Nitrogen Generators



Nitrogen Generator
No. 2700-09A No. 2700-11A No. 2700-12A

Nitrogen Generator AI
  • State-of-the-art membrane separation technology produces dry nitrogen up to 99.9% pure
  • Eliminates drawbacks of conventional nitrogen sources—gives you control of rate and purity of nitrogen production
  • Delivers gas flows up to 400 SCFH or more depending on nitrogen purity requirements (even higher flows possible if only dryness is desired)
  • Compact, lightweight design allows set-up wherever there's a compressed air supply
  • Ideal for the complete range of cleanroom applications—from glove boxes to automatic storage systems
  • Simplicity of field-proven design ensures completely reliable, economical operation, virtually eliminates maintenance
  • Three models available with three flow ranges.

This Nitrogen Generator represents a series of advances by the world leader in hollow-fiber membrane technology used in the first artificial kidney. It gives you complete control of the production of nitrogen for use in a wide range of cleanroom applications—and in most cases quickly pays for itself.

State-of-the-Art and State-of-the-Budget 
A nitrogen membrane provides a low-cost, highly efficient means of separating air into its component gases. Because this technology requires no moving parts and consumes relatively little energy, it is surprisingly economical to operate and maintain—the main expense is the energy required to provide a stream of compressed feed air. Each system contains gas pressure control valves and instruments, a coalescing filter and carbon filter (which removes particles and liquid vapors from the feed line), and the nitrogen membrane module.

The membrane module consists of bundles of hollow fiber, semipermeable membranes. Each fiber has a perfectly circular cross-section and a uniform core through its center. The wall thickness of each fiber is thus consistent, which contributes to the physical strength of each membrane. Because the fibers are so small (about the diameter of a human hair), a great many can be packed into a limited space, providing an extremely large membrane surface area that can produce a relatively high volume product stream.

The hollow fibers are assembled parallel to a central core tube, and the bundle is inserted into an outer case to form the air separation module. Compressed air is introduced into the center of the fibers at one end of the module and contacts the membrane as it flows down to fiber bores. Oxygen, water vapor and other "fast gases" pass through the outside of the fibers. The oxygen-rich gas stream then flows through the fiber bundle to the periphery of the case, where it is discharged as a by-product.

While all but a small fraction of the oxygen passes through the membrane material to the exterior of the hollow fibers, most of the nitrogen present in the feed air is contained within the hollow fiber membrane. Since water vapor passes through the membrane along with the oxygen, this nitrogen product is essentially moisture-free. The nitrogen stream emerges at a pressure slightly below that of the feed air pressure.

Design Simplicity Means Easy, Reliable Operation
Because the heart of the system, the membrane module, contains no moving parts, it requires no maintenance. The only attention a system typically needs is an occasional filter change. 

Each Nitrogen Generator consists of a membrane module, controls and instrumentation, and coalescing filters and traps to remove oil and liquids, organic contaminants and other particulates from the feed air. Installation merely requires piping compressed air to the system, and piping the nitrogen to its destinations. Order Terra's oil-less clean air compressor separately.

flow chart

Nitrogen Flow

Nitrogen Generator


High-Capacity Nitrogen Generator

  • Provides high-volume of 99%+ pure Nitrogen for a wide range of process requirements
  • Holding tank has 60 gallons of N2 ready to use
  • Compact housing requires a minimum amount of floor space 

Terra’s HC (high-capacity) Nitrogen Generator provides a continuous flow of 99%+ Nitrogen, providing a reliable alternative to re-fillable storage tanks.

A combination compressor/dryer (included) provides the feed air for the nitrogen-producing membrane and prefilters.

  On-Site Nitrogen Generation: The Practical, Reliable Alternative

For more and more manufacturers, on-site nitrogen membrane separation has become a preferable alternative to conventional sources of purified nitrogen (whether in liquid customer stations or nitrogen cylinders).

High-volume suppliers of purified nitrogen typically rely on the cryogenic distillation process, which provides excellent purity levels (99.99+%) but is energy intensive and hence inherently expensive. For occasional nitrogen requirements that demand ultra-high purity, these sources remain the most economical; but for many other applications—including most high-volume storage situations—non-cryogenic generation on-site makes better sense.

Optimal Source of Purge Gas for Glove Boxes, Desiccators, and Other Enclosures 
Membrane systems can be sized to deliver as little as 100 SCFH (Standard Cubic Feet per Hour) efficiently and economically, and in most cases lead to significant savings, even when high purity levels are necessary.

For nitrogen-purged storage and process systems with automatic humidity controls (like Terra desiccators, glove boxes and automated stockers), this purity level may not even be necessary. Terra systems automatically regulate the nitrogen purge to maintain the most critical humidity levels typically required, which can generally be achieved with purity levels below the 99.99% for which you are currently paying.

Long-Term Stability, Complete Supply Control
These membrane nitrogen separators provide additional savings—and greater convenience—by eliminating the need to rent tanks and pay for delivery services. Of course, they also free you from price increases from your nitrogen distributor. Once your system is installed, you pay only minimal electricity expenses: your gas costs remain completely predictable.

And your supply remains secure. You'll never need to worry about overbuying to compensate for tight supplies or delivery disruptions.

  Complete Product Control

The purity of nitrogen, flow rate of the gas, and feed air temperature and pressure all affect the performance of the membrane separation system. By altering these variables, you can deliver nitrogen with precisely the right purity and flow for your applications.

Nitrogen purity can be regulated (up to a maximum of 99.9%) by adjusting the input air pressure and temperature. In most cases, the greatest system efficiency is achieved at purities of 95-99%, levels adequate for most cleanroom applications. See Figure 1.

The flow rate of the enriched nitrogen product is a function of the purity required. The higher the nitrogen purity required, the lower the flow rate produced, assuming constant feed air temperature and pressure. To produce a higher purity nitrogen product, more oxygen must permeate the membrane. You increase oxygen permeation by increasing the pressure difference across the membrane. This transports more gas, including more of the total oxygen content of the feed air, through the membrane. With more oxygen permeating the membrane, the oxygen level in the nitrogen product gas is reduced and purity improved.

Feed air temperature also affects the performance of the system. The higher the feed air temperature, the higher the feed air flow rate required, assuming constant air pressure and nitrogen purity. As feed air temperature rises, the membrane permeability increases, requiring an increased feed air flow rate to maintain product flow. However, feed air temperature also affects the membrane material. High feed air temperature shortens the life of the membrane. See Figure 2 for the relationship between feed air temperature and flow rate.

When the feed air temperature increases, the feed air flow required rapidly escalates. Therefore, the system must be designed to provide required feed air flow rate of the maximum anticipated feed air temperature, or an air conditioner must be used to control the feed air temperature.

Dew point is the temperature at which a given mixture of water vapor and gas is saturated. The dew point and trace contaminants of the nitrogen-enriched product gas are dependent on the water level and quality of the feed air. Operating in the purity range of 95-99% nitrogen, saturated feed air results in a product gas that contains less than 5 ppm water, depending on feed air conditions. The atmospheric dew point equivalent is -65°C (-85°F).

Water level in the feed gas is dependent on temperature and pressure. Therefore, if the feed air pressure is reduced, the dew point of the product may increase. If the temperature is increased, the feed dew point increases and the product stream dew point increases. Changes in dew point are minimized by using a refrigerated air dryer to condition the feed air.

Carbon dioxide in the product stream is typically less than 0.01% operating at 99% nitrogen, 135 psig and 25°C, based on feed air containing .03% carbon dioxide.