WHEAT STRAW PYROLYSIS ANALYSIS BY THERMOGRAVIMETRY AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY

The effect of the heating rates and the existence of a Ni-catalyst on the thermogravimetric characteristics of wheat straw were investigated by thermogravimetry and gas chromatography-mass spectrometry. The weight loss of wheat straw was not markedly by the heating rates, over a temperature range from 220.6 and 391.2 degrees C, although to obtain the same weight loss, the corresponding temperature was increased and the heating rates was enhanced. The thermogravimetric kinetic parameters of wheat straw were calculated both without catalyst and with 0.5% Ni-catalyst, by the method of Kissinger; the apparent activation energy values of wheat straw were of 93.92 and 119.80 KJ.mol(-1) and the frequency factors lnA were 17.82 and 23.02 min(-1) respectively. The weight loss of wheat straw wasnot markedly influenced by the Ni-catalyst while pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) evidenced that at 800 degrees C, the presence of the catalyst influecned the peak intensities derived form cellulose, hemicellulose and lignin. It was concluded tat the Ni-catalyst favors a more analytic effect on wheat straw lignin that is the total value of the peak area from phenolic compounds and vanillin was higher than Mal from furfural and levoglucosan.