Study On Catalysts For Aromatization Of Light Alkane

In this paper, a study of light alkane of oil field as raw materials, production process of light alkane aromatization catalysis BTX aromatics was discussed. Zn/HZSM-5 as catalyst to the carrier, the active component impregnation La, Ce, Pr and Tb were introducted, rare earth elements on the catalytic activity of different components were filtered. Under normal pressure, a continuous flow fixed bed reactor studied the types of rare earth modified catalysts, the mass fraction of the load structure on the release of results. The results shown that aromatization based on the introduction of rare earth elements such as: La, Ce, Pr and Tb, etc. catalytic performance of the 0.5% Zn/HZSM-5 modified aromatization catalyst was improved in varying degrees, shown that the rare earth Ce, La, Pr, Tb was a light alkane aromatization catalyst for a good agent, even though the role of different, but to varying degrees, were able to improve the performance of aromatization. Tb in particular the role, which was significant to adding into catalyst Zn/HZSM-5, improved the catalytic activity, so that the conversion of C5 of light alkane rose from 65.5% to 95.3%, BTX yield rose from 44.2 percent to 66.6 percent. In the rare earth-Zn/HZSM-5 catalyst system, the rare earth had not a catalytic effect, but rather as a catalyst agent for the catalyst from the main component Zn modulation effect. Evaluation of catalyst activity through a reaction system to adding the amount of rare earth, the best catalyst system reached its adding rare-earth Tb/Zn atomic ratio of 0.06. Then the reaction temperature, weight hourly space velocity of raw materials for the purpose of the composition of products, selection of appropriate place to be constitutive of the reaction temperature was 540℃, weight hourly space velocity 1.0h-1 respectively. Finally, filled catalyst 1000ml, mainly on the stability and regeneration of catalyst performance was investigated, the results of single-cycle study: liquid yield of 65~72% of between fluctuations in aromatics content was from 56.6% to 58.4%. Response per cycle of about 30 days, renewable for about 3-5 days later, the catalyst activity could still maintain a relatively high liquid yield of 60% to 70%, aromatics content of 52%~57%, could be industrial enlarge the design. Aromatization Tb-Zn/HZSM-5 and the stability of the catalyst were studied, the reaction of eight cycles, each cycle reaction time up to 30 days (720 hours), the catalyst for carbon-burning renewable seven total visits of 5760 hours. The results shown that, Tb-Zn/HZSM-5 the activity of the catalyst had good stability; the preparation method was reliable and repeatable. It could meet the requirements of the purpose of industrial applications.