Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Determination of Mixing Ratio of Mixed Refrigerants and Performance Analysis of Natural Gas Liquefaction Processes

혼합냉매 혼합비에 따른 천연가스 액화공정 성능 비교

  • Kim, Min Jin (Department of Chemical Engineering, Pukyong National University) ;
  • Yi, Gyeong Beom (Department of Chemical Engineering, Pukyong National University) ;
  • Liu, Jay (Department of Chemical Engineering, Pukyong National University)
  • 김민진 (부경대학교 화학공학과) ;
  • 이경범 (부경대학교 화학공학과) ;
  • 유준 (부경대학교 화학공학과)
  • Received : 2013.08.27
  • Accepted : 2013.09.25
  • Published : 2013.12.01
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Abstract

A mixed refrigerant cycle (MRC) has been widely used in liquefaction of natural gas because it is simple and easily operable with reasonable equipment costs. One of the important techniques in MRC is selection of a refrigerant mixture and decision of its optimum mixing ratio. In this work, it is examined whether mixture components (refrigerants) and their mixing ratio influence performance of general MRC processes. In doing this, mixture design and response surface method, which are well-known statistical techniques, are used to find optimal mixture refrigerants and their optimal mixing ratio that minimize total energy consumption of the entire liquefaction process. A MRC process using several refrigerants and various mixing ratios is simulated by Aspen HYSYS and mixture design and response surface method are implemented using Minitab. According to the results, methane ($C_1$), ethane ($C_2$), propane ($C_3$) and nitrogen ($N_2$) are selected as best mixture refrigerants and the determined mixture ratio (mole ration) can reduce total energy consumption by up to 50%.

혼합냉매를 사용하여 천연가스를 액화하는 혼합냉매공정(Mixed refrigerant cycle, MRC)은 공정이 간단하고 장치비가 적게 들며 운전 또한 용이하여 널리 채택되고 있는 공정이다. MRC에서 중요한 기술 중 하나는 혼합냉매를 선택하고 최적의 혼합비를 결정하는 것이다. 본 연구에서는 일반적인 MRC에서 혼합냉매와 혼합냉매의 혼합비가 공정의 성능에 미치는 효과를 살펴보았다. 이를 위해 통계적 기법 중 실험계획법의 하나인 혼합물 설계와 반응 표면법을 이용하여 전체 공정의 에너지 소비가 최소가 되게 하는 최적의 냉매를 선택하고 그 혼합비를 결정하였다. 여러 냉매와 혼합비에 따른 MRC 공정의 모사는 Aspen HYSYS를 사용하였으며 혼합물설계와 반응 표면법은 Minitab을 사용하였다. 연구결과 냉매로는 methane ($C_1$), ethane ($C_2$), propane ($C_3$)과 nitrogen ($N_2$)가 선택되었으며 에너지 소비를 최소화하는 혼합비(몰 비) 또한 구할 수 있었다.

Keywords

References

  1. Chang, H. S., Lee, B. N. and Gu, B. S., "A Raise Plan of competitiveness of Internal Company in the overseas Plant market,"Construction & Economy Research Institute of Korea, 19, 2-30(2007).
  2. Cha, J. H. Lee, J. C. Roh, M. I. and Lee, K. Y., "Determination of the Optimal Operating Condition of the Hamworthy Mark I Cycle for LNG-FPSO," Journal of the Society of Naval Architects of Korea, 47(5), 733-742(2010). https://doi.org/10.3744/SNAK.2010.47.5.733
  3. Shukri, T., "LNG Technology Selection," Hydrocarbon Engineering, 9(2), 71-74(2004). https://doi.org/10.1061/(ASCE)1084-0699(2004)9:2(71)
  4. Kirillov, N. G., "Analysis of modern natural gas liquefaction technologies," Chemical and Petroleum Engineering, 40, 7-8(2004).
  5. Cao, W.-S., Lu, X.-S., Lin, W.-S., Gu, A.-Z., "Parameter Comparison of Two Small-scale Natural Gas Liquefaction Process in Skid-mounted Packages," Appl. Therm. Eng., 26, 898-904(2006). https://doi.org/10.1016/j.applthermaleng.2005.09.014
  6. Barclay, M. A., Yang, C. C. "Offshore LNG: The Perfect Starting Point for the 2-phase Expander," Offshore technology conference (2006).
  7. Finn, A. J., Johnson, G. L. and Tomlinson, T. R., "LNG Technology for Offshore and Mid-Scale Plants. Proceedings of the Seventy-Ninth Annual Convention of the Gas Processors Association," p. 429-450, Atlanta, Georgia, March 13-15, 2000.
  8. Kennett, A. J., Limb, D. I. and Czarnecki, B. A., "Offshore Liquefaction of Associated Gas - A Suitable Process for the North Sea," 13th Annual OTC in Houston, pp 31-40 (1981).
  9. Little, W. A., Method for Efficient Counter-current Heat Exchange Using Optimized Mixtures. U.S. Patent 5,644,502, 1997.
  10. Alexeev, A. and Quack, H., Refrigerant mixture for a mixturethrottling process. U.S. Patent 6,513,338, 2003.
  11. Gong, M. Q., Luo, E. C., Zhou, Y., Liang, J. T. and Zhang, L., "Optimum Composition Calculation for Multicomponent Cryogenic Mixture Used in Joule-Thomson Refrigerators," Advances in Cryogenic Engineering, 45, 283-290(2000).
  12. Boiarskii, M., Khatri, A. and Kovalenko, V., "Design Optimization of the Throttle Cycle Cooler with Mixed Refrigerant," Cryocoolers 10, 457-465(1999).
  13. Cao, W.-S., Lu, X.-S., Lin, W.-S. and Gu, A.-Z., "Parameter Comparison of Two Small-scale Natural Gas Liquefaction Process in Skid-mounted Packages," Appl. Therm. Eng., 26, 898-904 (2006). https://doi.org/10.1016/j.applthermaleng.2005.09.014
  14. Helgestad, D.-E., Modelling and optimization of the C3MR process for liquefaction of natural gas, Process Systems Engineering - Specialization Project Fall 2009.
  15. Robert, C. R., The Properties of Gases and Liquids, 4th ed., McGraw-Hill Book Company, 1987.
  16. Venkatarathnam, G., Cryogenic Mixed Refrigerant Processes, Springer, 2008.
  17. Jung in Yoon et al., Characteristics of Cascade and C3MR Cycle on Natural Gas Liquefaction Process, World Academy of Science, Engineering and Technology 35, 2009.
  18. Park, C. C., et al., Characteristics of LNG Refrigeration on two-stage Cascade Cryogenic Cycle by using C3MR Refrigerant, SAREK, 53-58 (2011).
  19. Lee, K.-Y., et al., "Determination of the Optimal Operating Condition of the Dual Mixed Refrigerant Cycle at the Pre-FEED stage of the LNG FPSO Topside Liquefaction Process," Comput. Chem. Eng., 49(11), 25-36(2013). https://doi.org/10.1016/j.compchemeng.2012.09.008
  20. Eretech, Perfect Business with new Minitab, 2005.
  21. Kim, E.-J., et al., "Basic Design of Mixed Refrigerant Cycle in Bench Scale Unit LNG Plant's Liquefaction Process," SAREK, 729-734(2009).

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