzzy control is described. And the experiment of designed controller action is performed in various operation points for controller performance test.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.155-160
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• 2005

Gravity thickening process has been widely used in WTP sludge thickening at domestic water treatment plant. The operation method of the process is very simple, however, the process requires long detention time about 24~48 hours for sludge thickening, uses polymer, and low total solids of thickened sludge to increase sludge thickening efficiency. To solve there problems, we studied about flotation process, especially, electro-flotation (EF) process in WTP sludge thickening. Electro-flotation process is simpler than dissolved-air-flotation(DAF) process because EF needs only electrode and current to generate micro-bubbles and the operation is easy. This study was performed at two batch columns to compare interface height, total solids, effluent turbidity between an electro-flotation thickening and a gravity thickening. According to the result, an electro-flotation thickening was that interface height was decreasing, total solids had high concentration, and effluent turbidity was low in comparison with a gravity thickening. Also, it will make the high efficiency of following process, such as a dehydrating process and digestive process. because of high total solids and low moisture content in the sludge.

• Journal of the Korean Society of Safety
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• v.36 no.5
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• pp.79-85
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• 2021

A standard engineering model that reflects the current organization system and engineering operation process of domestic nuclear power plants was developed based on the Standard Nuclear Performance Model developed by the American Nuclear Energy Association. The level 0 screen, which is the main screen of the engineering model computer system, consisted of an object tree structure, which provided information that is phased down from a higher structure level to a lower structure level (i.e., level 3). The level 1 screen provided information related to the sub-process of the engineering operation, whereas the Level 2 screen provided information related to each engineering operation activity. In addition, the Level 2 screen provided additional functions, such as linking electronic procedures/guidelines, providing electronic performance forms, and connecting legacy computer systems (such as total equipment reliability monitoring system, configuration management systems, technical information systems, risk monitoring systems, regulatory information, and electronic drawing system). This screen level increased the convenience of user's engineering tasks by implementing them. The computerization of an engineering model that connects the entire engineering tasks of an establishment enables the easy understanding of information related to the engineering process before and after the operation, and builds a foundation for the enhancement of the work efficiency and employee capacity. In addition, KHNP developed an online training module, which operates as an e-learning process, on the overview and utilization of a standard engineering model to expand the understanding of standard engineering models by plant employees and to secure competitiveness.

• KSBB Journal
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• v.15 no.4
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• pp.346-351
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• 2000

Several solvents or combinations of solvents were tested for the extraction of wet or dried biomass at different extraction mode from plant cell cultures. Methanol gave the highest paclitaxel recovery with the least amount of solvent usage. before extraction drying of biomass wass helpful to decrease solvent usage in extraction step./ in this case drying method was very important to obtain high yield from dried biomass. In thid mode of operation counter-current extraction process can be able to decrease solvent usage but paclitaxel recovery was almost same with both batch and counter-current mode of operation. The number of extraction times was at least four to obtain high yield(>99%) from cell and one to obtain highyield(>96%) from cell debris in batch mode. Equilibrium (i.e. the ratio of paclitaxel in biomass to paclitaxel in the extraction solvent) was reached within 5 minutes. The minimum methodal concentration (90%) and solvent amount(biomass : solvent=1 Kg : 1L) are enough to obtain high yield(>98%) for extraction from biomass.

• Journal of the Korean Society of Safety
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• v.38 no.1
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• pp.25-33
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• 2023

In this study, we determined the failure rate and fire status of electric motors widely used in domestic and industrial devices and analyzed the associated fire risks by identifying the electrical and temperature characteristics of electric motors under the normal and restrained operation modes in industrial sites and laboratories. A 2.2kW motor used for driving a conveyor during the vulcanization process in a rubber product manufacturing plant was employed as the study object and was exposed to a high- temperature environment as this motor is widely used in industrial sites. The current amplitude was 4.45-4.50 A during normal operation and 38.2-41.5 A during restrained operation due to the pinching of products and semi-finished products (i.e., 8.5 times higher than that during normal operation). The leakage current amplitude was 0.33 mA during both operation modes. The temperature of the workplace in summer was 42.38℃, indicating a poor environment for the installed motor. In the laboratory, the current and temperature of the coil inside a 3.7kW motor were measured under the restrained operation mode as performing measurements of the coil inside the motor in industrial sites is challenging. The current amplitude during normal operation was 3.5 A, whereas that during restrained operation for 30 s was 51.7-58.6 A, which is 14.8-16.7 times higher than that of normal operation. Moreover, the temperature of the motor coil increased from 22.9℃ to 101℃. Based on the experimental data, we derived the temperature increase formula according to the restrained operation time by performing a regression analysis and verified the time at which the temperature exceeded the stipulated limit for the insulation grade. The findings presented in this paper can be utilized to establish fire-prevention measures and perform safety management of motors of the same type or with a similar capacity.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.6
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• pp.463-471
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• 2020

A 1,000 ㎥/d DAF(dissolved air flotation) pilot plant was installed to evaluate the performance of the floating process using the Nakdong River. Efficiency of various DAF operations under different conditions, such as hydraulic loading rate, coagulant concentration was evaluated in the current research. The operation conditions were evaluated, based on the removal or turbidity, TOC(total organic carbon), THMFP(trihalomethane formation potential), Mn(manganese), and Al(aluminum). Also, particle size analysis of treated water by DAF was performed to examine the characteristics of particles existing in the treated water. The turbidity removal was higher than 90%, and it could be operated at 0.5 NTU or less, which is suitable for the drinking water quality standard. Turbidity, TOC, and THMFP resulted in stable water quality when replacing the coagulant from alum to PAC(poly aluminum chloride). A 100% removal of Chl-a was recorded during the summer period of the DAF operations. Mn removal was not as effective as where the removal did not satisfy the water quality standards for the majority of the operation period. Hydraulic loading of 10 m/h, and coagulant concentrations of 40 mg/L was determined to be the optimal operating conditions for turbidity and TOC removal. When the coagulant concentration increases, the Al concentration of the DAF treated water also increases, so coagulant injection control is required according to the raw water quality. Particle size distribution results indicated that particles larger than 25 ㎛ showed higher removal rates than smaller particles. The total particel count in the treated water was 2,214.7 counts/ml under the operation conditions of 10 m/h of hydraulic loading rate and coagulant concentrations of 60 mg/L.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.551-556
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• 2004

Coagulation process is one of the most important processes in water treatment procedures for stable and economical operation, and coagulant dosing of this process for most plants is generally determined by the jar test. However, this method does not only take a long time to analyze and get the result but also has difficulties in applying to automatic control. This paper shows the feasibility of applying neural network to control the coagulant dosing automatically in water treatment plant. To be specific, the predicted results of the neural network model is shown to be similar to that of jar test. The input variables for learning the neural network are turbidity, water temperature, pH, and alkalinity. Combining the neural network and SCD(Streaming Current Detector) for feedforward and feedback control of injecting coagulant, a rapid change of the raw water quality can be accommodated.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.1983-1989
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• 2020

The human reliability analysis is a method by which, in general terms, the human impact to the safety and risk of a nuclear power plant operation can be modelled, quantified and analysed. It is an indispensable element of the PSA process within the nuclear industry nowadays. The paper herein presents a sensitivity study of the human reliability analysis performed on a real nuclear power plant-specific probabilistic safety assessment model. The analysis is performed on a pre-selected set of post-initiator operator actions. The purpose of the study is to investigate the impact of these operator actions on the plant risk by altering their corresponding human error probabilities in a wide spectrum. The results direct the fact that the future effort should be focused on maintaining the current human reliability level, i.e. not letting it worsen, rather than improving it.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.5
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• pp.108-115
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• 2000

This paper presents a variant type process planning system for machining of dies for auto-body production. Through the analysis of dies and their manufacturing processes, the authors categorized the press dies into 15 groups according to the similarity of machining features. After critically reviewing current manufacturing procedures, a standard process plan was defined for each group. The authors present MP3D the process planning system built on the standard process plan database, and show how they apply it at the die manufacturing plant of an automobile company. MP3D is expected to reduce major losses in machining such as reworking caused by mistakenly uncut features and eventually to help to accumulate the knowledge of operators. The operation sheet MP3D produces is also used in monitoring the progress of manufacturing of dies. This paper explains the whole development cycle of a process planning system from process analysis to application so that it can help readers to develop and apply a process planning system to their machine shops.