Generic Optimal Temperature Profiles for a Class of Jacketed Tubular Reactors

Abstract This paper deals with the optimal and safe operation of jacketed tubular reactors. Despite the existence of advanced distributed controllers, optimal steady-state reference profiles to be tracked are often unknown. In Logist et al. [2008], a procedure which combines analytical and numerical optimal control techniques, has been proposed for deriving optimal analytical (and thus generic) references, and it has been illustrated for plug flow reactors. The aim of this paper is to illustrate the general applicability of this procedure by allowing dispersion. As dispersion significantly complicates a possible solution process (due to second-order derivatives and split boundary conditions), hardly any generic results are known. Nevertheless, the dispersive plug flow reactor model is important for practice, since varying the dispersion level allows to mimic an entire reactor range, i.e., from plug flow to perfectly mixed reactors. As an example a jacketed tubular reactor in which an exothermic irreversible first-order reaction takes place is adopted. It is shown that the procedure yields generic reference solutions for ( i ) three different cost criteria, and ( ii ) different dispersion levels.

[1]  P. Daoutidis,et al.  Robust control of hyperbolic PDE systems , 1998 .

[2]  Panagiotis D. Christofides,et al.  Predictive Output Feedback Control of Parabolic Partial Differential Equations (PDEs) , 2006 .

[3]  Filip Logist,et al.  Derivation of generic optimal reference temperature profiles for steady-state exothermic jacketed tubular reactors , 2008 .

[4]  Stanislaw Sieniutycz,et al.  Optimal temperature profiles for parallel-consecutive reactions with deactivating catalyst , 2001 .

[5]  P. V. Danckwerts.  Continuous flow systems , 1953 .

[6]  Denis Dochain,et al.  Optimal temperature control of a steady‐state exothermic plug‐flow reactor , 2000 .

[7]  Johannes P. Schlöder,et al.  An efficient multiple shooting based reduced SQP strategy for large-scale dynamic process optimization: Part II: Software aspects and applications , 2003, Comput. Chem. Eng..

[8]  M. Kubicek,et al.  Numerical Solution of Nonlinear Boundary Value Problems with Applications , 2008 .

[9]  Anil Kumar,et al.  Optimal temperature profiles for nylon 6 polymerization in plug‐flow reactors , 1983 .

[10]  Dominique Bonvin,et al.  Dynamic optimization of batch processes: I. Characterization of the nominal solution , 2003, Comput. Chem. Eng..

[11]  Panagiotis D. Christofides,et al.  Robust Control of Parabolic PDE Systems , 1998 .

[12]  Donald E. Kirk,et al.  Optimal control theory : an introduction , 1970 .

[13]  Johannes P. Schlöder,et al.  An efficient multiple shooting based reduced SQP strategy for large-scale dynamic process optimization. Part 1: theoretical aspects , 2003, Comput. Chem. Eng..

[14]  Wolfgang Marquardt,et al.  Detection and exploitation of the control switching structure in the solution of dynamic optimization problems , 2006 .