New Control Strategies for Raw Mix Preparation

Control of raw mix composition in many cement plants is poor due to the inadequacy of conventional sampling and analysis systems. Potential sampling errors and delays in sampling and analysis prevent plant operators from taking effective and timely control actions. A new type of analysis system based on prompt gamma neutron activation analysis (PGNAA) permits elemental analysis of bulk solids in nearly real time. Raw mix control systems based on PGNAA and using feedback or predictive control algorithms were simulated by computer, and their performance was compared with simulated conventional raw mix control methods based on batch X-ray fluorescence analysis. Results show that the rapidity of analysis and small sampling error afforded by on-line PGNAA systems allow superior raw mix control.