Comparative study of nitrogen migration among the products from catalytic pyrolysis and gasification of waste rigid polyurethane foam

•More gaseous product and volatile N are generated in the gasification process.•N2 is the main gaseous N-containing product in both pyrolysis and gasification.•CaO can significantly enhance the formation of N2 and suppress that of char N.

Pyrolysis and gasification of waste rigid polyurethane foam (WRPUF) were performed in fixed-bed reactor to investigate the nitrogen migration among the products in the thermal conversion process. The influences of the temperatures and catalysts on the product distribution were also studied. Through the thorough analysis of nitrogenous products, the nitrogen migration mechanism in the pyrolysis and gasification of WRPUF was investigated so as to find out the selectivity of fuel-N migration. As the results have shown, the higher the temperature is, the more gas products are generated from catalytic pyrolysis and gasification; gas productive rate is higher in gasification process than in pyrolysis; compared with pyrolysis, more volatile N is generated in gasification process; N2 is the main gaseous nitrogen containing product in gas-phase product, followed by ammonia and hydrogen cyanide; the productions of nitrogen dioxide and nitric oxide are relatively small; among all the additives, calcium oxide is the best catalyst which facilitates the migration of fuel-N in WRPUF into the pollution-free N2 in thermal conversion.

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