Conference paper
Economic Optimization of Spray Dryer Operation using Nonlinear Model Predictive Control
Department of Applied Mathematics and Computer Science, Technical University of Denmark1
Scientific Computing, Department of Applied Mathematics and Computer Science, Technical University of Denmark2
GEA Process Engineering A/S3
Dynamical Systems, Department of Applied Mathematics and Computer Science, Technical University of Denmark4
Department of Electrical Engineering, Technical University of Denmark5
Automation and Control, Department of Electrical Engineering, Technical University of Denmark6
Center for Energy Resources Engineering, Centers, Technical University of Denmark7
In this paper we investigate an economically optimizing Nonlinear Model Predictive Control (E-NMPC) for a spray drying process. By simulation we evaluate the economic potential of this E-NMPC compared to a conventional PID based control strategy. Spray drying is the preferred process to reduce the water content for many liquid foodstuffs and produces a free flowing powder.
The main challenge in controlling the spray drying process is to meet the residual moisture specifications and avoid that the powder sticks to the chamber walls of the spray dryer. We present a model for a spray dryer that has been validated on experimental data from a pilot plant. We use this model for simulation as well as for prediction in the E-NMPC.
The E-NMPC is designed with hard input constraints and soft output constraints. The open-loop optimal control problem in the E-NMPC is solved using the single-shooting method combined with a quasi-Newton Sequential Quadratic Programming (SQP) algorithm and the adjoint method for computation of gradients.
The E-NMPC improves the cost of spray drying by 26.7% compared to conventional PI control in our simulations.
| Language: | English |
|---|---|
| Publisher: | IEEE |
| Year: | 2014 |
| Pages: | 6794-6800 |
| Proceedings: | 53rd IEEE Conference on Decision and Control (CDC 2014)IEEE Conference on Decision and Control |
| ISBN: | 1467360899 , 1467360902 , 1479977454 , 1479977462 , 9781467360890 , 9781467360906 , 9781479977451 and 9781479977468 |
| Types: | Conference paper |
| DOI: | 10.1109/CDC.2014.7040456 |
| ORCIDs: | Poulsen, Niels Kjølstad , Niemann, Hans Henrik and Jørgensen, John Bagterp |
E-NMPC design Feeds Humidity Mathematical model Moisture Newton method Optimal control Powders SQP algorithm control system synthesis dairy products drying economically optimizing nonlinear model predictive control free flowing powder hard input constraints liquid foodstuffs moisture nonlinear control systems open loop systems open-loop optimal control problem optimal control predictive control process control quadratic programming quasiNewton sequential quadratic programming raw milk production residual moisture specifications single-shooting method soft output constraints spray dryer operation spray drying cost improvement spray drying process control sprays water content reduction
