• Corrosion Science and Technology
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• 제20권5호
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• pp.242-248
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• 2021

Unforeseen failures of boilers in power plants may affect the continuation of electricity generation. Main failures in boilers are influenced by the tube material, tube position, boiler service temperature and pressure, and chemical composition of the feed water and coal. This investigation was intended to find answers on the causes and mechanism of failure of the fire-side boiler water-wall tubes, due to perforation and corrosion. The tube conformed to the material requirements in terms of its chemical composition and hardness. Microscopic examination showed ferrite and pearlite indicating no changes in its microstructure due to the temperature variation. SEM test showed a single layer and homogenous film density particularly on the area far from perforation. However, layers of corrosion product were formed on the nearby perforation area. EDX showed that there were Na, Ca, S, and O elements on the failed surface. XRD indicated the presence of Fe₂O₃ oxide. The failure mechanism was identified as a result of significant localized wall thinning of the boiler water wall-tube due to oxidation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1692-1697
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• 2004

The once-through heat recovery steam generator is ideally matched to very high temperature and pressure, well into the supercritical range. Moreover this type of boiler is structurally simpler than drum type boiler. In drum type boiler, each tube play a well-defined role: water preheating, vaporization, superheating. Empirical equations are available to predict the average heat transfer coefficient for each regime. For once-through heat recovery steam generator, this is no more the case and mathematical models have to be adapted to account for the disappearance of drum type economizer, boiler, superheater. General equations have to be used for each tube of boiler, and actual heat transfer condition in each tube has to be identified.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.373-378
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• 2003

It is important that overheat protection of super heated tube in boiler operation and maintenance. The overheat of super heat tube can make damage and rupture of tube material, which causes accidental shutdown of boiler. The super heated tube overheat is almost due to the lack of uniformity of gas temperature distribution. There are two ways to protect overheat of super heated tube. The one is to control hot gas operation pattern which is temperature or flow distribution. the other is to control super heated steam flow distribution. The former is difficult than the later, because of control device design. In this paper steam flow control method which uses orifices is proposed to protect overheat of super heat tube.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1146-1151
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• 2005

This paper deals with the control problem of a natural circulation water tube boiler with constraint conditions. Some linearized models for the water tube boiler are proposed around some operating points, and the model based predictive control law is adopted to control the plant accounting for constraints. In this controller, the Kalman filter is used for the state estimation, and the controller is designed based on the linearized model. The control performance of the designed controller is exemplified via some nonlinear simulations around the operation point, which show it works well.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.837-841
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• 2001

Almost all power plant boiler has temperature distribution nonuniformity problem in heat transfer tube flow path. It can cause hot spot damage of superheated or reheated heat transfer section and reduce maintenance schedule when nonuniformity is severe. There are two solutions for improvement temperature nonuniformity. one is change of gas flow distribution of gas path and the other is contorl steam flow in tube bank. Of course, first method is very difficulty to apply but second method is'nt. In this paper, control steam flow is used to solve temperature nonuniformity of power plant boiler.

• 한국CDE학회논문집
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• 제12권6호
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• pp.461-465
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• 2007

There have been 3E problems of energy, economy and environment since the earth has its history. Especially, the energy and environment problems have been getting serious after the modem industry revolution. Therefore, the demand of gas as an eco-friendly energy source is getting increased. With the demand of gas, the installation and use of gas boiler is also increased, so human life injury by the waste gas(CO) of boiler goes on increasing every year. It is the content about a life of the exhaust tube which is used at Gas boiler in this paper. We explain also the course to apply the 6SC(6 Step Creativity)of practical TRIZ and evaluate the resolution.

• 설비공학논문집
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• 제18권12호
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• pp.992-998
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• 2006

This study is to optimize design parameters for waste heat recovery boiler with water tube and three drum. The design optimization considered here is to find the most economic dimension of the boiler considered which results in a minimum cost in producing a unit amount of steam per given period of operation. For this purpose, optimize design have to determine what are the main parameters of affecting the total cost of producing a unit amount of steam which is comprised of manufacturing cost of the boiler, operating cost of the fan etc.

• 설비공학논문집
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• 제20권7호
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• pp.478-485
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• 2008

The extreme steam temperature deviation experienced in the superheater of a tangentially fired boiler can seriously affect its economic and safe operation. This temperature deviation is one of the main causes of boiler tube failures. The steam temperature deviation is mainly due to the thermal load deviation in the lateral direction of the superheater. The thermal load deviation consists of several causes. One of the causes is the non-uniform heat flow distribution of burnt gas on the superheater tube system. This distribution is very difficult to measure in situ using direct experimental techniques. So, we need thermal load model to estimate the tube temperature. In this paper, we propose a thermal load distribution model by using CFD analysis and plant data. We successfully predict the tube temperature and the steam flow rate in a final superheater system from the thermal load model and one dimensional heat-flow system analysis. The proposed model and analysis method would be valuable in preventing the frequent tube failure of the final superheater tubes.

• 사물인터넷융복합논문지
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• 제8권1호
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• pp.23-29
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• 2022

본 연구의 개발대상 제품은 선박 및 발전용 EGB(Exhaust Gas Boiler-폐열보일러) 종류로써 디젤 엔진, 가스 엔진, 가스 터빈 등에서 나오는 배기 가스의 여열을 이용하여 물을 가열하여 고온·고압의 증기나 온수를 발생시키는 열회수 장치이다. 발생된 증기나 온수는 선박의 선실 난방 및 온수 시설이나 HFO Heating, 터빈 구동에 필요한 동력원으로 사용된다. 폐열보일러의 원리는 여열을 가진 고온의 배기 가스가 보일러의 Tube를 통과하면서 물을 데우는 역할을 한다. 데워진 물은 스팀 형태로 선실이나 터빈장치로 보내어져 사용하게 되는 구조이다. 본 연구에서는 EGB의 열전달 부품인 관형 튜브를 Plate Tube로 대체하여 열전달 표면을 늘려 효율을 극대화하는데 목표가 있다.

• 전기저널
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• 6호통권66호
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• pp.26-31
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• 1982