A nitrogen generator makes almost pure nitrogen from outside air. By using an active carbon filter, oxygen (around 21% in air) is removed from it. After saturation due to binding with oxygen, the active carbon (Carbon Molecular Sieve, cms) must be regenerated. Each nitrogen generator has two tanks with activated carbon that alternately adsorb and regenerate. These functions swap at regular intervals (‘swing’), so that cleaned activated carbon can start a new adsorption cycle. In this way a continuous flow of nitrogen (N2) is created.
Two types of nitrogen generators
We offer two types of nitrogen generators. VPSA (Vacuum Pressure Swing Adsorption) technology works at a low pressure of around 1 bar. A pump creates the air pressure to bind oxygen to the cms during adsorption. A vacuum pump removes oxygen from the cms during regeneration. VPSA technology is relatively inexpensive to purchase and to service. A VPSA also uses relatively little energy at flows up to 40 m3/h. VPSAs are available up to 60 m3/h. This generator has two injection modes and circulation mode. Residual oxygen in the injection mode is 1% or 3%, respectively, as a standard. The oxygen pulldown to 5% in the circulation mode is approximately 20% faster, because the generator takes air from a cold store (two ducts instead of one) rather than using outside air, which is already lower in O2. The standard service interval is every 2,000 hours.
Pressure Swing Absorption
PSA (Pressure Swing Absorption) technology works at a higher pressures of 6-10 bar. Usually we use compressed air of 7.5 bar. Our standard PSA generators have flow rates of 12-150 m3/h at 1% residual O2. An important aspect of a PSA is the air/N2 ratio. Most common machines work at ratios of about 3.5. The great merit of our PSA is a ratio of 2.6, which saves 25% energy. On your request, we supply a generator with a compressor (Kaeser), a compressed air tank, a product tank and additional filters, if required. We can supply food grade machines, and we do tailor made applications on request.