This is the toughest point. The price of cylinder nitrogen is not just the "gas cost," but also includes transportation costs, cylinder rental fees, deposits, cylinder replacement labor, and the waste of unused residual gas (usually 5% to 10%). On the other hand, the marginal cost of a nitrogen generator is almost only the electricity cost—air is free.
The overall cost of using a nitrogen generator in the long term is lower than that of a traditional nitrogen cylinder, with a payback period of 1 to 2 years. It should be noted that the overall cost is extremely sensitive to electricity prices and gas load rates—intermittent gas use and long-term low-load operation of the equipment will significantly increase the unit cost.
The most easily overlooked problem with gas cylinders is that the pressure decreases as the remaining gas is used up. When a cylinder is used up to the end, both the flow rate and pressure will fluctuate. In scenarios such as precision welding and laser cutting, this will be directly reflected in blackening, slag buildup, and fluctuations in yield.
Nitrogen generators, on the other hand, have constant pressure output and continuously adjustable purity from 97% to 99.999% . The same equipment can switch between different processes (such as laser cutting 99.99% → food packaging 99.5%), which is something that steel cylinders cannot achieve by having "fixed purity at the factory".
This is the underlying motivation for many companies to replace equipment. 15MPa high-pressure steel cylinders are themselves a source of danger: handling, bumping, tipping, failure to undergo inspection, and damage to the cylinder valve can all cause physical explosions; nitrogen is colorless and odorless, and leaks can cause suffocation in confined spaces.
Modular nitrogen generators can operate under normal temperature and low pressure conditions, without high-pressure containers or the risk of low-temperature freezing. They also eliminate the compliance burden of regular annual inspections of high-pressure gas cylinders, dedicated warehouses, explosion-proof facilities, and dedicated personnel for record keeping . According to the "Technical Regulations for Gas Cylinder Safety" (TSG 23-2021) and local emergency management requirements, the storage, upright fixing, classification and isolation, and handling of gas cylinders are all high-frequency deduction points in daily inspections.
There is no need to keep a dedicated gas cylinder room, arrange for people to move and register, connect with suppliers to place orders and reconcile accounts, or keep gas cylinder ledgers and annual inspections. The equipment is fully automatic with PLC and can be operated without human intervention. Routine maintenance only requires periodic replacement of filter elements and molecular sieves.