Effect of Coke Fissure on Clearance between Coke Cake and Oven Wall

Abstract

It is essential for old coke ovens to avoid pushing trouble because this trouble, which has increased gradually with the aging of coke oven, negatively affects coke stable production and coke oven service life. As one of effective approaches to improve pushing condition is to maintain sufficient clearance between coke cake and heating wall, it is important to clarify control factors for the lateral shrinkage of coke cake. At the beginning, the relationship between fissure existence form to the inside of coke cake and clearance was investigated by using X-ray computed tomography scanner and image processing system. And it was clarified the importance of controlling fissure ratio, especially total fissure length closely correlated with fissure density. Then, the influence of Ro variance (σRo/Ro) as the characteristic factor of coal blend on fissure in coke cake and clearance was estimated. As a result, the clearance was strongly dependent upon σRo/Ro and its effect was verified at the commercial operation. Eventually, it was cleared that σRo/Ro of coal blend was one of the important parameter to control clearance.