Experimental investigation of volumetric exergy transfer coefficient in vertical moving bed for sinter waste heat recovery

Abstract

The volumetric exergy transfer coefficient of sinter bed layers in vertical tank for sinter waste heat recovery has been presented. Correlations involving relevant variables to predict the local and mean volumetric exergy transfer coefficient, Nusselt number and the non-dimensional exergy flux have been deduced by using the second law of thermodynamics and non-equilibrium thermodynamics theory. The relationships of the local and mean volumetric exergy Nusselt number with the local and mean volumetric heat transfer Nusselt number and Reynolds number are analyzed. The experimental results of exergy transfer characteristics in sinter moving bed with different cooling air flow rate and different sinter mass flow rate are obtained from a homemade moving bed set up, and the influences of the height of gas-solid heat exchange section, Reynolds number and gas-solid water equivalent ratio on exergy transfer characteristics are graphically and analyzed. The research results indicates that air-sinter exergy transfer process is mainly determined by the exergy transfer caused by temperature difference, and the impact of exergy transfer due to internal pressure loss is relatively small for given vertical tank and sinter particles. There is an ideal range of gas-solid water equivalent ratio, which makes exergy transfer more efficient.