Production of hydrogen-rich fuel gas from waste plastics using continuous plasma pyrolysis reactor

There is a serious concern about the large amount of accumulated plastic waste all around the world. Synthetic polymers such as polyethylene terephthalate (PET), polypropylene (PP), and polyethylene (HDPE, LDPE) are substantially present in the plastic waste generated. There are various methods reported to minimise such plastics waste with certain limitations. To overcome such limitations the present study have been carried out in which thermal decomposition of plastic waste of PET, PP, HDPE, and LDPE studied using a novel plasma pyrolysis reactor. The major objective of this work is to investigate the viability of the continuous plasma pyrolysis process for the treatment of various plastic wastes with respect to waste volume reduction and production of combustible hydrogen-rich fuel gas. The effect of temperature and feed flow rate on product gas yield, product gas efficiency, solid residue yield, and H₂/CO ratio has been evaluated. The experiments have been carried out at different temperatures within the range of 700-1000 °C. Plasma pyrolysis system exhibited combustible hydrogen-rich gas as a product and solid residue. Liquid products have not been observed during plasma pyrolysis, unlike conventional pyrolysis. The reaction mechanism of plastic cracking has been discussed based on literature and products obtained in the present work. The effects of feed flow rate and temperature on exergy efficiency were studied using the response surface method. The mass, energy, and exergy analyses have also been carried out for all the experiments, which are in the range of 0.95-0.99, 0.48 to 0.77, and 0.30 to 0.69, respectively.