Catalytic cracking of chlorinated heavy wax from pyrolysis of plastic wastes to low carbon-range fuels: Catalyst effect on properties of liquid products and dechlorination

Catalytic conversion of useless chlorinated heavy wax (chlorine, 0.14 wt%) obtained from pyrolysis of refuse plastic fuel was studied using iron oxide impregnated HY zeolite to produce a useful liquid product. It was found that the largest liquid fraction (gasoline and kerosene/ diesel, 66.9 wt.%) with very low chlorine content was achieved when using Fe[3]/HY among impregnated HY catalysts. This demonstrated that the Fe impregnated HY catalyst had a dual function of catalytic cracking of HY zeolite and dechlorination of iron oxide. Excessive impregnation of Fe, i.e., Fe[20]/HY, showed the least cracking activity of heavy wax owing to the catalyst having lowest total acid sites, but yielded liquid product with the lowest chlorine content (60 ppm) among the tested catalysts. The spent catalysts were deposited by a significant amount of soft coke and chlorine, and they were totally restored by thermal treatment in air (700 ℃).