A nonlinear process model based control (nonlinear PMBC) algorithm, which is based upon using a nonlinear approximate model, and a state variable control (SVC) algorithm have been tested on a medium fidelity simulation of a drum-type coal-fired boiler. A simple PI controller was also tested as a point of reference. The simulation was based upon the Cromby 2 model and was used to test each controller for 10 different upset scenarios that included soot blowing, load ramps and changes in burner tilts. The simulation had control valve hysteresis, control valve dynamics and temperature sensor dynamics added to it. The nonlinear PMBC controller had the best control performance yielding factors of 3 to 5 times reduction in steam temperature Variability over the optimally tuned PI controller for the 10 upset scenarios. The SVC controller outperformed the PI controller in 8 out of 10 of the upset scenarios, but typical variability reductions of only 20% were observed.