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Inventory pinch based, multiscale models for integrated planning and scheduling‐part II: Gasoline blend scheduling
Author(s) -
Castillo Pedro A. Castillo,
Mahalec Vladimir
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.14444
Subject(s) - scheduling (production processes) , mathematical optimization , schedule , computer science , nonlinear system , nonlinear programming , production planning , swing , job shop scheduling , pinch analysis , integer programming , linear programming , operations research , mathematics , engineering , process integration , production (economics) , process engineering , mechanical engineering , physics , quantum mechanics , economics , macroeconomics , operating system
Integration of planning and scheduling optimizes simultaneous decisions at both levels, thereby leading to more efficient operation. A three‐level discrete‐time algorithm which uses nonlinear models and integrates planning and detailed scheduling is introduced: first level optimizes nonlinear blend models via multiperiod nonlinear programming (NLP), where period boundaries are initially determined by the inventory pinch points; second level uses fixed recipes (from the first level) in a multiperiod mixed‐integer linear program to determine first an optimal production plan and then to optimize an approximate schedule which minimizes the total number of switches in blenders and swing tanks; third level computes detailed schedules that adhere to inventory constraints computed in the approximate schedule. If inventory infeasibilities appear at the second or the third level, the first‐level periods are subdivided and blend recipes are reoptimized. Algorithm finds the same or better solutions and is substantially faster than previously published full‐space continuous‐time model. © 2014 American Institute of Chemical Engineers AIChE J , 60: 2475–2497, 2014