Rosendo Monroy-Loperena

A block-algebra approach to the solution of ∑iaiλ−ci equations

Abstract A bordered matrix is proposed, that with block-algebra manipulations rebuilds the form of the equation given in the title. It is shown that the determinant of the bordered matrix results in a Standard Eigenvalue Problem , where the roots are exactly the eigenvalues of the resulting problem. Even more, the block-algebra operations involved are extremely simple. Likewise, a specialized iterative procedure to find one eigenvalue for a Standard Eigenvalue Problem, based on multivariable Newton, is presented. Numerical experiments are presented to show the reliability of the proposed approach taken to find one or all the roots of the equation given in the title.

Nonlinear PI control of an ethylene glycol reactive distillation column

Abstract The control problem of an ethylene glycol reactive distillation column is studied in this work. The control objective is to regulate the ethylene glycol composition in the product by manipulating the reboiler boil-up ratio. By using an estimator of the input-output modeling error, a first-order output-feedback compensator is designed which is shown to be equivalent to a PI controller with antireset windup structure. The ability of the controller to regulate the product composition in the face of unknown nonlinearities and sampled/delayed measurements is shown via a numerical simulation on a rigorous dynamical model.

An indirect feedforward composition controller for distillation columns

This paper addresses the problem of designing an indirect feedforward controller, also called cascade control, to regulate the product composition of distillation columns to overcome load disturbances. The overall controller is composed of two cascaded controllers. The primary controller is basically a low-gain controller, which uses slow (delayed) composition measurements to provide servo responses (composition control). The secondary controller has the structure of a high-gain proportional-integral (PI) controller with an antireset windup scheme, which uses fast temperature measurements at a given distillation tray to track the output of the primary controller. In this way, the secondary controller also provides protection against load disturbances. A simulated example is used to illustrate the functioning of the proposed controller.