THERMAL-STRESS AND DEFORMATION OF COKE LA YER DURING CARBONIZATION

The non-uniform shrinkage and matrix strength of coke during coal carb onization have a great influence on the size of metallurgical coke. Th e influence of coal properties and carbonization conditions on the the rmal stress and deformation of coke layer were evaluated by the carbon ization test and a mathematical simulation model. The deformation was defined by the curvature of coke layer. The coke-fissure formation beh avior in coke layer was investigated by the carbonization test using t hin coal layer. The fissure distributions and curvature of coke layer were measured by X-ray computerized tomography. The thermal tensile st ress leads to cause the curvature and coke fissure of coke layer. Ther e is a good relationship between the curvature, fissures and size dist ribution of coke and the curvature and thermal stress distributions ca lculated by the mathematical simulation model. The contraction coeffic ient and Young's modulus of coal have a great influence on the thermal stress and deformation of coke layer. As the thermal stress in coke l ayer increases along with increase of the heating rate and transverse temperature gradient of coal layer, the size of coke is decreased. It was clarified that the thermal stress and deformation of coke layer ar e controlled by coal properties and carbonization conditions.