Copyrolysis of Low-Grade Indian Coal and Waste Plastics: Future Prospects of Waste Plastic as a Source of Fuel

Copyrolysis of waste plastics with different materials, viz. coal, biomass is an ecofriendly and industrially acceptable waste management technique. In the present study, an attempt has been made to produce value-added products by utilizing waste plastics and low-grade North Eastern (NER) Indian coal through copyrolysis process. Three thermoplastics commonly found in municipal wastes [polyethylene terephthalate (PET), low density polyethylene (LDPE), polypropylene (PP)] and a simulated waste plastic mixture (MP) were selected and blended with NER coal at a mass ratio of 3:2 (coal/plastics). The experiments were performed at 500 °C, 600 °C, and 700 °C in nitrogen atmosphere at a heating rate of 10 °C/min. After analysis it was found that coal/PP and coal/LDPE produced a good quantity of tar, whereas coal/MP improved the quality of the char products. Significant interaction between coal and different types of plastics was observed in thermogravimetric analysis (TGA–DTG). Proximate, Fourier transform infrared (FT-IR) spectroscopy, and field emission scanning electron microscopy analyses were done for characterization of the char products. Furthermore, FT-IR, NMR, and gas chromatography–mass spectrometry analysis of the tar samples ensured that higher alkanes, alkenes, and aromatics which are comparable to that of the petrol-derived fuels are present in the tar samples; thus, it can be used as an alternative fuel for industrial heating purposes.