Abstract:

The pyrolysis products of corncob at different temperatures were analyzed on-line by using the pyrolysis-comprehensive two-dimensional gas chromatography-mass spectrometry(Py-GC×GC-qMS). The results showed that the 191 compounds were detected by GC×GC-qMS, including alcohols, acids, aldehydes, ketones, esters, furans, hydrocarbons, phenols, nitrogens and sugars when the corncob was pyrolyzed at 550℃ with 18 s. The main compounds included benzofuran, 2, 3-dihydro-, 1, 6-anhydro-beta-d-talopyranose and furfural, with GC contents of 9.15%, 8.8% and 5.21%, respectively. However, GC-qMS detected only 58 compounds, and no sugars were detected. The types of corncob pyrolysis products gradually increased with temperature increasing, reaching a stable value at 550℃. The influence of temperature on the contents of aldehydes, ketones and furans was not obvious, and the GC contents reached the maximum at 450, 550 and 500℃, which were 4.80%, 13.57% and 21.01%, respectively. Alcohols, acids and esters were easily be formed at low temperatures. Hydrocarbons were more easily be formed at high temperature, and the GC content was 10.77% at 600℃. The contents of phenols increased first and then decreased, and the maximum GC content was 23.77% at 450℃. The effect of temperature increase on the GC content of nitrogens and sugars was not obvious.

Key words: Py-GC×GC-qMS, corncob, temperature, pyrolysis products, on-line detection