DEVELOPMENT OF EFFECTIVE CATALYSTS FOR PROCESSING C3-C4 HYDROCARBONS

Abstract

The aim of the article is to study the effect of preparation and activation methods of a modified zeolite-containing catalyst on the activity and stability of catalytic properties displayed by it during the conversion of C3-C4 hydrocarbons. During the experiment, the industrial cracking catalyst OMNIKAT, which is a zeolite in the sodium form, was used as the initial one. Zinc, gallium, and REE (rare earth elements) were sequentially applied to decationized samples of this catalyst by ion exchange, impregnation, and dry mechanical mixing, and the effect of these methods on the catalytic properties of the zeolite-containing catalyst was observed. As a result of a comparative analysis of the regularities of aromatization of C3-C4 hydrocarbons, it was found that the mechanical mixing method is the most preferable, since it provides the best process performance. In order to improve the activity and stability of the catalysts, thermocouple and thermal activations were carried out during the preparation process. Further, differences were revealed for the thermocouple and thermal activation of the modified catalyst and their effect on the activity and selectivity of the zinc-galliumzeolite-containing catalyst with respect to ArH (aromatic hydrocarbons) in the process of conversion of C3-C4 hydrocarbons. The choice of these particular operations was dictated by the fact that preliminary thermal and thermal vapor treatment of the catalyst practically does not require significant capital expenditures, i.e., economically most acceptable. Regularities of reaction-regeneration cycles were established. Thus, the optimal technological parameters for the regeneration of catalytic compositions are: temperature - 600°C, atmospheric pressure, oxidizer - air feed rate - 2 h-1, which lead to the restoration of the activity and selectivity of the spent catalyst to the fresh level. Studies of the of oxidative regeneration process a zinc-gallium-zeolite-containing catalyst have shown that while maintaining a clearly regulated regeneration regime, the activity of the latter is restored. The main task of the research was the development of effective catalysts for the conversion of C3- C4 hydrocarbons. Therefore, in the first place, we compared the conversion rates and selectivity for ArH. The proposed catalyst is characterized by good operational properties (high activity and long service life), providing 59.2% by weight of the target product yield at 98.8% conversion of C3-C4 hydrocarbons.