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Optimal design of batch‐storage network with multitasking semi‐continuous processes
Author(s) -
Yi Gyeongbeom,
Reklaitis Gintaras V.
Publication year - 2006
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.10582
Subject(s) - sizing , raw material , process engineering , process (computing) , human multitasking , computer science , mathematical optimization , mathematics , engineering , chemistry , psychology , organic chemistry , cognitive psychology , operating system
The periodic square wave (PSW) model was successfully applied to the optimal design of a batch‐storage network. The network structure can cover any type of batch production, distribution, and inventory system, including recycle streams. Here we extend the coverage of the PSW model to multitasking semi‐continuous processes as well as pure continuous and batch processes. In previous solutions obtained using the PSW model, the feedstock composition and product yield were treated as known constants. This constraint is relaxed in the present work, which treats the feedstock composition and product yield as free variables to be optimized. This modification makes it possible to deal with the pooling problem commonly encountered in oil refinery processes. Despite the greater complexity that arises when the feedstock composition and product yield are free variables, the PSW model still gives analytic lot sizing equations. The ability of the proposed method to determine the optimal plant design is demonstrated through the example of a high density polyethylene (HDPE) plant. Based on the analytical optimality results, we propose a practical process optimality measure that can be used for any kind of process. This measure facilitates direct comparison of the performance of multiple processes, and hence is a useful tool for diagnosing the status of process systems. The result that the cost of a process is proportional to the square root of average flow rate is similar to the well‐known six‐tenths factor rule in plant design. © 2005 American Institute of Chemical Engineers AIChE J, 2006