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

The Era of Return of Waste Plastic to Feedstock Oil Social Background of the Emergence of Thermal Recycling Technology (1990s)
In Japan in the 1990s, waste disposal became a serious social problem as household waste increased, incineration facilities aged, and final disposal sites became increasingly tight. Waste plastics, in particular, were the most troublesome to local governments because incineration entailed the risk of dioxin emissions and because they do not decompose semi-permanently when disposed of in landfills. With the rapid increase in plastic consumption, disposal sites around the country were expected to fill up quickly, and the conventional methods of burning and burying were reaching their limits.

Under these circumstances, attention was focused on oilification technology using pyrolysis, or thermal recycling. Since plastics are originally derived from petroleum, heating them to an oxygen-free temperature of 300 to 500 degrees Celsius will break their molecular chains and reduce them to an oil content similar to gasoline or kerosene. In demonstration tests, it was estimated that about one liter of oil could be obtained from one kilogram of waste plastic, and the technology was expected to solve the problems of resource recycling and disposal sites in one fell swoop. In the mid-1990s, the development of this technology progressed from small equipment for municipalities to medium-scale plants for companies, and it was frequently covered in local government and environmental magazines.

At the time, this was before the enactment of the Basic Law for Establishing a Recycling-based Society, and both the national and local governments were searching for a specific recycling model. In anticipation of the Containers and Packaging Recycling Law enacted in 1995, the future of waste plastics became a major focus, and oilification technology was positioned as one of the technologies that would symbolize the future. Amid concerns about soaring crude oil prices and worries about dependence on foreign countries, the idea of extracting fuel from waste plastic was easy to understand and appealing in terms of both policy and private investment.

On the other hand, there were challenges. It was pointed out that the pyrolysis equipment was difficult to operate reliably, the quality of the oil produced was inconsistent, and if vinyl chloride was mixed in, chlorine-derived corrosion and gas emissions would become a problem. Maintenance and management costs were also high, and profitability was an issue on a municipal scale. However, when looking back over the period of the 1990s, oil conversion technology played an important role as a third option that emerged in the midst of the waste crisis.

It was also the starting point for today's chemical recycling research, and the trial and error of the time forms part of the foundation of the current resource recycling policy.