Year: 1976
Type: article
Abstract: In the last period of the 25th campaign, during which coke (B) made from an inferior coal mixture was used, a stagnant stock movement and an increase of pressure drop in the lower region occurred at the times when maximum volume of molten products was accumulated in the hearth. Observations with a fibre or bore-scope showed:(1) Feeding of flaky coke fines from above into the raceway around the tuyere nose;(2) Scattering of coke fines in the upper bosh (at the position BIII-1);(3) Alternative fluidization and rapid descent of flaky coke fines in the furnace center (at the position CII-1);(4) Rise of slag bath surface to a high level (at position CII-1).These phenomena together with the results of hot-model experiments made the authors conclude that the flaky coke fines, generated at some high-temperature region above the combustion zone as a result of a degradation of charged coke, accumulated gradually in the bosh and hearth and caused a marked increase of slag hold-up and of resistance to gas flow.Investigations on the cooled furnace contents after blowing-out suggested that the degradation, or the revelation of defects inherent in coke (B), might start at about 1000°C in the lower shaft and become remarkable in the belly. Though a degradation due to the gasification with CO2 may be supposed, other mechanisms should also be examined in view of a large quantity of alkaline matters adsorped by coke in the region from lower shaft to belly.
Source: 鐵と鋼 : 日本鐡鋼協會々誌
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W2519257580