Investigation on degradation of polyethylene to oil in a continuous supercritical water reactor

The effects of temperature, residence time, and pressure on the degradation of polyethylene (PE) to oil were investigated in supercritical water (SCW) using a 180-mL continuous reactor. The yield of oil product increases with the increase of temperature, reaching 79% at 530°C, and then decreases as the temperature further increases. The yield of gas product increases from 3% to 22% as the temperature increases from 500°C to 550°C. The product distribution shifts toward shorter chain hydrocarbons with the prolongation of reaction time. Furthermore, the ratio of alkenes to alkanes of products increases with the increase of temperature and pressure, and decreases with increasing reaction time. The effect of pressure on both products’ yield and composition is less significant.