SCHEDULING OF MULTIPURPOSE BATCH PLANTS WITH DIFFERENT STORAGE POLICIES: A COMPARATIVE STUDY BETWEEN S-GRAPH AND MILP METHODS

C.A. MÉNDEZ; S. FERRER-NADAL; F. FRIEDLER; L. PUIGJANER

Barcelona

Congreso; The 10th Mediterranean Congress of Chemical Engineering; 2005

Ingeniería Química de España

In this work, the short-term scheduling of a multipurpose multiproduct batch plant comprising (i) multiple batches for each product, (ii) shared storage tanks, (iii) different intermediate storage policies, (iv) sequence-dependent setup times, and (v) nonzero transfer times between stages is addressed. A direct comparison between an enhanced S-graph scheduling algorithm and an extended version of the MILP scheduling framework proposed by Méndez and Cerdá (2003) is presented. The S-graph algorithm is developed in C++ whereas the MILP framework is implemented within the modelling language GAMS (Brooke et al., 1998) and solved with CPLEX 7.5. Both resolution strategies are examined by efficiently solving different case studies taken from literature. Main strengths and limitations of each solution method are also pointed out.