A chemical production site consists of multiple production and utility plants. Production plants consume raw materials to produce chemical products. Utility plants provide utilities (mainly steam and electricity) for the use in production. Material and utility balances among the plants are essential for guaranteeing a feasible operation. In order to enhance profitability, the chemical production site has to deal with various management tasks from time to time like adding new profitable plants, retrofitting outdated processes and scheduling the production plan. Material and utility balances may be interrupted by these management activities. Careful studies are therefore necessary before making management decisions on the production site. Traditionally, engineers perform the studies based...[ Read more ]

A chemical production site consists of multiple production and utility plants. Production plants consume raw materials to produce chemical products. Utility plants provide utilities (mainly steam and electricity) for the use in production. Material and utility balances among the plants are essential for guaranteeing a feasible operation. In order to enhance profitability, the chemical production site has to deal with various management tasks from time to time like adding new profitable plants, retrofitting outdated processes and scheduling the production plan. Material and utility balances may be interrupted by these management activities. Careful studies are therefore necessary before making management decisions on the production site. Traditionally, engineers perform the studies based on their own experience together with simple material and utility balance calculations to evaluate the feasibility of the management suggestions. However, this approach is incapable to investigate a vast of possible solutions. It results in overlooking the site-wide interconnections among the production and utility plants, thus missing out improving opportunities. In this thesis, a multiperiod mathematical linear programming model is developed to handle the site-wide management, namely Site-Model. The model takes into account all plant's material and utility balances and their interconnections inside the site. It simultaneously includes other site-wide factors, such as, operating condition variations, production demands, inventory control strategy and electricity supply contract. Hence, the site-model is suitable for optimizing the site-wide profitability over a long management period. In addition to understand the model results thoroughly, the analytical technique of marginal values analysis (MVA) is also adopted in the site-model. Applications of budget planning, investment decision making and shutdown maintenance scheduling have been investigated to illustrate the site-model's capability.