Exergy transfer characteristics of gas solid heat transfer in sinter vertical tank

In order to strengthen the gas-solid heat transfer process in sinter bed layer and efficiently recover and utilize sinter waste heat resources, firstly, the vertical tank for sinter waste heat recovery was taken as the research object and the related expressions of exergy transfer coefficient and dimensionless exergy flux in vertical sinter moving bed were derived by non-equilibrium thermodynamics theory. Secondly, the simulation models of flow and heat transfer in vertical moving bed were established on the basis of porous medium and two-equation energy model. Finally, the reliability of simulation model was verified by the measurement data of self-made small test vertical tank and the effects of air inlet flow rate, air inlet temperature and height of cooling section on the exergy transfer characteristics of gas solid heat exchange in bed layer of vertical tank were analyzed numerically. The results show that the larger the air inlet temperature, the smaller the height of cooling section, and the larger the exergy transfer coefficient in bed layer. When the height of bed layer is lower, the exergy transfer coefficient in bed layer decreases with the increase of air inlet flow rate and the exergy transfer coefficient would be negative, which is unfavorable to the gas-solid heat transfer process in vertical tank. The dimensionless exergy flux in bed layer decreases with the increase of air inlet temperature and height of cooling section. When the temperature ratio is larger (Tg/T0>1.3), the dimensionless exergy flux in bed layer increases with the increase of air inlet flow rate. The simulated results of air outlet temperature under different working conditions are basically consistent with the test measurement data. The average relative error is only 4.93%, which proves the correctness of flow and heat transfer models in vertical moving bed. © 2021, Central South University Press. All right reserved.