Simulation And Model Predictive Control Of The Soda Ash Rotary Calciner

Abstract

The paper presents the dynamic simulation results obtained by modeling and control of the rotary calciner for sodium carbonate production by the endothermic decomposition of sodium sesquicarbonate. The calciner model with distributed parameters consists of three zones where the fuel flame is developed and raw material is heated up, the second zone is the reaction zone where most of the decomposition process is taking place and the third zone is the disengaging zone where solids and gases products separate and are evacuated. Dynamic responses to typical disturbances are presented and compared with industrial and literature data. As main target variable, the sodium sesquicarbonate content control at the discharge end of the calciner is investigated using different control approaches. The classical PID control and the Nonlinear Model Predictive Control (NMPC) algorithms are compared in mixed feedforward and feedback schemes.Incentives are revealed for particular control structures using feedforward NMPC, becoming also a feasible approach for the control of similar processes taking place in rotary calciners.