Simultaneous Achievement of Syngas Recovery and Toxic HCN Removal through Catalytic Gasification of Polyurethanes = Simultaneous Achievement of Syngas Recovery and Toxic HCN Removal through Catalytic Gasification of Polyurethanes

다국어 초록 (Multilingual Abstract)

Development of effective recycling technique for polyurethane (PU), which is one of the most common polymers used in electrical and electronic equipment and automobile, is an inevitable task. However, it is extremely difficult since there are wide variety of PU materials with different combinations and ratios of monomers. This work focused on pyrolysis technique, which cleaves several chemical bonds in polymers and produces gas, liquid, and solid by heat. One well-known major hurdle in the pyrolysis of PUs is the emission of toxic hydrogen cyanide (HCN) and the efficient removal of HCN must be achieved for the recovery of useful chemicals from PU wastes through the pyrolytic approach. In this work, product gas from thermal degradation of PU materials such as cushion (flexible PU foam) and insulator (rigid PU form) at 500 °C were converted into H₂-rich syngas and the toxic HCN in it was simultaneously removed by Ni/Mg/Al catalyst at 800 °C under 50 vol% steam/He flow. The resultant total gas production was maximum 1623 mL/g (H₂: 946 mL/g), which was ~30 times bigger than that obtained from simple pyrolysis of PUs. Meanwhile, there was a drastic reduction of HCN concentration in the product gas from a maximum at 2.8 to minimum 0.2 vol%.