Applied Chemistry for Engineering (공업화학)

The Korean Society of Industrial and Engineering Chemistry (한국공업화학회)
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Analysis on the Heat Exchange Efficiency of Kraft Recovery Boiler by Nose Arch Structure Using CFD

CFD를 활용한 크래프트 회수보일러 내부 노즈 아치 구조에 따른 열교환 효율 분석

  • Jang, Yongho (Green Materials and Processes R&D Group, Korea Institute of Industrial Technology) ;
  • Park, Hyundo (Green Materials and Processes R&D Group, Korea Institute of Industrial Technology) ;
  • Lim, Kyung pil (Project Part, MOORIM P&P Co.) ;
  • Park, Hansin (Project Part, MOORIM P&P Co.) ;
  • Kim, Junghwan (Green Materials and Processes R&D Group, Korea Institute of Industrial Technology) ;
  • Cho, Hyungtae (Green Materials and Processes R&D Group, Korea Institute of Industrial Technology)
  • 장용호 (한국생산기술연구원 친환경재료공정연구그룹) ;
  • 박현도 (한국생산기술연구원 친환경재료공정연구그룹) ;
  • 임경필 (무림P&P(주) 프로젝트부) ;
  • 박한신 (무림P&P(주) 프로젝트부) ;
  • 김정환 (한국생산기술연구원 친환경재료공정연구그룹) ;
  • 조형태 (한국생산기술연구원 친환경재료공정연구그룹)
  • Received : 2021.01.28
  • Accepted : 2021.02.19
  • Published : 2021.04.10
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Abstract

A kraft recovery boiler produces steam for power generation by the combustion of black liquor from the kraft pulping process. Since saturated steam became superheated in a superheater above the furnace, it is important to increase the heat exchange efficiency for the superheated steam production and power generation. A nose arch at the bottom of the superheater is important for blocking radiation from the furnace which causes corrosion of the superheater. But the nose arch is the main reason for creating a recirculation region and then decreasing the heat exchange efficiency by holding cold flue gas after the heat transfer to saturated steam. In this study, the size of recirculation region and the temperature of flue gas at the outlet were analyzed by the nose arch structure using computational fluid dynamics (CFD). As a result, when the nose arch angle changed from 106.5° (case 1) to 150° (case4), the recirculation region of flue gas decreased and the heat exchange efficiency between the flue gas and the steam increased by 10.3%.

크래프트 회수보일러(kraft recovery boiler)는 펄프 공정에서 생성된 흑액을 연소하여 발전용 스팀을 생산하는 장치이다. 특히 연소로 상단부에 존재하는 과열기(superheater)는 포화 증기가 연소가스와 열교환을 통해 과열 증기로 전환되는 구간으로, 연소가스와 포화 증기 사이의 열교환 효율 향상은 발전용 과열 증기 생산량 증가 및 발전 효율이 증가하므로 매우 중요하다. 과열기 하단부에 위치한 노즈 아치는 과열기의 부식의 원인이 되는 연소로에서 발생한 복사열을 막는 중요한 역할을 하지만, 연소가스 유동을 방해하여 포화증기와 열교환이 끝난 저온의 연소가스가 과열기를 나가지 못하고 재순환되어 열교환 효율을 저하시키는 직접적인 원인이 된다. 따라서 본 연구에서는 CFD를 활용하여 노즈아치 구조에 따른 재순환 영역의 크기와 연소가스 출구 온도를 비교하였다. 결과적으로 노즈 아치 하단부 각도를 106.5°에서 150°로 변경할 경우 연소가스의 재순환 영역이 감소하여 연소가스와 과열기 사이의 열교환 효율이 10.3% 향상되는 것을 확인하였다.

Keywords

References

  1. V. Maakala, M. Järvinen, and V. Vuorinen, Optimizing the heat transfer performance of the recovery boiler superheaters using simulated annealing, surrogate modeling, and computational fluid dynamics, Energy, 160, 361-377 (2018). https://doi.org/10.1016/j.energy.2018.07.002
  2. J. H. Noh, D. S. Kim, and Y. J. Sung, The isolation of kraft lignin from black liquor during Korean red pine kraft pulping and evaluation of the isolated kraft lignin, Journal of Korea TAPPI, 49, 170-177 (2017).
  3. A. Tejado, C. Pena, J. Labidi, J. M. Echeverria, and I. Mondragon, Physico-chemical characterization of lignins from different sources for use in phenol-formaldehyde resin synthesis, Bioresource Technol., 98, 1655-1663 (2007). https://doi.org/10.1016/j.biortech.2006.05.042
  4. J. H. Cho, Environmental features and actions of pulp & paper, Journal of Korea TAPPI, 41, 13-21 (2009).
  5. B. Emami, Numerical Simulation of Kraft Recovery Boiler Sootblower Jets, PhD Dissertation, University of Toronto, Toronto, Canada (2009).
  6. J. Hu, Q. Zhang, and D. J. Lee, Kraft lignin biorefinery: A perspective, Bioresource Technol., 247, 1181-1183 (2018). https://doi.org/10.1016/j.biortech.2017.08.169
  7. E. Vakkilainen, Kraft Recovery Boilers - Principles and Practice, Suomen Soodakattilayhdistys r.y., Helsinki, Finland (2005).
  8. R. Horton, T. Grace, and T. Adams, The effects of black liquor spray parameters on combustion behavior in recovery furnace simulation, IPST Technical Paper Series, 435, 1-33 (1992).
  9. A. Lundborg, Simulation of the Flue Gas Flow through the Superheater in a Recovery Boiler, Master Dissertation, KTH-Royal Institute of Technology, Stockholm, Sweden (2005).
  10. K. J. Tak and J. H. Kim, Corrosion effect on inspection and replacement planning for a refinery plant, Comput. Chem. Eng., 117, 97-104 (2018). https://doi.org/10.1016/j.compchemeng.2018.05.027
  11. M. Kawaji, X. H. Shen, H. Tran, S. Esaki, and C. Dees, Prediction of heat transfer in the kraft recovery boiler superheater region, Tappi Journal, 78, 214-221 (1995).
  12. R. Holkar, B. Ramdas, E. Kunal, and B. Haridas, Cfd analysis of gas flow behaviour in economizer, J. Mech. Civil Eng., 11, 31-39 (2014).
  13. M. Granda, M. Trojan, and D. Taler, CFD analysis of steam superheater operation in steady and transient state, Energy, 199, 117423 (2020). https://doi.org/10.1016/j.energy.2020.117423
  14. K. Kumar, Integrated Computational Fluid Dynamics and 1D Process Modelling for Superheater Region in Recovery Boiler, Master Dissertation, Aalto University, Helsinki, Finland (2019).
  15. E. Vakkilainen, R. Horton, and T. Adams, The effect of recovery furnace bullnose designs on upper furnace flow and temperature profiles, IPST Technical Paper Series, 436, 1-26 (1992).
  16. V. Maakala, M. Jarvinen, and V. Vuorinen, Computational fluid dynamics modeling and experimental validation of heat transfer and fluid flow in the recovery boiler superheater region, Appl. Therm. Eng., 139, 222-238 (2018). https://doi.org/10.1016/j.applthermaleng.2018.04.084
  17. ANSYS Fluent User's Guide, USA (2019).
  18. ANSYS Fluent Theory Guide, USA (2013).
  19. H. T. Cho, B. J. Cha, S. W. Kim, J. W. Ryu, J. H. Kim, and I. Moon, Numerical analysis for particle deposit formation in reactor cyclone of residue fluidized catalytic cracking, Ind. Eng. Chem. Res., 52, 7252-7258 (2013). https://doi.org/10.1021/ie302509q
  20. H. T. Cho, J. H. Kim, C. H. Park, K. H. Lee, M. J. Kim, and I. Moon, Uneven distribution of particle flow in RFCC reactor riser, Powder Technol., 312, 113-123 (2017). https://doi.org/10.1016/j.powtec.2017.01.025
  21. J. P. Van Doormaal and G. D. Raithby, Enhancements of the SIMPLE method for predicting incompressible fluid flows, Numerical Heat Transfer, 7, 147-163 (1984).