Reduction of the CO emission from wood pellet small-scale boiler using model-based control

The paper presents new approach in reducing of the CO emission in exhaust gases from small-scale wood pellet boilers. The results are obtained by control of the airflow to the boiler using a model-based nonlinear predictive controller. The complex-structure nonlinear model designed, and simplified to the nonlinear block-oriented Hammerstein system. Finally, the Hammerstein system is used to design the nonlinear predictive controller of the combustion process. The effectiveness analysis of the designed control algorithm under operating conditions at nominal heat power shows that 1) the airflow changes to the boiler is crucial for the CO concentration in the flue gasses and 2) accurate control of the airflow may lead to a significant reduction of the CO emission without any changes of the boiler design. The paper shows that reducing CO emissions from small-scale wood pellet boilers decreased by 35-50% of the original value with low implementation cost to fit industrial scale. (c) 2021 Elsevier Ltd. All rights reserved.