The key component of the nitrogen systems is the PRISM® membrane separator modules. Each module contains thousands of hollow fiber membranes allowing the oxygen water vapor and carbon dioxyde in compressed air to be selectively removed, resulting in a nitrogen rich product stream. By adjusting the airflow rate through the membrane module, different nitrogen and flow rates can be produced.
The membranes are formed into hollow fibres to obtain maximum membrane surface per unit of volume. Thousands of fibres are bundled into a casing that protects the fibres, routes the gas properly from feed to product end – and creates handy and standardized units that can easily be stacked together for modular capacity increase of the system.
Separating Gases Trough Membrane Fibres
The air that we breathe contains approximately 78% Nitrogen, 21% Oxygen and 1% other gases (Argon, H2O). The PRISM® membranes utilize this unlimited supply of raw material to produce specific purities of Nitrogen.
Atmospheric air is compressed, filtered, heated and fed to the bore side of the membranes. As the air flows inside the individual fibres, O2, CO2 and H2O (vapour) contained in the air, permeate faster than nitrogen through the membrane walls to the low-pressure side of the fibres. The bore side air is gradually depleted of the fast gases – consequently increasing the Nitrogen percentage. The final product can then be lead directly to the consumer, or be stored in a N2 receiver tank for later usage.
Air Products Norway was the first company to commercialize hollow fiber membranes for air separation onboard ships and offshore installations. The first on-site nitrogen generation plant using hollow fiber membranes onboard a ship was installed in 1984 and the first on an offshore platform in 1985. To date Air Products Norway has delivered more than 1000 PRISM® membranes nitrogen systems on a wide variety of ship applications, and more than 220 PRISM® membranes nitrogen systems for offshore installations. The systems have been installed on offshore production installations all over the world. Download PDF
Air Products supplies some of the most reliable membrane separators in the industry. We have the flexibility to manufacture membrane separators that are inserted as cartridges into pressure vessels or as one-piece devices. Our membranes have proven their durability during years of use in refineries, petrochemical plants, gas fields, military aircraft flight testing, and military shock and vibration testing.