A particle-size regulated approach to producing high strength gasification-coke by blending a larger proportion of long flame coal

Abstract

To produce a qualified gasification-coke by blending a larger proportion of low-rank coal, the effects of blending ratio, particle size distribution, and maceral components on the coke strength were studied, and a new coking mechanism was put forward in terms of the physical texture. The results show that the influence of coal particle size varies with the different cohesiveness of coals. Fat coal (FC) with a smaller size gets a better performance on the coke strength, while a larger size is needed for gas coal (GC), and the optimum size of long flame coal (Shenfu coal, SFC) varied with its blending ratio. SFC and GC should be crushed coarsely (2–3 mm surpasses 40%) to act as the framework with the less external surface in the viscous embedded state. FC should be crushed finely (<0.2 mm) to form flowing metaplast that being filled uniformly in the gap between these coarse particles, thus reinforcing the embedded state and leading to a high coke strength with a less blend of FC (25 wt%). Moreover, liptinite enriched in the coarse particles of GC and SFC improves the cohesiveness of blended coal moderately. A qualified gasification-coke (M25 > 90%, CRI > 50%, CSR > 35%) can be obtained by blending >40 wt% SFC with this new coking mechanism.