生物质秸秆热重分析及几种动力学模型结果比较

Thermogravimetric analysis was used to study the pyrolysis characteristics of two biomass samples, corn straw and rice straw, at different heating rates of 5 K/min, 10 K/min, 20K/min, 40 K/min in a stream of N2. Four methods: Coats-Redfern，Doyle，Kissinger and DAEM, were used to determine the kinetic parameters, including reaction order, frequency factor and activation energies. The results indicated that the kinetic parameters were different with different methods. The pyrolysis process can be described by first-order global model for both corn straw and rice straw and their activation energy was 68.8 kJ/mol and 70.0 kJ/mol (weight loss from about 5 w% to 80 w%) at the heating rate of 10 K/min, respectively, with the method of Coats-Redfern. Almost the same results were obtained with Doyle and DAEM model. Pyrolysis of the two biomass samples was a complicated reaction and their activation energies varied with increasing weight loss. The model of Doyle and DAEM was efficient method to provide more information of pyrolysis of the biomass samples.