Multi-objective optimization and off-design performance based on thermodynamic -economic-environmental analysis of organic Rankine & Kalina cycles for roller kiln waste heat recovery

Heat recovery from roller kiln's flue gas and cooling gas is interest topic to make ceramic tile production cleaner and more sustainable. Comparatively, the parallel double-evaporator regenerative organic Rankine cycle (PD-RORC) & Kalina cycle (PD-KC34 (Kalina cycle 34)) provide a good solution for a roller kiln's low-temperature double heat sources utilization. In this research, the off-design performance of the multiobjective optimized PD-RORC & PD-KC34 based on thermodynamic-economic-environmental model is investigated to provide dependable assessment for the roller kiln's waste heat recovery. Firstly, the multiobjective optimization of PD-RORC & PD-KC34 is carried out considering thermodynamic, economic and environmental factors, and TOPSIS method is used to select the optimal Pareto solution. Then, the influences of the roller kiln's operating conditions and heat sink on the off-design performances of PD-RORC & PD-KC34 are further explored. The results show that, under the optimal condition, PD-RORC has superior exergy efficiency ((W)over dot(eta ex)) and environmental performance with eta(ex) of 49.76% and environment impact load (EIL) of 0.096 mPE(China,90)/kWh while PD-KC34 has better net power output ((W)over dot(net)) and economic behavior with (W)over dot(net) of 250.72 kW and electricity production cost (EPC) of 0.090 $/kWh. In addition, excess air coefficient has the greatest impact on (W)over dot(net), eta(ex), EPC and EIL for PD-RORC and PD-KC34. On the whole, PD-KC34 has higher sensitivity on (W)over dot(net) and eta(ex) while PD-RORC shows greater sensitivity on EPC and EIL.