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The structure of the yield of products of catalytic cracking of vacuum gasoil and repeated cracking of light naphtha in the high-temperature region was investigated. The results of the studies served as the basis for developing catalytic cracking technology with a high yield of light olefins.With the increase in the demand for production of propylene as feedstock for petrochemistry and stiffening of environmental requirements for motor fuels that increase the proportion of alkylate and MTBE in automotive gasolines, the world oil refining industry is examining the role of catalytic cracking on a finely disperse catalyst alone as a source of high-octane gasolines. A trend toward expanding the range of application of this process with orientation both in the traditional direction and toward maximum output of light olefins -ethylene, propylene, and butylenes " has recently been noted.The leading Western companies -licensers of catalytic cracking technology -offer DCC (Shaw ECG, Axens), MAXOFIN (KBR), PETROFCC (UOP), MILOS (Shell GS), INDMAX (Lummus Tech), etc., processes that increase the yield of propylene to 12-22 wt. % and the yield of butylenes to 10-15 wt. %. The yield of light olefins is a function of the feedstock quality and increases with an increase in the paraffins and naphthenes in the composition.Russian oil companies are also considering the prospects for increasing the demand for feedstock for production of polypropylene and other petrochemical products both abroad and within the country. The technical regulation that sets more rigorous standards for the quality of automotive gasolines in 2012 reflects the necessity of increasing the yield of butylenes for subsequent manufacture of alkylate and MTBE as components of automotive gasolines. To satisfy these demands, many Russian OR are planning to equip new cat crackers oriented toward maximum production of propylene and butylenes in the future.In consideration of the growing interest in catalytic cracking with a high yield of light olefins, research and planning-design studies to create domestic technology and equipment for this process were conducted.

A new domestic catalytic cracking process with a high yield of light olefins which corresponds to the best foreign analogs with respect to the technical and economic indexes is described. This process differs from the traditional process by more severe conditions of cracking the feedstock, an increased content of ZSM-5 additive in the equilibrium catalyst, and conducting repeated cracking of light naphtha in an additional continuous reactor.In developing and implementing technology for catalytic cracking with a high yield of light olefins, the results of experimental studies on a micropilot unit [1], experience in designing modern catalytic cracking systems with traditional technology [2,3], and revamping of nine active units of different types (G-43-107, KT-1, 1A/1M, GK-3, etc.) were used. The distinctive features of the process are conducting it at high temperatures and catalyst recycle ratios, the high content of zeolite ZSM-5 catalytic additive in the equilibrium catalyst, and repeated cracking of light naphtha in an additional continuous reactor in more severe conditions than in cracking of fresh feedstock.The new process provides for the following basic reactor block technological and implementation units, most of which have worked reliably in industrial cat crackers:• basic continuous reactor, including a regenerated acceleration section, a feedstock input unit with high-efficiency spray nozzles [8] and an upward-flow feedstock-catalyst contact section;• an additional continuous reactor for cracking recycling light naphtha in an ascending stream of regenerated catalyst in severe conditions that split low-molecular-weight hydrocarbons;• centrifugal-inertial separators [9] at the end of the basic and supplementary continuous reactors that ensure fast separation of feedstock and light naphtha cracking products from the used catalyst;• high-efficiency one-stage reactor cyclones directly connected to the centrifugal-inertial separators;

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