Parametric analysis and system optimization of a novel steam production system by synthetic cascade utilization of industrial waste heat

A great deal of waste heat is released in many industrial procedures, resulting in not only serious energy waste but also heat pollution. To alleviate this phenomenon, in-depth analyses of a steam generation system, whose novelty lies in synthesis of mechanical vapor recompression and thermal power conversion processes for dealing with low-grade waste heat utilization, are performed. Determination of organic Rankine cycle (ORC) working fluid and thermal power conversion cycle are conducted in detail. Then, parameter analyses and optimization are investigated. The simulation results show that the ORC–based system performs well in efficiency improvement and cost reduction with 69.41% higher exergy efficiency and 9.66% lower cost per ton of steam than the transcritical carbon dioxide-based system. In addition, there is an optimum flow rate of ORC working fluid for thermodynamic performance. A lower steam compression ratio and a higher heat source temperature are beneficial to improve techno-economic performance. At last, according to optimized results, the steam production yield and exergy efficiency of the ORC–based system are 2.50% and 44.31% under the 100 °C heat source condition, as well as the cost per ton of recycled steam is 7.67 $/ton. The optimizations of the system, working fluid, and parameters provide valuable information for improving system performance