Scheduling model

In order to ensure the completeness of the model that takes the PIS operational philosophy into account, the basic scheduling model developed by Majozi and Zhu (2001) has to be modified as follows. 

The production scheduling model has been presented in detail in Chapter 2 of this textbook, but is briefly presented in this section of the chapter for purposes of continuity and facilitation of understanding. For a detailed explanation of each of the production scheduling constraints, the reader is referred to Chapter 2. 

The final constraints necessary to complete the scheduling model are constraints that ensure all operations occur within the time horizon. These are given in constraints... 

Fig. 8.3 Resulting schedule for illustrative example one using the zero effluent scheduling model...

The presented mathematical formulation is an extension of the scheduling model proposed by Majozi and Zhu (2001), which uses a state sequence network (SSN) representation. This formulation is based on an uneven discretization of time framework (see Chapter 2, Fig. 2.4) as shown in Fig. 10.1. A time point corresponds to the beginning of a particular task and is not necessarily equidistant from the preceding and the succeeding time points, as it encountered in discrete-time formulations. The... 

In addition to the time representation and material balances, scheduling models are based on different concepts or basic ideas that arrange the events of the schedule over time with the main purpose of guaranteeing that the maximum capacity of the shared resources is never exceeded. As can be seen in Figure 8.5 and Table 8.1, we classified these concepts into five different types of event representations, which have been broadly utilized to develop a variety of mathematical formulations for the batch scheduling problem. Although some event representations are more... 

The scheduling models for each refinery convert the preceding information into detailed unit-level directives that provide day-by-day operating conditions or set points. 

Petroleum refining is a central and crucial link in the oil supply chain and has received extensive attention over the last decades. However, despite all the progress that has been made in developing planning and scheduling models, a general... 

Pinto, J.M., Joly, M and Moro, L.F.L. (2000) Planning and scheduling models for refinery operations. Computers el Chemical Engineering, 24, 2259. 

Eq.(l 1) is included to rectify capacity availability in the planning model. This correction is done based on the scheduling model task assignment (Wijt,)- Eq.(ll) should he merely apphed to those equipments which are production bottlenecks. Additionally, it is worth to mention that it must be checked that market demand is not actually the bottleneck process in the plarming period, where scheduhng is performed. 

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