Exhaustive schemes for efficient refining of the C 3 -C 4 hydrocarbon fraction using zeolite type Y catalysts to obtain a high-octane additive are proposed.C 3 -C 4 hydrocarbon fractions in gas-condensate fields and oil refining are a mixture of paraffins of normal and iso structure and olefins. The most effective and rational direction in utilizing such large-tonnage resources of these gases is synthesis of liquid hydrocarbons, for example, a high-octane additive (HOA) for gasolines.More exhaustive refining of petroleum feedstock and an increase in gasoline supplies are obtained as a result.Oligomerization of the propane-propylene (PPF) or butane-butylene (BBF) fractions -Dimersol-G, and alkylation of isobutane with olefins on liquids catalysts are widely used in industry to obtain HOA. n-Butane (propane) Dehydrogenation stage Alkylation stage on SHC Alkylate fractionation stage BBF (PPF) Oligomerization stage Alkylate Oligonaphtha Oligonaphtha fractionation stage Fig. 1. Processing with the first version.
Industrial procedures for the production of alkylate are associated with use of dangerous and toxic liquid catalysts. Developments are being made worldwide to convert the alkylation process to solid-acid catalysts. These catalysts are characterized, however, by a short service life. The potential for improvement in the operational properties of solid-acid catalysts by the introduction of small amounts of promoters to the reaction is examined.Throughout the world, the portion of alkylate in the overall consumption of components has reached 25% in automotive gasolines, and more than 60% in aviation gasolines. The volume of alkylate production exceeds 70 million tons/year abroad, and a total of 0.5 million tons/year in Russia. According to forecasts for the next several years, use of alkylate in the United States will double [1].The operational and ecological properties of alkylate satisfy requirements set forth in modern European and American standards for fuel utilized by automotive internal-combustion engines. Industrial procedures for its production are associated with use of such dangerous and toxic liquid catalysts as sulfuric or hydrofluoric acid, requiring use of equipment for neutralization of the acid, vessels for washing of the product, and tanks for storage of the fresh and spent acid. Hydrofluoric acid is again more dangerous by the fact that it is capable of forming stable aerosols during an emergency leakage. In this connection, the development of an alkylation procedure using catalysts devoid of deficiencies inherent to liquid acid catalysts is one of the promising problems. Some of these catalysts may become new heterogeneous catalysts that are developed on a zeolite base. Manifesting high selectivity, activity, stability, and capability of regeneration, which are required for successful alkylation [2], zeolites ensure the production of high-quality alkylate.Type NaY zeolites are inactive in the alkylation process. Only essentially complete ion exchange of Na + ions for NH 4 + , Ca 2+ , and RZ 3+ cations with intermediate stages of calcination at 570-600°C merely results in their manifestation of Lewis and Bronsted acid centers, which are required for the formation of
The importance of the technical refitting and restructuring of vinyl-chloride production, which occupies a leading position in heavy-tonnage industrial-organic synthesis, is noted. The design of a hydrogenation unit, the purpose of which is to enhance the conversion of acetylene up to 100%, is proposed. The hydrogenation reactor is redesigned, and a hydrogen after drier and static mixer are incorporated into the process-flow diagram. Improvement in the technico-economic indicators of the process is achieved as a result of the modernization.Vinyl chloride is one of the heavy-tonnage chloroorganic products -in Russia, its production amounted to more than 650,000 tons in 2004 [1].At the present time, the so-called chlorine-balanced oxychlorination of ethylene is showing promise in the production of vinyl chloride.Undesirable organic products, one of which is acetylene, are formed during the pyrolysis of trichloroethane. In the stage of oxychlorination (Fig. 1), the acetylene, which enters the flow of hydrogen chloride, promotes the formation of secondary products -chloral, trichloroethylene, and tetrachloroethylene [2]:
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