Hycomp Performance Under Pressure™

Helium Compression

Description:
Helium is a unique molecule that is used for much more than inflating balloons at the county fair. After hydrogen, helium is the lightest element and has the smallest molecular cross-section of any gas. Helium is one of the rare gases in our earth’s atmosphere in which it is present in a concentration of only 5 ppm. It is completely inert to chemical reaction and radiation. Its thermal conductivity surpasses that of any other inert gas and is three times greater than neon, its nearest inert competitor. Helium’s boiling point of -452.1^oF (-268.9^oC) gives it refrigeration capabilities beyond those of any other substance. Helium provides a high rate of permeability and ease of detection with only slight solubility in the bloodstream. It is nonflammable and is only slightly soluble in water. It is usually shipped at high pressures at or above 2400 psig at 70oF (16 550 kPa at 21.1^oC) in cylinders and in bulk units. It is also shipped as a cryogenic liquid.

Safety, Storage & Handling:
Gaseous helium is commonly stored in high pressure cylinders, hydril tubes, or tube trailers. Liquid helium is commonly stored at the consumer site in cryogenic liquid cylinders, portable customer stations, and specially designed insulated tanks. To minimize helium transfer losses, the shipping container for liquid helium is normally used for storage.

Users of liquid helium must also take special precautions in addition to those necessary for the safe handling of such inert liquefied gases as nitrogen and argon. The extremely low temperature of liquid helium makes these special precautions imperative; it can solidify all other gases and cause air to condense on any uninsulated or inadequately insulated pipe through which it passes. This can result in a localized oxygen-enriched atmosphere and possible dripping of oxygen-enriched liquid air.

Liquid helium must not be allowed to come in contact with air and must be equipped with pressure relief devices that prevent back-leakage of air into liquid helium equipment. Plugging by solidified air constitutes a serious safety hazard.

Similarly, if air enters and plugs the vent of a helium container, a serious hazard is created. Therefore, the vents of liquid helium containers must be tested on delivery and periodically checked to make sure they remain clear. The use of open-neck dewar flasks for liquid helium also increases the possibility of the neck tube plugging from transfer or gauging of the contents. Users of liquid helium should obtain information on safe handling and equipment from their suppliers and the .

Liquid and gaseous systems should be designed and installed only under the direction of personnel thoroughly familiar with liquid and gaseous helium equipment and in full compliance with all state, provincial, and local requirements.

Disposal of helium gas may be accomplished by positioning the cylinder discharge valve away from personnel and slowly venting to a well-ventilated outdoor location remote from personnel work areas. Do not attempt to dispose of any residual helium in compressed gas cylinders. Return cylinders to the supplier with residual pressure, the cylinder valve tightly closed, and with the valve protective cap in place.

Handling Leaks & Emergencies: Ventilate enclosed areas to prevent the formation of oxygen-deficient atmospheres caused by the release of gaseous helium or by the evaporation on liquid helium. Personnel, including rescue workers, should not enter areas where the oxygen concentration is below 19.5 percent, unless provided with an SCBA or air-line respirator.

Avoid contact of the skin with liquid helium or its cold boil-off gas. Flush liquid helium spills with water to disperse the spill. Cryogenic liquids will cause burns similar to thermal burns when they come in contact with the skin and must be treated immediately. Thoroughly flush the affected skin area with tepid water, between 100oF and 105oF (37.8oC and 40.6oC), until the skin temperature returns to normal. Get medical attention as soon as possible.

First Aid: Skin Contact - In case of frostbite from exposure to helium, the frostbitten part should be placed in warm water, 100oF to 105oF (37.8oC to 40.6oC). If warm water is not available, or it is impractical to use, wrap the affected part gently in blankets. Let circulation re-establish itself naturally. Encourage the victim to exercise the affected part while it is being warmed. Consult a physician.

First Aid: Physiological Effects - Helium is nontoxic and inert. It can act as a simple asphyxiant by diluting the concentration of oxygen in air below levels necessary to support life. Inhalation in excessive concentrations can result in dizziness, nausea, vomiting, loss of consciousness, and death. Death may result from errors in judgment, confusion, or loss of consciousness, which prevent self-rescue. At low-oxygen concentrations, unconsciousness and death may occur in seconds without warning.
Gaseous helium must be handled using all the precautions necessary for safety with any non-flammable, nontoxic compressed gas.

All precautions necessary for the safe handling of any gas liquefied at very low temperatures must be observed with liquid helium. Extensive tissue damage similar to burns can result from exposure to liquid helium or cold helium vapors.

Methods of Manufacture: Helium is extracted from natural gas cryogenically, then purified via cryogenics or pressure swing adsorption processes, or both, and is generally liquefied for the reason of distribution economics.

Currently all major quantities of helium worldwide are recovered as a by-product of natural gas processing. Until 1995 the majority of worldwide helium was recovered in the United States (Wyoming, Utah, Colorado, Kansas, Oklahoma, and Texas), although there is also helium recovery in Poland, Russia and China. In 1995 a major facility came on-stream in Algeria, recovering helium from the tail-gases of a large liquefied natural gas plant.

Uses:
Helium is used as an inert gas shield in arc welding, as a lifting gas for lighter-than-air aircraft, and as a gaseous cooling medium in nuclear reactors. It is also used to provide a protective atmosphere for growing germanium and silicon crystals for transistors, to provide a protective atmosphere in the production of such reactive metals as titanium and zirconium, to fill cold-weather fluorescent lamps, to trace leaks in refrigeration and other closed systems, and to fill neutrons and gas thermometers. Its thermal conductivity makes it an important gas for lasers and fiber optic production. It is used extensively in chromatography due to its inertness and high thermal conductivity. It is used in cryogenic research such as for superconductivity. In mixtures with oxygen, it has medical and diving applications. Radioactive mixtures of helium with krypton are available to users licensed by the Nuclear Regulatory Commission. NASA uses helium for purging and pressurizing the liquid hydrogen tanks of spacecraft because it is the only element that remains a gas in the extreme cold necessary to maintain the liquid hydrogen fuel used in many rockets and the Space Shuttle. Liquid helium is used for cooling superconductive magnets, used in magnetic resonance imaging, and in magnetic separation.

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Additional gas specific articles: Argon - Carbon Dioxide - Natural Gas - Nitrogen