Test bench for radiative waste heat recovery in steel mills

This paper presents the design, manufacturing, and validation of a test bench for a radiation waste heat recovery system, which can reproduce the operating conditions of a real steelmaking factory, in particular, continuous casting. The experimental unit consists of three main components: an emitter, a heat capturing device and a thermal oil loop. The influence of different operating conditions, including emitter surface temperature, thermal oil inlet temperature, and oil mass flow rate, on the performance of the recovery unit was evaluated. Additionally, the impact of the corner effect was studied to determine the effect on the radiation heat transfer. The results showed that the proposed experimental unit can achieve surface temperatures up to 1000 °C, which are like those found in the selected area of the steelmaking process. The temperature of the emitter was found to have a substantial effect on the performance of the heat recovery unit, especially when the temperature is below 800 °C. The oil inlet temperature and mass flow rate were also found to influence the thermal radiation heat transfer rate and the recovery efficiency of the device. The findings reveal the importance of the maximum temperature, oil inlet temperature, and oil mass flow rate for optimizing the waste heat recovery system. This study proposes a valuable experimental methodology for analysing thermal radiant heat recovery units under real conditions, which can be helpful in developing optimized systems to harness waste heat from high-temperature energy-intensive industries, considerably reducing their carbon footprint.