• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.390-393
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• 1991

This paper describes nonlinear 4th order models for a natural circulation drum-boiler. The models lire derived from energy balance and mass balance principles. They can be characterized by a few physical parameters that are easily obtained from construction data. The models also require steam tables for a limited operating range, which can be approximated by polynomials. The models have been validated against real plant operating data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.10a
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• pp.271-278
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• 1997

The flow of steam through a safety valve vent pipe system in the boiler has been analyzed to provide a design basis of diffuser silencer for attenuating shock-shell and jet noise. Numerical analysis to estimate inner fluid of silencer and noise propagation outside silencer are performed. The distribution curve of fluid information to provide average values about inner fluid of silencer is presented by theoretical analysis.

• Journal of the Korean Society of Combustion
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• v.18 no.4
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• pp.1-11
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• 2013

The oxy-fuel combustion is $CO_2$ capture technology that uses mixture of pure $O_2$ and recirculated exhaust as oxidizer. Currently some Oxy-fuel power plants demonstration project is underway in worldwide. Meanwhile research project for converting 125 MWe Young-Dong power plant to 100 MWe oxy-fuel power plants is progress. In this paper, 1 D process analytical approach was applied for conducting process design and operating parameters sensitivity analysis for oxy-fuel combustion of Young-Dong power plant. As a result, appropriate gas recirculation rates was 74.3% that in order to maintain normal rating superheater, reheater steam temperature and boiler heat transfer patterns. And boiler efficiency 85.0%, CPU inlet $CO_2$ mole concentration 71.34% was predicted for retrofitted boiler. The oxygen concentration in the secondary recycle gas is predicted as 27.1%. Meanwhile the oxygen concentration 22.4% and moisture concentration 5.3% predicted for primary recycle gas. As the primary and secondary gas recirculation increases, then heat absorption of the reheater is tends to increases whereas superheater side is decreased, and also the efficiency is tends to decrease, according to results of sensitivity analysis for operating parameters. In addition, the ambient air ingression have a tendency to lead to decline of efficiency for boiler as well as decline of $CO_2$ purity of CPU inlet.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.23-31
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• 2018

Stress of a steam separator, equipment of the high-pressure (HP) evaporator for a HRSG, was analyzed and evaluated according to ASME Boiler & Pressure Vessel Code Section VIII Division 2. First, from the analysis results of the piping system model of the HP evaporator, reaction forces of the riser tubes connected to the steam separator, i.e., nozzle loads, were derived. Next, a finite element model of the steam separator was constructed and analyzed for the design pressure and the nozzle loads. The results show that the maximum stress occurred at the bore of the riser nozzle. The primary membrane stresses at the shell and nozzle were found to be less than the allowable stress. Next, the steam separator was analyzed for the steady-state operating conditions of operating pressure, operating temperature, and nozzle loads. The maximum stress occurred at the bore of the riser nozzle. The primary plus secondary membrane plus bending stress at the shell and nozzle was found to be less than the allowable stress.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.246-252
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• 2016

Since thermal power plant (TPP) equipment is operated under very high pressure and temperature, failures of the equipment give rise to severe losses of life and property. To prevent the losses, fault detection method is, therefore, absolutely necessary to identify abnormal operating conditions of the equipment in advance. In this paper, we present Mahalanobis distance (MD) based fault detection method for steam boiler tube in TPP. In the MD-based method, it is supposed that abnormal data samples are far away from normal samples. Using multivariate samples collected from normal target system, mean vector and covariance matrix are calculated and threshold value of MD is decided. In a test phase, after calculating the MDs between the mean vector and test samples, alarm signals occur if the MDs exceed the predefined threshold. To demonstrate the performance, a failure case due to boiler tube leakage in 200MW TPP is employed. The experimental results show that the presented method can perform early detection of boiler tube leakage successfully.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.77-86
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• 1992

This paper discusses the thermodynamic study on the suction cooling-steam injected gas turbine cycle. The aim of this study is to improve the thermal efficiency and the specific output by steam injection produced by the waste heat from the waste heat recovery boiler and by cooling compressor inlet air by an ammonia absorption-type suction cooling system. The operating region of this newly devised cycle depends upon the pinch point limit and the outlet temperature of refrigerator. The higher steam injection ratio and the lower the evaporating temperature of refrigerant allow the higher thermal efficiency and the specific output. The optimum pressure ratios and the steam injection ratios for the maximum thermal efficiency and the specific output can be found. It is evident that this cycle considered as one of the most effective methods which can obtain the higher thermal efficiency and the specific output comparing with the conventional simple cycle and steam injected gas turbine cycle.

• Journal of IKEEE
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• v.26 no.3
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• pp.349-354
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• 2022

In thermal power plants, boiler models have been used widely in evaluating logic configurations, performing system tuning and applying control theory, etc. Furthermore, proper plant models are needed to design the accurate controllers. Sometimes, mathematical models can not exactly describe a power plant due to time varying, nonlinearity, uncertainties and complexity of the thermal power plants. In this case, a neural network can be a useful method to estimate such systems. In this paper, the models of boiler steam system in a thermal power plant are developed by using a generalized regression neural network(GRNN). The models of the superheater, reheater, attemperator and drum are designed by using GRNN and the models are trained and validate with the real data obtained in 540[MW] power plant. The validation results showed that proposed models agree with actual outputs of the drum boiler well.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.36-44
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• 2013

This paper is written for the development and application of boiler fuel control algorithm and distributed control system of coal-fired power plant by the steps of design, coding, simulation test, site installation and site commissioning test. Fuel control algorithm has the upper algorithm and it is boiler master control algorithm that controls the fuel, feed water, air by generation output demand. Generation output demand by power load influences fuel control. Because fuel can not be supplied fast to the furnace of boiler, fuel control algorithm was designed adequately to control the steam temperature and to prevent the explosion of boiler. This control algorithms were coded to the control programs of distributed control systems which were developed domestically for the first time. Simulator for coal-fired power plant was used in the test step. After all of distributed control systems were connected to the simulator, the tests of the actual power plant were performed successfully. The reliability was obtained enough to be installed at the actual power plant and all of distributed control systems had been installed at power plant and all signals were connected mutually. Tests for reliability and safety of plant operation were completed successfully and power plant is being operated commercially. It is expected that the project result will contribute to the safe operation of domestic new and retrofit power plants, the self-reliance of coal-fired power plant control technique and overseas business for power plant.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2812-2822
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• 2000

Several methods have been developed to predict the rupture time of the boiler tubes in thermal power plant. However, existing life prediction methods give very conservative value at operating stress of power plant and rupture strain cannot be well estimated. Therefore, in this study, rupture time and strain prediction method accounting for creep, corrosion and heat transfer is newly proposed and compared with the current research results. The creep damage evolves by continuous cavity nucleation and constrained cavity growth. The corrosion damage evolves by steam side and fire side corrosion. The results showed good correlation between the theoretically predicted rupture time and the current research results. And rupture strain may be well estimated by using the proposed method.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2584-2586
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• 2000

A drum level control is one of the most important control systems in thermal power plant. The control objective of drum level of boiler in thermal power plant is to maintain drum level at constant set-point regardless of disturbance such as main steam flow. The implemented drum level controller is the cascade PI controller. The important factor in drum level controller is the parameters of two PI controllers. The tuning of PI controller parameter is tedious and time-consuming job. In this paper, the relay feedback Ziegler - Nichols tuning method extended to auto-tune cascade PI drum level controller. Finally, the simulation result using boiler model in Power Plant shows the validity of auto-tuned cascade PI controller.