Dynamic modeling and control of soybean meal drying in a direct rotary dryer

This paper presents the analysis of the dynamic model and the application of Proportional, Integral and Derivative (PID) control in the soybean meal drying in a industrial direct rotary dryer by computational tests. Therefore, load disturbances as step, pseudorandom, and impulse were applied in the inlet speed and in the inlet moisture of soybean meal in the dryer. Later, the output responses for perturbations were investigated with control systems. The application of feedback PID control showed satisfactory results, returning expected output moisture. According to the Integral Square Error (ISE) the manipulated variables that showed better controllability were the inlet speed, when the perturbation was in the soybean meal inlet moisture; and the inlet temperature of drying air, when the perturbation was in the inlet speed of soybean meal. These results are coherent with literature and conclude that the tuning feedback PID control keeps the output moisture of soybean meal inside the specifications with fast results. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.