Ways of enhancing strength of coke made at higher carbonizing rates

Where accelerated coking is practised, up to 40 mm/h, charges should be modified by increasing the proportion of lean coal. Weakly caking coals should not be incorporated as they tend to stress the coke product. In accelerated coking, charges should contain 80-90% of -3mm coal, as a coarser size consist increases degradation. A higher proportion of fines, on the other hand, leads to increased abrasion. Selective crushing with pneumatic separation, as well as preheating to 150 C, are recommended to improve product quality, the two processes being combined wherever possible. Dry quenching is obligatory in accelerated coking, as it raises coke permeability and strength, whilst at the same time reducing resistivity and abrasion.