Designs of drop-film sprinklers based on cellular polymeric shells formed by a layer of intersecting cylindrical (or other shape) polymeric fibers are described. The dependence of the evaporation number on the relative flow rate of air is investigated for the designs presented. An empirical relationship is derived for calculation of the pressure drop in the cooling-tower sprinkler, which permits most accurate determination of the load on the fan and the optimal operating conditions of the cooling tower.The temperature regime of any production process is ensured by the use of circulating water-supply systems normally equipped with mechanical-draft and chimney-type cooling towers.Closed autonomous water-supply systems [1], which provide for delivery of water to a production process with the required volumes and appropriate quality, function for the purpose of rational utilization of water resources at industrial establishments, since water cooling is currently most economically expedient for basic and auxiliary equipment.Industrial water-supply systems consist of a set of interrelated structures -water intakes, pumping plants, and installations to clean and improve the quality of the water, which regulate both the reserve tanks, water coolers, and distributing network of pipelines. Some of the enumerated structures cannot be used in the water-supply systems, depending on the purpose and local conditions [2].The circulating water that passes through the production cycle is cooled to the required temperature in chimney-type or mechanical-draft cooling towers. The requirements set forth for the temperature of the circulating water by various industrial establishments depend on the production process and operating properties of the equipment. A temperature in excess of that regulated for the circulating water will lead to reduction in output of production and degradation of its quality.The effectiveness of the water-cooling process in cooling towers is determined by structural characteristics of the packings (sprinklers), which ensure the required surface area of phase contact with minimal aero-and hydrodynamic resistances.Despite a wide variety of sprinkler designs for cooling towers, the need currently arises for the development of new highly effective designs adapted to manufacture, which are formed from polymeric materials, since a trend toward an increase in output of articles formed from these materials with different dimensions and cross-sectional shapes is observed in industry.The sprinklers may be film or drop-film, depending on the character of the dominant cooling surface. Different types of sprinklers may also have extremely different designs of individual components and dimensions.Results of analysis of familiar structures are used in developing new sprinkler designs for cooling towers. Let us examine the operating principles of the sprinklers and their structural characteristics. In each specific case, the sprinklers should correspond to technical requirements established by government standards with resp...
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
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