Understanding Pulverized Coal Injection in Blast Furnace Oct21

Understanding Pulverized Coal Injection in Blast Furnace...

Understanding Pulverized Coal Injection in Blast Furnace Pulverized coal injection (PCI) is a well-established technology for hot metal (HM) production in a blast furnace (BF). It is practiced in most of the BFs and all the new BFs are normally built with PCI capability. The composition and properties of the coal used for injection can influence the operation, stability and productivity of the BF, the quality of the HM, and the composition of the BF gas. The coals being used for the PCI are described in the article under link ‘http://ispatguru.com/coal-for-pulverized-coal-injection-in-blast-furnace/’. The critical aspects of PCI systems include coal preparation, its storage and distribution to ensure uniform feed of coal to each tuyere without fluctuations in the coal delivery rate and its combustion through lance design and oxygen (O2) injection. Coal preparation Pulverization of coal is carried out in a single or multiple grinding mills (pulverizers) depending on the requirements. Grinding and distribution of the coal to the injection lances constitute a major operating cost. Coal reclaimed from coal storage is screened for the removal of the foreign material and any large lump of coal is crushed. The coal is then fed into the mill where it is pulverized and dried. Coal of the required size is transported out of the mill by the hot gas stream, collected in a bag filter and conveyed to the storage bins. Grinding and transport are carried out under an inert atmosphere to minimize the risk of ignition of the dry coal particles. The resultant particle size distribution of the pulverized coal affects it handleability in pneumatic transport equipment and, at high injection rates, its combustibility. Pulverizers grind coal to one of the two size fractions namely (i) pulverized coal where around 70 % to 80 % of...