Plant Process Model

Boiler Software Model

• The boiler model is of high fidelity replica simulation of the reference boiler and caters for the following:

1. Asymmetric burner arrangements
2. Power manoeuvres
3. Shut down
4. Start up
5. Heat transfer by radiation, convection & conduction
6. Boiler filling and emptying
7. Boiler tube leaksEffects of soot build-up (controlled by malfunction insertion)
8. Flue gas composition

• The model simulates the combustion of the fuel at each burner level and continuously calculates on a first principles basis, the current ignition conditions in the furnace. The combustion of fuel at every burner level is simulated including the generation of gaseous combustion products such as CO, CO2, SO2, N, H2O, O2 as well as ash and combustion residues due to incomplete combustion of fuel.

• The simulation also considers that incomplete combustion at one or more burners may, depending on ignition conditions, cause the ignition (secondary combustion) of the unburned fuel further up in the furnace. The model also takes into account fuel water content, coal burner efficiency, coal particle size and fuel calorific value, which are controlled by malfunction insertion and external parameter adjustment respectively. The primary airflow dynamics through the mill together with the grinding medium is also odeled.

• The wear of the mill liners is affected by malfunction insertion.Flame and flue-gas enthalpy is calculated on a first principles basis with the subsequent energy transferred to the water-walls and heater elements by radiation and convection. Energy input from preheated air is also taken into account as well as heat loss from the furnace.