Optimization of a Reverse Osmosis Desalination and Indirect Ocean Capture for a Polygeneration System

With increasing carbon dioxide emissions from power and heat generation, various decarbonization strategies are being explored to produce clean energy. Polygeneration systems are a promising approach to supply the energy needed. These systems incorporate numerous processes and technologies to convert various raw materials into multiple energy streams. To capitalize on the vast ocean resources worldwide, reverse osmosis desalination (ROD) and indirect ocean capture (IOC) technologies are considered within polygeneration system. This study focuses on optimizing an ROD/IOC process unit incorporated in a polygeneration system that produces heating, cooling, purified water, and hydrochloric acid (HCl) according to demand. The optimization approach employs a mixed integer linear programming (MILP) model that considers net output, capacity, demand, and binary variable vectors. The model aims to maximize the profit while minimizing the carbon-associated price. The optimal results indicate the selection of a combined heat and power (CHP) unit operating at 7500 kW, the chiller at 1500 kW, the reverse osmosis desalination (ROD) unit at 130.5 tons per hour, and the electrolytic cell with a gaseous diffusion anode (EGDA) operating at 80 tons per hour. The system achieves a net positive profit between €447,000 to €4,691,000 per year depending on the carbon-associated price. A trade-off between the profitability and the carbon-associated price was established. This study contributes to the field of negative emission technologies (NETs) and emphasizes the importance of optimizing polygeneration systems for sustainable energy transition.