Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

Experimental Study on Characteristics of Ammonia Conversion Rate of Urea Aqueous Solution in 250℃ Exhaust Pipe

250℃ 이하 배기관에서 우레아 수용액의 암모니아 전환율 특성에 관한 실험적 연구

  • Ku, Kun Woo (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Park, Hong Min (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Hong, Jung Goo (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.)
  • 구건우 (경북대학교 기계공학부) ;
  • 박홍민 (경북대학교 기계공학부) ;
  • 홍정구 (경북대학교 기계공학부)
  • Received : 2014.07.25
  • Accepted : 2014.11.19
  • Published : 2015.02.01
Download PDF
⟨ Previous Next ⟩

Abstract

The NOx emissions from diesel engines and industrial boilers are a major cause of environmental pollution. The selective catalytic reduction of urea is an aftertreatment technology that is widely used for the reduction of NOx emissions. The objective of this study was to investigate the characteristics of the thermal decomposition of a urea aqueous solution using laboratory-scale experimental equipment under conditions similar to those of marine diesel engines. A 40 wt. urea aqueous solution was used in this study. It was found that the total conversion rate varied with the inflow gas conditions and flow rates of the urea aqueous solution. In addition, there were conversion rate differences between NH3 and HNCO. At inflow gas temperature conditions of $210^{\circ}C$ and $250^{\circ}C$, the $NH_3$ conversion rate was found to be higher than that of the HNCO, depending on the residence time.

디젤 엔진과 산업용 보일러에서의 질소산화물(NOX) 배출은 환경오염을 유발시키는 주요물질 중의 하나이다. 이러한 질소산화물 발생을 저감시키기 위한 방법으로 후처리 기술 중의 하나인 우레아 선택적 촉매 환원(Urea-SCR)기술이 널리 사용되고 있다. 본 연구에서는 선박용 디젤엔진의 배기가스 조건을 모사한 실험실 스케일의 실험장치를 통해 우레아 수용액의 열분해 특성에 대해 고찰하였다. 40 wt. %의 우레아 농도를 가진 우레아 수용액을 사용하였고, 모사가스의 온도와 유속변화, 우레아 수용액의 유량에 따른 총 전환율 뿐만 아니라 암모니아($NH_3$)와 이소시안산(HNCO)의 전환율 차이를 알아보았다. $210^{\circ}C$와 $250^{\circ}C$ 모사가스 온도에서 체류시간에 따라 암모니아의 전환율이 이소시안산의 전환율보다 높게 나타남을 확인하였다.

Keywords

References

  1. Ciardelli, C., Nova, I., Tronconi, E., Chatterjee, D., Bandl-Konrad, B., Weibel, M. and Krutzsch, B., 2007, "Reactivity of NO/$NO_2$-$NH_3$ SCR System for Diesel Exhaust Aftertreatment: Identification of the Reaction Network as a Function of Temperature and $NO_2$ Feed Content," Applied Catalysis B, Vol. 70, pp. 80-90. https://doi.org/10.1016/j.apcatb.2005.10.041
  2. Nakajima, F. and Hamada, I., 1996, "The State of the Art Technology of NOx Control," Catalysis Today, Vol. 29, pp. 109-115. https://doi.org/10.1016/0920-5861(95)00288-X
  3. IMO Resolution MEPC. 176 (58), Revised Marpol Annex VI.
  4. Hirata, K., Niki, Y., Kawada, M. and Iida, M., 2009, "Development of Marine SCR System and Field Test on Ship," International Symposium on Marine Engineering, BEXCO, Busan, Oct. 2009.
  5. An, T. H. and Kim, M. Y., 2014, "Numerical Investigation of the Spray Behavior and Flow Characteristics of Urea-Water Solution Injected into Diesel Exhaust Pipe," Trans. Korean Soc. Mech. Eng. B, Vol. 38, No. 1, pp. 41-48. https://doi.org/10.3795/KSME-B.2014.38.1.041
  6. Lundstrom, A., Snelling, T., Morsing, P., Gabrielsson, P., Senar, E. and Olsson, L., 2011, "Urea Decomposition and HNCO Hydrolysis Studied over Titanium Dioxide, Fe-Beta and ${\gamma}$-Alumina," Applied Catalysis B, Vol. 106, pp. 273-279. https://doi.org/10.1016/j.apcatb.2011.05.010
  7. Suzuki, T., Saito, A., Fujimatsu, T. and Hayashida, K., 2007, "Development of A Simple System of Dropsizing: Part 1: Development Story and Outline of The System [in Japanese]," Journal of the ILASS-Japan, Vol. 16, No. 54, pp.34-46.
  8. Suzuki, T., Saito, A., Fujimatsu, T. and Hayashida, K., 2008, "Development of A Simple System of Dropsizing: Part 2: Some Examples of Measurements [in Japanese]," Journal of the ILASS-Japan, Vol. 17, No. 58, pp. 44-51.
  9. Dong, H., Shuai, S. and Wang, J., 2008, "Effect of Urea Thermal Decomposition on Diesel NOx-SCR Aftertreatment Systems," SAE Technical Paper, 2008-01-1544.
  10. Lefebvre, A. H., 1989, Atomization and Sprays, Hemisphere Publishing Corporation, New York, pp.136-140.
  11. Kim, J. Y., Ryu, S. H. and Ha, J. S., 2004, "Numerical Prediction on the Characteristics of Spray-Induced Mixing and Thermal Decomposition of Urea Solution in SCR System," 2004 Fall Technical Conference of the ASME Internal Combustion Engine Division, pp. 165-170.
  12. Bernhard, A. M., 2012, "Catalytic Urea Decomposition, Side-Reactions and Urea Evaporation in the Selective Catalytic Reduction of NOx," Ph.D dissertation, ETH Zurich, Switzerland, Thesis No. 20813.