n-butane isomerization in the gas phase and under supercritical conditionsстатья
Информация о цитировании статьи получена из
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Дата последнего поиска статьи во внешних источниках: 29 ноября 2015 г.
Аннотация:The aromatization of n-butane under supercritical conditions on gallium-, zinc-, and platinum-modified high-silica zeolites with a modulus of 30-70 was first studied, and the experimental data were compared to the results of a study of this process in the gas phase. It was found that the operational efficiency of catalysts for n-butane conversion under supercritical conditions was much higher than that for the gas-phase reaction in terms of activity, productivity, and resistance to poisoning by condensation products. The aromatization of gaseous n-butane at 530 degrees C and 1 atm was characterized by rapid catalyst deactivation. The selectivity for the benzene-toluene-xylene (BTX) fraction was higher than 50%. Under supercritical conditions at 430-560 degrees C and 100-200 aim, the selectivity of formation of aromatic compounds decreased by a factor of 2, whereas the yield of C-1-C-3 cracking products increased by the above factor. On the other hand, it was found that an increase in the productivity of catalysts by a factor of 20-50 with the retention of almost 100% activity for several days of operation is an advantage of the process performed under supercritical conditions. The almost complete conversion of butane under supercritical conditions was found on promoted HZSM-5 zeolite samples. The thermogravimetric analysis of spent samples suggested a higher degree of catalyst carbonization under supercritical conditions, as compared with that in the reaction performed in the gas phase. However, the deposition of 2030 wt % condensation products on the catalysts had no detectable effect on the high activity of the catalysts in the reaction performed under supercritical conditions.