Replacing conventional fuels in USA, Europe, and UK with plastic pyrolysis gases – Part II: Multi-index interchangeability methods

Highlights: • Waste plastics can be a source of fuel with quality similar to natural gas (NG). • NG can be replaced with HCl-scrubbed gas from PVC pyrolysis at 700 °C. • Pyrolysis of plastic mixtures at 900 °C produces gas suitable for US and EU burners. • PET gases are least suitable for replacing with NG due to their low calorific value. • PE and PP gases are not acceptable for NG burners due to their incomplete combustion. - Abstract: The global increase in natural gas (NG) consumption and its steady decline in availability have spurred the search for new or alternative energy sources, such as pyrolysis gases. This article examines whether it is possible to burn pyrolysis gases from common plastic wastes in conventional burners without any adjustment to burner design. To determine the interchangeability of individual gases, several multi-index methods applicable to combustion devices in Europe, the USA, and the UK were used. This report is a continuation of a previous article (Part I) discussing the results of graphical methods for determining interchangeability. Similar to Part I, the results here imply that poly(vinyl chloride) (PVC) gases produced at a minimum of 700 °C have the highest replacement potential, and gases produced by polystyrene (PS) pyrolysis at 900 °C also conform with replacement requirements. For plastics mixtures, gases generated by pyrolysis at a minimum of 700 °C would be suitable alternatives to NG. These findings may contribute to plastic waste reduction as well as the discussion of reducing NG consumption. There is significant potential for follow-up research in this area, because the replacement of conventional fuels with gases obtained from wastes has not yet been sufficiently explored.