Recovery of Resources from End-of-life Industrial Products by Using Liquefaction or Gasification

Abstract

In normal resource recovery processes, the manually dismantled waste products are pulverized and sorted by using differences in specific gravity. However, new technology using chemical reactions is required to recover useful materials from composite wastes such as printed circuit boards and carbon fiber reinforced plastics. Our research group has been developing three material recovery technologies employing hydrogen donor solvents, recycled solvents derived from biomass, and low temperature steam gasification with catalysts. A liquefaction method using partially hydrogenated aromatic compounds as a solvent liquefied resol phenol, which is hard to liquefy using other technologies, and could produce clean fuel that contains almost no toxic organic chlorine compounds from polyvinyl chloride. The use of a liquefaction method employing an ester exchange reaction is limited to certain types of plastics, such as epoxy resin, but thermosetting resins can be liquefied under mild conditions and atmospheric pressure with this technology. We also found that solvents can be produced from biomass or previously liquefied plastics. Steam gasification with catalysts can be applied to all organic materials such as plastics, wood, and rubber. Furthermore, the technology is very energy efficient because the operational temperature is much lower than that of conventional gasification.