Enhanced efficiency in recycling of waste plastics

NIPPON STEEL CORPORATION

Chemical recycling of waste plastics by using coke oven

Outline

For over 20 years, Nippon Steel has strived to carry out and expand chemical recycling (into ore reducing agents and chemical product materials) of waste plastics, using a coke oven process (which makes coke -- an ore reducing agent for steel making), with the aim of reducing emissions of global greenhouse gases (totally 3.07 million tons of CO2 reduction).
In response to further requests from society, we are taking up the challenge to make high-density waste plastic moldings in order to moderate the operating impact of coke ovens when handling waste plastics in vast volume.
The project is currently in the process of technological development based on cooperation among our research laboratories, steelworks, and relevant head office divisions. We intend to establish technologies within the next year or two and to subsequently introduce them to the waste plastic molding lines of existing facilities.

Description

1) Target to achieve in our challenge
We will take up the challenge to improve the density of waste plastic moldings in order to moderate the operating impact of coke ovens when handling waste plastics in vast volume (prevention of the generation of an operating impact even when increasing volume by 20%).

2) Issues to overcome to realize the challenge
・ To establish a high-densification method (theory) and apply it to operational benchmarks
It is difficult to maintain the density of the moldings at a high level because melting degrees vary when molding waste plastics. We are currently considering and testing a theory to enable steady high densification.
・ To expand and ensure the collected amount of waste plastics
At present, the Japan Containers and Packaging Recycling Association has a preferred bidder rule, in which the procurement amount of chemical recycling, conducted by Nippon Steel and other companies, has been unstable. Re-examination of the rule by the government is needed.

3) Specific actions
・ Evaluation and confirmation of the high-densification method: Fiscal years 2020-2021
- Design and manufacture of off-line testing equipment
- Verification testing of the high-densification method and checking of operational conditions and other factors

・ On-line testing: Fiscal years 2021-2022
- Design and manufacture of equipment modification, based on what is confirmed off-line
- Modification of existing facilities, and trial operation and adjustment
- Evaluation of the use of a coke oven in making high-density moldings

・ Verification of the actual equipment: Fiscal year 2022 and beyond
- Modification of the actual equipment and the promotion of high densification of the molding process at each steelworks

4) Potential quantified and other impacts in case of the accomplishment of the challenge
・ Improvement of CO2 emission reduction: Approximately 120,000 tons/year
・ Increase in the amount of effectively-used waste plastics, which cause problems in Japan and overseas (expanded use as chemical materials and reducing agents)