Abstract
The influence of formed coke properties on the phenomena in the lower part of the blast furnace has been researched with two kinds of model experiment in order to establish the formed coke using technology.
First, the influence of physical properties of formed coke on the deadman structure was investigated using a semicircular model capable of simulating the heat transfer in the furnace.
The deadman having low void fraction is generated during using formed coke due to the formed coke properties with high bulk density and low void fraction. This structure results in the increase of metal hold-up, suppresses the gas entering into the deadman and leads to the lack of heat in this area.
In order to improve the deadman structure for smooth gas entering, it is effective to charge 50mass% formed coke in the peripheral area or to mix 50mass% formed coke with normal coke previously.
Second, the influence of strength and reactivity of formed coke on the reaction and permeability was investigated using a 90° sector model capable of simulating the reaction and heat transfer in the lower part of the furnace.
The fine coke generation in the raceway can be suppressed and the permeability is kept stably by use of formed coke having higher strength at room temperature than normal coke.
High reactive formed coke is burnt rapidly in the raceway, resulting in the acceleration of pulverized coal heating and combustion. The use of high reactive formed coke leads to the improvement of reducing efficiency of the furnace due to the decrease of CO2 gasification temperature and the increase of CO gas amount.
