Thermogravimetric Characteristics of Wheat Straw Lignin
نویسندگان
چکیده
The thermogravimetric characteristics of wheat straw EMAL (Enzymatic Acidolysis Lignin) were analyzed. The effect of the heating rates on the thermogravimetric characteristics of wheat straw and the wheat straw influence on pyrolysis were investigated. The influence of various heating rates on wheat straw was significant, the pyrolysis rate of wheat straw EMAL increased at temperatures between 200 and 500 °C. At a temperature above 200 °C, the pyrolysis rate of wheat straw EMAL was clearly accelerated, since all DTG curves and the maximum temperature corresponding to pyrolysis shifted to high temperature areas, two maxima being also recorded on the DTG curves. The thermogravimetric dynamics parameters of wheat straw were calculated by the methods of Kissinger and Ozawa, respectively; the activation energy of wheat straw EMAL was of 103.92 and 107.69 KJ·mol, respectively, and the frequency factor, lnA, of 19.21 and 20.60 min. The fitting degree of the Kissinger method was better than that of the Ozawa one. At a pyrolysis temperature over 400 °C, the influence of the lignin present in wheat straw on wheat straw thermal behavior was very clear, lignin pyrolysis dominating over that of wheat straw.
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