Effect of particle-size distribution and degree of saturation on coal-compacting processes within a coke-making operation

The bulk density of an oven charge is a very important factor for the selection of the coking coals and coke quality in a coke-making process for producing blast furnace coke. Major factors influencing the bulk density of coal are moisture content, particle surface properties, particle shape, particle-size distribution, and particle density. The bulk density can be increased significantly through compacting the coal to a coal cake prior to oven charging. The objective of the compaction processes is the production of a cake with high density and as well as a sufficient mechanical strength in order to ensure a trouble-free cake charging into the coke oven. The present article deals with the evaluation of the compaction process based on lab-scale test work. The two subprocesses of densification and strengthening during both stamping and pressing were theoretically and experimentally investigated using compaction test units in combination with a strength-test device. Systematic investigations showed that particle-size distribution and degree of saturation have significant influence on cake density and mechanical properties of the coal cake.