ABSTRACT

The process industry can be considered as a specific domain within planning and scheduling. This is due to a number of specific characteristics, which have been well documented and will be discussed in this chapter. The subject of study in this chapter is the batch chemical industry, being a subset within the process industry domain. The batch chemical industry is characterised by very complex and long processes and process structures. Process structures are complex due to the large variety in processes and consequently the large variety in resources that are used in that industry. In addition, many sequencing constraints dictate the operational scheduling of the jobs, such as sequences with no-wait restrictions on them. The processes themselves are long, with days more typical than hours needed to characterise their length. In addition, a customer order consists of a fairly large number of jobs, thus resulting in lead times typically measured in months rather than weeks.