Characters of pyrolysis and gasification of nitrogen-rich wood waste

With the development of the wood-processing industry, the artificial timber board is widely used for furniture, interior finishes, and wooden buildings. Due to the vast use of nitrogenous adhesives, the scrapped artificial timber board is named as nitrogen-rich wood waste, which has a great impact on environment. The gasification is one of the most important techniques for utilizing wood-based waste. Because of the clean and efficient characteristics, this technique can be used to dispose the nitrogen-rich wood waste. In order to study the gasification characteristics, gasification and pyrolysis of the nitrogen-rich wood waste and pine saw dust in Ar and Ar+O2 atmosphere were carried out in TG-MS-FTIR and the fixed bed, respectively. The effects of reaction conditions on the gasification-pyrolysis process and product distribution were studied. For the TG analysis, the experiments were carried out in Ar and Ar+O2 atmosphere, respectively. The reaction temperature increased from room temperature to 1 200 ℃ by a heating rate of 10 ℃/min. The wave number region of FTIR was 400-4 000 cm-1, the working voltage of the mass spectrometer was 70 eV, and the mass-to-charge ratios were 16, 28, 44, 17, 27, 30, 43, and 46, respectively. In the fixed bed experiments, the reaction temperature was 750 ℃ and the reaction atmosphere of pyrolysis was Ar (Gasification: Ar+O2). The results showed that the TG and DTG curves of these two materials presented similar stage divisions. The DTG peak value of nitrogen-rich wood waste was about 70% of that of pine saw dust, although the temperature of peak value of nitrogen-rich wood waste appeared ahead 15-20 ℃ than that of pine saw dust, which was earlier than that of pine saw dust in the DTG curve. Furthermore, the DTG curve of nitrogen-rich wood waste possessed a shoulder peak at 280-300℃, but it can not be observed in the DTG curve of pine saw dust. In the experiments of TG-MS-FTIR and fixed bed, the compositions of main gas products were similar for these two feedstocks. However, the CH4 concentration of nitrogen-rich wood waste was much higher than that of pine saw dust during pyrolysis and gasification. More precisely, the CH4 concentration of nitrogen-rich wood waste was 48% higher than that of pine saw dust in the fixed bed gasification. These results suggested that the gasification of the nitrogen-rich wood waste had a better prospect of application. In addition, the nitrogen-rich wood waste generated much more gaseous nitrogen pollutants than pine saw dust. The NH3 concentration generated from the nitrogen-rich wood waste was about 147 times of that from pine saw dust. This indicated that gaseous nitrogen pollutants can be a barrier for the utilization of nitrogen-rich wood waste. In summary, the results from this study can be served as a constructive and meaningful reference for the treatment and high-efficiency utilization of nitrogen-rich wood waste.