Relationship between Acidity and Activity on Propane Conversion over Metal-Modified HZSM-5 Catalysts

A systematic study of the comparative performances of different metal-impregnated HZSM-5 catalysts (Zn, Ga, Mo, Co, and Zr) for propane conversion is presented. The physicochemical properties of catalysts were characterized by means of XRD, BET, SEM, TEM, FTIR, XPS, 27Al MAS NMR, NH3-TPD and Py-FTIR. It was found that the acidities of the catalysts were significantly influenced by loading metal. More specifically, Mo-, Co- or Zr-modified catalysts showed a large metal size and low acidic density, resulting high olefin selectivity, while Zn- or Ga-modified catalysts maintained their small metal size and acidic density, and mainly reduced B/L due to the Lewis acid sites created by Zn or Ga species, resulting in high aromatics selectivity. Experimental results also showed that there is a balance between metals size and medium and strong acidity on propane conversion. Moreover, based on the different acidity of metal-modified HZSM-5 catalysts, the mechanism of propane conversion was also discussed.

Managerial Approach to the Main Risks Associated with the Use of Catalytic Cracking Plants

The unprecedented technological development of the last decades has spanned a number of top industrial areas and industries, characterized by the use of highly technological and complex technological equipment in the context of the pursuit of demanding technological processes. The different exploitation of the involved lines and technological installations, assuming their quasi-continuous operation, by significantly reducing the weight of stops caused by various failures / failures, in the circumstances of adequately protecting the health of staff and the population, as well as in the context of environmental conservation, requires ensuring and maintaining high levels of reliability and technical security. Industrial practice has shown that no matter how much they invest to achieve and maintain a high level of the reliability of a technological system, an ideal reliability cannot be ensured, a system that does not degrade in time. The reliability of a technological system is determined by all the factors involved in its implementation - the design, realization and exploitation of the system. The concepts of technical and technical risk are indissolubly linked to the notion of major damage. This is one of the possible consequences of a technical accident and essentially involves both the cessation of the system's ability to properly perform its functions and the alteration or disappearance of its physical integrity in the context of particularly serious consequences on the state of technological equipment related, health and / or life of the staff employed and possibly the population, the quality of the environment or the equilibrium of the ecosystem. This paper considers the analysis of the risks associated with the activity of the catalytic cracking plant at the Lukoil Ploieşti refinery and presents the actions applied to the equipment and the measures that are applied to prevent the occurrence of any hazards and accidents on the plant. The purpose of these measures applied to catalytic cracking equipment is to protect employees and the population. Catalytic cracking is one of the basic processes in the Petrotel Lukoil refinery, which ensures the conversion of high-octane petroleum fractions into high octane gas and high olefin gas needed for the petrochemical industry, and will probably represent the catalytic process with the greatest share in processing for long time oil.

Olefine Production from Syngas over Bimetallic Supported

<p>Bimetallic cobalt-containing catalysts supported on alumina have been studied in the Fischer-Tropsch synthesis. It has been shown that a promotion of Co/Al₂O₃ by iridium leads to dispergation of both metals. It was supposed that the metal dispergation occurred due to M-M interaction with formation of the bimetallic nano-particles of cluster type. These particles have the high catalytic activity, selectivity and stability in the Fischer-Tropsch synthesis. It was observed that by regulation of the process conditions it is possible to obtain the definite hydrocarbon fractions. Thus, the increase both CO+H₂ ratio and space velocity is accompanied by high olefin yield.</p>