Modelagem e simulação de uma planta integrada HTST de suco de laranja natural com controles fuzzy e convencional. / Modeling and simulation of one fuzzy and conventional plant integrated HTST of natural orange juice with controls.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The mathematical modeling, dynamic simulation and control of a plate heat exchanger with three sections: regenerator, heater and cooler for the natural orange juice HTST (High Temperature Short Time) pasteurization process have been carried out. From the plate heat exchanger mathematical modeling and the dynamic simulation, it has been possible to obtain the pasteurization process reaction curves (process variables as a time function under step disturbances of the external and manipulated variables) and to predict the dynamic behavior of the orange juice under several operating conditions. These reaction curves have been used for the controllers tuning, as well as in the process characterization. It has been found that the orange juice outlet temperature has non-linear characteristics for step changes in the utilities mass flow and linear characteristics for step changes in the orange juice and utilities inlet temperatures. It has also been found that the dynamic response of the orange juice outlet temperature to variations in the utilities mass flow and inlet temperature, as well as in the orange juice inlet temperature, most closely approaches the second-order transfer function. The conventional logic PID and the non conventional fuzzy logic, settled to the feedback control strategy with SISO (Single Input/Single Output) configuration have been studied. The simulator has been first codified in Matlabè software for the process characterization and later in Simulink for the controlling work. The conventional PID and non conventional fuzzy PI and fuzzy PID logic controllers performance for the pasteurization temperature control has been evaluated for the process stabilization condition aspects under set-point and load step changes. For set-point step changes, it has been found that the conventional PID as well as the non conventional fuzzy PI and fuzzy PID logic controllers have obtained good performances. For load step changes, the conventional PID logic controllers have obtained successful results for all step changes. The results with fuzzy logic controllers have been successful for the orange juice inlet temperature step change and not very successful for the utilities inlet temperature step changes.

ASSUNTO(S)

suco de laranja - pasteurização controllers (pid) controladores pid

ACESSO AO ARTIGO

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