Abstract: Comparison of cooking kinetics between cotton stalk and wheat straw was studied in this paper. A novel experimental and calculating method for the study of cooking kinetics was established. By application of identical liquor ratio as used in actual cooking conditions, activation energies of soda-AQ cooking of cotton and wheat pulps were obtained from determinations of effective alkali concentration and residual lignin content, as well as from calculation of reaction rate constant. Activation energies of soda-AQ cooking of cotton stalk and wheat straw were basically unchanged during the whole cooking period. Activation energy of soda-AQ cooking of wheat straw was 51.0 kJ/mol which was lower than that of soda-AQ cooking of cotton stalk at 138.1 kJ/mol, which indicated that delignification of wheat straw was easier than that of cotton stalk during soda-AQ cooking.

Key words: wheat straw, cotton stalk, raw material of paper making, soda-AQ method, delignification