How Do Membrane Nitrogen Generators Work?

In laboratory settings, membrane-based nitrogen generators are invaluable for their ability to provide a continuous, on-demand supply of nitrogen gas with adjustable purity levels. Their applications span across analytical instrumentation, life sciences, chemical synthesis, and environmental testing, among others. By ensuring a consistent and reliable source of nitrogen, these generators help maintain the precision, safety, and efficiency of various laboratory processes and experiments. Outside of the lab, these systems are widely used in industries like food packaging, electronics manufacturing, and chemical processing. Here’s a detailed explanation of how they work:

Basic Principles of Membrane Nitrogen Generators 

1. Compressed Air Supply: The system starts with a supply of compressed air, which contains approximately 78% nitrogen, 21% oxygen, and trace amounts of other gases (like argon, CO2, etc.).

2. Membrane Module: The heart of the system is the membrane module, which contains a bundle of hollow fibers made from special polymeric materials. These fibers are selectively permeable, meaning they allow certain gases to pass through faster than others.

3. Selective Permeation: The membrane filters separate gases based on their permeation rates:

- Fast Gasses: Oxygen, water vapor, and carbon dioxide have higher permeation rates and pass through the membrane more quickly.

- Slow Gasses: Nitrogen and and other inert gases permeate the membrane more slowly.

4. Gas Separation: As compressed air flows through the hollow fibers, fast gases permeate through the membrane walls and are removed as a byproduct (often vented as waste). The slower-permeating nitrogen gas continues along the length of the fibers and is collected as the primary output.

5. Nitrogen Purity Control: The purity of of the nitrogen output can be controlled by adjusting parameters such as:

- Flow Rate: Higher flow rates generally result in lower nitrogen purity because there’s less time for separation.

- Pressure: Higher feed air pressure can increase the driving force for permeation, affecting the purity and flow of the nitrogen.

- Fiber Length and Diameter: Longer and thinner fibers enhance separation efficiency.

Key Components of Membrane Based Nitrogen Generators 

- Air Compressor: Provides the compressed air needed for the system. 

- Pre-Treatment Filters: Remove particulates, oil, and water from the compressed air to protect the membrane and ensure efficient operation. 

- Membrane Module: The core component where gas separation occurs. 

- Flow Control Valves and Regulators: Manage the air pressure and flow rate through the system to control nitrogen purity and output rate.

- Monitoring and Control System: Ensures the system operates within set parameters and maintains the desired nitrogen purity and flow rate.

Advantages of Membrane-Based Nitrogen Generators

- Affordable: Membrane based models are considerably less expensive than PSA (pressure swing adsorption) models. PSA nitrogen generators can typically be considered “all in one” systems in the sense that they have a built-in air compressor and can generate nitrogen when supplied with electricity.  Largely due to the internal compressor, a PSA generator can easily cost twice as much as a membrane nitrogen generator.

- Compact and Lightweight: Membrane systems are generally more compact and lighter than other methods like PSA nitrogen generation.

- Low Maintenance: They have fewer moving parts, resulting resulting in lower maintenance requirements and operational costs.

- Continuous Operation: Membrane systems can provide a continuous supply of nitrogen without the need for cyclic regeneration processes.

- Energy Efficiency: They typically consume less energy compared to other nitrogen generation methods. Organomation’s NITRO-GEN nitrogen generator does not require electricity to operate! 

→ Discover: Which Nitrogen Generator Technology is Right For Me?

Applications of Membrane-Based Nitrogen Generators in Laboratories 

Membrane-based nitrogen generators play a crucial role in modern laboratories across various fields, providing a reliable and continuous supply of high-purity nitrogen gas. This versatility makes them indispensable for a wide range of scientific and research applications. Here’s a detailed look at their use in laboratory settings: 

1. Analytical Instrumentation 

a. Gas Chromatography (GC): Nitrogen is used as a carrier gas in gas chromatography, ensuring efficient separation of compounds within the chromatograph. Its inert nature prevents reactions with analytes, leading to accurate and reproducible results.

b. Liquid Chromatography-Mass Spectrometry (LC-MS): Nitrogen serves as a nebulizing and drying gas in LC-MS systems, aiding in the desolvation of the liquid phase and ensuring the proper ionization of samples for mass spectrometric analysis.

c. High Performance Liquid Chromatography (HPLC): In HPLC, nitrogen is used for degassing solvents and providing a stable mobile phase, enhancing the precision and reliability of the analysis.

d. Fourier Transform Infrared Spectroscopy (FTIR): Nitrogen purges the FTIR system to remove atmospheric water vapor and CO2, which can interfere with the accurate measurement of sample spectra.

2. Laboratory Gas Supply

a. General Laboratory Use: Nitrogen is widely used as a blanket gas to create an inert environment for sensitive experiments, preventing reactions with oxygen and moisture. It is essential for storing and handling reactive chemicals and samples.

b. Sample Preparation: In sample preparation processes, nitrogen is used to purge and dry samples, ensuring they are free from contaminants and moisture, which can affect analytical results. Discover how Temple University uses a membrane nitrogen generator to prepare environmental samples.

c. Purging and Inerting: Nitrogen is employed to purge and inert various laboratory equipment and systems, such as glove boxes, ensuring a controlled atmosphere for handling air-sensitive compounds.

3. Life Sciences and Biotechnology 

a. Cell Culture Incubators: Nitrogen is used to control the atmosphere in cell culture incubators, providing an optimal environment for the growth and maintenance of cell cultures by regulating oxygen levels.

b. Cryopreservation: In cryopreservation, liquid nitrogen is used to store biological samples, such as cells, tissues, and genetic material, at ultra-low temperatures, ensuring their long-term viability and integrity.

c. Fermentation and Bioreactors: Nitrogen maintains anaerobic conditions in fermentation processes and bioreactors, supporting the growth of specific microorganisms and optimizing the production of biopharmaceuticals and other bioproducts.

4. Chemical Synthesis and Analysis 

a. Inert Atmosphere Reactions: Nitrogen provides an inert atmosphere for conducting chemical reactions, preventing unwanted side reactions with oxygen or moisture and ensuring the purity and yield of synthesized compounds.

b. Solvent Evaporation: Nitrogen is used in rotary evaporators and other solvent evaporation systems to enhance the removal of solvents from chemical samples, speeding up the process and ensuring the complete drying of samples.

c. Glove Boxes: In chemical synthesis and analysis, nitrogen is used in glove boxes to maintain an oxygen-free environment for handling air-sensitive and highly reactive materials.

5. Environmental and Atmospheric Testing

a. Calibration Gas Production: Nitrogen is used to produce calibration gases for environmental testing instruments, ensuring the accurate calibration of equipment measuring air quality, emissions, and other atmospheric parameters.

b. Sample Storage and Transport: Nitrogen provides an inert environment for the storage and transport of environmental samples, preserving their integrity and preventing contamination or degradation.

c. Simulation of Atmospheric Conditions: Nitrogen is used in environmental chambers to simulate specific atmospheric conditions, allowing researchers to study the effects of various environmental factors on materials and biological samples.

6. Safety and Cleanliness

a. Purging and Leak Testing: Nitrogen is used to purge and leak-test laboratory equipment and systems, ensuring they are free from contaminants and leaks, and maintaining safety and operational integrity.

b. Cleanroom Applications: In cleanroom environments, nitrogen helps to maintain low humidity and prevent particle contamination, supporting the sterile conditions required for sensitive research and manufacturing processes.

If you need more details on a specific laboratory application or how these systems integrate with other lab equipment, feel free to ask our team at sales@organomation.com. 

→ Next: Nitrogen Generators: Everything You Need To Know