The following example will illustrate the order of magnitude of the "dust correction"
A typical ID fan for a 3000 tpd 5 stage kiln operates with the following data:
Gas flow Q1 = 112.1 m³/s
Gas density 1 = 0.643 kg/m³
Static pressure Δps = 5170 Pa
Dust load s = 42 g/m³ = 0.042 kg/m³

The power consumption of the selected ID fan with these data is Pgas = 730 kW

In other words, the dust contributes to the ID fan power consumption with about 48 kW or 6.5%.