Development of partial liquefaction system for liquefied natural gas carrier application using exergy analysis

다국어 초록 (Multilingual Abstract)

The cargo handling system, which is composed of a fuel gas supply unit and cargo tank pressure control unit, is the second largest power consumer in a Liquefied Natural Gas (LNG) carrier. Because of recent enhancements in ship efficiency, the surplus boil-off gas that remains after supplying fuel gas for ship propulsion must be reliquefied or burned to regulate the cargo tank pressure. A full or partial liquefaction process can be applied to return the surplus gas to the cargo tank. The purpose of this study is to review the current partial liquefaction process for LNG carriers and develop new processes for reducing power consumption using exergy analysis. The developed partial liquefaction process was also compared with the full liquefaction process applicable to a LNG carrier with a varying boil-off gas composition and varying liquefaction amounts. An exergy analysis showed that the Joule-Thomson valve is the key component needed for improvements to the system, and that the proposed system showed an 8% enhancement relative to the current prevailing system. A comparison of the study results with a partial/full liquefaction process showed that power consumption is strongly affected by the returned liquefied amount.

참고문헌 (Reference)

1 Lee, Sanggyu, "The study on natural gas liquefaction cycle development for LNG-FPSO" 4 : 880653-, 2013

2 Cao, Wen-sheng, "Parameter comparison of two small-scale natural gas liquefaction processes in skidmounted packages" 26 (26): 898-904, 2006

3 Alabdulkarem, Abdullah, "Optimization of propane pre-cooled mixed refrigerant LNG plant" 31 (31): 1091-1098, 2011

4 Ding, He, "Optimization of expansion liquefaction process using mixed refrigerant $N_2-CH_4$" 93 : 1053-1060, 2016

5 Nogal, Frank Del, "Optimal design of mixed refrigerant cycles" 47 (47): 8724-8740, 2008

6 Choi, D.K., "Hybrid FGS system with partial Re-Liquefaction unit for MEGI propelled LNG carrier" 2014

7 Yumrutas, Recep, "Exergy analysis of vapor compression refrigeration systems" 2 (2): 266-272, 2002

8 Tirandazi, Behnam, "Exergy analysis of C2+ recovery plants refrigeration cycles" 89 (89): 676-689, 2011

9 Morosuk, T., "Evaluation of the PRICO liquefaction process using exergy-based method" 27 (27): 23-31, 2015

10 Shin, Younggy, "Design of a boil-off natural gas reliquefaction control system for LNG carriers" 86 (86): 37-44, 2009

11 Vink, K.J., "Comparison of baseload liquefaction processes" 1998

12 Remeljej, C.W., "An exergy analysis of small-scale liquefied natural gas (LNG) liquefaction process" 31 (31): 2005-2019, 2006

13 Chang, Ho Myung, "A thermodynamic review of cryogenic refrigeration cycles for liquefaction of natural gas" 1 : 127-147, 2015