1996 Volume 82 Issue 10 Pages 805-810
The inner crack of formed coke (FC) causes degradation of coke particles during the transportation and results in low permeability in the blast furnace. Mechanism of inner crack generation of FC during carbonization was investigated by in-situ observation using of a furnace equipped with X-ray generator. The in-situ observation of formed coke elucidated that the inner crack was generated at the semi-coke temperature region with decrease of the radial temperature gradient. The crack was observed at the high heating rates or at the heating patterns with keeping temperature above the re-solidification temperature of FC. Thermal stress analysis indicated that the plastic strain at the re-solidification remains and causes the inner crack at the decrease in temperature gradient. The heating pattern with small temperature gradient at the re-solidification temperature was suggested to prevent inner crack generation.