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Helium recovery

Helium belongs to rare elements and has unique properties. It is characterized by chemical inertness and low ability of participation in nuclear reactions, higher thermal conductivity and lower electric conductivity as compared to other gases, low solubility, light weight, low(near the absolute zero) boiling temperature, non-toxicity, the absence of colour and odour, non-flammability in gaseous state and a number of other valuable properties.

Such combination of properties predetermines ever-growing use of helium in various areas of science and engineering: aviation and astronautics, ship-building, chemical, metallurgical and welding facilities, nuclear engineering, medicine, chromatography, cryogenic engineering, etc.

Practically entire helium produced in the world is consumed by the countries included in the top ten of developed countries. The first place in helium consumption in the world market is occupied by the USA, the second by the Western Europe countries, the third by Japan.

Principal raw materials for helium production are natural and oil-well gases.

Helium production costs are almost inversely proportional to helium concentration in the gas being processed. Helium prime cost depends also on the complexity of gas processing (additional recovery of ethane, technical propane-butane, WFLC, natural gasoline, etc.), the plant capacity, quantity of initial contaminating impurities in gas, plant location, local conditions of gas consumption and transportation.

Estimated energy costs of helium recovery from gases containing 0.02, 0.05, 0.35% of helium are 250, 100 and 18 kWt h/cub.m, respectively.

In today's Russia, helium is produced at the helium plant (HP) in Orenburg from natural gas having low helium content (up to 0.055% by volume).HP operates five installations, each having a capacity of 3.0 billion cub.nm/h in terms of source gas. Along with helium, ethane and wide fraction of liquid hydrocarbons are recovered from gas.

The process and major process equipment used at HP were developed and implemented by our institute in 1970s-1980s.

At present, the problems of integrated gas processing with recovery of helium and valuable hydrocarbon products are in the area of activities of LENNIICHIMMASH Ltd. Helium recovery from natural gas on industrial scale is performed by the condensation-stripping method. Cold sources for the cooling and condensation process are: adiabatic process of gas expansion in a turbo-expansion unit (TEU); throttle effect using the potential of gas supplied for processing, and closed-circuit cooling cycles (propane cycle, nitrogen cycle, hydrocarbon-nitrogen mixture cycle).

Use of one or several cold sources depends on parameters of source gas supplied for processing, on requirements imposed on quality of helium concentrate that can be conveyed to an underground storage facility or for further processing in order to produce pure helium. Hydrocarbon condensate produced by cooling is subjected to rectification for production of valuable commercial products: ethane fraction, wide fraction of light hydrocarbons, technical propane-butane, stable natural gasoline or individual liquid components, depending on the demand. The process and main process equipment for integrated gas processing have been sufficiently optimised by LENNIICHIMMASH Ltd. Equipment for a plant having a capacity of up to 3.5 billion cub.nm/year in terms of source natural gas can be manufactured in Russia (except for TEU, some types of compressor and pump equipment and some portion of cold quick-acting valves).

With economy rehabilitation and further development of science and engineering, we should expect the advent of fundamentally new, efficient technical devices using special properties of helium, which must lead to a significant increase in demand for helium in the country. In addition, there is a prospect of organization of export helium supplies to markets of Japan, China, countries of Southeast Asia and Western Europe. Therefore, a pressing problem is implementation of integrated processing of natural gases from large fields of Eastern Siberia that have high helium content (from 0.15 to 0.6 %).

For effective and rational use of helium of the Eastern Siberia and Republic Sakha (Yakutia) within the bounds of the federal program “Helium of Russia” in 2006 the working (expert) group of leading specialists of JSC “Gazprom”, Russian Academy of Sciences (RAS), specialized branch institutes, helium engineering enterprises, first-rate Russian manufactures and users of helium was established. The leading specialists of LENNIICHIMMASH Ltd became members of the expert group of JSC “Gazprom”.

High helium content of gas and the use of integrated gas processing technology will allow a significant cut of helium prime cost as compared to the cost of helium produced at Orenburg helium plant; the cost will be comparable with that of helium produced in the USA. Further, realization of excess products in the international market, including payments with those products to investors, may solve the problems of gas field development in Eastern Siberia. In foreign countries, it is preferred to transport and sell helium in liquid state. Therefore, it is necessary to organize in Russia a system for liquid helium in-plant storage, transportation and distribution featuring up-to-date technologies and services.

In conditions of lack of roads in regions of Eastern Siberia and Republic of Sakha (Yakutia), it is reasonable to transport helium to the user in liquid state, in large-size tank cars by railway to ports and then by sea. Deliveries to China can be transported by direct railway communication. Small lots can be transported by air.