Effect of Coke Pore Structure on Coke Tensile Strength before/after CO₂ Reaction and Surface-breakage Strength

Abstract

The surface-breakage behavior of coke is examined to make clear the influence of the pore structure on the tumbler strength. This behavior is formulated numerically on first order rate equations consisted of coarse and fine powder generation rates. Each generation rates are estimated from particle size distribution of coke after the tumbler test. The relations between pore volume of coke and the powder generation rate constants are investigated. The rate constant of the coarse powder generation increases with increasing coarse pore volume of coke, and the rate constant of the fine powder generation depends on the fine pore volume. The tumbler strength estimated from the pore volume of coke is in a good agreement with the measured value. Furthermore, the effect of coke pore structure on tensile strength before/after CO₂ reaction is studied. The pore volume of coke over 100 μm has a large influence on tensile strength. Tensile strength after CO₂ reaction is affected by the pore volume under 1 μm. In the coke with larger pore volume under 1 μm, the coke degradation is suppressed after CO₂ reaction because gasification occurred preferentially at the surface of the coke.