Exergy And Economic Multi-Objective Optimization Of Organic Rankine Cycles For Waste Heat Recovery

Effective heat and power supply to offshore installations leads to environmental benefits, but the efficiency is often limited by requirements and constraints connected to the offshore environment. An exergetic and economic optimisation of gas turbines exhaust heat recovery on offshore platforms is performed to identify optimal approaches to produce heat and power. Four different configurations are presented, with heat delivery at ۳ heat demand levels and power production by an organic Rankine cycle (ORC). Two different working fluids (Toluene and R۱۲۳) are considered. Using genetic algorithm optimization method, the optimal configuration and working fluid were identified for low, medium, and high heat demand scenarios. The results indicated that R۱۲۳ outperforms toluene as a working fluid. For high heat demand (QproC=۱۲ MW), the series configuration with R۱۲۳ is the most suitable choice, as it provides a better balance between power production and investment cost compared to other options. For medium heat demand (QproC=۸ MW), the parallel configuration with a preheater and R۱۲۳ is optimal, while for low heat demand (QproC=۴ MW), the parallel configuration with a preheater and recuperator using R۱۲۳ is most appropriate. In these cases, the highest power outputs were calculated as ۲.۷۹ MW, ۳.۵۶ MW, and ۵.۱۲ MW respectively, while the specific investment costs for the proposed configurations were evaluated as $۱.۸۹۳/W, $۱.۶۳۱/W, and $۱.۶۳/W.

کلیدواژه ها:

Offshore platforms ، Waste heat recovery ، Cogeneration ، ORC ، Genetic algorithm ، Exergy