MODELING AND CONTROLLER DESIGN OF AN INDUSTRIAL OIL-FIRED BOILER PLANT

In this study, a physical boiler system is modeled as a multivariable plant with two inputs (feed water rate and oil-fired flow rate) and two outputs (steam temperature and pressure). The plant parameters are modeled by identification based on experimental data collected directly from the plant. The routines of System Identification Toolbox with structure selection for Autoregressive Moving Average together with Recursive Least Square (ARX) were used to identify the model. The identified ARX model was validated using Akaike's Final Prediction Error (FPE) criterion. The identified model was further subjected to test, using the validation input data; simulated model outputs for both temperature and pressure agree closely with the actual plant outputs with error of 8% and 9% respectively. Furthermore, Proportional Integral Derivative (PID) Controller was developed to control the identified model. Simulation studies were carried out; the results obtained indicate the effectiveness of the technique. The controller was able to track the temperature and pressure set points steadily and rapidly.