Pyrolysis treatment of waste polyurethane foam in the presence of metallic compounds

• The influence of metallic compounds on pyrolysis of polyurethane foam was studied.
• The addition of metal chloride increases the yield of gas and char.
• More than 30% of the initial sample was fixed as char by ZnCl2.
• The addition of metal salts enhances the yield of ammonia.

The influence of the presence of some metal salts and oxides on pyrolysis of polyurethane (PUR) foam has been studied with thermogravimetric analysis, TGA, and a lab-scale reactor. The pyrolysis products of the latter at 800 °C were analysed with gas chromatography–mass spectrometry, XRD and ion metre. The addition of metal chloride decreased the yield of liquid products, and increased the yield of carbonaceous residue, which could be ascribed to the Lewis acidic nature of the examined salts. Zinc chloride exhibited especially high ability to fix carbon in the polymer as char; the carbon yield reached more than 30% of the initial carbon in the sample. This is considerably high, as essentially no residue remained in the lab-scale pyrolysis of polyurethane foam at 800 °C. As for the nitrogen-containing pyrolysis products, the addition of metallic compounds enhanced the yield of ammonia. This result implies that the addition of metallic compounds is effective for the emission control of nitrogen-containing products from polyurethane foam.