Energy, exergy, sustainability, and economic analysis of a waste heat recovery for a heavy fuel oil-based power plant using Kalina cycle integrated with Rankine cycle

• Waste heat recovery of a 50 MW heavy fuel oil-based power plant is examined. • Kalina cycle and Rankine cycle integrated with Kalina cycle has been analyzed. • Combined Kalina cycle with Rankine cycle produce 4075 kW with COE of 0.0175 $/kWh. • Combined cycle offers 60% more environmentally sustainable than Kalina cycle alone. In this study, a comparative thermodynamic, exergy, economic, and environmental analysis was conducted between two cycles for waste heat recovery, focusing on enhancing the performance of a peaking power plant. The Kalina cycle, either as a stand-alone system or in combination with the Rankine cycle, is examined using waste heat from the Katakhali 50 MW HFO-based peaking power plant, Bangladesh as the heat source. The Rankine-Kalina combined cycle is proposed to overcome the limitations of stand-alone systems, leveraging their synergistic temperature adaptability and ammonia-water mixture properties. EBSILON Professional software is used for system modeling, whereas parametric optimization is conducted via an engineering equation solver (EES). Results indicate that the combined cycle can provide 348 kW more power output at an electricity cost of only 0.0175 $/kWh than the stand-alone Kalina cycle. The combined cycle produces around 4075 kW with 27% and 59% as energy and exergy efficiencies, respectively, whereas 3725 kW, 25% and 54% for the stand-alone cycle. Economic analysis shows that the combined cycle involves capital costs approximately $370,000 lower with a reduced payback period (1.94 years) than the stand-alone Kalina cycle, primarily due to its high energy conversion. In addition, the combined cycle is almost 60% more environmentally sustainable. The best operating condition for the suggested configurations is determined through parametric analysis to achieve high output power with low electricity cost. The combined cycle addresses both efficiency and scalability gaps in existing technologies by maximizing energy extraction across a wide temperature range. Finally, it can be concluded that the proposed cycle can be an effective model to generate power by recovering waste heat for power plants operating in Bangladesh.