Production of fuel by co‐pyrolysis of Makarwal coal and waste polypropylene through a hybrid heating system of convection and microwaves

The bituminous coal of the Makarwal range of Pakistan and waste polypropylene were converted into gaseous and liquid fuel using a hybrid heating process based on microwave metal interactions. The mixture of coal and polypropylene was heated by the volumetric heating generated by absorption of the microwaves and the conventional heating produced by the sparking of copper under microwave power in a domestic microwave oven. The heat generation capacity and range of sparking of copper were increased by the use of tightly coiled copper antenna. The heat generation efficiency of copper antenna was found to vary with variation in the shape of the copper antenna. Four types of antenna were used in the pyrolysis process, i.e. the antenna made of tightly coiled copper, copper mesh antenna, copper strips antenna and copper cylinder antenna. It was observed that copper coil and copper mesh antenna were more efficient and responsible for higher percent conversions while the multi‐strip antenna was next and the least percent conversion was observed for single strip cylinder of copper. The amount of products and the relative concentrations of the oil, wax and gases were observed to vary with variations in the relative amount of coal and polymers. Both the gaseous product and aqueous fraction were analysed for sulphides using lead acetate reagent. The gases were also analysed for the presence of alkynes and alkenes using aqueous solutions of copper‐I chloride and potassium permanganate respectively. The oily product which was composed of oil and wax was analysed by GC‐FID and GC‐MS analyses. Copyright © 2016 John Wiley & Sons, Ltd.