About Gas Generation

• Generally, a lower cost of supply than bulk storage systems
• An inflation-proof, readily-available gas supply
• No demurrage fees, facility charges, or transportation costs
• No waiting for critical deliveries
• Increased safety due to minimal use of high-pressure or cryogenic gas
• Automatic operation meets fluctuating demands
• Simple operation does not require extensive training or knowledge
• A secure and dependable gas supply source

The most common oxygen generation technology uses the Pressure Swing Adsorption (PSA) process. PSA separates specific gas species from a mixture of gases, which are under pressure, by taking advantage of the unique molecular characteristics and affinity for adsorbent materials of each species of gas.

Unlike cryogenic distillation techniques of gas separation, PSA operates at near ambient temperatures. Special adsorptive materials (e.g. zeolites) are used as a molecular sieve, adsorbing the target gas species at high pressure. To collect the purified gas, the process switches to low pressure, which allows the gas to desorb from the
adsorbent material.

The Vacuum Pressures Swing Adsorption (VPSA) process is a variation on the Pressures Swing Adsorption (PSA) process, which is more applicable for certain applications. VPSA uses a feed blower instead of an air compressor to supply air to the system and the purified gas is collected using a vacuum blower to desorb the adsorber vessels. The use of different technology in VPSA results in a significant decrease in the power consumption of the system. Although power savings are clear with this system, they are typically cost effective only for plants requiring very large oxygen producing capacities.

Membrane separation isolates nitrogen from atmospheric air by selective permeation across a membrane wall. The membrane used in this method consists of a bundle of selectively permeable hollow fibers. These fibers allow the “fast” gases (oxygen, carbon dioxide and water vapour) to permeate the membrane wall much faster than the “slow” gas (nitrogen).

The membrane separates the original gas mixture into two streams. One stream, called the permeate, contains oxygen, carbon dioxide and water vapour. The other stream, called the product, consists of high-pressure nitrogen. The permeate is vented to the atmosphere and the product, nitrogen, exits the downstream end of the membrane for delivery to the end-user or to a booster if further compression is required.

The purity of the product can be adjusted by changing the operation conditions. If the nitrogen flow rate is decreased, nitrogen purity increases and conversely, by increasing nitrogen flow, nitrogen purity is decreased. A flow/purity control valve at the discharge end of the nitrogen stream, downstream of the flow meter and nitrogen analyzer, allows finite control of flow and therefore purity.

Nitrogen Blanketing

Atmospheric oxygen and moisture can degrade certain chemicals, surfaces of solids, and stored food products. Nitrogen's inert properties can protect these fragile, flammable or explosive items by keeping them from coming into contact with oxygen. This process, called nitrogen blanketing, replaces the air these items are stored in with nitrogen gas. 

Nitrogen Purging

Refineries, petrochemical plants, marine tankers and transport trucks all use nitrogen to purge equipment, storage tanks and pipelines of dangerous vapours and gases or before refilling. Nitrogen purging is also used to maintain an inert and protective atmosphere in tanks storing flammable liquids. During purging inert nitrogen gas pushes liquids though lines, to clear them or to propel "pigs" through pipelines to sweep out one material before using the line to transport another material. Nitrogen purging also extends the shelf life of packaged foods by preventing oxidation, mold, insect infestation and moisture migration.

Sparging

The inert properties of nitrogen also protects against loss of quality caused by oxidation when storing products such as vegetable oil or wine. Air can be expelled from liquids by a process known as sparging. Sparging uses a process of bubbling nitrogen gas through a liquid. The action of sparging also removes unwanted volatile components, including volatile organic compounds, which allows products to meet pollution reduction regulations. Nitrogen blanketing can further protect liquids in storage tanks when the vapour space is filled with nitrogen.

RANA’s oxygen concentrator system incorporates three oxygen supplies, which are carefully engineered to ensure your hospital enjoys a safe, secure, continuous and reliable supply of inexpensive on-site oxygen.

Primary Supply

The oxygen supplied by the concentrator to the oxygen storage tank comes from the Primary Supply.

Secondary Supply

Should there be increased demand the Secondary Supply will immediately and automatically be activated, ensuring a continuous flow of monitored high quality oxygen.

Reserve Supply

As an additional assurance, the Reserve Supply will automatically be activated should the Secondary Supply line pressure drop below an acceptable level.