The Era of Return of Waste Plastics to Feedstock Oil Social Background of the Emergence of Thermal Recycling Technology (1990s)

The Era of Return of Waste Plastics to Feedstock Oil Social Background of the Emergence of Thermal Recycling Technology (1990s)
In Japan in the 1990s, waste disposal and resource recycling were simultaneously facing a critical situation. In particular, waste plastics were the most troublesome waste for municipalities because of the concern about dioxin emissions if incinerated and semi-permanent residues if disposed of in landfills. With the rapid increase in plastic consumption, final disposal sites across Japan were strained, and the limits of the burn and bury method were beginning to be seen.

Against this backdrop, attention turned to thermal recycling technology, which uses pyrolysis to return waste plastic to raw material oil. By heating the waste plastic in an oxygen-free environment at 300 to 500 degrees Celsius and breaking the molecular chains, oil similar to gasoline or kerosene is generated, and it was said that about one liter of oil could be obtained from one kilogram of waste plastic. In the mid-1990s, small-scale equipment for municipalities and medium-scale plants for companies entered the demonstration stage, and were repeatedly introduced in environmental journals.

At the time, the national and local governments were searching for a model for a recycling-oriented society in anticipation of the implementation of the Containers and Packaging Recycling Law. With concerns about soaring crude oil prices and dependence on imports, the clear idea of converting waste plastic back into fuel attracted attention from a policy perspective. On the other hand, there were many problems, such as corrosion and gas generation due to the inclusion of vinyl chloride, operational stability, variations in the quality of the oil produced, and maintenance and management costs. Nevertheless, in view of the waste crisis of the 1990s, oil conversion technology was positioned as an important option, and it became the starting point that formed the foundation for later chemical recycling research.