Pyrolysis gases produced from individual and mixed PE, PP, PS, PVC, and PET—Part II: Fuel characteristics

The current energy industry relies heavily on fossil fuels. As reserves of fossil fuels are diminishing, the demands for alternative forms of energy are growing. Therefore, the search for alternative fuels is crucial. This article discusses pyrolysis gases generated from major plastics as possible future successors to fossil fuels. The novelty of this study lies in the comprehensive discussion of the fuel characteristics of different pyrolysis gases that are so far unpublished. The article builds on Part I, which predominantly focused on the production and physical properties of pyrolysis gases from plastics. Various properties are determined by combining experimental and mathematical methods. An interesting aspect of the gases produced from poly(ethylene terephthalate) (PET) is their high upper flammability limits, which are 61.46% on average. Gases from poly(vinyl chloride) (PVC) are characterized by very high laminar burning velocities, with an average value of 178.62 cm s⁻¹, which is about five times higher than that of natural gas (NG). Gases produced from PVC at 500 and 700 °C have autoignition temperatures almost identical to that of NG. Furthermore, the results presented in this article show that, according to standards proposed by the California Air Resources Board and the Gas Research Institute, none of the pyrolysis gases are suitable fuels for gas engines, because the methane number of no gas meets the minimum value of 65 required in the EU and USA. This article discusses results valuable for determining the potential suitability of pyrolysis gases for use in power-engineering facilities, including combustion engines, and includes information on further research prospects.