PSA Nitrogen Generation

The Cost of Delivered Gas

A site that takes delivered liquid nitrogen or cylinder gas pays for the gas, the road transport, the cylinder rental, the change over labour, and the security stock that covers a missed delivery. For a continuous consumer the recurring cost adds up to two to four times the cost of generating the same nitrogen on site from compressed air.

A SorbiTech on site pressure swing adsorption package converts that variable opex into a predictable capital plus electricity cost and removes the logistics risk of a missed delivery. The same package serves food blanketing, vessel purging, pipeline inerting, laser cutting, and any duty up to several thousand cubic metres per hour.

How PSA Nitrogen Works

Compressed air is passed through a carbon molecular sieve under pressure. The sieve adsorbs oxygen and moisture faster than nitrogen, so nitrogen passes through to a buffer tank. The bed is regenerated by dropping the pressure to vent the captured oxygen; a second adsorber produces while the first regenerates, and the two beds alternate every 60 to 120 seconds to give a continuous flow.

The separation is kinetic, not equilibrium. Oxygen has a slightly smaller molecular diameter than nitrogen and diffuses into the CMS pore network several times faster. SorbiTech supplies the CMS grade matched to the cycle timing and the contracted purity.

What Sets the Design

Purity, flow, and feed air quality fix the package size.

• Required nitrogen purity: 95 to 99.999 percent
• Peak and average flow demand, including diurnal and shift variation
• Recovery, which trades against purity and CMS volume
• Feed air quality, which must reach ISO 8573 class 1.4.1 or better
• A deoxo polishing step where the duty requires above 99.99 percent nitrogen
• Adsorption pressure: 7 to 10 barg, set by the compressor selection

Feed Air Quality and CMS Life

Carbon molecular sieve is intolerant of liquid water, oil, and particulate. Refrigerated or membrane drying of the feed air to a pressure dew point of 3 °C or lower, a coalescing filter for oil and water, and a particulate filter ahead of the inlet are non negotiable. With a correctly conditioned feed the SorbiTech CMS gives seven to ten years of service.

A breach of the feed specification shortens CMS life by months. Continuous feed dew point and oil carryover monitoring are the cheapest insurance the operator can install.

Common Use Cases by Industry

• Food and beverage: blanketing of wine, beer, and dairy vessels at 99.5 to 99.9 percent purity to displace oxygen and preserve flavour
• Pharmaceuticals: inert atmospheres for reactor blanketing and sterile filling at 99.9 to 99.999 percent purity
• Electronics: dry nitrogen for SMT reflow ovens and wave soldering at 99.9 percent to reduce dross formation
• Metals: laser cutting cover gas at 99.5 to 99.9 percent, where the savings versus delivered liquid run into hundreds of thousands of euros per year for a busy cutting line
• Oil and gas: tank blanketing, pipeline pigging propellant, and emergency vessel inerting at 95 to 99 percent purity

Outcome

On site generation replaces delivered gas with a capital plus electricity cost. Payback is typically under 24 months for continuous demand and the lifetime cost of nitrogen falls by 50 to 70 percent. SorbiTech delivers the duty as a turnkey PSA nitrogen generation package engineered by SorbiTech, for sites under industrial gas and air separation. A rental unit covers commissioning or bridging supply before the permanent package is installed. SorbiTech delivers the duty as the PSA nitrogen generation package charged with the CMS N₂ grade, with sector context under the industrial gas sector and the food and beverage sector.