• 제어로봇시스템학회논문지
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• 제6권4호
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• pp.254-260
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• 2000

This paper deals with the development of fault tolerant control for a nonlinear boiler system with noise and disturbance. The MCMBPC(Multivariable Constrained Model Based Predictive Control) is adopted for the control of the specific boiler turbin model. The fault detection and diagnosis are accomplished with the Kalman filter and two bias estimators. Once a fault is detected, two Bias estimators are driven to estimate the fault and to discriminate Process fault and sensor fault. In this paper, a fault tolerant control scheme combining MCMBPC with a fault compensation method based on the bias estimator is proposed. The proposed scheme has been applied to the nonlinear boiler system and shown a satisfactory performance through some simulations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.390-395
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• 2003

The effect of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rate are experimentally investigated by using an once-through boiler with FGR system. The purpose of this study is to develop the FGR control system for reducing NOx in a boiler. Intake and exhaust oxygen concentrations, and equivalence ratio are applied to discuss the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that NOx emissions are decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.327-329
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• 2006

In this paper, PLC program for flowing type steam boiler control is presented. The function of the implementation are flowing type steam boiler, PLC control, interpretation of PLC command, and temperature scheme. The flowing type steam boiler approach is based on master-slave control concept. To show validity of the developed PLC program, severial experiments are illustrated.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.97-104
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• 2018

This paper proposes supplementary control of conventional coordinated control of a power plant which directly affects network frequency. The supplementary control with dynamic matrix control is applied for 1000 MW power plant with ultra-supercritical (USC) once-through boiler. The supplementary control signal is added to the boiler feedforward signal in the existing coordinated control logic. Therefore, it is a very practical structure that can maintain the existing multi-loop control system. This supplementary controller uses the step response model for the power plant system, and on-line optimization is performed at every sampling step. The simulation results demonstrate the effectiveness of the proposed supplementary control in a wide operating range of a practical 1000 MW USC power plant simulator. These results can contribute the stable operation of power system frequency.

• 대한기계학회논문집B
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• 제34권5호
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• pp.547-552
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• 2010

본 연구에서는 VIStA(Vortex Inertial Staged Air) 버너를 개조하여 관류보일러에 적용하였다. 개조는 크게 2가지 부분에서 이루어 졌는데, 먼저 원형에서 채택한 예혼합 연소 방식을 사용상 편의와 안전을 위해 비예혼합방식으로 변경하였다. 연소 방식의 변경에 따라 공기 1차, 2차에 별도의 송풍기를 사용하던 공급 방식도 변경하여 본 연구에서는 하나의 송풍기로부터 공기를 공급받아 댐퍼를 통하여 1, 2차 연소실에 분할하여 공기를 공급하도록 하였다. 본 연구에서는 질소 산화물(NOx)의 생성을 억제하는 최적의 운전 조건을 찾기 위하여 전체 공기비 및 1, 2차 연소실로의 공기 분배 비율에 따른 NOx 생성 특성을 관찰하였다. 본 연구에서 산업용 보일러에 적용하기 위해 개조한 비예혼합 방식의 VIStA 버너를 설치한 결과, 기존의 일반 버너에 비해 균일한 화염을 얻었고 질소 산화물을 최대 20%까지 줄일 수 있는 것을 확인하였다.

• 대한기계학회논문집B
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• 제36권4호
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• pp.413-418
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• 2012

본 연구에서는 VIStA (Vortex Inertial Staged Air) 버너를 개조하여 관류보일러에 적용하였다. 2차 공기를 노즐을 통해 공급하던 원형과 달리 선회기를 통해 공급함으로써 화염을 안정화하고 일산화탄소(CO)의 발생량을 저감하였다. 그러나, 이러한 개조과정에서 질소산화물(NOx)의 발생이 증가하는 문제가 발생하였다. CO와 NOx 발생량을 함께 제어하기 위하여 본 연구에서는 화염분할을 적용하였다. VIStA 버너는 2개의 연소실이 있고 각각의 연소실에 공급되는 공기량을 댐퍼로 조절하며 3가지 종류의 화염분할 장치를 설계, 장착하여 공기비, 연소부하에 따른 연소 특성을 파악하였다. 화염분할을 통하여 CO 농도 증가는 10 ppm 이내로 유지하면서 NOx의 발생량은 25%까지 저감하는 결과를 얻었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1603-1604
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• 2007

The load of power plants changes every from time to time according to which steam flow of boiler changes. the feed water control is very important for the power plant to be operated in its stability conditions. In case of circulation type boiler, the instability of feed water control leads to instability of drum level control. The higher level of drum water can induce bad quality steam to go into turbine which means the possibility of damage. The lower level of drum water can induce the tubes of boiler water wall to be overheated. In case of once through type boiler, the instability of feed water control leads to bad cooling of superheaters. The less the feed water flow is, the more heated the superheater is. It is necessary for the turbine driving feed water pump to be controlled for the optimal feed water flow in the large capacity power plant. The speed of turbine is controled for the feed water flow. By the way, the optimal control of steam valve is necessary for the speed control of turbine. Therefore, the various kinds of the steam valve structures are introduced in this paper

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1663-1664
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• 2008

Many years ago, most of thermal power plants built in this country were of subcritical pressure, of medium or small size, of constant pressure operations and of drum type steam generators with circulation type boilers. But, nowadays almost all of them were of high efficiency, of supercritical pressure, of big capacity, of sliding pressure operations, and of once through type steam generators. Presently built once through boilers introduce turbine bypass systems to variable pressure operation which eliminates unexpected materials in boiler tube during startup, minimizes fuel loss by short startup period and eventually improve both total efficiency and power system stability.

• 대한기계학회논문집B
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• 제31권5호
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• pp.405-415
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• 2007

The effects of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rates are experimentally investigated by using an once-through boiler with a FGR system. The purpose of this study is to develop the FGR control system for reducing $NO_x$ emissions in boilers. Intake and exhaust oxygen concentrations, and equivalence ratio are considered to figure out the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that $NO_x$ emissions are markedly decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated. One can also conclude that the reduction in $NO_x$ emissions is more considerably influenced by the variation of equivalence ratio due to the FGR rate than the fuel consumption rate.

• 대한기계학회논문집B
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• 제37권2호
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• pp.187-196
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• 2013

화력발전용 관류보일러 화로벽관에서의 밀도파 불안정 예측을 목적으로 수치모델을 개발하였다. 시간 도메인에서 1 차원 유한체적법을 적용하여 관내 비정상상태의 유동장을 계산하였으며, 화로벽관의 평행관 연결을 모사하기 위해 헤더의 모델도 포함하였다. 평행관들 가운데 하나의 관에 열 섭동을 부가 후 관 입출구 유량의 변동을 관찰함으로써 밀도파 불안정을 찾았다. 개발된 모델은 문헌의 실험결과와 검증을 거쳐 700MW 보일러 화로벽관에 적용하였다. 그 결과 Takitani 의 실험결과에서는 평행으로 연결된 우회 유량이 줄어들수록 불안정 경계 열량이 상승하는 경향이 있었던 반면, 보일러 화로벽관의 경우에는 평행관 모델링에 크게 영향을 받지 않음을 확인하였다.