Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

KINETICS OF LIGHT ALKANE OXIDATION:FROM DETAILED MODELING TO PROCESS DEVELOPMENTMikhail Yu. Sinev, Vladimir S. ArutyunovOP-I-5Semenov Institute of Chemical Physics, R.A.S., 4 Kosygin street, Moscow 119991, RussiaFax: (+7-495) 951 2191; E-mail: sinev@chph.ras.ruOxidative transformations of light alkanes (LA) from methane to butanes attract not onlyscientific, but also industrial attention, since these processes may open a potentially efficientway to produce valuable chemicals and intermediates (alcohols, aldehydes, acids, olefins)from relatively cheap and abundant feedstocks (natural and associated petroleum gases).However, these reactions suffer from low selectivities to target product(s) due to their higherreactivity as compared to LA. Their accessible yields are determined by kinetic factors, i.e.overall reaction network and kinetic parameters of «elementary» reactions. Therefore, deepfundamental understanding of both homogeneous and heterogeneous reactions at near toelementary reaction step level is of prime importance for process development.The processes under consideration with high probability proceed via so-calledheterogeneous-homogeneous reaction schemes. This means that both gas-phase and surfacetransformations of initial and intermediate species are of crucial importance for the overallreaction rate and product distributions. In the case of «homogeneous» LA oxidationheterogeneous transformation proceed over the reactor walls and various «inert» inserts, aswell as on the surface of soot and other carbonaceous particulates formed as by-products. Onthe other hand, it was demonstrated by several authors (see, e.g., [1,2]) that catalytic oxidationof LA proceeds via the formation and further transformations of free radicals (FR). As aresult, the overall process can be represented by a kinetic scheme that includes homogeneousand heterogeneous elementary reactions of initial reactants (alkane, oxidant), reactiveintermediates such as FR and molecular products including target products of partialoxidation, e.g. olefins and/or oxygenates. Recently we have formulated the set of main rulingprinciples for the development of kinetic model applicable to processing of hydrocarbon gasesand able to describe the major regularities of LA partial oxidation and used for the processdevelopment [3]. They include− thermodynamic consistency;− model fullness;− independence of kinetic parameters;− openness of the description.35