On-line Optimisation of Rotary Cement Kilns

The paper describes a computer control system for the optimisation of four cement kilns in Malmo, Sweden. The scheme underwent acceptance trials in June 1970. The “hill climbing” optimisation technique is employed which checks a series of actual or derived plant constraints by a complex logical sequence. The paper describes how the individual programs for each kiln were built up on line as plant experience was obtained. Stress is laid on the practical advantages of this approach as compared with the more normal method of offline development with subsequent on-line application. Description is made of the novel programming technique which allows complex optimisation strategies to be set up and modified by a control engineer with no programming experience whilst the computer remains on line. The paper stresses the significance of this facility in terms of reduction of system commissioning times. Benefits of the optimisation are listed, which amount to production increases of up to 10% and fuel savings of up to 6%.