Thermal Removal of Nitrogen Species from Wood Waste Containing Urea Formaldehyde and Melamine Formaldehyde Resins

The removal of nitrogen from wood board waste through a low temperature pyrolysis (523-573 K) is investigated with two analytical methods. The kinetic study of the thermal behaviour of wood board and of its components (wood, UF and MF resins) shows the feasibility of removing thermally nitrogen from wood board waste. Indeed, the range of temperatures associated with the degradation of wood is different from the one obtained for the degradation of UF and MF resin. Isothermal conditions enable the determination of a kinetic model for degradation of wood board and of its components and demonstrate that the thermal behaviour of wood board is not the reflection of the sum of its components' behaviour. FTIR analysis of gas products confirms the feasibility removing nitrogen thermally and enables the evaluation of the optimum treatment conditions (temperature/duration). Elementary analysis of the treated samples and study of their low heating value (LHV) enable to quantify the efficiency of the thermal treatment in terms of nitrogen removal and of energy recovery. Results show that around 70% of the initial nitrogen can be removed from the waste, and that the temperature of treatment (between 523 K and 573 K) does not influence the efficiency in terms of nitrogen removal. Nevertheless, the ratio Residual energy/Initial energy (between 76% and 90%) is improved with the lowest temperature of treatment.