Inert materials such as coke breeze have a great influence on the contractile and fissure formation behavior of the coke cake as well as coke quality. Firstly, the contraction coefficient and Young's modulus of semi-cokes, which were produced with the different blending conditions of inert materials, inert brand, grain size and blending ratio, were measured. And then coke shrinkage and fissure formation in coke oven were evaluated by the carbonization test and a mathematical simulation model.
Due to the inert materials, micro cracks are generated inside the coke and contraction coefficient and Young's modulus decrease. Inert type, grain size and blending ratio affect the contraction coefficient curve and shrinkage ratio declines with the increase of the difference between coal and inert contraction coefficient, grain size and addition ratio. The existence of inert material also has an important effect on the coke cake structure. Clearance enlarges with the increase of inert size to around 0.30-0.50 mm, but further size increase gives negative effect to clearance. It is considered that the decrease in macro fissure becomes smaller than the increase in micro crack with the rise of inert size.
