2.2.2. Summary of Parameters

The kinetic parameters obtained for *S. bigelovii* and *P. dactylifera* leaves from all three methods are summarized in Table 1. The Kissinger method gives one value for the activation energy for the whole process. This value tends to correspond more closely with conversion near peak values at which the Kissinger model was developed. Kinetic parameters for the FWO and KAS method vary with conversion with low values of activation energy at stages prior to active pyrolysis. Activation energy rises during the active phases but tends to reduce at higher conversions during the passive phase for both KAS and FWO methods.

There is very scarce or no literature study on the kinetic parameters of these two biomasses using these methods to compare. Sait et al. [9] have reported activation energies below 44 kJ mol−<sup>1</sup> for date palm biomass, which significantly deviates from the values reported here, 146–204 kJ mol−1. The activation energy values reported here are in the same order of what has been reported for other non-arid-land lignocellulosic biomass [15–17]. Gasparovic et al. [15] determined the kinetic parameters of wood chip using the generalized isoconversional method and activation energy values of between 131.56 and 215.94 kJ mol−<sup>1</sup> depending on the conversion. Kongkaew et al. [17] also determined the kinetic parameters for pyrolysis of rice straw using Kissinger, FWO and and KAS methods and obtained 172.62 kJ mol−<sup>1</sup> for the Kissinger method and activation energy values between 180.54 to 220.27 kJ mol−<sup>1</sup> and 181.95 to 221.72 kJ mol−<sup>1</sup> for FWO and KAS, respectively [17]. The same author also obtained 1.46 ×·10<sup>11</sup> min−<sup>1</sup> as the pre-exponential factor using the Kissinger method as well. Bartocci et al. [16] have reported activation energies for the three main components of lignocellulosic biomass, 154.1 kJ mol−1, 224.7 kJ mol−1, and 190.5 kJ mol−<sup>1</sup> for hemicellulose, cellulose, and lignin, respectively.

This shows the activation energy values obtained for both *P. dactylifera* leaves and *S. bigelovii* are within the range of values obtained by other authors using other non-arid-land lignocellulosic biomasses as reactants. Since the Kissinger method adopts the same method to obtain an average value of activation during active pyrolysis, these values are more comparable with values obtained from other authors using different biomasses. FWO and KAS methods, though generally more accurate than the Kissinger method [18], tend to cite averages which also depend on data points. These estimates, however, help to understand the pyrolysis reaction and calculate reaction constants at various stages of the pyrolysis. Also, the fact that the present results are similar to those obtained for non-arid-land lignocellulsic biomass, has interesting implications, e.g., the scale up of the studied arid-land biomass can benefit from the non-arid-land technology.


**Table 1.** Sumary of kinetic parameters *E* (kJ/mol) and *A* (1/min) for *S. bigelovii*, *P. dactylifera* by different methodologies.
