Thermal Model Test Of Large Particle Fluidized Calcining Cement Clinker Process - High Temperature Fluidized Bed Stability Study

Because of the intrinsic disadvantages of shaft kiln process and the uneventemperature field in the packed bed of raw meal, the quality of clinker producedis poor and the application of the cement is limited. In an effort to overcome theintrinsic problems of the shaft kiln process, Institute of Powder Engineeringmanaged to produce cement clinker by Coarse Particle Fluidization.The effects of operation parameters upon stability of Coarse ParticleFluidized Bed in high temperature were investigated by experiments. Using a hotmodel a series of experiments were performed to burn clinker in fluidizationprocesses. In the experiments the authors took considerations of the results of acold model tests that were achieved in an early research program.The ranges of operation parameters for the bed properly working wereacquired and the operation procedures were summarized. Furthermore, thecriteria for scale-up of laboratory device were discussed and suggested. It wasverified that the fluidized bed may properly operated if the air flow rate and rawmeal feeding rate were carefully monitored, regulated and controlled. The desiredsuperficial gas velocity was in range of 6~8m/s. The average pressure of unitbed height was measured to be 9kPa. The critical gas velocity for initiatingfluidization was 5.2m/s in the condition of l350℃, average diameter of granules4.4mm. It was found that to prevent caking of the raw meal in the bed thesuperficial gas velocity should be enlarged.When the average diameter of granules is 4.4mm, the static bed height ofmateriel is 1 .89m. The average pressure is 17.01kPa.