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...

Slag splashing technique in converter operation Mar24

Slag splashing technique in converter operation...

                     Slag splashing technique in converter operation  The erosion of refractory lining of a converter has a major contribution for the low lining life. Erosion occurs because of chemical erosion due to attack of slag and molten metal on the refractory of the converter at the high operating temperatures and because of thermal shocks as well as due to mechanical wear.  Slag splashing technique has been developed to counter this erosion and produce a freeze lining. Today slag splashing has become a powerful tool not only for increasing of the lining life of the converter but for increasing of the converter availability and maximizing of production besides reducing of the refractory and gunning costs. History Slag splashing technique was first developed in 1970 but was not put to large scale use. The Indiana Harbour plant of LTV steel was first to report success in 1992 with respect to improvement in the lining life by the use of this technique. Slowly this technique was used in the other steel melting shops of the world. Inland no. 4 BOF shop has reported a lining life of plus 60,000 heats. The process The slag splashing steps are as follows At the end of the previous heat the liquid steel is tapped in steel teeming ladle and molten slag remains in the converter. The converter operator visually inspects the slag condition to determine the quantity of slag conditioner to be added. The converter operator visually inspects the converter lining to determine if any specific area of the lining needs special attention. The molten slag is conditioned with respect to its temperature, FeO and MgO contents by the addition of a conditioner in required quantity. The converter is rocked for slag coating of the charge pad and tapping pad....