Power Generation from Low Grade Industrial Waste Heat

The objective of this study is to investigate the economic viability of non-conventional power cycles such as Kalina Cycle System 11 (KCS-11) and Organic Rankine Cycle (ORC) to convert waste heat of aluminum smelters into electricity. A comparison between both technologies is carried out using a model that combines market economic parameters and energy performances obtained from the thermodynamic analysis. Indicator such as specific cost of power generation has been determined for different capital cost scenarios. Additionally, a sensitivity analysis is conducted to determine the effect of governing parameters on the economics. The results show that KCS-11 performances are superior to those obtained with ORCs under the same operating conditions. The overall efficiency based on the energy content of the thermal effluent is in the range of 2.4% to 8.5% depending on the heat source temperature. In addition, results reveal that a specific net power output of 16kW per ton of aluminum annual production is technically achievable and a specific cost of power generation around 6¢/kWh appears to be feasible. 