The Constraints Aggregation Technique for Control of Ethanol Production

In the article a new method for control and optimization of the ethanol production process was presented. The fed batch reactor for ethanol production can be described by the system of the nonlinear differential-algebraic equations. The new control approach base on the direct shooting method, which leads to a medium- or large-scale nonlinear optimization problem. In the presented research, three main aims of the optimization with the differential-algebraic constraints are indicated. The first one is the minimization of the cost function, which represents a process performance index. The second and third aims are to provide consistent initial conditions for the system to be solved and to ensure the continuity of the differential state trajectories. For these reasons, the large number of decision variables and equality constraints, connected with both consistent initial conditions for the differential-algebraic system and continuity of the differential state trajectories, was treated using the constraints aggregation technique. The direct shooting approach together with constraints aggregation technique enables us to obtain a new form of the nonlinear optimization task.