DEVELOPMENT AND APPLICATION OF THE NEW MICRO/NANOMETER COATING ON CHECKER BRICK FOR ENERGY SAVING IN BF HOT STOVE

摘要

A new micro/nanometer coating for checker brick in BF hot stove has been developed and used in some Chinese BF. The properties and microstructure of the coating were revealed by emissivity instrument, transmission electronic microscope (TEM) and optical microscope (OM) respectively. The results showed that the emissivity of coating is higher than 0.90; and its thickness is about 270 urn. There is an infiltration area of approx 3 mm which endow with the coating high cohesion and good performance of anti-stripping between the coating and the substrate. Obvious improvement on radiation heat transfer capability and checker brick protection was confirmed by laboratory experiment. The application of coating on the checker brick in a blast furnace of 1750m~3 indicated that the coating makes the blast temperature increase of 28 deg C and reduces the fluctuation of blast temperature before blowing into BF. The reasons for energy saving and increasing blast temperature by the new coating are that the high emissivity coating strengthens heat transfer by radiation and increase the temperature of the surface which provides faster heat-up times. As a result, both the heat transfer efficiency in the hot stove and the blast temperature are increased which increase the pulverized coal injection rate and reduce the coke rate.