High-temperature and low-oxygen combustion technology for carbon rotary kilns

Taking a carbon rotary kiln for example, numerical simulations were conducted on gas and solid spaces of the kiln using Fluent and Matlab softwares. Through changing temperature and oxygen mass concentration of primary air, temperature field distributions are obtained in different conditions. The results indicate that, if the low-temperature flue gas instead of the primary air is injected to the kiln at the kiln outlet, the temperature of the gas and solid particles in the cooling zone will be lower, but the length of the calcining zone will not be shortened notably. Therefore, suggestions were put forward, as the low temperature flue gas from the waste heat recovery device after rotary kiln or mixing the high-temperature gas from the kiln inlet, or the primary normal air mixing with the low-temperature gas is injected to the kiln at the kiln outlet, low oxygen atmosphere area can be formed. By the method, solid particles can be cooled, meantime, the solid particles burning loss can be reduced, which lead to the increment of the kiln actual yield.