A schematic diagram of the plant for getting nitrogen-xenon mixture from "dirty" oxygen of air-fractionating plant (AFP) is shown and described. Industrial plant test data are presented in the form of relationship of the adsorber operation time with the temperature of the "dirty" oxygen at the inlet and of the duration of the application stage with the xenon concentration at the inlet.The heavy rare gases krypton and xenon are finding wide use in domestic and global science and technology. In spite of these gases being relatively dear, their industrial production has been going up steadily.Several potential sources for industrial production of krypton and xenon are known, among which are tail streams of ammonia production (nitrous gases), radioactive tail gases of nuclear power plants, etc. Universally recognized and essentially the only source for industrial production of these gases, however, is atmospheric air, which contains 1.14 vol. ppm of krypton and 0.086 vol. ppm of xenon.Because of the small content of these elements, industrial atmospheric air processing for their extraction is inefficient, and at present use is being made of the method of Kr and Xe extraction in the air fractionation process in large air-fractionating plants (AFP).For this purpose, modern AFPs are generally provided with a unit for production of a primary krypton concentrate (PKC) where the krypton and xenon content rises to what is admissible for further treatment (0.2-0.4 vol. % Kr and 0.015-0.03 vol. % Xe).Several industrial methods are known for getting krypton and xenon, of which fractionation and adsorption-fractionation methods have found the widest application. All these methods are based on treatment of PKC [1]. However, because of temporary decline in demand for heavy rare gases in the late eighties and early nineties of the past century, the Kriogenmash OAO, which is the only enterprise producing large-scale AFPs in Russia and exporting them to some foreign countries, discontinued inclusion of the PKC extraction unit in the process lines of their plants (AFPs of the type of etc.).At present, in Russia and in former Soviet Union countries and beyond, there are quite a few AFPs with such modifications of the process lines, which are not suitable for getting the desired (full-valued) PKC. In this situation, as simple
It is shown that the problem of cold accumulation is complicated, and the importance of cold carriers, the temperature of generated and accumulated cold, methods of its utilization, and particularly for large users of cold, i.e., air cooling machines and vapor-compression refrigeration machines, are noted.The clearly defined problem of saving electrical energy and energy resources has stimulated specialists in very different fields to look not only for methods for reducing energy consumption, but also to develop storage and transforming electrical energy and heat, that will make it possible to optimize their generation and consumption. We are convinced that this also relates directly to low-potential heat, i.e., cold. Various aspects of this problem are still far from being studied in relation to the level of contemporary possibilities, although it has been realized for a long time in simple versions both abroad and in Russia, and in countries with a continental and warm climate.The main reasons for performing studies of this problem are, on one hand, a constant increase in the proportion of electrical energy for the purposes of generating cold, and, on the other hand, the existing difference in the costs of electrical energy during the day and at nighttime. The cost of 1 kW·h may vary by a factor of 1.5-4 (at night, the cost of electrical energy is less). In addition, the problem of accumulating cold has a direct relationship to the use of natural daily and seasonal changes in the temperature of thee environment with which potentially it is possible to provide a reduction in energy consumption for cold generation, i.e., to accomplish energy saving.Among objects that may be commercially suitable for using cold accumulation systems, it is possible to note large refrigeration stores, sporting structures, large objects of air conditioning, heavy-load ships, and also objects of large tonnage production and consumers of liquefied natural gas (LNG). Everyday refrigeration technology and climate technology also may be considered as objects for using these accumulators. The necessary control of electrical energy consumption during the day and at night is entirely real: so-called two tariff networks for electrical energy are already used, most extensively in newly built homes. In addition, especially under conditions of the northern latitudes, it is possible to realize pre-cooling of natural cold accumulators (water ice, etc.) with their further use for other purposes, including generation of lower temperature cold, for example, in natural gas liquefaction.It is clear that the problem of cold accumulation is complicated and there are important technical questions relating to the possible cold carrier, the temperature of generated and accumulated cold, methods of its utilization, and what is particularly important for large cold consumers, i.e., refrigeration machines for generating cold.We analyze the technical side of the problem of cold accumulation in fact for its large consumers in the field of moderately low and cryo...
The major landmarks in the history of cryology are noted. The most important developments in the domain of cryogenic engineering are analyzed. The urgency of production and use of industrial gases, especially of helium, is underscored. The potentials of engineering cryology in solving problems of protection of human environment and its use in medicine, space technology, nanotechnologies, etc., are shown.Cryology originated in the 18th century within the framework of heat science. Marked acceleration of development of cryology occurred in the second half of the 19th century in the course of creation of the earliest refrigerating machines and apparatuses and performance of physical research into liquefaction of gases.The 20th century witnessed impetuous development and growth of refrigerating and cryogenic machine building and climate (air conditioning) engineering. At the present time, a large and exceptionally important area of scientific, practical, and commercial activity, namely, engineering cryology, has been taking shape (Fig. 1).The activities of foreign and domestic firms confirm how much various low-temperature equipment is in demand and how essential artificial refrigeration is for various areas of technology and life.For instance, in the last quarter of the 20th century, TKhM-300 type of low-temperature (t ≈ -100°C) air refrigerating machines operating in V. S. Martynovskii, S. K. Tumanskii, and M. G. Dubinskii vacuum cycle (Turbokholod Company) were built for rapid foodstuff freezing. Another type of air refrigerating machines, also for fast freezing of products, which operate in a low-pressure cycle were also built under the supervision of A. Sh. Kobulashvili (companies Turborefrigeratory and Skagen).Air refrigeration cycle for recondensation of oxygen vapors (T ≈ 90 K) during its prolonged storage was first realized at the Bauman Moscow Higher School of Engineering (MVTU) in the 1960's under the supervision of I. V. Marfenina.VNIIkholodomash-Kholding OAO led by O. M. Tagantsev has made a great contribution to the development of domestic refrigerating machine building: the company has developed, jointly with the Moscow plant Kompressor, a series of 50-MKT-type standard-sized ammonia refrigerating machines; created an SK-16 spiral compressor with a 16 kW refrigerating capacity at t 0 = -15°C and VB series of glandless screw compressors; ensured series production of screw compressors having optimum profile (shape) of the rotors with a refrigerating capacity ranging from 25 to 3200 kW operating on ammonia, propane, and refrigerants R22 and R134a. New centrifugal (radial-flow) compressors have been developed under the supervision of I. Ya. Sukhomlinov, and a range of marine refrigerating machines (1MKhM V250, 3MKhM V290, and MKh-0.35) have been built around them. A new generation of conditioners and bromine-lithium absorption refrigerating machines with a refrigerating capacity ranging from 300 to 6000 kW has been developed. Most of the built low-temperature refrigerating systems are fully automated.New e...
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