Heterogeneous systems are included in many chemical processes such as gas purification, wastewater treatment, heterogeneous catalysis, adsorption and extractive metallurgy, where chemical reaction or adsorption occurs at the interface between the phases in heterogeneous processes. The rate of a chemical reaction might depend on various factors such as pressure, temperature and catalyst. Study on reaction rate is necessary for control of the rate and interpretation of the reaction mechanism.
In this work, a new generalized DKM was formulated and its characteristics were studied in comparison with other kinetic models.
This DKM is one form of DKMs based on conversion rate of solid reactants, where the reaction rate is expressed as a function of concentration of fluid, DKM rate of solid and conversion rate.
By using this DKM, we derived the kinetic equations and their solving methods and obtained the simulation curves in batch system and continuous system (a fixed bed reactor, for an example). For batch system, the kinetic equations are a set of simultaneous ordinary differential equations, which can be solved with ODE function in MATLAB. For continuous system, they are partial differential equations, which can be solved by using forward finite differential method. The kinetic parameters were calculated by using the nonlinear least-squares fitting method. These rate equations can be used in kinetic analysis for heterogeneous reactions and adsorption processes.
Characteristics of this DKM include quantitative description of solid change process based on conversion rate, utility for physical and chemical adsorptions, simultaneous consideration of changes of adsorbate and adsorbent, and general treatment of solid reactants.
This DKM is a semi-empirical and generalized kinetic model, which can be used in kinetic study on heterogeneous processes.
The result has been published in the "Reaction Kinetics, Mechanisms and Catalysis" under the title of "Kinetic modeling, Heterogeneous reaction, Adsorption, Deactivation kinetic model" (https://doi.org/10.1007/s11144-024-02638-6).
