Pulverized Coal Injection (PCI)
Coal injection – dense phase conveying
State-of-the-art blast furnaces feature pulverized coal injection (PCI) systems. The injection of up to 200 kg of coal per ton of hot metal replaces nearly the same amount of coke and, therefore, reduces production cost of the blast furnace iron.
New developments such as the Oxi-Coal-System, two lances per tuyere, pre-heating of the coal to be injected, and a high conveying gas load result in increased injection rates of pulverized coal. Plugging is avoided with the injection system developed by KÜTTNER, and abrasion of the piping is minimal.
The processing of the raw coal to injection quality is achieved in a coal grinding and drying plant. The hot stove waste gas, or the combustion of blast furnace top gas, can be employed as heat source for drying. The milling takes place in either a vertical mill or a hammer mill, depending on the required grain size. The pulverized coal is separated in a bag filter.
Kuttner has delivered plants for hard coal and blends with volatiles between 8-42 Vol% and Hardgrove indices of 40-95 ºHGI.