• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.60-67
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• 1995

Ocassionally, many chemical plants experienced unexpected shutdown and suffered serious economic loss caused by boiler accidents due to mis-operations during the start-up or shutdown. A strategy to prevent such accidents is proposed here by using the form of frame for the recognition of all needed conditions, i.e., the states of the boiler, hazardous or dangerous conditions, each level conditions, transition network and heuristic knowledge of human operators. The expert system based on this strategy is considered to be an available method to predict all of the hazardous conditions in boiler plants.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.101-106
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• 2011

In the present paper, the phenomena of abnormal noise and vibration due to acoustic resonance of CFBC(Circulating Fluidized Bed Combustion) boiler was presented. The acoustic resonance which occurred in the gas path of CFBC boiler system was caused by coincidence of vortex shedding frequency of tube bank and acoustic natural frequency of duct and hopper. And, the phenomena of beating arose from the interference of two closed resonant waves at 66.4Hz and 70.8Hz. There are two control methods for acoustic resonance in this system. The first method is to change the vortex shedding frequency from the structural alterations on the tube bank. And the second method is to change the acoustic natural frequency of the gas path with the installation of anti-noise baffles. The second one which is relatively easy to apply, was adapted in this study. As a result, the noise and vibration level have been decreased by 41dB and 94% at 66.4Hz, respectively. And the improvement of noise and vibration at 70.8Hz was identified by sensory evaluation.

• Journal of Electrical Engineering and Technology
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• v.11 no.4
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• pp.848-859
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• 2016

System failures in thermal power plants (TPPs) can lead to serious losses because the equipment is operated under very high pressure and temperature. Therefore, it is indispensable for alarm systems to inform field workers in advance of any abnormal operating conditions in the equipment. In this paper, we propose a clustering-based fault detection method for steam boiler tubes in TPPs. For data clustering, k-means algorithm is employed and the number of clusters are systematically determined by slope statistic. In the clustering-based method, it is assumed that normal data samples are close to the centers of clusters and those of abnormal are far from the centers. After partitioning training samples collected from normal target systems, fault scores (FSs) are assigned to unseen samples according to the distances between the samples and their closest cluster centroids. Alarm signals are generated if the FSs exceed predefined threshold values. The validity of exponentially weighted moving average to reduce false alarms is also investigated. To verify the performance, the proposed method is applied to failure cases due to boiler tube leakage. The experiment results show that the proposed method can detect the abnormal conditions of the target system successfully.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.6
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• pp.55-62
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• 2007

Actual states of energy utilizations were investigated and analyzed on three representative rural villages in Chungcheongnam-Do. Rural residents were almost using the ondol boiler as a heating facility and oil(diesel, kerosene) and electricity(night thermal-storage power service) as a heating energy. There were a few households using briquette or firewood in a fuel hole with Korean hypocaust. Most of their cooking facilities were gas ranges using LPG. The most popular hot-water supply system was an oil boiler and the next was an electricity boiler. The amount of energy use in a rural household generally showed 20,000 to 40,000 won/month of the electric power rate, 400 to 800 liter/year of the oil and 60 to 120 kg/year of the LPG. Prompt measures should be taken to promote the spread of new and renewable energy such as solar heat, biomass and wind power, etc.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.567-571
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• 1989

This paper describes the improvement of thermal power plant turbine control system by analyzing nonlinear characteristics. The turbine control depends on the frequency variation and boiler condition. The nonlinearity of turbine control is the result of governor/valve properties, steam condition and boiler thermal unbalance. Nonlinear analysis is divided into two; main steam valve position - turbine output anal governor response. Of course, every analysis must be done on considering plant operating condition. In this paper, after analyzing turbine control nonlinearity by numerical method and actual results, the sensitive operating load which corresponds to frequency is proposed, on guarranteed boiler stability. This idea is implemented at Pyung Tack thermal power plant, and the practical results are showed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.1
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• pp.1-10
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• 1992

The purpose of this paper is to provide an efficient method of operating and designing HVAC systems for reasonable energy consumption in building. Accroding to the conditions of indoor temperature and humidity, and the methods of dividing and grouping the capacity of boiler and refrigerator, the amount of their annual energy consumptions is simulated by using an energy analysis program which is developed in this paper, and opatimal design methods of HVAC system are suggested as well.

• Journal of the Korean Society of Combustion
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• v.18 no.2
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• pp.23-31
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• 2013

Compact steam boiler is a useful heat exchanger in a space-intensive system. There are some constraints in terms of sizing and designing the space confined in the system which is usually used in vessels. In this study, design considerations for heavy duty heat exchangers of compact steam boilers are presented and evaluated. Especially, evaporator tubes of marine boiler which are exposed to a high temperature environment are considered. Also, extended surface designs with a high temperature are examined. In order to determine the criteria with considerations of both heat transfer rate and pressure drop in the heat exchanger, they are evaluated with major variables, such as the tube diameter, the number of tubes, and the tube length. Finally, the design parameters are estimated as the bare tubes are installed instead of the finned tubes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.23 no.9
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• pp.1085-1097
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• 1999

A separate heat pipe system capacity of 3,700kW has been developed and applied to preheating the blast furnace gas for recovery of the waste heat from boiler. The system is designed to preheat the blast furnace gas up to $126^{\circ}C$ by using tho boiler exhaust gas of which temperature is $180^{\circ}C{\sim}220^{\circ}C$. The arrangement of the fin tubes as well as the shape of the fin has been carefully determined to minimize the fouling problems. The heat pipe system was found to be stable in circulation of the working fluid and the range of the temperature variation of the preheated blast furnace gas was within $10^{\circ}C$. It was proved through a long-term test that the selected tube arrangement and the shape of the fins are proper to prevent the fouling problems and that the pay-back period of the system Is within one year.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.687-692
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• 1991

To reduce the complexity in constructing a fuzzy logic controller of multivariable systems, three major methods are presented. One is the method of constructing single-input-single-output fuzzy logic controllers after decoupling the target system. Another is the method of using fuzzy relation matrices which indicate the relation between each input and output. The other is the method of using the hierarchically classified inputs which dominantly influence one output than other inputs. Using the last two methods, simulation results of fuzzy logic controller implemented on 160MW boiler-turbine plant model are also shown.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.3
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• pp.85-90
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• 2006

The purpose of this research is to design an imitation boiler similar to the waste heat boiler installed on a plasma melting furnace in order to acquire a capability of a thermal design as to the circulation of heat and the discharge of noxious gas inside a boiler and to improve the efficiency of a waste heat boiler using the CFD (Computation Fluid Dynamics) program. The position of corrosion and the generation of a clinker inside a boiler due to temperature changes, combustion gas flows, and corrosive gases inside a boiler are examined to design the structure of an efficient boiler and recycle energy. As a result of this research, the boiler installed on a plasma melting furnace met the conditions of design by cooling the combustion gases discharged after the second combustion from an exhaust port, originally at 1,200 degrees Celsius, down to around 450 degrees Celsius. On the other hand, the circulation of corrosive gases (SOx and HCL) may lead to the generation of corrosion or a clinker in the upper and lower parts of an exhaust port more easily than any other parts of a boiler. Accordingly, the corrosion on the inside and outside walls of a boiler may result in a shortened lifespan of a boiler and an inability to recycle waste heat in an efficient manner. A prevention against corrosion at high and low temperatures needs to be considered in detail.