Haraldrud Municipal Solid Waste Combustion Plant in Oslo: Optimizing, Stabilizing and Modeling the Combustion Process

Abstract

This thesis has studied Haraldrud MSW combustion process. Haraldrud is a realcombustion plant burning waste for citizens of Oslo. A thoroughly description ofthe combustion process has been presented based on manipulating and analyzing theprocess, together with long discussions with the plant engineers. Working with a realplant is time-consuming, challenging and very informative. Rarely theories are easyto implement on a real plant, and the focus of this thesis has been to connect theoryand practice. All simulations are based on real process data.Burning MSW is a complex process to control, and several factors including;unknown calorific value, regulation of the waste flow, and the long time constant formeasuring and regulating the energy contributes to this. Today s unknown calorificvalue and measuring the energy from the combustion can be calculated from flue gasmeasurements. By implementing these in a new controller at Haraldrud the variationin energy from the combustion will be reduced and results in waste flow increase.One method to develop a model and estimate the model parameters is to decide amodel set and estimate the model parameters based on system identification theory.An open-loop system identification test was applied to the combustion process. Further,the model parameters to a MIMO ARX model were estimated from recordedtest data. It was concluded that the process variation in the gathered open-loopdata was too large, which resulted in a poor model. The model should instead beestimated based on closed-loop identification.Another method to estimate the model parameters is to use a control law toestimate the parameters on-line. Gradient method is one control law and has beenvalidated from recorded process data. The simulation shows that the estimated andmeasured outputs followed each other perfectly.