Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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Design and Evaluation of Multiple Effect Evaporator Systems According to the Steam Ejector Position

증기 이젝터 위치에 따른 다중효용증발시스템의 설계 및 성능분석

  • Kim, Deukwon (Department of Mechanical Engineering, Graduate School KAIST) ;
  • Choi, Sangmin (Department of Mechanical Engineering, KAIST)
  • 김득원 (한국과학기술원 기계공학과 대학원) ;
  • 최상민 (한국과학기술원 기계공학과)
  • Received : 2016.08.08
  • Accepted : 2016.09.19
  • Published : 2016.11.10
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Abstract

The evaporation of water from an aqueous solution is widely used in the food, desalination, pulp, and chemical industries. Usually, a large amount of energy is consumed in the evaporation process to boil off water due to atmospheric pressure. As a way of improving the energy efficiency of the evaporation process, the combination of multiple effect evaporation and thermal vapor recompression has been proposed and has become a successful technique. In this study, 4 multiple-effect falling film type evaporators for sugar solution are designed and the energy efficiency of the system is analyzed in response to the selection of the steam ejector position. Energy efficiency is increased and vapor is more compressed in the steam ejector as the Thermal Vapor Recompression (TVR) is arranged in the rear part of the evaporator system. A simplified 0-dimensional evaporator model is developed using non-linear equations derived from mass balances, energy balances, and heat transfer equations. Steam economy is calculated to compare the evaporation performance of the 4 proposed evaporators. The entrainment ratio, compression ratio, and expansion ratio are computed to check the ejector performance.

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References

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