PETROLEUM PROCESSING AND PETROCHEMICALS ›› 2025, Vol. 56 ›› Issue (2): 123-130.

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RESEARCH ON PLASMA TREATMENT TECHNOLOGY FOR WASTE CATALYSTS OF CATALYTIC CRACKING

  

  • Received:2024-07-10 Revised:2024-09-06 Online:2025-02-12 Published:2025-01-16

Abstract: Plasma technology was adopted at vitrification treatment of waste catalysts generated from catalytic cracking processes in the petrochemical industry. Firstly, the basic physical and chemical characteristics of the waste catalyst were analyzed. Furthermore, the waste catalyst was directly fed into the plasma arc, and the microstructure, phase composition, and particle size distribution of the waste catalyst before and after treatment were characterized. Finally, the influence of different proportions of silica and calcium oxide additives on the plasma treatment of waste catalysts was investigated. The experimental results show that the waste catalyst exhibited a quasi-spherical shape with a normal particle size distribution (D50=65.9 μm). After plasma treatment, the morphology and structure of the waste catalyst undergo significant changes. Importantly, there is a clear wide distribution of bulging peaks within the diffraction angle range of 15°―35°, and the content of amorphous material in the powder reaches 83.9%. Moreover, the glass content of waste catalysts after thermal plasma treatment further increases by adding SiO2 powder, and the glass content in the product reach 93.2% when the blending ratio of SiO2 is 40%.The glass content in the product decreased after the further addition of CaO. However, the glass content in the product remained as high as 92.4% when the compatibility ratio of CaO was 15%, which fully meets the minimum requirement of the national standard for the mass fraction of glass content in solid waste. At the same time, the concentration of metal elements in the product leaching solution significantly decreases. Therefore, plasma treatment technology has significant effects on the vitrification treatment of waste catalysts and has good application prospects.

Key words: plasma, waste catalyst, silica, amorphous material