fig-1
Figure 1: The boiler simulation facility (BSF) is a 15MW pilot scale oxy-coal boiler owned and operated by Alstom. The boiler was designed for characterizing the combustion process and heat transfer within the boiler to better understand the design and operation of tangentially-fired boilers. Various ports are located at different levels within the boiler. At each port, probes are inserted into the boiler and measurements are taken at different locations across different levels. Measurements include temperature, heat flux, and species concentrations.

V/UQ Analysis. Initial sensitivity analysis showed several uncertain simulation parameters had a strong influence on the resultant temperature, O2, or heat flux fields in the simulation. The V/UQ analysis, helps in determining the uncertainty in these simulation parameters, and finding values of this parameters where consistency between simulation results and experiments exist.


 

Thermal Conductivity [W/(m-K)]

Uncertainty in the thermal conductivity within the refractory, or the emissivity of the walls due to ash deposition, has a strong impact on thermal boundary conditions of the system.

Coal Feed Rate [kg/s]

Uncertainty in the coal flow rate can have a large impact on the combustion process.

Devolatilization rate [kg/s]

A one-step coal devolatilization rate is employed within Arches to describe the rate of reaction of the coal particles. Uncertainity in this parameter can have a large effect on the chemistry in the system.

 

 

 

 

fig-2a fig-2b fig-3
Figure 2: These plots show the prior uncertainty attributed to the experimental measurements (red bars). Also shown is the range of simulation output after varying the wall thermal conductivity. The consistent space for this one-dimensional analysis is shown with the green bars. Future work will include more parameters in the V/UQ analysis. Figure 3: The plot above shows the temperature response to the particle size distribution. The effect of the change is clearly seen below when the boundary conditions are updated to reflect the new PSD.

 

coal-gas-source gas-temperature
small-particles large-particles