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Control structure synthesis for operational optimization of mixed refrigerant processes for liquefied natural gas plant
Author(s) -
Husnil Yuli Amalia,
Lee Moonyong
Publication year - 2014
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.14430
Subject(s) - refrigerant , process (computing) , liquefaction , control theory (sociology) , liquefied natural gas , process control , steady state (chemistry) , computer science , variable (mathematics) , control variable , natural gas , process engineering , control (management) , engineering , mathematics , chemistry , mechanical engineering , gas compressor , waste management , mathematical analysis , geotechnical engineering , machine learning , operating system , artificial intelligence
The best control structures for the energy optimizing control of propane precooled mixed refrigerant (C 3 MR) processes were examined. A first principles‐based rigorous dynamic model was developed to analyze the steady‐state and dynamic behaviors of the C 3 MR process. The steady‐state optimality of the C 3 MR process was then examined in a whole operation space for exploring the feasibility of the energy optimizing control for possible control structures. As a result, the temperature difference (TD) between the warm‐end inlet and outlet MR streams was exploited as a promising controlled variable to automatically keep the liquefaction process close to its optimum. The closed‐loop responses were finally evaluated for every possible control structure candidate. Based on the steady‐state optimality and the dynamic performance evaluation, several control structures with a TD loop were proposed to be most favorable for the energy optimizing control of the C 3 MR process. The proposed optimality approach can be applied to any natural gas liquefaction process for determining a proper controlled variable for optimizing operation. © 2014 American Institute of Chemical Engineers AIChE J , 60: 2428–2441, 2014