The Dawn of Waste Plastic Oil Conversion Equipment - KUROKI PROCESS-6 and the 1998 Embryonic Move Toward a Recycling Society (September 1998)

The Dawn of Waste Plastic Oil Conversion Equipment - KUROKI PROCESS-6 and the 1998 Embryonic Move Toward a Recycling Society (September 1998)

At the end of the 1990s, Japan was at a major turning point toward a "recycling-oriented society. After the collapse of the bubble economy, interest in sustainability grew rapidly as the economy rebuilt, and the Kyoto Protocol was adopted in 1997. While the reduction of greenhouse gases was being questioned internationally, waste reduction and resource recycling were becoming urgent issues in Japan. Against this backdrop, the Containers and Packaging Recycling Law was fully enforced in 1997, and the recycling of waste plastic was incorporated into the system.

As if in response to this institutional change, "oilification technology" began to gain prominence. This method of pyrolyzing used plastics at high temperatures and recycling them as hydrocarbon oil has attracted attention as an "ideal technology" that does not emit dioxin or NOx as incineration does, and allows resources to be recycled.

However, the ideal is not without its difficulties. In existing equipment, the furnace corroded due to the contamination of chlorinated plastics, and the time and effort required for sorting and maintenance costs were major barriers. In addition, the market price of recycled oil ranged from 70 to 100 yen per kilogram, which was less economical than that of heavy oil A (about 30 yen) at the time.

In this difficult situation, the "KUROKI PROCESS-6" oil conversion equipment developed by Nippo Sangyo of Suita City, Osaka Prefecture, made a strong presence. Its unique structure, which combines a screw drum and screw pump, enables high-temperature cracking at 450°C or higher, and the yield rate of pyrolysis oil is an astonishing 97% or higher. The carbon byproduct is less than 1%, which is excellent, and the system is suitable for continuous operation because of its automatic discharge capability. Furthermore, the processing cost is less than 30 yen/kg at 100 kg/h, and 18 yen/kg at maximum capacity, a level surpassing that of natural oil.

However, technology alone does not make a sustainable business. What was suggested in this paper was a new operating model in which small and medium-sized companies and local governments jointly own equipment in a cooperative fashion, establishing a stable supply system for waste plastic and a sales network for recycled oil. This represents a departure from the conventional model of single installation, and was noted as a bridge to a regional circular economy.

Also noteworthy was the development of oil conversion technology for "thermosetting resins" conducted at the same time by the National Research Institute of Natural Resources and Environmental Technology and Mitsui Coal Liquefaction. The company was the first in the world to successfully convert materials that had previously been impossible to recycle, such as phenol resin and urea resin, into oil through liquid-phase decomposition, and in the future, by using waste oil as a solvent, the company was looking to establish a technology to simultaneously process waste plastic and waste oil.