Numerical Simulation Study on the Thermal Efficiency of Hot Blast Stoves

Abstract

Thermal efficiency is one of the important indices used to evaluate the operational energy efficiency of hot blast stoves. In this study, a method for calculating the thermal efficiency of hot blast stoves was developed based on simulation results. The working process of top combustion hot blast stoves was numerically simulated through the established 3D fluid flow heat transfer model. The system thermal efficiency of hot blast stoves was calculated according to the simulation data, referring to the Chinese national standard, “measurement and calculation method of the heat balance of blast furnace hot blast stove” (GB/T 32287-2015). In particular, a “segmented calculation and accumulate by time” method was proposed based on the air supply curve to more precisely calculate the heat carried away by the hot blast. The results indicate that when the burning air supply cycles increased from 120 to 240 min, the thermal efficiency showed a trend of first decreasing and then increasing, with the value ranging between 70.39% and 72.48%. The reason for the decrease in thermal efficiency at a burning cycle of 150 min is explained based on heat transfer theory combined with the structural characteristics of hot blast stoves. This study provides a convenient and effective method for calculating the thermal efficiency of hot blast stoves, which helps us to evaluate and improve the operating process of hot blast stoves.