Effect of blast furnace coal injection upon bosh coke properties, coke combustion and furnace permeability
A single tuyere rig was modified for coal injection studies using a wide range of coal types, size grading and levels of injection. The effect of varying blast operating conditions during coal injection on coal combustion, raceway size and action was investigated. In general coal injection increased blast pressure, raceway size and instability while reducing raceway temperature and blast kinetic energy. Although coal injection brought about increases in the level of fines production, the overall size changes in the vessel were small. The petrographic examination of the fines showed that coal injection contributed directly in terms of uncombusted injected coal residue, and indirectly in terms of increasing levels of mechanical action in the active regions of the coke bed, and weakening of the coke by coal ash/slag interaction with the coke surface. In general, the extent of these effects decreased with increasing injectant coal rank and to a lesser extent with increasing grain size. Increasing blast temperature during coal injection produced a further increase in raceway size and instability with both granular and PF grade coal when compared with the coke-only case. Oxygen enrichment simply acted as a correction for the fall in raceway temperature.
Bibliographic Reference: EUR 12010 EN (1988) MF, 157 pp., ECU 8, blow-up copy ECU 20
Record Number: 198910372 / Last updated on: 1994-12-01
Original language: en
Available languages: en