METHOD AND DEVICE FOR CONTROLLING A PROCESS FOR BURNING A LIME CONTAINING MIXTURE TO BURNT LIME

摘要

A method and a device (1 ) for controlling a process for burning lime containing mixture (CaCO3) and converting it to calcinated lime (CaO) in a rotary kiln (2), said rotary kiln (2) having an elongated cavity (3) surrounded by a wall (4) and a burner (5) arranged to heat the cavity (3). The method comprises collecting measurement data of the temperature in the wall (4) at a plurality of measuring points along the longitudinal axis (20) of said cavity (3), predicting the actual temperature gradient along the longitudinal axis (20) of said cavity (3) based at least on said measurement data of the temperature in the wall (4), and by means of a thermal model describing the temperature along the cavity (3) of the kiln (2), determining a desired temperature gradient along the cavity (3) based on the predicted temperature gradient along the cavity (3) and a predetermined control strategy controlling the temperature in the kiln (2) so that the area of deposition of lime on the inside of the walls (4) of the kiln (2) is controlled and the drawbacks of the lime deposition is reduced.