Abstract
The coke degradation mechanism was considered in order to suppress the fine coke increase during high-rate pulverized coal injection. The following conclusions were derived as a result of model experiment.
(1) The reasons why the fine coke increases at the tuyere level during high-rate pulverized coal injection are the degraded coke surface existence because of the lack of gasification by O2 and the increase of gasification by CO2 in the raceway.
(2) The use of high reactive coke is effective in order to suppress the coke degradation.
(3) The permeability in the lower part of the blast furnace is controlled by the fine coke amount at the bosh level during high-rate pulverized coal injection. The decrease of load on the coke bed is effective in order to suppress the coke degradation at the bosh level.
(4) In order to apply the model experimental results to the actual blast furnace, it is necessary to consider the effect of coke strength at room temperature and the decrease of coke surface strength after gasification during the use of high reactive coke.
