Gasification for material recycling—A solution to the plastic flood?

Abstract

AbstractSince 1950, only 9% of all plastic produced has undergone recycling, and a mere 10% of that has been recycled multiple times. Most discarded plastic (around 73%) ends up in landfills or is improperly managed, resulting in widespread littering. The main reason for low recycling rates is the lack of recycling technology for multi‐polymer and multi‐layer materials and unsortable mixed plastic waste. This plastic waste is one of the most accumulating types, including for example single‐use food packaging with an average lifetime of less than 6 months. These multi‐layer films, consisting of various polymer types, are not feasible for traditional mechanical recycling, which requires well‐sorted, clean, and homogeneous materials. Several methods for plastic recycling have been proposed to address this issue and tackle the overwhelming influx of plastic waste, among which steam gasification stands out as one of the most promising approaches for recycling mixed, contaminated, and unsortable plastics. This method utilizes high temperatures (800°C) to atomize the plastics, resulting in a gas mixture of , CO, and and small hydrocarbons. The resulting gas can be reformed through hydrocarbon syntheses, for example, via methanol to propylene and ethylene, and successive into new mono‐ and polymers of equal quality to fossil‐based plastics. Moreover, since the high temperatures atomize any organic structure, biomass can be used as a substitute for an extension of the carbon feed, ultimately reducing reliance on fossil feedstock. With these advantages, steam gasification can significantly increase recycling rates and contribute to a bio‐integrated circular carbon economy.