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.