Dissolution of Polyethylene in a Hydrocarbon Medium for the Subsequent Reprocessing by Hydroconversion

Factors influencing the dissolution of high-density polyethylene in petroleum tar to obtain a homogenized solution for the subsequent hydrogenation in the presence of a nanosized catalyst synthesized in situ under the hydroconversion conditions were studied. The calculation of the solubility indices shows that the best solvents for high-density polyethylene are low-molecular-mass alkanes and alkenes present in the paraffin–naphthene fraction of the tar. Because high-density polyethylene has crystalline structure, the dissolution occurs via swelling with the formation of a true solution depending on the ratio of high-density polyethylene to the tar. A conclusion was made that, to reach the best dissolution, the ratio of high-density polyethylene to the tar should be decreased, or the paraffin–naphthene fraction should be additionally introduced.