미분탄 석탄화력발전에서의 바이오매스 혼소 동향 및 전망

양원,Yang, Won 한국전력공사 2016 KEPCO Journal on electric power and energy Vol.2 No.4

바이오매스 혼소는 신재생 에너지의 비중을 늘리면서 석탄화력발전에서의 $CO_2$ 배출을 저감할 수 있는 단중기적으로 가장 효과적인 방법이다. 본 논문에서는 이 중 기존 화력발전소에 가장 적은 초기투자비로 적용할 수 있는 직접 혼소법에 대하여 주로 고찰을 수행하고, 국내외 현황 및 전망에 대해 기술하였다. 직접 혼소법은 바이오매스 전용 미분기를 사용하여 혼소율을 늘리는 방법과 저 혼소율에서 초기투자비를 최소화하는 기존 석탄 미분기 사용 바이오매스 혼소법으로 나눌 수 있다. 유럽 및 미국에서는 혼소율을 높이기 위해 많은 상용발전소에서 바이오매스 전용 미분기를 사용하여 10~20% 가량의 혼소율(열량 기준)로 운전을 수행하고 있으나, 국내의 경우에는 RPS 대응을 위해 3~5% 가량의 혼소율에서 기존 석탄 미분기를 그대로 사용하여 바이오매스 혼소를 수행하고 있다. 신기후체제가 시작되고 석탄화력발전에서의 $CO_2$ 저감 요구가 점점 더 증대될 것으로 예상되는 바, 향후 바이오매스 고혼소율이 수행될 수 있는 기술적/저책적 방안이 모색되어야 하며, 이 경우 발생할 수 있는 설비에의 악영향을 면밀히 고려한 연료 표준화 및 전처리 기술이 개발되어야 한다. Biomass co-firing to existing thermal power plants is one of the most economical and efficient way to reduce $CO_2$ emission from the plant. There are several methods of co-firing and it can be categorized into (1) Parallel co-firing, (2) Indirect co-firing, and (3) Direct co-firing. Parallel co-firing is the most expensive way to high-ratio co-firing because it requires biomass dedicated boiler. Direct co-firing is widely used because it does not need high capital cost compared with the other two methods. Regarding the direct co-firing, it can be classified into three methods- Method 1 does not need retrofit of the facilities because it uses existing coal mills for pulverizing biomass fuels. In this case high-ratio co-firing cannot be achieved because of poor grindability of biomass fuels. Method 2 needs biomass-dedicated mills and revision of fuel streams for the combustion system, and Method 3 needs additional retrofit of the boiler as well as biomass mills. It can achieve highest share of the biomass co-firing compared with other two methods. In Korea, many coal power plants have been adopting Method 1 for coping with RPS(Renewable portfolio standards). Higher co-firing ratio (> 5% thermal share) has not been considered in Korean power plants due to policy of limitation in biomass co-firing for securing REC(Renewable Energy Certificate). On the other hand, higher-share co-firing of biomass is widely used in Europe and US using biomass dedicated mills, following their policy to enhance utilization of renewable energy in those countries. Technical problems which can be caused by increasing share of the biomass in coal power plants are summarized and discussed in this report. $CO_2$ abatement will become more and more critical issues for coal power plants since Paris agreement(2015) and demand of higher share of biomass in the coal power plants will be rapidly increased in Korea as well. Torrefaction of the biomass can be one of the best options because torrefied biomass has higher heating value and grindability than other biomass fuels. Perspective of the biomass torrefaction for co-firing is discussed, and economic feasibility of biomass torrefaction will be crucial for implementation of this technology.

CFD analysis on bioliquid co-firing with heavy fuel oil in a 400MW_e power plant with a wall-firing boiler

Park, Jong Keun,Park, Sangbin,Ryu, Changkook,Baek, Se Hyun,Kim, Young Ju,Park, Ho Young Elsevier 2017 Applied thermal engineering Vol.124 No.-

<P><B>Abstract</B></P> <P>Liquid biomass derived from food processing, biodiesel production, or fast pyrolysis has good potential for use as fuel to displace diesel or heavy fuel oil (HFO) for heat and power, and a major demonstration was successfully conducted in a 400MW<SUB>e</SUB> HFO-fired power plant with a wall-firing boiler configuration using a BL blend of palm oil, its residue, and animal fat at a 20% co-firing ratio. When compared to a condition with HFO as fuel, the heat transfer rate on the membrane wall significantly decreased, and that of the convective heat exchangers in the upper furnace increased. This trend was different from what was observed at two smaller plants of 100 and 75MW<SUB>e</SUB>, both with a tangential-firing boiler.</P> <P>This study uses computational fluid dynamics (CFD) to investigate the reason for the difference in the heat transfer characteristics. In both boiler types, bioliquid (BL) combustion led to lower soot concentrations and a corresponding decrease in radiation. This directly reduced the heat absorption on the furnace wall by approximately 5% at 20%-BL co-firing in the wall-firing boiler, and it was predicted further decrease linearly by 14% at 100%-BL firing. However, the tangential-firing boilers had less than a 1% decrease in measured heat absorption on the furnace wall at 100%-BL firing. Such differences were attributable to the gas flow pattern of the two boiler configurations. The burner tilting and flue gas recirculation of the tangential-firing boilers also contributed to successful operation at 100%-BL firing. The conclusions indicate that without effective measures to control the heat absorption distribution, the capability of a wall-firing boiler for BL combustion is limited to low co-firing ratios.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bioliquid co-firing with fuel oil significantly changes heat transfer in a boiler. </LI> <LI> Lower soot formation decreases radiation on the furnace wall in bioliquid co-firing. </LI> <LI> Distribution of heat absorption is also influenced by furnace configuration. </LI> <LI> Tangential-firing boiler is more capable of bioliquid co-firing than wall-firing one. </LI> </UL> </P>

미분탄화력발전에서의 바이오매스 혼소 시 플랜트 성능특성 평가

문태영(Tae-Young Mun),Zelalem Tumsa Tefera,이은도(Uendo Lee),이정우(Jeung Woo Lee),양원(Won Yang) 한국연소학회 2014 한국연소학회지 Vol.19 No.3

The aims of this research were to evaluate effects of biomass co-firing to pulverized coal power plants and the variation of co-firing ratios on the plant efficiency related to power consumption of auxiliary system and flue gas characteristics such as production and component by process simulation based on the existing pulverized coal power plant. In this study, four kinds of biomass are selected as renewable fuel candidates for co-firing: wood pellet(WP), palm kernel shell(PKS), empty fruit bunch(EFB) and walnut shell(WS). Process simulation for various biomass fuels and co-firing ratios was performed using a commercial software. Gas side including combustion system and flue gas treatment system was considering with combination of water and steam side which contains turbines, condenser, feed water heaters and pumps. As a result, walnut shell might be the most suitable as co-firing fuel among four biomass since when 10% of walnut shell was co-fired with 90% of coal on thermal basis, flue gas production and power consumption of auxiliary systems were the smallest than those of other biomass co-firing while net plant efficiency was relatively higher than those of other biomass co-firing. However, with increasing walnut shell co-firing ratios, boiler efficiency and net plant efficiency were expected to decrease rather than coal combustion without biomass co-firing.

화재위치에 따른 CO₂소화제 전달특성

박찬수,최주석 한국화재소방학회 2003 한국화재소방학회논문지 Vol.17 No.4

선박기관실과 유사한 공간에 CO₂소화제를 방사하였을 때 화재위치에 따른 CO₂소화제 전달특성을 분석하기 위하여 전산묘사연구를 수행하였다. 화재위치를 변화시키면서 유동장과 농도장을 계산하였으며, 실험결과 화재화염위치가 유동패턴과 <TEX>$CO_2$</TEX>소화제 질량전달특성에 지배적인 영향을 미치는 것으로 나타났다. 1층과 2층으로 구성된 기관실의 2층 중앙 좌측영역에 화재화염이 위치하는 경우에는 에어 커턴과 같은 효과가 화재가 발생한 영역에서 나타났고, 이 영역으로의 질량전달을 방해하였다. 높이에 따른 특성에서는 1, 2충 중앙 좌측영역에 화재가 위치한 경우, <TEX>$CO_2$</TEX>소화제가 완전히 분사된 후에도 이 영역에 소화가능한계 이하의 등농도선이 형성되었다. 따라서 본 연구결과들은 <TEX>$CO_2$</TEX>소화장치 설비 시 <TEX>$CO_2$</TEX>소화제 분사노즐을 배열하는데 고려되어져야 할 것으로 생각된다. To analyze the transfer characteristics of CO₂extinguishant when extinguishant is injected into a closed space similar to a marine engine room, a numerical simulation was performed. Flow and Concentration fields are calculated according with the variation of the fire plume,s location. The results show that tile variation of fire plumes, location greatly effected on the flow patterns and the characteristics of CO₂extinguishant transfer. In case of the fire plume located at left region of the 2nd floor center in the engine room consisted of first and second floor, The effects similar to the air curtain is found and cut off the mass transfer. In the characteristics with hight, the iso-concentration line below the extinguishable limit is formed in the left region of the 1st and 2nd floor center after the CO₂extinguishant is completely injected. therefore I think that the results of this study are considered to arrange the CO₂injection nozzles for the CO₂fire fighting equipments.

국소방출방식 개념의 대향류 확산화염에서 CO2 소화효과에 관한 수치해석 연구

문선여,박충화,황철홍,오창보 한국화재소방학회 2012 한국화재소방학회논문지 Vol.26 No.4

The suppression mechanisms of carbon dioxide (CO2) as a representative fire suppression agent were revisited using a counterflow diffusion flame which could be applied the concept of a local application system. To end this, the low strain rate CH4/air counterflow diffusions with CO2 addition in either fuel or oxidizer stream were examined numerically using detailed-kinetic chemistry. Radiative heat loss due to radiating gas species including CO2 added was considered by the optically thin model (OTM). As a result, the critical CO2 volume fractions in the oxidizer stream required to extinguish the flame were in good agreement with the experimental data reported in the literature, while somewhat under-prediction was observed with CO2 added in the fuel stream. The surrogate agents were adopted to estimate the quantitative contribution with changing in global strain rate (ag) on the flame extinguishment among pure dilution effect, thermal effects including radiation heat loss and chemical effect due to the CO2 fire suppression agent. 소화약제의 국소방출방식 개념이 적용될 수 있는 대향류 확산화염을 대상으로 CO2 소화약제의 소화기구를 재조명하기 위한 연구가 시도되었다. 이를 위해 연료 또는 공기류에 CO2가 첨가된 낮은 총괄신장율의 CH4/air 대향류 확산화염이 상세반응을 이용한 수치해석을 통해 검토되었다. 첨가된 CO2를 포함한 복사 참여 화학종의 복사 열손실을 고려하기위하여 optically thin model(OTM)이 적용되었다. 주요 결과로서, 공기류에 첨가된 CO2의 소화농도 예측결과는 문헌에보고된 실험결과를 적절하게 예측하고 있으나, 연료류에 첨가된 경우 다소 과소 예측된 결과를 확인하였다. 소화효과에대한 정량적 분석을 위하여 가상의 소화약제의 개념이 도입되었다. CO2 소화효과의 분석을 통해 총괄신장율(ag)에 따른순수 희석효과, 복사 열손실 및 열용량에 의한 열적효과 그리고 CO2의 연쇄반응 억제를 통한 화학적 효과의 정량적 기여도를 구체적으로 확인할 수 있었다.

국소방출방식 개념의 대향류 확산화염에서 CO₂ 소화효과에 관한 수치해석 연구

문선여,박충화,황철홍,오창보,Mun, Sun-Yeo,Park, Chung-Hwa,Hwang, Cheol-Hong,Oh, Chang-Bo 한국화재소방학회 2012 한국화재소방학회논문지 Vol.26 No.4

소화약제의 국소방출방식 개념이 적용될 수 있는 대향류 확산화염을 대상으로 $CO_2$ 소화약제의 소화기구를 재조명하기 위한 연구가 시도되었다. 이를 위해 연료 또는 공기류에 $CO_2$가 첨가된 낮은 총괄신장율의 $CH_4$/air 대향류 확산화염이 상세반응을 이용한 수치해석을 통해 검토되었다. 첨가된 $CO_2$를 포함한 복사 참여 화학종의 복사 열손실을 고려하기 위하여 optically thin model(OTM)이 적용되었다. 주요 결과로서, 공기류에 첨가된 $CO_2$의 소화농도 예측결과는 문헌에 보고된 실험결과를 적절하게 예측하고 있으나, 연료류에 첨가된 경우 다소 과소 예측된 결과를 확인하였다. 소화효과에 대한 정량적 분석을 위하여 가상의 소화약제의 개념이 도입되었다. $CO_2$ 소화효과의 분석을 통해 총괄신장율($a_g$)에 따른 순수 희석효과, 복사 열손실 및 열용량에 의한 열적효과 그리고 $CO_2$의 연쇄반응 억제를 통한 화학적 효과의 정량적 기여도를 구체적으로 확인할 수 있었다. The suppression mechanisms of carbon dioxide ($CO_2$) as a representative fire suppression agent were revisited using a counterflow diffusion flame which could be applied the concept of a local application system. To end this, the low strain rate $CH_4$/air counterflow diffusions with $CO_2$ addition in either fuel or oxidizer stream were examined numerically using detailed-kinetic chemistry. Radiative heat loss due to radiating gas species including $CO_2$ added was considered by the optically thin model (OTM). As a result, the critical $CO_2$ volume fractions in the oxidizer stream required to extinguish the flame were in good agreement with the experimental data reported in the literature, while somewhat under-prediction was observed with $CO_2$ added in the fuel stream. The surrogate agents were adopted to estimate the quantitative contribution with changing in global strain rate ($a_g$) on the flame extinguishment among pure dilution effect, thermal effects including radiation heat loss and chemical effect due to the $CO_2$ fire suppression agent.

소사체의 혈중 헤모글로빈-일산화탄소 농도에 따른 연소형태 연구

최승복,오부열,최돈묵 한국화재소방학회 2012 한국화재소방학회논문지 Vol.26 No.3

Fire patterns have been used to determine the origin and cause of fires in every setting imaginable. However, it is very difficult to identify fire patterns and causes from the fire-damaged remains of a devastated structure. If someone was killed by the fire, it is possible to identify fire patterns by analyzing the Hb-CO concentration in charred bodies of deceased as well as the pace of the fire. For example, a low level of Hb-CO concentration in the charred bodies indicate a rapid fire with accelerants and the death was caused by severe heat and thick toxic fumes. However, a high level of Hb-CO concentration in the charred bodies demonstrates that the fire was slow and/or there was a flameless form of combustion. Thus, it is possible to identify fire patterns through analyzing the level of Hb-CO concentration on the dead from the fire. In this study, the Hb-CO concentration in the charred bodies was from 3 % at the case of gas burning oneself to death to 93 % at the death caused by smoldering fire. 심하게 소손된 화재현장은 남아 있는 잔존물만으로 초기 화재의 유형을 판단하기 곤란할 때가 많다. 화재로 인해 사람이 사망하였을 경우 혈중 헤모글로빈(Hb)-일산화탄소(CO) 농도는 생존 당시의 화재의 유형을 가늠할 수 있으며 촉진제를 사용한 급격한 화재의 경우 열기와 유독가스로 인해 재실자의 생존은 화재진행속도와 비례되어 체내 Hb-CO 농도는낮았으며, 훈소와 같이 서서히 진행되는 연소의 경우 오랜 시간 호흡하면서 체내에 축적되는 CO 농도는 증가하였다. 이러한 인체의 Hb-CO 농도를 분석하면 생존 시 어떠한 형태의 화재에 노출되었는지 알 수 있다. 휘발유로 분신한 자살의 경우를 포함해 훈소성 화재사에 이르기까지 Hb-CO 농도는 3 %에서 최고 93 %로 다양한 농도를 보였다.

UL 268 시험화원에 따른 CO센서의 화재감지센서로서의 적용성에 관한 연구

이춘하,성완기,이종화,김형권,지승욱,김시국 한국화재소방학회 2014 한국화재소방학회논문지 Vol.28 No.2

The purpose of this study is to test the adaptability of the CO sensor as a fire detector by analyzing its sensing characteristicson fire. In order to test the applicability, we designed and made a fire testing ground whose size is similar to thatregulated by UL 268, carried out real fire tests suggested by UL 268, and conducted a comparison analysis on the sensingcharacteristics between the CO sensor and a photoelectric smoke detector by different types of fire source. The experimentresult to the sensing characteristics of the CO sensor is about twice to three times faster than that of the photoelectricsmoke detector, proceeding with incomplete combustion such as paper and wood fire source in the initial fire. Especially in case of wood smoldering fire, sensing characteristics of the CO sensor is very excellent. 본 논문은 CO센서의 화재에 대한 감지특성을 분석 후 화재감지기로서의 적용성 판단을 하기 위한 논문이다. CO센서의 화재감지기로의 적용성을 판단하기 위해 UL 268에서 규정하고 있는 화재시험실과 유사한 규모의 화재실험장을 설계·제작하고, UL 268에서 제시된 화재시험기준에 준한 실화재실험을 실시하여 화원 종류에 따른 CO센서와 광전식연기감지기의 다양한 화원의 화재에서 발생하는 일산화탄소와 연기에 대한 감지특성을 측정하여 비교·분석하였다. 실험결과 종이화원 및 목재화원과 같이 불완전연소로 진행되는 초기화재에서 CO센서가 광전식연기감지기보다 약 2~3배 빠른 감지특성이 나타났다. 특히, 목재훈소화재에서 CO센서의 감지특성이 매우 우수한 것으로 나타났다.

온실가스 저감을 위한 암모니아 혼소가 초임계 화력 발전시스템 보일러에 미치는 열성능 영향성 평가

김성일(Seong-il Kim),곽형근(Hyung geun Kwak),양원(Won Yang) 한국연소학회 2021 한국연소학회지 Vol.26 No.4

Co-firing ammonia with coal is emerging as a transitional technology in the power industry for the major reduction of greenhouse gas emissions. Although ammonia has the disadvantages of low combustion reactivity and the generation of nitrogen oxides, it can effectively reduce greenhouse gas due to the generation of only moisture and nitrogen after the combustion. Therefore, for the efficient co-firing of the coal and ammonia in the power plant system, it is essential to evaluate the effect of co-firing ammonia on the boiler system. We selected the 870 MWe supercritical coal-fired boiler system and developed the process simulation model of the target boiler system. In this study, process simulation of the target boiler system was performed according to the ammonia co-firing ratio of 0, 5, 10, 20, and 30%. In addition, the effect of ammonia co-firing on the boiler thermal performance was evaluated according to the load condition and the quality of coal. As the ammonia co-firing ratio increases, the flue gas flow rate and the radiation and convective heat transfer rate decrease. Accordingly, the main and reheat steam temperatures decrease. Although the reduction of carbon dioxide is quantitatively confirmed according to the co-firing ammonia, the boiler thermal efficiency decreases due to the increase in the amount of moisture in the flue gas.

화재화염이 유동 및 CO₂소화제 전달특성에 미치는 영향

박찬수,최주석 한국화재소방학회 2002 한국화재소방학회논문지 Vol.16 No.4

선박기관실과 유사한 공간내로 <TEX>$CO_2$</TEX>소화제를 분사했을 때 화재화염이 공기유동 및 <TEX>$CO_2$</TEX>소화제전달 특성에 미치는 영향을 분석하기 위하여 수치해석을 수행하였다. 노즐 위치에 따라 유동장과 <TEX>$CO_2$</TEX>농도장을 계산하였다. 한 경우를 제외한 모든 경우에서 시계방향과 반시계방향 재순환 유동이 노즐 좌, 우측영역에 형성되었으며, 이러한 재순환 유동이 질량전달과 <TEX>$CO_2$</TEX>소화제 확산경로에 큰 영향을 미치는 것을 알 수 있었다. 화재화염이 위치한 1층 영역에서는 <TEX>$CO_2$</TEX>소화제 확산경로가 재순환 유동 확장경로와 일치하였다. To analyze the effect of fire plume on the characteristics of air flow and <TEX>$CO_2$</TEX>, extinguishant transfer when extinguishant is injected into a closed space similar to a marine engine room with fire plume, a numerical simulation on a space was performed. Flow fields and <TEX>$CO_2$</TEX>, concentration fields are calculated according with the variation of the location of nozzles. In all cases excepting the case of all nozzles located in the right side of ceiling, an counterclockwise & clockwise recirculation flow was found in the region of the right and left side of the nozzle on the second floor and such a recirculation flow greatly affected mass transfer and the diffusion process of <TEX>$CO_2$</TEX>, extinguishant. In the region of the first floor with fire plume, the diffusion process of <TEX>$CO_2$</TEX>, extinguishant was in agreement with the extension process of recirculation flow. It is considered that the result of this study can be useful to designing the arrangement of nozzles for the CO₂fire fighting equipments in a marine engine room.