• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.5
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• pp.424-431
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• 2007

This thesis proposed H-Bridge Multi-Level Inverter for Fluidized Bed Combustion Boiler Secondary Air Fan in 200MW thermal power plant. The adjustable speed drive systems improve the efficiency in lightly load condition and extend the life span of motor by limiting the over current at starting. H-Bridge Multi-level Inverter is composed of the several series low voltage power cell inverters, which have the independent isolated do link, in each phase. KEPRI(Korea Electric Power Research Institute) has successfully completed to develop, install, and commission H-Bridge Multi-level Inverter(6.6kV, 1MVA). This thesis gives a full detail about H-Bridge Multi-level Inverter, proposed boiler DCS(Distributed Control System) logic, and commissioning test result.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.255-262
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• 2020

Blended cement with fly ash and bottom ash from Circulating Fluidized Bed Combustor boiler(CFBC) burned at a low temperature, can be high heat of hydration and abnormal setting caused by higher volumn contents of Fe₂O₃, free-CaO, SO₃. In this study, the ground CFBC bottom ash powder mixed with blast furnace slag was used as substitute activator of gypsum and recycled iron slag was produced from mix and pulverized by ball mill to increase the recycling rate. The effect on compressive strength of cements with the mixture of original and hydrated bottom ash mixtures with BFS with small water, respectively, was analyzed, and it was found that the hydrated bottom ash activator was more effective in initial strength development. To improve the initial strength of blended cement, an activator mixed with a blast furnace slag and bottom ash mixing ratio of 5:95 and 10:90, respectively, the slag cement by about 6%, and it was analyzed to develop an initial strength similar to gypsum as a conventional activator.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.452-455
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• 2008

The co-combustion of coal and three kinds of RDFs(Refuse Plastic Fuel) mixture has been experimented in a commercially operating CFB coal boiler respectively and the pollutant emissions such as SOx, NOx, TSP and dioxine were measured at the stack. The mixing ratio with coal was 7.5% RPF, 7.5% RDF and 10% SDF respectively. During co-combustion, dioxine emission level was very low and SOx, NOx and TSP were decreased comparing the single coal combustion. Emitting dioxine concentration was proportioned to the chlorine content of RDF. These RPF, SDF and RDF could be determined to be a good alternative fuel of general coal.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.856-863
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• 2018

In order to investigate the re-carbonation behaviors of limestones in an oxy-circulating fluidized bed combustor (Oxy-CFBC), the re-carbonation characteristics of domestic 4 different limestone samples were analyzed in a thermogravimetric analyzer (TGA-N1000) with the higher concentration of $CO_2$. Effect of reaction temperature ($600{\sim}900^{\circ}C$) and $CaCO_3$ content (77~95%) of limestones were determined and the mass change of the CaO was observed. Under the temperature of $800^{\circ}C$, the conversion rate increased with increasing reaction temperature. However, the conversion rate decreased with increasing reaction temperature over $800^{\circ}C$. In the case of $CaCO_3$ content, the conversion was remarkably different at $870^{\circ}C$. In addition, reaction rate equations for simulating the re-carbonation of limestone by using gas solid reaction models were proposed in this study.

• Journal of the Korea Institute of Building Construction
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• v.18 no.1
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• pp.25-31
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• 2018

In this study, the Controlled Low Strength Material (CLSM) was investigated to utilize the bottom ash and fly ash generated in the Circulating Fluidized Bed Combustor (CFBC). It was confirmed that the CFBC fly ash (CFBC-F) and CFBC bottom ash (CFBC-B) had an irregular particle shape through SEM measurement. According to the results of the hazard analysis, it was also confirmed that they were environmentally safe. In the case of mixing with CFBC-F, the unit quantity was increased. Regarding the rate of change of length, shrinkage in the range of -0.05~0.50% occurred in the air dry curing condition and expansion in the range of 0.1~0.6% in the sealed curing condition. Compressive strength was increased in the sealed curing condition compared to the air dry curing condition because there was enough moisture for hydration reaction in the long term. Therefore, the results of this study are likely be used as basic research data of mine filler materials.

• Resources Recycling
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• v.27 no.6
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• pp.68-75
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• 2018

The rare earth elements (REE) contents in coal ashes generated from domestic circulating fluidized bed combustion (CFBC) were identified for evaluating the exploitation possibilities for recovering rare earth elements. Total REE contents for all of the samples in this study ranged from 82.2 ~ 311.7 ppm, much lower than the 403.5 ppm given on the average value of world coal ash. As a result of analysis using REE concentration and Outlook coefficient, six types of coal ashes falls in the unpromising area (I). These results suggest that it is difficult to recover rare earth element from coal ashes at this stage. It has been confirmed that to recover rare earth elements in coal ashes, research on the pretreatment and concentration process for critical REE is requirement.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.262-264
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• 2007

최근 전압 및 주파수 가변을 이용하여 전동기의 속도를 제어하여 전동기 경부하시 베인에서 소모되는 에너지 절감효과를 얻을 수 있는 인버터 시스템이 널리 사용되고 있다. 이에 전력연구원은 6.6kV, 1MVA급 인버터 개발 및 동해화력 발전처에 설치, 보일러 점화 전/후 시험, 계통 병입 후 부하 시험 등을 국내 최초로 성공적으로 완료하여 현재 이차 공기 송풍기 구동용 인버터는 상업 운전 중이다. 본 논문에서는 기존 동해화력 발전 설비와 신규 인버터 시스템의 인터페이스 부분에 해당하는 보일러 DCS 로직과 계통 병입 후 시운전 결과에 대하여 상세히 기술하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.53-54
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• 2018

최근 화력 발전소 보일러 튜브의 노후화로 인해서 불시정지 빈도수 및 재가동 시간이 늦춰지고 있다. 이는 막대한 경제적, 사회적 손실로 이어지며, 이를 예방하기 위해서는 상태기반 정비가 필요하다. 현재의 상태기반 정비는 센서, 신호 수집장치, 신호 분석단계를 거쳐 전문가가 진단하기 때문에 즉각적으로 대응하기 어려운 문제점이 있어서 설비의 재가동 시간이 늦춰지고 있다. 따라서 본 논문에서는 전문가의 도움 없이 자동으로 상태를 진단하기 위해서 머신러닝 기법 중 하나인 서포트 벡터 머신(SVM)을 이용한 진단 알고리즘을 구현하고, 이를 탑재한 진단장치를 개발하여 비전문가들도 즉각적으로 대응할 수 있게 하여 불시정지 시간과 빈도수를 줄이고자 한다.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.15-16
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• 2014

With the increasing trend in CFB(Circulating Fluidized Bed) boiler scale, the EHE(External Heat Exchanger) must be adopted to the large-scale boilers to recover insufficient heat transfer surface. In this study, the numerical analysis model for EHE in commercial 300MWe CFB boiler was developed with the inclusion of mechanistic model, which enables the heat transfer prediction. Finally, the calculated absorbed heat and derived heat transfer coefficient are evaluated through the verification with experimental data.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.71-77
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• 2005

Combustion of RDF and wastewater sludge was performed in a 0.1MWth bench scale circulating fluidized bed combustor(CFBC), Combustion characteristics of the RDF and sludge mixture demonstrated stable combustion conditions. Component analysis, Combustion characteristics was measured before and after the test, and applications for commercial 1MWe CFBC boiler were prepared. The release of hazardous components such as $SO_2$ and HCl was relatively low values of 50 and 150ppm, respectively.