Abstract
This paper presents a practical planning method for optimal water allocation in a total system consisting of water-using and water-treating process units. The method uses a heuristic rule and a linear programming algorithm. The heuristic rule regarding a sequence of process units is used to simplify an integrated system structure. The algorithm uses repeatedly a linear programming technique to solve a linearized problem for a set of constant values of some parameters. By using the combination of these two approaches, a total system structure is determined so as to minimize the total cost associated with fresh water and water treatment subject to constraints derived from material balances and interrelationships among process units. The method is illustrated by its application to an optimal water allocation problem in a petroleum refinery.
