关键词: 反应动力学, 催化, 固定床, 乙基环己烷, 乙烯, 丙烯

Abstract:

The cracking performance of ethylcyclohexane on a mesoporous catalyst based on ZSM-5 molecular sieve was investigated in an apparatus with a fixed-bed reactor. The results showed that ethylcyclohexane had good cracking performance, the conversion was above 80%, the yield of ethylene and propylene reached 41% (mass), the yield of total light olefins was near 50% (mass), and the main components of liquid products were benzene, toluene and xylene. As reaction temperature increased, the yield of ethylene increased monotonously, and those of propylene and butene showed maxima. With the consideration of both thermal and catalytic reactions, a kinetic model involving 14 reactions was established for the catalytic pyrolysis of ethylcyclohexane. The experimental data were obtained at reaction temperatures of 600, 620, 640 and 660℃, and the reaction rate constants were estimated by genetic algorithm regression analysis. Apparent activation energies and pre-exponential factors were subsequently calculated according to the Arrhenius equation. All of the apparent activation energies obtained were below 90 kJ·mol^-1, indicating that the mesoporous ZSM-5 catalyst provides high catalytic activity for ethylcyclohexane catalytic pyrolysis. The model predicted values were in good agreement with the experimental data, and the average relative errors of the main products were below 10%.

Key words: reaction kinetics, catalysis, fixed-bed, ethylcyclohexane, ethylene, propylene