The combustion dynamics of coal, wood chips and their mixture is investigated. Load change capability and the effect of the individual control variables, for example the mixture ratio of different fuels, on pilot-scale CFB boiler dynamics were also studied. Disturbances in fuel feeding cause fluctuations in the flue gas concentrations. Changes in the heating value are possible due to varying moisture content of the fuel. Both these disturbances affect the instantaneous firing rate in a boiler. Also the characteristics of the fuels have to be taken into consideration when designing boiler control systems. When co-firing two fuels with clearly distinct combustion characteristics, direct assumptions based on each fuel’s characteristics cannot be made about combustion behaviour of their mixture. Combustion experiments with coal and wood chips and their co-firing were carried out in a pilot-scale CFB reactor (VTT) and a large-scale CFB boiler (Chalmers). A comparison of the combustion in the two different size reactors, provides information about scaling. The combustion responses due to changes in the fuel feeding of the two circulating fluidized beds are analyzed by a dynamic model.
|Publication status||Published - 2007|
|MoE publication type||A4 Article in a conference publication|
|Event||6th European Conference on Coal Research and its Applications - University of Kent, Canterbury, United Kingdom|
Duration: 5 Sep 2006 → 7 Sep 2006
- Fuel mixtures
Nevalainen, H., Jegoroff, M., Saastamoinen, J., Tourunen, A., Jäntti, T., Kettunen, A., Johnsson, F., & Niklasson, F. (2007). Firing of coal and biomass and their mixtures in 50 kW and 12 MW circulating fluidized beds: Phenomenon study and comparison of scales. Fuel, 86(14), 2043-2051. https://doi.org/10.1016/j.fuel.2007.04.006