Shin, Younggy Lee, Yoon Pyo 2024-01-20T22:03:48Z 2024-01-20T22:03:48Z 2021-09-03 2009-01 0306-2619 https://pubs.kist.re.kr/handle/201004/132837 Onboard boil-off gas (BOG) reliquefaction is a new technology that liquefies BOG and returns it to the cargo tanks instead of burning it off during a voyage. For the commercial development of this technology, an object-oriented dynamic simulation is presented which facilitates the design of the plant and control system for the thermal process. A reliquefaction process based on the reverse Brayton cycle has been designed, and its static thermodynamic states at the design BOG load are presented. To make the cycle work for any BOG load, an idea was sought that would achieve a heat balance with the work extracted by the expander. Dynamic simulations were conducted for all operating modes, including start-up and idle. It was found that the expander exit temperature is the key process variable for control and that the process control works successfully when three actuators are activated in three different BOG load regimes. The study also shows that control of the separator pressure to keep the vapor fraction at the throttle valve exit as low as possible is an efficient method for purging nitrogen from BOG. (c) 2008 Elsevier Ltd. All rights reserved. English ELSEVIER SCI LTD TOOL Design of a boil-off natural gas reliquefaction control system for LNG carriers Article 10.1016/j.apenergy.2008.03.019 1 APPLIED ENERGY, v.86, no.1, pp.37 - 44 APPLIED ENERGY 86 1 37 44 scie scopus 000260203400005 2-s2.0-50349102286 Energy & Fuels Engineering, Chemical Energy & Fuels Engineering Article TOOL Process control LNG BOG Reliquefaction Object orientation Dynamic modeling Heat exchanger Cold box Brayton cycle