Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Flow Behavior and Mixing Characteristics of Rice Husk/Silica Sand/Rice Husk Ash

왕겨/모래/왕겨 회재의 유동 및 혼합 특성 연구

  • Kim, Bo Hwa (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Seo, Myung Won (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Kook, Jin Woo (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Choi, Hee Mang (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Ra, Ho Won (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Yoon, Sang Jun (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Mun, Tae Young (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Kim, Yong Ku (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Lee, Jae Goo (Climate change research division, Korea Institute of Energy Research (KIER)) ;
  • Rhee, Young Woo (Graduate School of Energy Science and Technology, Chungnam National University (CNU))
  • 김보화 (한국에너지기술연구원 기후변화연구본부) ;
  • 서명원 (한국에너지기술연구원 기후변화연구본부) ;
  • 국진우 (한국에너지기술연구원 기후변화연구본부) ;
  • 최희망 (한국에너지기술연구원 기후변화연구본부) ;
  • 라호원 (한국에너지기술연구원 기후변화연구본부) ;
  • 윤상준 (한국에너지기술연구원 기후변화연구본부) ;
  • 문태영 (한국에너지기술연구원 기후변화연구본부) ;
  • 김용구 (한국에너지기술연구원 기후변화연구본부) ;
  • 이재구 (한국에너지기술연구원 기후변화연구본부) ;
  • 이영우 (충남대학교 에너지과학기술대학원)
  • Received : 2016.02.05
  • Accepted : 2016.03.04
  • Published : 2016.08.01
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Abstract

We investigate fluidization characteristics of the mixture of rice husk, silica sand and rice husk ash as a preliminary study for valuable utilization of rice husk ash obtained from gasification of rice husk in a fluidized bed reactor. As experiment valuables, the blending ratio of rice husk and sand (rice husk: sand) is selected as 5:95, 10:90, 20:80 and 30:70 on a volume base. Rice husk ash was added with 6 vol% of rice husk for each experiment and air velocity to the reactor was 0~0.63 m/s. In both rice husk/sand and rice husk/sand/ash mixture, the minimum fluidization velocity (Umf) is observed as 0.19~0.21 m/s at feeding of 0~10 vol.% of rice husk and 0.30 m/s at feeding of 20 vol.% of rice husk. With increasing the amount of rice husk up to 30 vol.%, $U_{mf}$ can not measure due to segregation behavior. The mixing index for each experiment is determined using mixing index equation proposed by Brereton and Grace. The mixing index of the mixture of rice husk/sand and rice husk/sand/ash was 0.8~1 and 0.88~1, respectively. The optimum fluidization condition was found for the good mixing and separation of rice husk ash.

Lab-scale 기포유동층 반응기(D=0.1 m, H=1.5 m)에서 왕겨와 모래를 혼합하여 가스화를 통해 합성가스를 얻고 남은 왕겨 회재는 고부가가치 물질로 사용하기 위한 연구의 선행연구로서 왕겨/유동사/왕겨 회재(실리카)의 혼합 및 유동 특성을 규명하였다. 왕겨/유동사를 5:95, 10:90, 20:80, 30:70의 부피비로 유속 범위(0~0.63 m/s)조건으로 수행하였으며, 또한 왕겨 회재는 왕겨를 기준으로 부피비 6%로 결정하였다. 왕겨/유동사, 왕겨/유동사/왕겨 회재의 혼합실험을 통해 왕겨 부피비 0%, 5%, 10%에서는 최소유동화속도가 0.19~0.21m/s임을 확인하였고, 20%일때는 0.3m/s로 증가하였으며, 30%일때는 분리현상이 나타나 최소유동화속도가 측정 되지 않았다. 또한, 실험데이터에 따라 Brereton과 Grace의 mixing index를 이용하여 각 조건 별로 mixing index값을 도출한 결과 왕겨/유동사의 혼합은 0.8~1, 왕겨/유동사/왕겨 회재의 혼합은 0.88~1 사이임을 확인하였다. 이를 통하여 왕겨/유동사의 혼합과 왕겨/유동사/왕겨 회재 혼합의 최적 조업조건을 도출할 수 있었으며, 운전조건을 결정할 수 있었다.

Keywords

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