Air separation

Air separation

Separation of atmospheric air into its primary constituents. Nitrogen, oxygen, and argon are the primary constituents of air. Small quantities of neon, helium, krypton, and xenon are present at constant concentrations and can be separated as products. Varying quantities of water, carbon dioxide, hydrocarbons, hydrogen, carbon monoxide, and trace environmental impurities (sulfur and nitrogen oxides, chlorine) are present depending upon location and climate. Typical quantities are shown in the table. These impurities are removed during air separation to maximize efficiency and avoid hazardous operation.

Three different technologies are used for the separation of air: cryogenic distillation, ambient temperature adsorption, and membrane separations. The latter two have evolved to full commercial status. Membrane technology is economical for the production of nitrogen and oxygen-enriched air (up to about 40% oxygen) at small scale. Adsorption technology produces nitrogen and medium-purity oxygen (85–95% oxygen) at flow rates up to 100 tons/day. The cryogenic process can generate oxygen or nitrogen at flows of 2500 tons/day from a single plant and make the full range of products.

Composition of dry air
Percent Parts per million
Component by volume Component by volume
Nitrogen 78.084 Carbon dioxide 350–400
tOxygen 20.946 Neon 18.2
Argon 0.934 Helium 5.2
Krypton 1.1
Xenon 0.09
Methane 1–15
Acetylene 0–0.5
Other hydrocarbons 0–5

Air separation is a major industry. Nitrogen and oxygen rank second and third in the scale of production of commodity chemicals; and air is the primary source of argon, neon, krypton, and xenon. Oxygen is used for steel, chemicals manufacture, and waste processing. Important uses are in integrated gasification combined cycle production of electricity, waste water treatment, and oxygen-enriched combustion. Nitrogen provides inert atmospheres for fuel, steel, and chemical processing and for the production of semiconductors.

References in periodicals archive ?
Praxair will build, own and operate multiple air separation plants that will supply high-purity nitrogen and oxygen to EverDisplay Optronics, the first mass producer of 4.
Under the terms of the agreement, Linde will conduct a front-end engineering and design (FEED) study for new air separation units, according to UAE state news agency, WAM .
The air separation units are expected to produce around 40,000 tons-per-day of oxygen to support the production of about 2.
today announced it has signed a long-term agreement to build, own and operate an air separation plant that will supply 700 tons per day of nitrogen to Samsungs display manufacturing complex in Tangjeong, South Korea.
NYSE: PX) has started up a large air separation plant in northern China for the Yankuang Guohong Chemical Co.
M2 EQUITYBITES-January 26, 2016-Praxair China announces new air separation plant
USPRwire, Mon Dec 21 2015] Adsorbents Market by Type (Molecular Sieves, Activated Carbon and Alumina, Silica Gel,Clay, and Others), by Application (Petrochemicals, Water Treatment, Air Separation & Drying, and Others), and by Region - Global Trends and Forecast to 2020
The company owns one of the Asia's largest air separation units.
Shahryari said the projects include water purification facilities, air separation unit, sewage treatment and a furnace.
Summary: Muscat: Muscat Gases Co said that its new air separation plant at Sohar Industrial Estate .
Gulf Cryo, a leading manufacturer of industrial, medical and speciality gases in the Middle East, is building a new air separation plant in Abu Dhabi.
BOC India, a member of The Linde Group, will invest Rs 600 crore for an air separation unit (ASU) at Tata Steels plant in Jamshedpur for the supply of over 4,000 tpd of gaseous oxygen, nitrogen and argon.