Patent ID: 8340825

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