Thermogravimetric Analysis on The Pyrolysis
Two varieties of Philippine rice hulls, R-302 and R-19 were pyrolyzed at three heating rates of 10, 20 and 50 K/min using a dynamic thermogravimetric analyzer (TGA) in a nitrogen environment. Results show that the decomposition of hemicellulose starts at lower temperature than cellulose. Lignin decomposes at higher temperature than hemicellulose and cellulose. An abrupt weight loss can be noticed at second peak of active pyrolysis. As the heating rate is increased, there is a shift to higher temperature and total percentage weight loss showed a very slight change. Likewise, the rates of degradation of the two varieties are practically similar. Kinetic parameters were obtained using Arrhenius law and global mass loss kinetic models. Results show that the major components of the rice hulls have the following order of activation energy: cellulose>hemicellulose> lignin.Key words: rice hulls, thermogravimetric analysis, pyrolysis Rice hull or husk is the thin but tough outer sac of the rice grain. It accounts for about 20% by weight of the whole rice (Grist, 1975; Beagle, 1978). It is considered a major agricultural waste in rice producing countries like the Philippines. An estimated 150 thousand metr
The values of E and A for each heating rate were obtained from the plots of Y= ln[{1/(f-ff)}(df/dt)] versus 1/T. Figure 5 shows the Arrhenius plot of the two stage decomposition of rice hull variety R-19 at a heating rate of 20 K/min. Figure 6 shows the Arrhenius plot of the 3-stage decomposition of rice hull variety R-302 at a heating rate of 20 K/min. Htg. Rate 10 K/min 20 K/min 50 K/min Over-all 10 K/min 20 K/min 50 K/min Over-all E, kJ/mol 89.94 90.3 87.45 90.9 45.44 46.54 37.99 49.61 Range, K 503-651 497-669 469-690 469+690 652-862 670-857 691-836 652-862
Some common words found in the essay are:
R-302 R-19, K/min Over-all, Peak TempK, Williams Besrel, K/min Figure, Variety Lump, Williams Besler, Arrhenius Law, Shimadzu TGA-50, Liou Chang, rice hulls, rice hull, weight loss, et al, 50 k/min, hemicellulose cellulose, kinetic parameters, heating rate, 20 k/min, r-302 r-19, 50 k/min over-all, global mass loss, teng et al, et al 1998, kinetic parameters rice,
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