28.05.2024 International Scientific Journal "Science and Innovation". Series A. Volume 3 Issue 5
Abstract. In this work, the results on the creation of highly efficient catalytic systems with new content modified with various elements are summarized. At the same time, the effect of the nature of the modifying element, as well as the high-temperature treatment with water vapor, on the texture, acidic characteristics and catalytic properties of the zeolite catalyst in the conversion of dimethyl ether to ethylene and propylene was considered. In order to increase the stability of the Mg-Zn-Zr-B/YuKTs catalyst, it was proved that unmodified Mg-Zn-Zr-B/YuKTs exhibited high activity when it was modified with P and Fe and used in the synthesis of ethylene and propylene from methanol and dimethyl ether. In the work, the catalytic conversion of dimethyl ether to ethylene and propylene was carried out on the Mg-Zr-Zn-B-YuKTs catalyst under the following optimal conditions: (T = 340 oC, R = 0.1 MPa, Var = 1000-2000 h-1. Raw materials: DME (15%) ÷ N2(85%). In the case of modification of zeolite catalysts containing zirconium and magnesium with B, it was proved that in almost all cases, an increase in the selectivity for C2-C4 ethylene and propylene and a decrease in the amount of paraffins were observed. According to the obtained results, with an increase in zirconium concentration from 0.4 to 3.2 wt.%, there is an increase in the selectivity for C2-C4 ethylene and propylene from 42.1 to 74.5 wt.%. Paraffins are formed from 0.4 wt.% to 57 wt.% of zirconium. Thus, Mg-Zn-Zr-B/YuKTs is an effective catalyst of methanol to ethylene and propylene, the addition of water to the raw material as a diluent significantly increases the activity of the catalyst and the yield of target products increases and the time of stable operation of the catalyst increases. Also, as a result of studying the textural and physicochemical characteristics of the catalyst by IR-spectroscopy, differential thermal analysis and thermogravimetry methods, it was proved that the treatment of zeolite with zirconium and boron compounds does not lead to the destruction of the zeolite structure.
Keywords: dimethyl ether, methanol, ethylene, propylene, conversion, catalyst, synthesis, kinetic law.
SCIENCE & INNOVATION