Catalytic characteristic and kinetic modeling of cotton stalk pyrolysis

The kinetic characteristic of cotton stalk pyrolysis catalyzed by six kinds of additives including NaOH, Na₂CO₃, Na₂SiO₃, NaCl, TiO₂ and HZSM-5 was investigated by using the thermogravimetric analysis. The weight loss behavior was simulated by assuming the three main components of the cotton stalk sample to experience the first order parallel and independent pyrolysis reactions. The pyrolysis kinetic parameters were estimated by the nonlinear least squares algorithm. The results show that the kinetic parameters of the three components are changed by adding additives. Under the action of the alkaline additives, the activation energies of cellulose and hemicellulose can be reduced to a greater degree. The stronger the basicity of the additives, the lower the pyrolysis activation energies for the cellulose and the higher for the hemicellulose. Neutral additive NaCl has little effect on the pyrolysis activation energy. Surface acidic additives make the pyrolysis activation energies increase for the cellulose and hemicellulose. However, all the additives have no significant effects on the pyrolysis activation energies for lignin.