Kinetics of co-pyrolysis of coal,tar and straw mixed briquette

According to different models,the kinetic parameters of co-pyrolysis of a mixture are easy to diverge and have a wide range. Co-pyrolysis of briquettes consisting of coal samples (ZC and XL),straw ( ST) and coal tar ( T) was studied by thermal analysis (TGA). On this basis,the kinetic parameters of single pyrolysis and mixed co-pyroly- sis were calculated and compared using isoconversional models ( Ozawa-Flynn-Wall ( OFW) and Kissinger-Akahira- Sunose (KAS)),and the underlying reasons for the difference are analyzed. The experimental results show that the py- rolysis time of the individual components can be reduced at a higher rising temperature rate,while the heating of indi- vidual components occurs more efficiently in the interior of the particles at lower heating rates. The average value of activation energy in the individual pyrolysis is calculated by KAS and OFW method is as follows:ZC >XL >T >ST. Whether the method of isoconversional or isothermal is used for pyrolysis reaction of different materials,the calculation of kinetic parameters is influenced by the selected calculation method. With the increase of pyrolysis temperature,the weight loss firstly increases and then decreases,and the difference of weight loss between the experimental value and the calculated value of E1,E2,E3 and E4 reaches the maximum at 800 ℃ . By comparing the experimental value and calculated value of co-pyrolysis weightlessness of briquettes,the synergistic effect in co-pyrolysis is not obvious.