Industrial Wood-Chip Boiler Automation and Combustion Optimisation with Secondary Air PI Controller Tuning

This master thesis is written at the Tallinn Technical University, Faculty of Information Technology, Department of Computer Control, in cooperation with Valmet Automation OY in Tallinn. According to contract with Rapla district heating Valmet Automation OY provides biomass boiler complete automation and controller tuning to optimize boiler work. To establish control system and optimisation thesis author reviews biomass boiler system technology, different controller tuning methods and Valmet Automation hardware, software and technical material. All acquired technical knowledge is used to create automation logic programs and applied those to industrial computer. Trial and Error tuning method is used to find parameters to all PI controllers. Study of combustion control is performed to find out which technique to use in practise to improve steady state combustion process control. Secondary air control loop is chosen to control oxygen concentration in the furnace. Tests with real plant are carried out and analysed. Two open loop controller tuning methods are applied and results are analysed. Finally the overall thesis is discussed and conclusions are drawn.