Dynamic Controlof theCement Pro wV a

A control study ofthecementmanufacturing process hasculminated intheinstallation ofadirect digital control (DDC) systemwhichautomatically controls boththeball-mill blending of rawmaterials forkiln feedandthekiln-cooler combination. Ineach case, thecontrol schemes weredeveloped bydetermination ofthe process dynamics, computer simulation andanalysis, andfield application attheplant. Theblending control schemefinally de- -veloped isbasedonmeasurement ofball-mill output composition -with anX-rayanalyzer, andonaconcept ofnoninteracting feedfor- ward-feedback control. Thekiln-cooler control schemeutilizes con- ventional andadvanced control techniques suchasnonlinear, feed- forward andadaptive compensations, andoptimization. Thiscon- trol schemeincludes coordinated loops forcontrol ofburning zone temperature bymanipulation offuel rateand/or kiln speed, forcon- trol ofkilnexit temperature andoxygenbyIDfanspeed, andfor maximization ofproduction ratebytrimmanipulation ofkiln speed. Thecontrol schemes arebeing applied attheplant withaDDC sys- temwhichprovides maximumoperating flexibility withextensive simplification oftheoperator-computer interface. Thedirect digital control operating experience hasbeenveryfavorable.