Energy and exergy analysis of waste heat recovery from pressurized hot smothering steel slag by solar organic Rankine cycle

In this study, the energy and exergy of the organic Rankine cycle driven by steel slag waste heat and solar energy were analyzed for various system configurations. In the system design, the technology of crushing waste heat pressurized hot smothering technology of steel slag rolls was considered. Subsequently, a regenerator was integrated into this system. The heat transfer and power conversion processes were numerically simulated using distributed parameters. The effects of various factors, such as solar collector area, regenerative coefficient, working fluid superheat, and flow rate, on the solar organic Rankine cycle system were analyzed. The results indicated that, under constant conditions, an optimal solar collector area of 800 m(2) was identified for the system. Increasing the superheat in the organic Rankine cycle power generation system from 25 to 45 K resulted in a decrease in the work performed by the expander, leading to a reduction in both the thermal efficiency and the exergy efficiency of the system by 2.5% and 4.9%, respectively. Furthermore, when the mass flow rate of the circulating working fluid increased from 2.86 to 3 kg s(-1), there was a noticeable improvement in the system's thermal and exergy efficiency. Specifically, the thermal efficiency increased by 1.7%, and the exergy efficiency increased by 1.8%. Comparatively, the thermal efficiency of the steel slag waste heat coupling regenerative solar organic Rankine cycle exhibited an 11.5% increase compared to the basic organic Rankine cycle. Additionally, the exergy efficiency demonstrated a notable increase of 7.5%.