Low volatile anthracite coals (< 10% Vdaf - dry ash free) present particular combustion difficulties in terms of achieving low unburned carbon levels, good ignition, flame stabilisation and minimum load without oil support firing. To optimise each of these requirements Doosan Babcock has developed a unique furnace and burner technology that integrates the furnace into the combustion process. The features inherent in Doosan Babcock downshot firing furnaces are specifically designed to achieve optimum combustion conditions. The combination of low velocity non turbulent fuel and air entry in conjunction with a 'U' or 'W' shaped flame path ensures a prolonged residence time with stable and efficient combustion. Both natural circulation and once through supercritical downshot boiler designs are available.

To date Doosan Babcock has supplied over 5,000 MW of this type of boiler as far afield as Pha Lai in Vietnam, the first large coal fired power station in Vietnam, which burns what is the lowest volatile indigenous anthracite anywhere in the world.