Heat, Electricity, and Fuel Gas Ploy-Generation System on an Island based on Plastic Waste Gasification in Supercritical Water

Plastic pollution in the ocean has become a serious threat to the health of marine life and even terrestrial life. It is also a challenge to transport it landside for recycling. A system to recycle the plastics in situ on an island was proposed with the aim to convert the plastics to fuel gases, such as H2, CH4, and CO. As one of the most abundant thermoset plastics in the ocean, epoxy plastics were recycled in this system. They were gasified in supercritical water driven by concentrated solar energy. A heat exchanger and turbine were used for electricity. The fuel gas could be stored in the gas tank at 4 MPa. The energy and exergy efficiency in this system were analyzed, and the effects of temperature, pressure, and feedstock concentration were discussed. The typical conditions were as follows: temperature 600 °C; pressure 25 MPa, and feedstock concentration 5 wt %. The mole fractions of these products were 48.13%, 22.97%, 0.84%, and 28.06%, respectively. Additionally, the energy and exergy efficiency were 51.75% and 45.22%, respectively.