Sign up | Login

0 » Gases


CO2

CARBON DIOXIDE

  • International symbol: CO2
  • Properties: Carbon dioxide is a colorless, odorless, slightly acid gas and about 1,5 times as heavy as air at normal atmospheric temperatures. It is normally inert, non-flammable and nontoxic. CO2 can be found in three physical phases:
    • Gas phase: gas CO2
    • Liquid phase: liquid CO2 (compressed gas)
    • Solid phase: dry ice
  • Materials of construction: The common commercially available metals can be used for dry carbon dioxide installations. Any carbon dioxide system at the user’s site must be designed to contain safely the pressures involved, and must conform with all state and local regulations.
  • Manufacture: Unrefined carbon dioxide gas is obtained from the combustion of coal, coke, natural gas, oil or other carbonaceous fuels; from by-product gases from ammonia plants, lime kilns, etc.; and from fermentation processes. The gas obtained from these sources is liquefied and purified by several different processes to a purity of about 99,9 per cent.
  • Commercial uses: Solid carbon dioxide is used quite extensively to refrigerate dairy products, meat products, frozen foods, and other perishable foods. It is also used as a cooling agent in many industrial processes, such as grinding heat-sensitive dyes and pigments, shrink fitting of machinery parts, etc. Solid carbon dioxide placed in liquefiers provides a source of gaseous carbon dioxide.
    Gaseous carbon dioxide, obtained from liquid or solid CO2, is used to produce urea (raw in fertilizer production), methanole, aspirin, colors, drugs and lubricant additives, in sugar industry, in the foam-polymer industry, in tanning of veal leather, in the production increase of oil from an oil source, in biological purification installations, as a propellant gas in sprays, replacing fluoro-chloro-hydrocarbons which harm the ozone layer. Also, carbon dioxide is used to carbonate soft drinks, metallic water and beer, as a food preservative, as a chemical inert “blanket” in food processing (as it is inert and non-toxic and prevents from oxidization which causes reduction of smell of products like coffee, fruits, vegetable, wines and meat). Other applications are : metal welding, pressure pumping, in greenhouses (as it helps plants’ growth), in medical purposes (it is used with a mixture of oxygen for the recovery of suffocation victims, as CO2 is stimulant for neurocells).
    Liquid carbon dioxide is used as a fire extinguishing agent in portable and built-in fire extinguishing systems, as CO2 is inert, insulating, “clean” and doesn’t leave residues after its use. It is most suitable for use in areas which include : liquid or gas fuels, electrical staff, common material like wood, paper, clothes. It is also used for pre- and post-chilling trucks, containers and for controlling chemical reactions.
  • Physiological Effects: Contact between the skin and carbon dioxide can result in frostbite, and must be avoided. Solid carbon dioxide must be handled with heavy gloves, for careless handling of it leading to contact with the skin may cause injuries like severe burns.
  • Handling precautions: CO2 is present in the atmosphere to the extent of 0,03 per cent by volume and is normal to body processes in limited amounts. However, high concentrations become dangerous in their effect of diluting or depleting the oxygen content in the air. Precautions with regards to ventilation are required. When entering areas where a high concentration of carbon dioxide gas is present, do not use air-breathing masks. Gas masks of type which feeds clean outside air to the breathing mask are required.
NITROGEN

  • International symbol: N2
  • Properties: Nitrogen makes up the major portion of the atmosphere (78.03 per cent by volume, 75.5 per cent by weight). It is a colorless, odorless, flavorless, nontoxic and almost totally inert gas, and is colorless as liquid. Nitrogen does not burn. It combines with some of the more active metals, such as lithium and magnesium, to form nitrides, and at high temperatures it will also combine with hydrogen, oxygen and other elements. It is employed to give inert protection against atmospheric contamination in many non-welding applications. Nitrogen is only slightly soluble in water and most other liquids, and is a poor conductor of heat and electricity. As a liquid at cryogenic temperatures it is non-magnetic, stable against mechanical shock, and free of toxic or irritant vapors.
  • Materials of construction: Gaseous nitrogen is non corrosive and inert, and may consequently be contained in systems constructed of any common metals and designed to withstand safely the pressures involved. At the temperature of liquid nitrogen, ordinary carbon steels and most alloy steels lose their ductility, and are considered unsatisfactory for liquid nitrogen service. Satisfactory materials for use with liquid nitrogen include stainless steel, brass, and aluminum.
  • Manufacture: Nitrogen is produced commercially at air separation plants by liquefaction of atmospheric air and removal of the nitrogen from it by fractionation.
  • Commercial uses: Nitrogen has many commercial and technical applications.
    As a gas it is used in: agitation of color film solution in photographic processing; blanketing of oxygen-sensitive liquids, and of volatile liquid chemicals; the production of semiconductor electronic components; the blowing of foam-type plastics; food processing and packing; inhibition of aerobic bacteria growth; magnesium reduction of aluminum scrap; and the propulsion of liquids through pipelines, pressurizing aircraft tires and emergency bottles to operate landing gear; purging, in the brazing of copper tubing for air conditioning and refrigeration systems; the purging and filling of electronic devices, high-voltage compression cables, pipelines and related instruments; and the treatment of resins in the paint industry.
    As a liquid it is used: as a coolant for electronic equipment, for pulverizing plastics, and for simulating the conditions of outer space; for creating very high-pressure gaseous nitrogen; in food and chemical pulverization; for the freezing of expensive and highly perishable foods, such as shrimp; for the freezing of liquids in pipelines for emergency repairs; for low-temperature stabilization and hardening of metals; for the preservation of whole blood, livestock sperm, and other biologicals; for refrigeration shielding of liquid hydrogen, helium and neon; for the removal of skin blemishes in dermatology; missile and space programs.
  • Physiological Effects: Nitrogen can act as a simple asphyxiant by displacing needed oxygen in the air inhalation of it and in excessive concentrations can result in unconsciousness without any warning symptoms, such as dizziness.
  • Handling precautions: Gaseous nitrogen must be handled with all the precautions necessary for safety with any nonflammable, nontoxic compressed gas. All the precautions necessary for the safe handling of any gas liquefied at very low temperatures must be observed with liquid nitrogen. Severe burn-like injuries result from contact between the tissues and liquid nitrogen.
    When dealing with such gases it is very significant to:
    • Ventilate well the closed areas because the leakages create a shortage of oxygen and there is a possibility that suffocation can occur.
Section under construction
home page | sitemap | iso ελληνικά | english
FSS Florian Security Systems S.A., 30 Athinon Avenue, 10441 Athens | Tel: +30 210 5227672 | Fax: +30 210 5225173 | Email: fss@fss.gr