• 조명전기설비학회논문지
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• 제25권7호
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• pp.40-48
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• 2011

An attemperator is a part of the 4-stage superheater in the boiler system of the thermal power plant. The attemperator receives the over-heated steam and makes the steam with proper temperature by adjusting the control valve of the cold steam. In this paper, the attemperator is modeled considering physical point of view and the linearized model is derived for the control purpose. To overcome the integral windup phenomenon due to the opening limitation of the control valve, an anti-windup PI controller is proposed to the attemperator and compared with the PI controller operated in the thermal power plant in view of control performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2307-2309
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• 2002

A simulator had been developed and will be used for reliability verification on turbine control programs for boiler feed pump in power plant prior to its actual operation in field. A mathematical model on thermal dynamics pertaining to prime mover steam turbine and pump was realized and included in this simulator. Also, many design and operating data acquired from fields were utilized in order to decide mechanical and thermal dynamic characteristics such as friction loss windage loss and inertia. A user can decide closing or opening velocity of steam stop valves and steam regulation valves. This simulator is able to generate steam pressure, turbine speed, pump power.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.770-777
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• 2016

It has been a challenge for researchers to accurately measure high temperature creep strain online without damaging the mechanical properties of the pipe surface. To this end, a noncontact method for measuring high temperature strain of a main steam pipe based on digital image correlation was proposed, and a system for monitoring of high temperature strain was designed and developed. Wavelet thresholding was used for denoising measurement data. The sub-pixel displacement search algorithm with curved surface fitting was improved to increase measurement accuracy. A field test was carried out to investigate the designed monitoring system of high temperature strain. The measuring error was less than $0.4ppm/^{\circ}C$, which meets actual measurement requirements for engineering. Our findings provide a new way to monitor creep damage of the main steam pipe of a boiler of an ultra-supercritical power plant in service.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1999년도 특별강연 및 춘계학술발표대회 개요집
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• pp.293-294
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• 1999

• 동력기계공학회지
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• 제16권1호
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• pp.58-64
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• 2012

Power plant boiler is one of the most important utilities providing steam to turbine in thermal power plant. It is composed of thousands of boiler tubes for high efficient heat transfer. Boiler tube material is used in such high temperature and pressure as $540^{\circ}C$, $170kg/mm^2$. The boiler tube material is needed to resist corrosion damage, creep damage and fatigue damage. 2.25%Cr-1Mo steel is used for conventional boiler tubes. In these days steam temperature and pressure of the power plant became higher for high plant efficiency. So, the material property of boiler tube must be upgraded to meet the plant property. Several boiler tube material was developed to meet such condition. X20CrMoV12.1 steel is also developed in early 1980's and used for superheater and reheater tubes in supercritical boilers. The material has martensitic structure, which is difficult to evaluate the material degradation. Boiler tube material at severe condition was tested to evaluate long term and short term degradation and creep. Through long term and high temperature degradation test, lath structure was decreased and recrystallization has been proceeded by sub-crystal. And in this research the effect of temperature and stress on boiler tube characteristic,for example, deformation by creep was changed rapidly at relatively high temperature and stress because creep was affected easily by temperature and stress.

• KEPCO Journal on Electric Power and Energy
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• 제2권3호
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• pp.403-407
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• 2016

In general, drum-type boilers are designed for base load duty and applied under constant pressure operation mode. Recently, however conditions often occur that even drum-type boilers have to operate at partial load conditions. A feasibility study on adopting the sliding pressure operation for drum-type boiler was conducted, and corresponding performance changes and effects on the equipment were analyzed by utilizing a process simulation model. As a result, the conclusion was reached that drum type boilers are able to adopt the sliding pressure operation and can improve of net efficiency at part load operation in spite of the Rankine cycle efficiency reduction due to the decreases in main steam pressure. Because of thank to improvement of high pressure turbine stage-1 internal efficiency and power savings of boiler feed water pump. The sliding pressure operation is advantageous in terms of stress level relief for boiler tube as well as maintaining the rating steam temperature at part load condition. However, cautions are required because the drum boilers have poor dynamic response characteristics which may get worse during the sliding pressure operation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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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.

• 한국가스학회지
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• 제2권4호
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• pp.1-6
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• 1998

중화학 플랜트의 고온고압 요소인 증기 발생기(steam generator)의 드럼, 헤더 및 헤더 스터브 설계에 응력해석에서 부터 도면자동작도, 제작용 서류 자동생성에 이르기까지의 제반설계과정을 체계적으로 연결시킨 설계정보 통합 관리로 단순 설계오류를 줄이고, 또한 설계변경에 대해 신속한 재설계가 가능한 효율적인 설계를 도모하기 위하여 "피로수명을 고려한 헤더스터브 형상설계 모듈", "TRD301을 기초로한 후육내압부 운전조건(기동/정지 조건) 및 수명평가 모듈", "헤더 및 드럼부 자동작도 모듈"을 개발하였다. 이에 따라 형상설계 모듈을 이용하여 설계된 스터브 형상을 토대로 수명평가 모듈로 수명을 평가한 후 상세설계 도면 및 관련 서류의 자동작도로 이어지는 일관된 종합설계 시스템을 구축하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2342-2344
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• 2000

Many years ago, most of thermal power plants built in this country were of subcritical pressure, of medium or small size, of constant pressure operation, of drum type steam generator. But, nowadays, almost all of them were of high efficiency, of supercritical pressure, of great capacity(about 500MW), of sliding pressure operation, of once through type steam generator. Presently built once through boiler introduces turbine bypass systems to variable pressure operation which eliminates unexpected materials in boiler tube during startup, minimizes fuel loss by short startup period, eventually improves total efficiency and power system stability

• 한국자동차공학회논문집
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• 제22권3호
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• pp.1-11
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• 2014

The aim of this study is to investigate the effect of SCR reactor on the exhaust emissions characteristics in order to develop a urea-SCR aftertreatment system for reducing $NO_x$ emissions. The experiments are conducted by using a flue tube LPG steam boiler with the urea-SCR aftertreatment system. The urea-SCR aftertreatment system utilizes the ammonia converted from 17% aqueous urea solution injected in front of SCR catalyst as a reducing agent for reducing $NO_x$ emissions. The equivalence ratio, urea injection amount, ammonia slip and $NO_x$ conversion efficiency relative to boiler load are applied to discuss the experimental results. In this experiment, the average equivalence ratio is calculated by changing only the fuel consumption rate while the intake air amount is constantly fixed at $25,957.11cm^3/sec$. The average equivalence ratios are 1.38, 1.11, 0.81 and 0.57 when boiler loads are 100, 80, 60 and 40%. The $NO_x$ conversion efficiency is raised with increasing urea injection amount, and $NH_3$ slip is also boosted at the same time. Consequently, the $NO_x$ conversion efficiency relative to boiler load should be examined in combination with urea injection amount and $NH_3$ slip. The results are calculated by 89, 85, 77 and 79% for the boiler loads of 100, 80, 60 and 40%. The appropriate amount of urea injection for the respective boiler load can be not discussed by only $NO_x$ emissions, and should be determined by considering the $NO_x$ conversion efficiency, $NH_3$ slip and reactive activation temperature simultaneously. In this study, the urea amounts of 230, 235, 233 and 231 mg/min are injected at the boiler loads of 100, 80, 60 and 40%, and the final $NH_3$ slips are measured by 8.48, 5.58, 11.97 and 11.34 ppm at the same conditions. THC emission is affected by the SCR reactor under other experimental conditions except 100% engine load, and CO emission at only 40% engine load. The rest of exhaust emissions are not affected by the SCR reactor under all experimental conditions.