The pyrolysis reactions of sawdust were studied by means of a thermogravimetric analyzer(TGA). The experimental results show that the heating rate of 0.9-1.1mg sample has the little effect on the reaction rate, activation energy. Generally, the TG-curves for wood sample in He flow showed that the major loss commenced at 220-230℃ and the decomposition was rapid up to 400℃.
The effects of catalysis on the thermogram characteristics, such as the total weight percent pyrolysed and the temperature at which the maximum rate of pyrolysis occured, were analysed by thermal cracking model. Results for wood containing additive ($K_2CO_3$) were mainly affected by concentration of $K_2CO_3$.
The pyrolysis of wood cellulose, lignin in He flow from 25-800℃ was followed by IR-Spectroscopy. Series of spectra recorded at various stage of carbonization showed that although the main decomposition occured near 350℃, mixtures of mostly aliphatic material predominate in the 350-400℃ range, but declined in extent to be replaced by mixtures of aromatic material above 500℃. Further carbonising causes discret spectral feature to decline and disappear near 600℃.
The $K_2CO_3$ drastically altered the wood cellulose and lignin pyrolysis. The $K_2CO_3$-impregnated wood became chared at 200℃. Above 500℃, the metallic potassium was evolved markedly.
The effects of potassium carbonate($K_2CO_3$) in catalyzing between wood char and steam have been studied in the temperature range 600-1000℃ using TGA. The catalyzed reaction is rapidly accelerated than pure wood gasification and the mechanism is understood poorely by cyclic mechanism.
