Treball de Fi de Màster 
                                                       
                     Màster universitari en Enginyeria Industrial 
                                                       
                                                        
                                                       
                                                       
                                                       
         SMALL-SCALE PASTEURIZATION PLANT: MODELLING FOR 
                                     REAL-TIME CONTROL 
                                                       
                                                       
                                                       
                                                       
                                                       
                                                       
                                                       
                                                        
                   
                   
                   
                      Autor:            Sandra Terradellas Balaguer  
                      Director/s:       Dr. Carlos Ocampo Martínez 
                                        Dr. Sebastian Tornil Sin                     
                      Convocatòria:   Octubre 2016  
                   
                   
                                                                                           
                                                                                          
                                                                                      
                                    Escola Tècnica Superior 
                             d’Enginyeria Industrial de Barcelona 
                   
        Abstract
         The pasteurization process is one of the most common treatments in the food in-
        dustries in order to eliminate harmful pathogenic and spoilage microorganism. The pro-
        cess consists in maintaining a high temperature stablished during a short period of time
        (HTST).
         Most of the pasteurization plants are controlled by tradicional PID (Proportionas-
        Integral-Derivative). Much effort has been made to develop advanced controllers. How-
        ever, an accurate model that describes the system is required. The main of the present
        project is to develop a dynamical model for a pasteurization plant for a real-time control.
        Experimental plant consists in a small-scale pasteurization plant PCT23 MKII completely
        monitorized owned by the enterprise Armfield.
         The first task refers to modelling the different elements of the plant. Each one is
        modelled using the physical principles resulting a nonlinear model. Different parameters
        of the proposed model are later estimated by experimental data. Finally, the complete
        model is validated by new experimental data. Linear parameter-varying (LPV) model
        represents a class of non-linear systems that can be controlled using powerful linear-like
        techniques. As a nonlinear model is proposed to describe the real system, the second task
        refers to develop LPV) model.
         Results shows that the proposed models fit the experimental data with an error lower
                          iii
     than a 3 %. Advanced controllers could be designed using these models. As a first ap-
     proach a PID controller has been designed. The control objective is leading the controlled
     variables (temperatures) in order to reach the set point rejecting the disturbances.