The main goal of studying the kinetics of heterogeneous reactions consists in prediction of the thermal behavior of the system conducted in other temperature conditions, as well as the possibility of effective control and optimization of the quality parameters of the final product. In addition to the practical aspect that is indisputably important, knowledge of the kinetic parameters also presents a theoretical interest. For example, to understand the processes of interaction of biomass with activating agents, in the context of obtaining the activated carbons. These processes have to date been scarcely investigated. The reaction kinetics may be completely described by knowing the global kinetic triplet: activation energy (Ea), pre-exponential factor (A) and reaction model. However, use of the Arrhenius equation to describe the kinetics of heterogeneous reaction remains controversial and the explanation for this comes from the complexity of the processes that must be described. Often it is impossible to separate a heterogeneous reaction into the elementary processes- a strictly necessary condition for obtaining the veridical set of data. Nevertheless, the existence of equilibrium between activated and inactivated molecules, in accordance with the distribution law, offers a physical and empirical reason to apply the Arrhenius equation for description of the heterogeneous processes. In this study we used Coats-Redfern model of reaction, assuming that the studied processes follow a first-order reaction. These assumptions are based on the broad application of the mentioned model in the study of biomass pyrolysis, which provides reproducible and comparable results. The studied processes include dehydration and combustion of nut shells in the air atmosphere, pyrolysis of cellulose and hemicellulose and activation of nut shells with phosphoric acid in the nitrogen atmosphere. Linearization of Coats-Redfern equation in the form: ln[-ln(1-α)/T2)] = f(1000/T) allows to calculate the kinetic parameters, which are shown in Table 1. Table 1. Kinetic parameters for elementary processes of dehydration, pyrolysis and combustion of nut shells. Elementary Process Temperature range, K Ea, kJ/mol A, s-1 R2 dehydration 293-463 30.04 2368 0.975 hemicellulose pyrolysis 503-593 155.88 1.1*1014 0.989 cellulose pyrolysis 596-676 177.24 1.4*1014 0.974 phosphoric acid activation 750-1100 86.84 5115 0.993 combustion 686-866 110.87 3.39*106 0.996 The physical significance of Ea and A parameter is closely related to the formation of the activated complex at elementary step of reaction, which is not valid for heterogeneous kinetics. Interpretation of the experimental values of activation energy and pre-exponential factor may be realized in terms of transition state theory and such concepts, as: energy barrier of the reaction and the vibration frequency of activated complex. In this context, Ea is a temperature coefficient of the global rate indicating its sensitivity to temperature variation. According to the transition state theory, the parameter A is the frequency factor characterizing the amplitude or intensity of global reaction rate.