Thermal efficiency analysis of the rotary kiln based on the wear of the lining

Abstract

The thickness of the lining is reduced from 230 mm to 80 mm due to long-term wear, resulting in low thermal efficiency of the rotary kiln. The thermal resistance, which is positively correlated with the thickness of the lining, is one of the most important factors determining the thermal efficiency of the rotary kiln. The thermal efficiency of the rotary kiln can be improved by introducing insulation material with lower thermal conductivity into the lining. The average heat flux is used as the thermal efficiency evaluation index of the 4×60 m rotary kiln under no-load conditions in this work. A numerical experiment was conducted for the temperature and heat flux of the inner surface of the lining, as well as the temperature of the outer surface of the shell during the wear of the lining. There are two cases considered, one with and one without insulation materials in lining. According to the analysis, when the lining in the high temperature zone of the rotary kiln wears to 80 mm, the average heat flux of the inner surface of the lining increases by 105.03%. However, after the addition of insulation material, the average heat flux on the inner surface of the lining increases by 40.38% (wears to 80 mm). Compared to the thermal efficiency of the rotary kiln without heat insulation material, the average heat flux of the inner surface of the lining is reduced by 36.36% (230 mm), and it is reduced by 99.01% (wears to 80 mm). A significant advantage of this solution is that it can increase the thermal efficiency of the rotary kiln, improve the insulation performance of the lining, reduce heat loss to the environment through the shell, and the results obtained can be used for the latest equipment design and existing equipment improvements.