CONVERSION OF MODEL C6-C14 ALKANES BASED ON ZEOLITE CONTAINED CATALYSTS

Abstract

For deep oil refining for the production of high-octane gasoline is crucial catalytic cracking, allows a variety of heavy raw materials to produce high-octane gasoline, petrochemical feedstock, production of carbon black and coke. Paraffins are the major component of many petroleum fractions. They are thermally and thermodynamically stable organic compounds. Splitting them on the catalyst has a high activation energy, therefore, comes at a significant rate only at elevated temperatures. The conversion of paraffin hydrocarbons more fully characterize the reaction conditions of cracking and therefore, in the studies is paid much attention. The definition of the primary products of cracking even a simple low molecular weight paraffins is difficult because of the quick secondary transformation of the formed olefins. In this paper, on the example of model C₆ –C₁₄ –alkane examines the impact of molecular chain length on the degree of conversion and composition of formed compounds in the process of hydrogen-free processing at La-Zn-Co/ Al₂O₃+ZSM catalyst. Analysis of the results shows that in equal conditions the degree of conversion of C₆-C₁₄ –hydrocarbons changes in number of (%) : hexane (85,0) > tetradecane (73,4) > octane (60,5). This is probably due to the fact that depending on the length of the molecular chain alkanes changing their adsorption capacity due to the different bond energies of C-C and the possibility of a large number of breaks C-C, C-H – bonds and moving C_xH_y – groups, etc. The structure and composition of the products resulting from the processing of
C₆-C₁₄ n-alkanes, indicate the development on the catalyst La-Zn-Co/ Al₂O₃+ZSM several transformations of paraffins. Developed on modified zeolite catalysts occurs simultaneously and in parallel several reactions: cracking, dehydrogenation, isomerization, dehydrocyclization, alkylation. With increasing process temperature the speed of these reactions increases considerably regardless of the length of the molecular chain alkane. Cracking and dehydrogenation of alkanes source occur with the formation of intermediate activated complexes with a low content of carbon atoms and the adsorbed olefin structures. In the future, depending on the nature of the active center of the catalyst develop various directions of transformation with the participation of intermediate activated complexes.