Thermocatalitic Conversion of n-Heptane and the Gas Condensate on Cuprum-Containing Zeolite Type ZSM-5
The effect of zinc concentration and conditions of thermocouple treatment on the acid and catalytic properties of zeolite ZSM-5 in the thermocatalytic conversion of nheptane and gas condensate was studied with the aim of obtaining lower C2-C4 alkenes. It is shown that the composition of the products of the thermal catalytic conversion of nheptane depends on the concentration of copper in HZSM-5. The introduction of HZSM-5 copper in an amount of up to 1.0 wt.% leads to a significant increase in
... ficant increase in the yield of alkenes and a decrease in the content of aromatic hydrocarbons. A further increase in the concentration of copper to 3.0 wt.%. In the zeolite helps reduce the yield of C2-C4 alkenes and increase its aromatizing activity. It is shown that the conditions of thermocouple treatment significantly affect the acidic and catalytic properties of 1% Cu-HZSM-5 catalyst in the conversion of gas condensate to lower C2-C4 olefins. Thermocouple treatment of 1% Cu-HZSM-5 at 650-700 0 С for 180 minutes leads to an increase in the yield of alkenes from 40.2 wt.% to 50.8 wt.% and a decrease in the content of aromatic hydrocarbons from 58.5 to 16.9 wt.%. The modifying effect of copper and TСТ on the activity and selectivity of catalysts is due to a change in their acid spectrum caused by zeolite de-illumination and the ratio of Brenstod and Lewis acid centers. Indeed, as can be seen from Table 2 , TСТ of samples reduces the total concentration and strength of acid centers, and first, a decrease in the concentration of strongly acidic centers is observed.On samples of 1% Cu -HZSM-5 subjected to TСТ, there is a general tendency to reduce the degree of conversion of gas condensate and reduce the formation of aromatic hydrocarbons, which is associated with a decrease in the concentration of strongly acidic centers. On all samples of 1% Cu -HZSM-5 subjected to TСТ at different conditions, an Thermocatalitic .... S. S. Dadasheva. increase in the yield of alkenes is observed, and the highest yield of alkenes (50.8%) is observed on samples in which the ratio of weak and strong acid centers is 1.62-1.70. An increase in the duration of TСТ at 700 °C does not significantly lower 240 °C. Concentration of strongly acidic centers (up to 45 μmol g-1), which leads to a decrease in the conversion of gas condensate (68.1 wt.%) and the yield of alkenes (44.6 wt.%).