Optimization of regeneration temperature for energy integrated water allocation networks

Abstract

The conservation of energy and water resources is vital to tackle climate change and ensure sustainability. Energy integrated water allocation networks simultaneously conserve these resources using heat exchangers and regeneration units. A hybrid solution strategy is proposed in this paper to achieve the minimum total annualized cost of these networks and offer market competitiveness. The proposed algorithm solves the mixed-integer non-linear programming problem formulated in this study through a heuristic-based non-linear programming technique. The ideology of Pinch Analysis is implemented to identify heuristics that explore the non-isothermal mixing potential of streams and optimize the regeneration temperatures. These heuristics can drastically reduce energy requirements, while the mathematical optimization of water reuse, recycling, and regeneration decreases water consumption. Capturing the trade-offs between energy consumption and heat exchangers ensures a lower total annualized cost. The potency of the algorithm developed in this work is exhibited using demonstrative examples from the literature. The variation in the operating cost, investment expense, and thereby, the total annualized costs with the temperature of regeneration units and the regeneration throughput are demonstrated in these examples. Optimal regeneration temperature can significantly reduce the total annualized costs of the overall system, as observed through these examples. In the single contaminant water network example, the total annualized cost is 45.3% lower compared to the literature. • Proposed approach integrates conceptual Pinch Analysis with numerical algorithm. • Energy conservation is achieved by optimizing regeneration temperature. • The hybrid algorithm minimizes the total annualized cost prior to network design. • The proposed algorithm reduces the total annualized cost by 45.3%.