Modeling, Simulation and Control of a Nonlinear Distributed Parameter Isotope Separation Process

In this paper, an original solution of modeling and control of a distributed parameter 13C isotope separation process is presented. The mentioned technological process takes place into a separation column, whose work ensures the 13C enrichment through carbon dioxide - carbamate chemical exchange. A main difficulty in the modeling - control problem approach is the fact that, besides that the process is a distributed parameter one, it presents strong nonlinearities in relation to both independent variables (the time and the position in the column height). For the tuning of the 13C isotope concentration controller, the relay method is used. Also, the initially obtained controller structure is modified in order to ensure the same set of performances at the variation of the second independent variable (the position in the column height). In this context, the 13C isotope concentration value is controlled using an adaptive algorithm. In the paper, some interesting simulations are presented which prove the main advantages of using a control structure with an adaptive controller: the possibility to control the 13C isotope concentration in any point from the column height; the possibility to reject the effect of the two types of disturbances which can occur in the process work; the possibility to satisfy a certain restrictive performance set; the possibility to adapt the controller parameters in order to obtain the same set of performances in any transversal section of the column.