410 / 2018-07-25 17:30:37

Pyrolysis Characteristic of Aspen Lignin and Analysis of Pyrolysis Products

全体主题 > 其它

Lignin is a kind of important potential source of phenols. Synchronous thermal analyzer (STA) and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) were used to study the pyrolysis characteristics and pyrolysis products of three kinds of aspen lignin including milled wood lignin (MWL), alkali lignin (AL) and Kalson lignin (KL) in this paper. The results showed that above three kinds of lignin have different pyrolysis characteristics between 30℃-800℃, the milled wood lignin has two weight-loss peaks at 298.5℃ and 378.4℃, alkali lignin has three weight-loss peaks at 228.7℃, 361.7℃ and 773.5℃, and Kalson lignin has only one weight-loss peak at 376.4℃. At the final pyrolysis temperature 800℃, the pyrolysis residue of milled wood lignin, alkali lignin and Kalson lignin was 33.47%, 39.64% and 49.93% of aspen lignin raw materials respectively, which indicates the difficulty degree of lignin pyrolysis is Kalson lignin > alkali lignin > milled wood lignin. When the pyrolysis temperature is 500℃, there is great difference between the types and relative content of pyrolysis products from above three types of aspen lignin, the relative content of total phenols in the pyrolysis product from milled wood lignin, alkali lignin and Kalson lignin is 54.28%, 48.96% and 37.65% respectively, the phenolic component with the highest relative content is 2,6-dimethoxyphenol, whose relative content in the pyrolysis product from above three kinds of lignin is 12.74%, 12.81% and 8.41% respectively, besides 2,6-dimethoxyphenol in the pyrolysis product from milled wood lignin there are other 3-methyl-2-methoxy phenol (5.44%), 3-methoxy catechol (6.43%) and 3-methoxy-4-hydroxy benzoic acid (7.48%) whose relative content is more than 5% respectively, in that from alkali lignin there are other guaiacol (5.7%), 3-methoxy pyrocatechol (6.08%) and 3-methoxy-4-hydroxy benzoic acid (8.32%) whose relative content is more than 5% respectively, and in that from Kalson lignin there are sulfur dioxide (6.44%), acetic acid (12.57%), 3-methyl-2 methoxy phenol (6.59%) whose relative content is more than 5% respectively.