Process Design and Analysis of BOG Re-liquefaction System with Pre-liquefaction of NGL

NGL 분리식 BOG 재액화 공정 고안 및 해석

Yun, Sang-Kook

  • Received : 2015.03.09
  • Accepted : 2015.06.11
  • Published : 2015.06.28


The boil-off-gases(BOG) in cryogenic LNG storage tanks are generating continuously due to the heat leakage and need to be re-liquefied by the effective way. As the present method to reliquefy BOG is using LNG cold energy to be supplied after low pressure primary pump, the demand of LNG flow rate should be over 10 times of BOG produced rate to reliquefy it. This research invented new effective re-liquefaction system having only 3~4 times of LNG flow rate against unit BOG, that the pre-liquefaction process of NGL and the use of high pressure LNG cold energy after secondary pump. By the analysis, it could be high efficient reliquefying system for all amount of BOG treatment even during the summer time, and improvement of operation safety and efficiency of LNG terminal.


LNG tank;BOG re-liquefaction;NGL pre-liquefaction;LNG cold energy


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