2006 Volume 92 Issue 12 Pages 833-840
In order to improve coke strength by technique of coal size control, it is essential to understand relationship between inert size and coke strength. The size and area of inert in coke was measured with a microscope and an image analysis technique and the effect of inert size on coke strength was investigated. Moreover the reason why DI150-6 leveled off at inert size of 1.5 mm was investigated.
The results are follows.
(1) When the inert size is between about 1.5 mm and 5 mm, surface breakage product (DI150-6) decreases as the size of inert in coke becomes smaller. When the inert size is over about 5.0 mm, volume breakage product(DI1506-15) decreases as the inert size becomes smaller.
(2) The effect of 1% inert in coke on DI150-6 and DI1506-15 was clarified.
(3) According to Hertzian contact theory and Griffith equation, it is estimated that the crack under 0.5 mm doesn't grow by fall of coke in drum tester. Critical inert size (1.5 mm) is appropriate values for this critical crack size (0.5 mm), because size of the crack around inert particle is equal to the inert size or is smaller than it.