Effect of charcoal blending with a vitrinite rich coking coal on coke reactivity

The aim of this work was to investigate the effect that adding charcoal to a coking coal has upon the CO2 reactivity and structure of cokes produced at a laboratory scale. Charcoal was added to a vitrinite-rich medium volatile coking coal in three amounts (3, 5 and 8 wt%) and in two different particle size ranges (below 1 mm and between 3 and 4 mm) and carbonization was conducted in a laboratorial scale coke oven. Thermogravimetric analyses were used to assess coke reactivity towards CO2 under isothermal and nonisothermal conditions. Morphological analyses via optical and scanning electron microscopies using samples from before and after gasification were also carried out. It was found that controlling the amount and the particle size of charcoal added, coke reactivity did not differ considerably from the reference coke, although the TGA indicated that the addition of charcoal has the tendency to increase coke reactivity. The main structural changes due charcoal addition were the increase of coke surface area and the decrease of its structural order, justifying the noticed increase of coke reactivity.