(192c) Recent Advances in Chemical Production Scheduling

Despite the large number of publications in the area during the last two decades, there is no unified notation for chemical production scheduling. In this talk, we first develop a framework for the description of scheduling problems in the chemical industries. While building upon ideas used in discrete manufacturing, the proposed framework accounts for features such as material handling restrictions which make chemical production different. Second, we present a classification of the various modeling approaches that have been presented in the process systems engineering (PSE) literature and offer some critical insights. Third, we briefly review a series of mixed-integer programming (MIP) models we have recently developed to address limitations of existing approaches. We focus on a discrete-time formulation that allows us to address problems in all types of facilities, including facilities with different material handling constraints (mixing/splitting). Finally, we present an overview of two solution methods we recently developed, namely, a constraint propagation algorithm for the calculation of parameters that are used to generate four types of tightening constraints, and a series of reformulations. The proposed methods are applicable to a wide range of problems and lead to dramatic computational improvements.