Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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A Simulation Study on the Cascade Refrigeration Cycle for the Liquefaction of Natural Gas [1]

천연가스 액화를 위한 캐스케이드 냉동사이클의 전산모사에 대한 연구 [1]

  • Kim, So-Hee (Department of Chemical Engineering, Kongju National University) ;
  • Cho, Jung-Ho (Department of Chemical Engineering, Kongju National University)
  • Received : 2010.11.30
  • Accepted : 2011.01.13
  • Published : 2011.01.31
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Abstract

In this paper, simulation works for a cascade refrigeration cycle using propane, ethylene and methane as a refrigerant have been performed for the liquefaction of natural gas using Peng-Robinson equation of state built-in PRO/II with PROVISION release 8.3. The natural gas feed compositions were supplied from Korea Gas Corporation and the flow rate was assumed to be 5.0 million tons per annual. Supply temperature for propane refrigerant was fixed as $-40^{\circ}C$, that for ethylene refrigerant as $-95^{\circ}C$, and that for methane refrigerant as $-155^{\circ}C$. Natural gas was finally cooled and liquefied to $-162^{\circ}C$ by Joule-Thomson expansion. Conclusively, 91.64% by mole of the natural gas liquefaction ratio was obtained through a cascade refrigeration cycle and Joule-Thomson expansion.

본 논문에서는 천연가스를 액화시키기 위해서 프로판, 에틸렌 및 메탄 냉매를 이용한 캐스케이드 냉동 사이클에 대한 전산모사를 PRO/II with PROVISION 8.3에 내장되어 있는 Peng-Robinson 상태방정식을 활용하여 수행하였다. 천연가스의 조성은 한국가스공사로부터 제공받은 것을 적용하였으며, 유량은 년간 500만톤으로 가정하였다. 프로판 냉매의 공급온도는 $-40^{\circ}C$로, 에틸렌 냉매의 공급온도는 $-95^{\circ}C$로 메탄 냉매의 공급온도는 $-155^{\circ}C$로 각각 정하였으며, 천연가스와 각각의 냉매의 최소 접근온도는 $3^{\circ}C$로 정하였다. 메탄 냉매에 의해서 $-152^{\circ}C$까지 냉각된 천연가스는 줄-톰슨 팽창에 의해서 $-162^{\circ}C$까지 냉각되어 액화가 일어나도록 하였다. 결론적으로 캐스케이드 냉동 사이클과 줄-톰슨 팽창을 통해서 천연가스의 액화율은 몰비로 91.64%임을 알 수 있었다.

Keywords

References

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