System Design of Plastics Recycling based on Quality Information Chain

Research Project , Research Report 2007

Jun NAKATANI Assistant Professor, Department of Chemical System Engineering, The University of Tokyo
Masahiko HIRAO Professor, Department of Chemical System Engineering, The University of Tokyo

Abstract

A framework of system design of plastics recycling based on quality information chain is developed. The subject of this article is mechanical recycling of post-consumer PET bottles in Japan. The “quality conversion matrix”, which links the quality of waste PET bottles and recycled PET resin, is described. Quality of recycled PET resin is estimated by multiplying quality vector of waste bottles by the quality conversion matrix, and the applicability to the intended products is simulated by confirming if the estimated quality of recycled resin satisfies the quality demands from PET resin users. As the amounts of utilities to run the recycling process are attached to the quality conversion matrix, the amounts of CO2 emissions and fossil resource consumptions are also estimated. In the case where the estimated quality does not satisfy the quality demands, quality parameters of waste bottles which need to be improved and optional modules which need to be included in the recycling process are specified under the required quality constraints utilizing linear programming. The requirements on the quality of waste bottles, along with the estimated CO2 emissions and fossil resource consumptions after achieving the quality demands, contribute to the multi-objective system design of plastics recycling.

Keywords:

quality information chain, post-consumer PET bottle, mechanical recycling, quality demand, linear programming