Место издания:ELSEVIER SCIENCE BV AMSTERDAM, NETHERLANDS
Первая страница:171
Последняя страница:263
Аннотация:The topical problems existing in the modeling of oxidation processes in gas chemistry, particularly in oxidative transformations of light (C1–C4) alkanes, are outlined. It is demonstrated that the requirements to adequate description of process kinetics in this case differ significantly from those which are satisfactory in combustion kinetics and, on the
other hand, in near-equilibrium petrochemical processes. The principles that could be utilized in developing consistent kinetic models are determined by the goal of modeling, which appears to be the most important factor controlling all the approaches and procedures. The models under discussion are aimed at (i) the rationalization of the reaction network responsible for the main features of the overall process, (ii) the description of light alkane oxidation, and (iii) optimization of the yield of some reactive intermediate product, such as olefins, saturated and non-saturated alcohols, aldehydes, acids, synthesis gas, etc. The latter defines the ranges of parameters (temperature, pressure, initial composition of reaction mixture) and the main ruling principles of modeling. It is concluded that comprehensive kinetic models should be based on the following principles: thermodynamic consistency, fullness, independence of kinetic parameters, openness of the description. The possibility of accurate description of phenomena under consideration is determined by a series of factors, including fullness of the model, adequate description of the reaction space (reactor itself and connecting tubing), correct accounting of heat- and mass-transfer processes, precision of kinetic parameters and even the form of their representation, etc. Another complicated problem is model verification. It is demonstrated that the comparison with experimental data is associated with serious difficulties and its applicability for the model verification is limited. Special attention is paid to the modeling of heterogeneous processes. Possible approaches to the description of elementary steps on oxide and metal surfaces and building of combined heterogeneous–homogeneous models are discussed. Some examples are given, mainly related to the joint description of C1–C2 hydrocarbon oxidation, and the ways of its expansion on higher hydrocarbons are traced.