The Effect of Plastic Addition on Coal Caking Properties.

The recycling process of waste plastics using coke ovens is now being studied. The effect of plastic addition on coal caking property was investigated. Thermal decomposition products of plastics interacted with coal during carbonization and the effect of plastic addition on coal caking property varied for kinds of plastics. The addition of polyethylene (PE), polypropylene (PP) and poly vinyl chloride (PVC) had little effect on coal caking property and coke strength. On the other hand, the addition of polystyrene (PS), polyethylene terephthalate (PET) and terephtalic acid (TFA) decreased the maximum fluidity and total dilatation, and deteriorated the coke strength. These differences were explained by the interaction between thermally decomposed products from plastics and coal. It is suggested that the radical formed as a result of PS or PET thermal decomposition may abstract hydrogen from coal, resulting in the decrease in coal caking property.