Synthesis of Heat-integrated Water Network with Interception Unit

Abstract Water and energy are two of the important elements in ensuring sustainability in the process industry. In the past decade, the synthesis of heat-integrated water network has gained good attention among the research community of process system engineering. Various techniques ranging from pinch analysis and mathematical programming have been proposed to solve this problem. Note however that most works have only considered direct reuse/recycle scheme, where water sources are heated/cooled prior to their recovery to the water sinks. In this work, the placement of water interception units will be considered. Apart from direct water reuse/recycle, water sources may be subjected to partial purification with the interception unit, where impurity loads are to be removed prior to their recovery. This is commonly known as water regeneration. A hybrid approach consisting of superstructural and transshipment models is proposed for the solution strategy. Even though the approach is based on mathematical programming framework, it emphasizes the targeting philosophy of pinch analysis. A literature example is solved, with the objective being to minimize water flowrates and cost targets. It is shown that water regeneration cost is an important factor that dictates the overall water flowrates and costs.