Bench-scale 연소로에서 가스 혼소를 통한 초 저 NO_x 석탄 버너 개발 연구

채태영,이재욱,이영재,양원,Chae, Taeyoung,Lee, Jaewook,Lee, Youngjae,Yang, Won 한국청정기술학회 2022 청정기술 Vol.28 No.2

This study developed and tested an ultra-low NO_x burner in an 80 kW combustion furnace. The experiment was conducted in an 80 kW single burner combustion furnace with changing the swirl numbers, total equivalence ratios, and primary/secondary oxidizer ratios. In this study, liquefied natural gas (LNG) was used as an auxiliary fuel to significantly reduce NO_x production. In a thermal power plant, the amount of NO_x generated during coal combustion is about 300 ppm. However, using the burner tested in this study, it was possible to reduce the amount of NO_x generated via LNG co-firing to 40 ppm. If the input amount of the primary oxidizer is enough for the gas to be completely combusted and the gas and coal are added simultaneously, the combusted gas forms a high-temperature region at the burner outlet and volatilizes the coal. As a result, the N contained in the devolatilized coal is discharged. Therefore, when the coal is subsequently burned, the amount of NO_x produced decreases because there is almost no N remaining in the coal. If a thermal power plant burner is developed based on the results of this study, it is expected that the NO_x generation will be significantly lower in the early stage of combustion.

80 kW 초 저 NOx 단일 버너 연소로에서 NOx 감소를 위한 운전특성 연구

채태영,Chae, Taeyoung 한국청정기술학회 2020 청정기술 Vol.26 No.3

본 연구는 80 kW급 단일버너 연소로에서 석탄 연소시 초저 NOx 버너 설계인자를 평가하기 위한 실험적 연구이다. 버너 설계 인자인 선회강도, 총 과잉 공기비, 버너 영역 과잉공기비, 1차/2차 산화제 비율, OFA 비율을 변경하여 총 81개 조건을 대상으로 실험을 수행 하였다. 실험 결과, 선회류가 약하면 연소로 출구에서 CO가 증가하고 연소로 내부 온도가 감소하는 것으로 나타났다. 그러나, 선회류가 강하면 NOx가 증가하기 때문에 적절한 선회류 강도를 결정하는 것은 NOx를 줄이는 데 중요한 요소이다. 1차/2차 산화제의 비율 또한 중요한 요소이며, 생성 된 NOx의 양은 산화제의 비율에 따라 달라진다. 2차 산화제의 비율이 증가하면 연소 초기에 NOx 방출량이 증가하고, 측정 된 배출구 NOx가 증가하게 된다. 그러나, 2차 산화제 비율이 감소하면 화염이 길어지고 CO가 증가한다. 본 연구에 사용 된 연소 시스템은 적절한 조건이 만족 될 때 O₂ 6%를 기준으로 최소 NOx가 82 ppm 생성되는 것으로 확인 되었다. 본 실험에서 대상으로 한 버너는 연소용 공기를 석탄을 이송하는 1차공기 외에 2차공기로 하나의 산화제 유동만 사용하는 방식으로서 추후 3차 및 4차공기로 분할하여 화염형태 및 반응을 세밀하게 제어할 경우 추가적인 NOx 감소가 가능할 것으로 예상된다. This experimental study investigates the design parameters to achieve ultra low NOx combustion of coal using a 80 kW capacity single-burner furnace. The influence of key design parameters such as SN, overall and burner-zone equivalence ratios, primary/secondary air ratio, overfire air (OFA) ratio were tested for a total of 81 cases. The results showed that weak swirl intensity of the burner leads to higher NOx emission whereas strong swirl intensity accompanies increased CO concentration desipte lower NOx emission. Therefore, finding an appropirate swirl intensity is essential for the burner design. Larger flow rate of secondary air increased NOx emission, whereas smaller flow rate stretches the flame and increased CO emission. The lowest NOx emission of 82 ppm (6% O₂) was achieved at the optimal condition of the present burner deisgn. It is expected to furrther lower the NOx emission by introducing splitting the burner secondary air into three or four streams.

80 kW<SUB>th</SUB>급 미분탄 연소 시스템에서 하수슬러지 혼소시 연소 특성 연구

채태영(Taeyoung Chae),이재욱(Jaewook Lee),이영재(Youngjae Lee),양원(Won Yang) 한국청정기술학회 2019 청정기술 Vol.25 No.1

하수슬러지의 열화학적 처리는 수분을 제거하여 연료로 사용되는 하수슬러지의 수분 함량을 낮추어 주는 기술이다. 열화학적 처리된 하수슬러지는 열량이 높아지기 때문에 에너지 집약적 과정이라고 할 수 있다. 이러한 공정 중에 소비되는 에너지를 절약하기 위해 하수슬러지의 수열 탄화 공정을 사용하였다. 수열탄화 공정은 하수슬러지를 사전 건조 없이 깨끗한 고체연료로 전환할 수 있다. 본 연구는 수열탄화 하수슬러지와 미분탄 연소 시스템의 혼소 특성을 조사하는 것을 목적으로 한다. 혼소 시 생성되는 유해물질 및 연소 효율의 변화를 측정하는 것을 목적으로 한다. 본 연구에 사용 된 연소 시스템은 80kWth급 연소로로서 1기의 선회류 버너가 장착되어 있다. 두 가지의 석탄을 주 연료로 사용하였고, 하수슬러지의 혼소율은 열량 기준 0% ~ 10%까지 진행하였다. 실험 결과 NOx는 400 ~ 600 ppm, SOx는 600 ~ 700 ppm 사이를 유지하였고, CO는 100 ppm 전후로 일정하게 유지되어 안정적인 연소를 확인할 수 있었다. 하수슬러지를 혼소할 경우, 혼소율이 증가할수록 NOx와 SOx의 배출량도 증가하였으나 그 편차가 크지 않았다. 연소 배가스에 포함된 오염 물질 배출은 혼소 비율 보다 주 연료인 석탄의 조성에 의해 크게 영향을 받는 것으로 밝혀졌다. Thermochemical treatment of sewage sludge is an energy-intensive process due to its high moisture content. To save the energy consumed during the process, the hydrothermal carbonization process for sewage sludge can be used to convert sewage sludge into clean solid fuel without pre-drying. This study is aimed to investigate co-firing characteristics of the hydrothermally carbonated sewage sludge (HCS) to a pulverized coal combustion system. The purpose of the measurement is to measure the pollutants produced during co-firing and combustion efficiency. The combustion system used in this study is a furnace with a down-firing swirl burner of a 80 kWth thermal input. Two sub-bituminous coals were used as a main fuel, and co-firing ratio of the sewage sludge was varied from 0% to 10% in a thermal basis. Experimental results show that NOx is 400 ~ 600 ppm, SOx is 600 ~ 700 ppm, and CO is less than 100 ppm. Experimental results show that stable combustion was achieved for high co-firing ratio of the HCS. Emission of NOx and SOx was decreased for higher co-firing ratio in spite of the higher nitrogen contents in the HCS. In addition, it was found that the pollutant emission is affected significantly by composition of the main fuel, regardless of the co-firing ratios.

125 ㎿<SUB>th</SUB> Oxy-PC Corner Firing Boiler 수치해석 연구

채태영(Taeyoung Chae),류태우(TaeU Yu),방병열(Byung Reol Bang),양원(Won Yang) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.38

Characteristics of oxy-PC(Pulverized coal) combustion are one of the key parameters for design of a PC boiler. In this study, a conventional corner-firing boiler for a 125 ㎿th PC power plant was numerically simulated under the conditions of air-PC and oxy-PC combustion, using FLUENT 6.3. We used discrete phase model for simulating behavior of coal particles, and drying, pyrolysis, char combustion, char gasification and volatile performed for various design conditions of an oxy-PC corner-firing burner such as flue gas recirculation ratio, velocities, temperatures and oxygen concentrations of the primary/secondary oxidizer. Simulation results of oxy-PC combustion were also compared with convectional air-PC conditions, and optimum operation conditions under the view of combustion, NOX emission and radiative heat transfer were discussed.

실험실 규모의 석탄 연소시스템에서 합성가스 재연소 특성 연구

채태영(Taeyoung Chae),이재욱(Jaewook Lee),류창국(Changkook Ryu),양원(Won Yang) 한국연소학회 2014 KOSCOSYMPOSIUM논문집 Vol.2014 No.5

전산유동 해석을 이용한 Oxy-PC 버너 형상 변화에 따른 화염 특성 연구

채태영(Taeyoung Chae),류창국(Changkook Ryu),양원(Won Yang) 한국연소학회 2012 KOSCOSYMPOSIUM논문집 Vol.- No.44

The oxygen concentration of primary oxidizer is decided under 10% due to flammable risk. It can be a spontaneous combustion inside burner or tube if the excess oxygen is added to primary oxidizer in Oxy-PC burner. In this case, the rest oxygen which can not be injected to primary oxidizer should be injected to another port. If added it to a second oxidizer, the ignition is unstable at outlet of burner. Accordingly an extra lancing port is needed to insert into the burner unlike other common air mode. And the flame formation and combustion characteristic differ from lancing port position. Therefore we observed flame formation which has stable combustion characteristic according to the shape and position of lancing port.

1㎿<SUB>th</SUB> 석탄 연소로에서 바이오매스 혼소 및 재연소를 통한 NOx 저감 연구

채태영(Taeyoung Chae) 한국연소학회 2020 한국연소학회지 Vol.25 No.3

This study was investigated co-firing of biomass and coal for NOx reduction using 1 MWth multi-burner furnace. NOx acts as a precursor of particulate matter formation and the minimization of its release from coal combustion has becomes an urgent issue. Three biomass types (wood pellet, torrefied biomass, and empty fruit bunch) were tested at different ratios through direct co-firing with coal and separate feeding as reburn fuel. It was found that the NOx reduction was achieved by up to 25% by direct co-firing and up to 50% by reburning. Although co-firing biomass as reburn fuel was more efficient for NOx reduction, further investigation is required for its applications in commercial plants.

60kW 연소 시스템에서 합성가스 재연소 특성 연구

채태영(Taeyoung Chae),이재욱(Jaewook Lee),조가람(Garam Jo),류창국(Changkook Ryu),강기섭(Kieseop Kang),양원(Won Yang) 한국연소학회 2013 KOSCOSYMPOSIUM논문집 Vol.2013 No.12

An experimental study was performed in a 60 kWth down-fired furnace to investigate characteristics of syngas reburning in combustion systems which use LNG and coal as a main fuel, reburn fuels used were CH4, CO, and H2. Measurements of local mean 02, CO, CO2, and NOx concentrations, and gas temperatures have been performed in the furnace for various conditions: species of the reburn fuels and stoichiometic ratio in the reburn zone. The reburning ratio tested for gas fuels was ranged from 5% to 20%, and 10% coal based on. In the result, maximum NOx reduction was 52.4% for LNG and 33.4% for coal. CH4 was observed to have the most significant effect to reduce NOx for both LNG and coal case. Additionally, NOx was observed to be more reduced for lower stoichimetric ratio in the reburn zone; i.e. higher reburn ratio.

전산유동해석을 이용한 100 MW<SUB>e</SUB>급 석탄 순산소 연소 실증 보일러의 설계 및 운전조건 평가

채태영(Taeyoung Chae),박상현(Sanghyun Park),홍재현(Jaehyeon Hong),양원(Won Yang),이상훈(Sanghoon Lee),류창국(Changkook Ryu) 한국연소학회 2011 한국연소학회지 Vol.16 No.2

??As one of the main technologies for carbon capture and storage in power generation, oxy-coal combustion is being developed for field demonstration in Korea. This study presents the results of numerical simulation for combustion in a single-wall-fired 100 MWe-scale boiler proposed for the initial design of the demonstration plant. Using a commercial CFD code, the detailed combustion, flow and heat transfer characteristics were assessed both for air-mode and oxy-mode combustion. The results show that stable combustion can be achieved in the dual mode operation with the current boiler configuration. However, the differences in the flow pattern and heat transfer between the two combustion modes need to be considered in the design and operation which is mainly due to the larger density and specific heat of CO₂ compared to N₂. Further development of the boiler design is required using improved numerical modeling for radiative heat transfer and combustion.

미분탄 연소 유연운전에 따른 연소 특성 및 회분 점착 특성 분석

채태영(Taeyoung Chae),이재욱(Jaewook Lee),곽형근(Hyunggeun Kwak),이영재(Youngjae Lee),양원(Won Yang) 한국에너지기후변화학회 2022 한국에너지기후변화학회 학술대회 Vol.2022 No.5