Journal of the Korean Society of Marine Environment & Safety (해양환경안전학회지)

The Korean Society of Marine Environment and safety (해양환경안전학회)
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Treatment Technology of N2O by using Bunsen Premixed Flame

분젠 예혼합 화염을 활용한 아산화질소 처리기술에 관한 연구

  • Jin, Si Young (Division of Marine System Engineering, Korea Maritime & Ocean University) ;
  • Seo, Jaegeun (Division of Marine System Engineering, Korea Maritime & Ocean University) ;
  • Kim, Heejae (Division of Marine System Engineering, Korea Maritime & Ocean University) ;
  • Shin, Seung Hwan (Division of Marine System Engineering, Korea Maritime & Ocean University) ;
  • Nam, Dong Hyun (Division of Marine System Engineering, Korea Maritime & Ocean University) ;
  • Kim, Sung Min (Division of Marine System Engineering, Korea Maritime & Ocean University) ;
  • Kim, Daehae (Clean Energy System R&D Department, Korea Institute of Industrial Technology (KITECH)) ;
  • Yoon, Sung Hwan (Division of Marine System Engineering, Korea Maritime & Ocean University)
  • 진시영 (한국해양대학교 기관시스템공학부 학부) ;
  • 서재근 (한국해양대학교 기관시스템공학부 학부) ;
  • 김희재 (한국해양대학교 기관시스템공학부 학부) ;
  • 신승환 (한국해양대학교 기관시스템공학부 학부) ;
  • 남동현 (한국해양대학교 기관시스템공학부 학부) ;
  • 김성민 (한국해양대학교 기관시스템공학부 학부) ;
  • 김대해 (한국생산기술연구원 청정에너지시스템연구부문) ;
  • 윤성환 (한국해양대학교 기관시스템공학부)
  • Received : 2020.12.01
  • Accepted : 2021.02.25
  • Published : 2021.02.28
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Abstract

Nitrous oxide is a global warming substance and is known as the main cause of the destruction of the ozone layer because its global warming effect is 310 times stronger than carbon dioxide, and it takes 120 years to decompose. Therefore, in this study, we investigated the characteristics of NOx emission from N2O reduction by thermal decomposition of N2O. Bunsen premixed flames were adopted as a heat source to form a high-temperature flow field, and the experimental variables were nozzle exit velocity, co-axial velocity, and N2O dilution rate. NO production rates increased with increasing N2O dilution rates, regardless of nozzle exit velocities and co-axial flow rates. For N2O, large quantities were emitted from a stable premixed flame with suppressed combustion instability (Kelvin Helmholtz instability) because the thermal decomposition time is not sufficient with the relatively short residence time of N2O near the flame surface. Thus, to improve the reduction efficiency of N2O, it is considered effective to increase the residence time of N2O by selecting the nozzle exit velocities, where K-H instability is generated and formed a flow structure of toroidal vortex near the flame surface.

아산화질소(Nitrous oxide, N2O)는 지구온난화 물질의 하나로 이산화탄소에 비해 지구온난화효과가 310배 강하고 분해하는데 120년이 소요되기 때문에 오존층 파괴에 주범으로 알려져 있다. 따라서 본 연구에서는 N2O를 저감하기 위해 고온 열분해 기술을 적용하여 N2O 저감 공정에서 발생하는 NOx 배출 특성에 대해 조사하였다. 고온 유동장을 형성하기 위해 동축 분젠 예혼합 화염을 열원으로 채택하였으며 실험 변수로는 노즐출구속도, 동축류 속도 및 N2O 희석률로 설정하였다. 실험 결과, NO 생성률은 노즐출구속도 및 동축류 유량에 관계없이 N2O 희석률이 증가함에 따라 증가하였다. N2O의 경우에는 연소 불안정성(Kelvin Helmholtz 불안정)이 억제된 안정된 예혼합 화염에서 다량으로 배출되었는데, 이는 화염 면 부근에서 감소된 N2O의 체류시간으로 인해 열분해 시간이 충분하지 않기 때문인 것으로 사료된다. 따라서 N2O의 저감 효율을 증진시키기 위해서는 K-H 불안정성이 발생되는 노즐출구속도를 선정하여 화염 면 부근에서 발생되는 와류(toroidal vortex) 형태의 유동 구조를 형성하는 것이 N2O의 체류시간을 증가시키는데 효과적인 것으로 판단된다.

Keywords

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