Control of Non-isothermal Chemical Reactors Based on a Potential Representation

The paper studies the problem of nonlinear feedback control design of non-isothermal Continuously Stirred Tank Reactors (CSTR). The objective is to construct a feedback controller such that a desired equilibrium of the closed-loop dynamic is asymptotically stable and such that the closed-loop vector field is a conservative vector field of a particular type, i.e., a gradient system. Properties of gradient systems in terms of dissipativity and their importance in the study of interconnected systems in the context of plantwide process control will be briefly discussed. The proposed technique is based on a decomposition of the open-loop vector field in terms of a dissipative part and a non-dissipative part. The latter is then cancelled through state feedback, in such a way that the closed-loop vector field associated to the system is divergence free. A numerical example is used to illustrate the proposed approach.