• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2347-2349
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• 2002

전기히터를 사용하는 축열기기의 보급이 급속히 활성화되고 모든 축열기기들이 심야전력 공급이 시작되는 22:00시에 동시에 가동이 시작되므로 심야전력 공급시작시간대에 전력수요피크가 발생하였다. 본 연구는 이러한 심야전력 공급시작시간을 상대적 저부하 시간대로 이동하기 위하여 대표적인 축열기기인 축열식 전기보일러의 적용할 심야전력 공급시간 자동제어장치 개발에 관한 것이다. 본 논문의 내용은 축열식 전기보일러의 축열조 잔열량에 따라 축열시작시간을 결정하는 자동제어장치의 알고리즘과 H/W, 그리고 시험실에서의 테스트와 현장에서의 검증작업을 포함한다.

• JOURNAL OF ELECTRICAL WORLD
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• no.1 s.49
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• pp.77-78
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• 1981

요즘은 자동화가 발달됨에 따라 모든 산업에 있어서 고도의 기술과 폭넓은 지식이 요구되게 되었다. 이러한 세대의 요구에 대응하기 위하여는 전기기술자라 할지라도 전기지식 뿐만 아니라 다른 분야의 지식도 어느 정도 알아 두어야 할 필요가 있다. 특히 기계와는 밀접한 관계에 있으므로 더할 나위가 없다. 그래서 빌딩에 시설되어 있는 기계설비중 비교적 중요하게 다루어지는 펌프(Pump), 보일러(Boiler), 냉동기(冷凍機), 공기조절기(空氣調節機)등에 대해서 그 기초적 지식과 실무요점에 관하여 설명하기로 한다.

• Journal of Energy Engineering
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• v.19 no.3
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• pp.156-162
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• 2010

3-D CFD(Computational Fluid Dynamics) work were carried out to investigate the combustion characteristics in a boiler depending on the variations in air supply condition. For the gas temperature, $O_2$, NO, SOx at the outlet of economizer, the predicted values were been compared with the measured data. With the verified CFD model, the effects of air flow rates through SOFA(Separated Over Fire Air) and CCOFA(Closed Coupled Over Fire Air) on the combustion behavior in a boiler were simulated, and the distributions of NOx and gas temperature were mainly compared each other. The change in SOFA air flow rate gave the more sensitive effect on NOx than that in CCOFA. The distributions of gas temperature at convection path are differed with the changes in SOFA and CCOFA flow rate, so the combustion modification such as yaw anlge adjustment are required to get an enhanced gas temperature distribution.

• Environmental and Resource Economics Review
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• v.21 no.3
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• pp.595-625
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• 2012

Recently environment-friendly pellet boilers have interests as emissions of greenhouse gases are regulated internationally and energy security becomes more important to oil addicted countries including Republic of Korea. But the Korean market for pellet boilers is on the initial stage due to the high production costs relative to other conventional boilers. Hence the Korean government has supported financially and promoted the pellet boiler business. In this sense, it would contribute market stratergy and effective promotion policy for both of the government and private companies if we can forecast market shares of pellet boilers appropriately. For this purpose, this study surveyed potential consumers' preferences on pellet boilers among various alternatives using a choice experiment reflecting intangible costs. As the market share of new technology increases, intangible costs decline. According to different intangible cost scenarios, we experimented people's preferences on oil, gas, electric, and pellet boilers. A multinomial logit model was employed to estimate coefficient parameters of common attributes for various alternative boilers. Based on the estimates, we forecasted market shares of individual boilers. We found that as intangible costs decline, the market share of pellet boiler increase substantically while market shares of electric and gas boilers decrease dramatically. The market share of oil boiler did not change significantly. Meanwhile, as people are more rich, more educated, and exposed to advertisement on pellet boilers, the likelihood of choosing the pellet boiler increases.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1669-1670
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• 2008

발전소를 포함한 플랜트 공정 제어로직 설계에서 제어대상인 공정의 특성을 파악하는 일이 중요한 출발점이라고 할 수 있다. 이 논문에는 국내 가동 중인 500MW 석탄화력발전소의 보일러 제어시스템을 교체할 목적으로 우선 현재의 제어로직을 분석한 내용을 기술한 것이다. 대상 발전소의 보일러는 관류형 초임계압 형식으로서 1990년대 초부터 건설되기 시작한 국내 표준모델 중 하나이다. 표준관류보일러의 일반특성과 제어원리에 대하여 고찰한 내용을 먼저 기술하였으며, 효과적인 제어목표를 달성하기 위해 보일러 특성을 제어로직에 반영한 증기압력제어, 급수유량제어 제어알고리듬을 차례로 기술하였다. 여기에 근거 자료 또는 참고자료로 사용된 그래프 등은 고찰대상인 실제 발전소에서 수집하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1628-1629
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• 2007

1990년대에 이 전 건설된 발전소 및 기타 플랜트 자동제어시스템으로 거의 아날로그 연산방식 시스템이 적용되었다. 이제 장기간 사용으로 인한 수명감소와 고장률이 증가하는 추세에 있으므로, 기존 아날로그 제어시스템을 디지털 제어시스템으로 개조하는 사업이 추진되고 있다. 아날로그 제어시스템에 설정되어 있는 주요 파라미터들은 플랜트의 운전특성을 장기간 반영하여 이루어진 것이므로, 개조에 사용될 새로운 디지털제어시스템의 초기 파라미터 설정에 그대로 적용하면 개조후 시운전이 원활하고 튜닝 기간을 단축할 수 있다. 본 논문에서는 현재 진행하고 있는 급수펌프 구동터빈 제어시스템 개조 프로젝트에서 제어 파라미터를 구하는 과정 및 디지털 시스템에 구현할 내용들을 제시하였다.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1397-1405
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• 2009

In recent decades, exergy analysis has been holding spotlight as a useful tool in the design, assessment, optimization, and improvement of energy system. This paper presents the results of the energy and exergy analysis of a steam turbine cogeneration system for industrial complex using two efficiency concepts of conventional one and exergetic one. In order to obtain the destroyed exergy of each component, mathematical analysis is conducted by using exergy balance and the second law of thermodynamics, according as the parameters are changed, such as the ratio of returned process steam, process steam supplied, temperature and pressure of boiler and power. The computer program developed in this study can determine the efficiencies and exergy destroyed at each component of cogeneration system. As a result of this study, a component having the largest destroyed exergy was boiler. And closed and opened feedwater heater had the lowest one. The affects to the cogeneration system due to the variation of process steam flow and return rate of condensed water is shown that the total electric power efficiency(${\eta}_E$) is decreased as increasing the return rate of condensed water under constant process steam flow. As the boiler pressure is increased for the more production of electricity, the efficiency of cogeneration system was decreased.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.692-699
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• 2013

In this study, isothermal (350, 375, 400, 425, 450, 500, $850^{\circ}C$) experiments were carried out using a custom-made thermobalance to analyze the thermal decomposition properties of refuse plastic fuel (RPF), which is to be used as a cofiring fuel with a sub-bituminous coal at commercial circulating fluidized bed (CFB) boiler in Korea. In isothermal pyrolysis results, no change in the reaction model was observed in the temperature range of $375{\sim}450^{\circ}C$ and it was revealed that the first order chemical reaction (F1) is the most suitable among 12 reaction models. The activation energy shows similar results irrespective of application of reaction model in that the activation energy was 39.44 kcal/mol and 36.96 kcal/mol when using Arrhenius equation and iso-conversional method ($0.5{\leq}X{\leq}0.9$) respectively. Mean-while, the devolatilization time ($t_{dev}$) according to particle size (d) of RPF could be expressed as $t_{dev}=10.38d^{2.88}$ at $850^{\circ}C$, operation temperature of CFB and for even distribution and oxidation of RPF in CFB boiler, we found that the relationship of average dispersion distance (x) and particle size was $x{\leq}1.58d^{1.44}$.

• Journal of the Korean Society of Combustion
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• v.23 no.1
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• pp.44-54
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• 2018

Heat and mass balance process modeling has been conducted for a coal-firing power plant to be used as a testbed facility for development of various plant systems and equipment. As the material and design of the boiler tube bundle and fuel conversion to the biomass have become major concerns, the process modeling is required to incorporate those features in its calculation. The simulation cases for two different generation load show the satisfying results compared to the operational data from the actual system. Based on the established process conditions, the hypothetical case using wood pellet has also been simulated. Additional calculations for the tube bundle has been conducted regarding the changes in the tube material and design.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.465-469
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• 2010

Air heater used in power plant helps increase the thermal efficiency of the boiler by recovering the heat from the boiler flue gas and thus preventing the loss of useful heat. This study investigates the effect of preventive maintenance on the performance of the air heater in a power plant. Performance indexes for the air heater are calculated to observe the changes in the performance and operation status of the air heater before and after preventive maintenance. The major performance indexes considered are temperature efficiency of the flue gas side, air leakage rate, heat recovery rate, heat transmission rate, and heat capacity ratio. The performance of the air heater is evaluated before and after preventive maintenance; our results show that all the abovementioned performance indexes are improved after the maintenance.