Evaluation of the Controllability of Distillation with Multiple Reactive Stages

Intensified schemes, such as reactive distillation, have been proposed to produce silane (SiH4). Several studies have been carried out around this intensified scheme focusing directly on its improvement in energy or economic criteria. However, these mentioned criteria do not ensure that the scheme is also optimal from the control point of view. There is a direct compromise between the economic criterion and the control criterion. Thus, the best controllable scheme is not necessarily the most economical and vice versa. Analyses have been proposed to evaluate the controllability of steady-state processes using open-loop with Singular Value Decomposition (SVD) under quantitative a criterion such as A? + ?sm with simplified first-order transfer functions. This work considers four feasible designs with multiple reactive zones and evaluates their controllability from their open-loop dynamic responses obtained from Aspen Dynamics� by calculating the condition number for different frequency ranges analyzing qualitative aspects and the A? + ?sm criterion evaluating the controllability of each scheme and the conditions of the simplification of their dynamic responses. For this, simplifications of first and second order transfer function models are compared with the models that robustly predict their behavior. The results of this study show that first order functions, despite their simplicity, can predict well the complex model of these distillation schemes. However, for low frequencies (i.e. ? < 10 rad/h) second order functions are better options because they capture the overshooting (damping) effect. The proposed methodology can be applied in global optimization with controllability as an additional criterion in the objective function.