Energy-saving effect and mechanism analysis of high emissivity coatings for BF hot-blast stoves

The energy-saving effect of high emissivity coatings for BF hot-blast stoves was studied and analyzed by comparing numerical simulations with industrial applications. It is showed that the simulation data agree with the industrial application results, proving a positive effect of the coating on energy transfer in a hot blast stove. The simulation results indicate that with the coating applied, the hot blast temperature can increase by 25 ℃ and the flue gas temperature decreases by 13 ℃. The energy-saving mechanism of the high emissivity coating in a hot blast stove was discussed based on the simulation results and thermal balance analysis. It is thought that the coating intensifies radiative heat transfer between gas and checker-brick surfaces during the combustion period, and further increases the energy storage capability and the surface temperature of checker bricks. In addition, the simulations show that CO₂ in the gas plays an important role in intensifying radiative heat transfer, and generally increasing 5% CO₂ in flue gas will make the temperature of hot air increase by 6 to 8 ℃.