Premium
A novel strategy for dynamic optimization of grade transition processes based on molecular weight distribution
Author(s) -
Weng Jinzu,
Shao Zhijiang,
Chen Xi,
Gu Xueping,
Yao Zhen,
Feng Lianfang,
Biegler Lorenz T.
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.14445
Subject(s) - process (computing) , computation , process optimization , scale (ratio) , molar mass distribution , computer science , mathematical optimization , polymer , process engineering , mathematics , materials science , engineering , algorithm , chemical engineering , physics , quantum mechanics , composite material , operating system
To achieve different end‐use properties of polymers, an industrial plant must produce several grades of the product through the same process under different operating conditions. As molecular weight distribution (MWD) is a crucial quality index of polymers, grade transition based on MWD is of great importance. Dynamic optimization of the grade transition process using MWD is a challenging task because of its large‐scale nature. After analyzing the relationships among state variables during polymerization, a novel method is proposed to conduct the optimal grade transition using dynamic optimization with a small‐scale moment model, combined with a steady‐state calculation of the MWD. By avoiding expensive computation in dealing with dynamic MWD optimization, this technique greatly reduces the computational complexity of the process optimization. The theoretical equivalence of this simplification is also proved. Finally, an industrial high‐density polyethylene slurry process is presented to demonstrate the efficiency and accuracy of the proposed strategy. © 2014 American Institute of Chemical Engineers AIChE J , 60: 2498–2512, 2014