| Abstract Scope |
This study explores the integration of an Ocean Thermal Energy Conversion (OTEC) system, operating as an Organic Rankine Cycle (ORC), with the Bayer process for alumina production. It investigates the thermodynamic and techno-economic feasibility of using low-grade waste heat from Bayer process cooling water at 50 °C, with a 20 °C heat sink, to generate power. A detailed thermodynamic analysis, applying polytropic efficiencies for the turbine and pump, evaluates ammonia and isobutane as working fluids under low-temperature conditions. Key performance indicators include net power output, thermal efficiency, and exergy efficiency. Results demonstrate meaningful energy recovery potential, with prospects for reducing both primary energy consumption and greenhouse gas emissions. However, economic viability is challenged by capital costs, especially for heat exchangers operating across narrow temperature differentials. The findings underscore the promise and limitations of ORC-OTEC integration as a decarbonization strategy for the energy-intensive alumina sector through innovative waste heat utilization. |