Air Liquide filed the original patents which led to the separation of air gases, oxygen, nitrogen and argon in particular. Today, as in the past, its comprehensive technological expertise puts it at the cutting edge of industrial gas production as well as distribution to the customer's point of use.

Industrial Gas Production

Air Liquide produces or separates industrial gases in two distinct ways:

• Either in its own plants: this involves air gas production units using cryogenic technology, or hydrogen and synthesis gas production units. Gases are liquefied at very low temperatures and can then be separated into their various components and removed at different levels in a distillation column.
  
  There are approximately 500 production units of various sizes in operation at the industrial sites of group subsidiaries in 60 countries. These production units supply:
• The group's own filling centers, which in turn distribute compressed gas cylinders;
• "Bulk" customers, who receive gas in "liquid" form;
• High gas consumer industries supplied by "tonnage gas" pipeline.
• Or at its customers' plants: this involves producing gas directly on the customer's premises, or "on-site". This may be done using cryogenic technology or gas separation technology based on adsorption or permeation. One example is FLOXAL™ service which enables nitrogen to be produced directly at the customer's site in compliance with various criteria involving purity, consumption profile, pressure and reserve security supply. The Compact VSA™ unit produces oxygen on-site using a non-cryogenic separation process involving adsorption on a molecular sieve.

  Dozens of on-site units are currently installed at customer sites throughout the world.

Industrial Gas Distribution

Our customers may be offered three main distribution methods:

• Compressed gas cylinders come in various sizes and are made of high-strength steel. The largest in Europe may contain, depending on the gas, about 10 cu meter (353 cu ft), at a filling pressure of 200 bar (2 900 psi). Equipped and maintained to ensure total safety, they are generally delivered to customers by a distributor using its own trucks. Cylinders are used for relatively low gas consumption requirements.
• Stationary storage tanks, cold converters or road tanker tanks, are super-insulated containers designed to store or transport gases in liquid form at temperatures ranging from -182 C to -269 C (-297 F to -452 F), depending on the gas. Storage tanks and cold converters are installed at the customer's site to provide a reserve gas supply and enable much greater self-sufficiency than is possible with cylinders. The group has built tens of thousands of these containers with which it serves its customers all over the world.
• Gas pipelines, which link the tonnage gas plant directly to the customer, ensure continuous and uniform supply of very large quantities of gas. Used mainly to supply oxygen, nitrogen and hydrogen, the Air Liquide group has a network of almost 7000 km of pipeline, primarily in Europe and the United States.