If CO2 shall be captured from the flue gases of coal fired power stations for subsequent dumping, a viable technology should be available also for retrofitting existing conventional pulverized coal fired power stations.
The main objective is to evaluate the effects of burning pulverised coal in oxygen enriched, recycled flue gas under atmospheric pressure.
The effect of burning coal in the above described way on the combustion process is effectively unknown.
Specific areas in the research relate to:
- Flame stability and turndown
- Pollutant formation (NOx, SOx and unburnt hydrocarbons)
- Carbon in ash
- Mineral matter transformations and ash deposition
- Fly ash quality
- Radiative properties of flames and in-furnace heat flux distributions.
The above factors will be evaluated in terms of the following parameters: - Burner design and operation
- Method of oxygen and recycled flue gas injection through the burner - Flue gas recycle ratio
- Recycled flue gas temperature
- Coal type
To underpin the experimental programmes, mathematical modelling will be performed. This will allow extrapolation of the results obtained in the experiments to conditions not studied directly in this programme such as operation at higher pressure. Input conditions for the mathematical model require that some complementary coal characterisation studies will be necessary. The results of this programme will enable the viability of employing this advanced combustion technology to be evaluated, particularly in terms of application of the technology to existing power plant in retrofit situation.
Experimentation will be performed at 2.5 MW total thermal input, using an IFRF furnace facility. This furnace is a segmental, watercooled, refractory lined chamber of internal dimensions of 2x2x6.25 m. Within the furnace, cooling surfaces are installed to extract in a controlled manner to simulate the temperature-time history of furnace gases in a full scale utility boiler.
Complementary mathematical modelling studies will be performed using the in-house computations fluid dynamic code "FLUENT".