Chapter 13 - Energy Conversion of Biomass and Recycling of Waste Plastics Using Supercritical Fluid, Subcritical Fluid and High-Pressure Superheated Steam

Abstract

Utilization of unused or waste biomass as fuels is receiving much attention owing to the reduction of CO2 emission and the development of alternative energy to expensive fossil fuels. On the other hand, the recycling of waste plastics is important for the prevention of the exhaustion of fossil resources. In this chapter, typical several examples of the energy conversion of biomass and the recycling of waste plastics using supercritical fluid, subcritical fluid, and high-pressure superheated steam were introduced: (1) bioethanol production from paper sludge with subcritical water, (2) hydrogen production from various biomass with high-pressure superheated steam, (3) production of composite solid fuel from waste biomass and plastics with subcritical water, (4) waste treatment and recovery of thermal energy with high-pressure superheated steam oxidation, (5) recycling of carbon fiber-reinforced plastic with high-pressure superheated steam and supercritical alcohol, (6) recycling of laminate film with subcritical water, and (7) recycling of cross-linked polyethylene with supercritical methanol.