Three different types of pulverised fuel-firing systems are used in large boilers:
- Horizontal or slightly angled swirl burners located in the front and/or rear walls of the furnace. In
a swirl burner the air, normally secondary air, is given a strong swirl about the axis of the
burner. The swirling action increases the mixing of combustion gases, air and fuel and
produces a short intense flame.
- Tangential corner-fired burners introduce the fuel and primary air at a tangent to an imaginary
circle in the centre of the combustion chamber. They produce a long low intensity flame that
swirls about a vertical axis.
- Vertical or downshot firing burners are located in the roof of the combustion chamber with the
flame projected downwards into the combustion chamber. This firing method is normally used
for anthracite.
