Thermo-economic assessment of air bottoming cycle technology for waste heat recovery purposes from the preheater tower of an Algerian cement plant

Abstract

The present work deals with the deployment of an air bottoming cycle as a technology for thermal energy valorization. This solution is integrated within the preheater tower on an Al-gerian cement plant. A combined MATLAB- Coolprop optimization tool has been developed to carry out a thermo-economic calculation allowing to design and optimize the air bottoming cycle and also check its economic returns. The developed code employs the genetic algorithm through a multi-objective function aiming to maximize the cycle’s net power output as a pri-ority objective, then minimize the heat exchanger’s area of exchange, and also maximize the cycle’s net present value. through the implemented models on it, the code gives the ability to confirm the applicability of this technology through the Algerian market which is character-ized by one of the cheapest prices of electricity in the world that doesn’t exceed 0.040 $ kWh-1. The obtained results highlight that the implementation of such technology for energy valori-zation purposes from the preheater tower of the selected cement plant can be a profitable and attractive solution, particularly in scenarios of water scarcity. Since the implementation of this technology presented a power capacity of 1.2 MW covering then around 7.8% of the electricity demand of the investigated cement plant. The economic analysis of the proposed ABC cycle pointed out a net present value of 6.59 M$, and a payback time less than 3.6 years, besides a Levelized cost of energy less than 0.017 $ kWh-1 which is a comparable value to the subsidized prices of electricity in the Algerian market.

Keywords

• Air Bottoming Cycle
• Waste Heat Recovery
• Thermo-Economic Optimization
• Cement Plant
• Heat Transfer Coefficient