Optimization ofWater Network Design for a Petroleum Refinery

This work discusses about the basic understanding and research done on the final year project entitled Optimization of Water Network Design for a Petroleum Refinery. A few sets of parameter were identified by a set of water-producing streams process sources with known flowrate and contaminant concentration, a set of water-using operations of process sinks with known inlet flowrate and maximum allowable contaminant concentration, a set of water-treatment technologies interception units and a set of freshwater sources. The objectives are to determine minimum freshwater used and wastewater discharged, optimum allocation of sources to sinks and optimum selection of interception devices or regeneration technologies with a fast computational time. Formulation of mixed-integer nonlinear programming (MINLP) optimization model involved a source-interceptor-sink superstructure representation with the application of water reuse, regeneration and recycle (W3R). Bilinear variables and big-M logical constraints are considered as a major problem in the optimization model which necessitates a solution strategy of using piecewise linear relaxation and tight specification of lower and upper bounds to ensure a global optimal solution is achieved within a reasonable time. A preliminary optimal solution will be obtained by implementing the model into GAMS modeling language