High Purity Nitrogen Generator: A Technical Overview
When operations require clean, dry nitrogen at high purities, a high purity nitrogen generator provides consistent gas output without reliance on delivered supply.
What is a High Purity Nitrogen Generator?
A high purity nitrogen generator is an engineered system that separates nitrogen (N₂) from ambient air using selective physical processes. These generators deliver nitrogen gas at purities typically between 99.9% and 99.9995%, depending on the application. The air is processed through a series of components, including compressors, filtration stages, purification beds or membranes, and purity analyzers to maintain consistent N₂ output within specified thresholds.
Impact of Nitrogen Purity on Process Integrity
In high-spec industrial environments, gas quality is tightly controlled. Contaminants like oxygen, water vapor, hydrocarbons, and particulates can cause chemical degradation, oxidation, or unintended reactions in sensitive processes. Applications requiring high-purity nitrogen include:
- Inerting and blanketing: Prevents oxidation in chemical storage and transfer systems.
- Electronics/semiconductors: Avoids microscopic defects caused by reactive impurities.
- Pharmaceutical manufacturing: Meets contamination control requirements.
- Modified Atmosphere Packaging (MAP): Maintains product stability.
A high purity nitrogen generator integrates gas analysis and quality control into the delivery loop to support process requirements.
How a High Purity Nitrogen Generator Works
Compressed Air Pre-Treatment Stages
Before nitrogen can be extracted, ambient air must undergo thorough pre-treatment to remove contaminants that would affect system operation. A typical pre-treatment train includes:
- Air Receiver Tank: Buffers pulsations and stabilizes inlet flow.
- Particulate Filter (Grade G): Removes large particles >1 µm.
- Coalescing Filter (Grade C): Extracts oil aerosols down to 0.01 µm.
- Activated Carbon Filter (Grade A): Adsorbs hydrocarbon vapors.
- Refrigerated or Desiccant Dryer: Reduces dew point to -40 °F or lower.
- Differential Pressure Gauges: Monitor filter element performance.
These steps allow clean, dry air to enter the separation unit, increasing process reliability and equipment life.
Two main technologies are used to extract nitrogen from air:
- Pressure Swing Adsorption (PSA): Ambient air is compressed and passed through pre-treatment filters to remove oil, particulates, and moisture. The dry, clean air then enters a dual-tower PSA unit packed with Carbon Molecular Sieve (CMS). Oxygen, CO₂, and other gases are adsorbed while nitrogen flows through. Towers alternate between adsorption and regeneration cycles, regulated by solenoid valves and a PLC. Purity is continuously monitored via inline oxygen analyzers.
- Membrane Separation: Air is filtered and dried before passing through bundles of hollow fiber membranes. Gases like O₂, CO₂, and H₂O permeate the membrane walls faster than nitrogen, which remains in the core stream. The nitrogen-rich stream exits as product gas, with the oxygen-rich permeate vented. This method is lower maintenance but has limited maximum purity (typically ~99.5%).
Both systems require regulated inlet pressure (typically 100-150 psig), dew point suppression (-40 °F or better), and proper downstream flow control to maintain product quality.
Learn more: Membrane vs. PSA Nitrogen Generators
PSA vs. Membrane Generators for High Purity Applications
Feature |
PSA Generators |
Membrane Generators |
| Purity Range | Up to 99.9995% | Up to 99.5% |
| Flow Capacity | Moderate to High | Low to Moderate |
| O₂ Analyzer | Required | Optional |
| Maintenance | Valve sequencing, CMS beds | Membrane inspection |
| Typical Use | High-purity applications | Mid-purity blanketing |
PSA systems are used in high-purity applications with continuous purity monitoring. Membrane units offer a compact alternative for lower-purity applications where complexity and space are considerations.
Design Criteria for Generator Selection
System selection depends on:
- Required flow rate (SCFM or Nm³/hr) under peak demand
- Target nitrogen purity and acceptable O₂ concentration
- Operating pressure required by end-use equipment
- Duty cycle (continuous or intermittent)
- Ambient conditions (e.g., 50-120 °F, RH%, elevation)
Other design elements may include dual-tower redundancy, receiver tanks for purity stabilization, purge cycle control, and auto-venting. NiGen engineers match system specifications to process demands and site requirements.
Outcomes of Using On-Site High Purity Nitrogen Equipment
Compared to bulk gas or cylinder supply, on-site generation provides:
- Integrated purity monitoring with inline O₂ sensors
- Stable pressure and dew point for process-grade N₂
- Reduced need for deliveries, storage, or manual handling
- Lower long-term operational cost
A properly specified on-site nitrogen generator allows consistent performance and process reliability with reduced dependency on third-party logistics.
High Purity Nitrogen Generator Maintenance & Operation
Control Systems & Instrumentation
High purity systems use automation and monitoring tools to support continuous operation:
- PLC-Controlled Cycle Logic: Sequences PSA valve operation and purge timing.
- HMI Touchscreen Displays: Interface for setpoints, trends, alarms, and diagnostics.
- Inline O₂ Analyzers: Zirconia or electrochemical sensors monitor gas purity.
- Remote Telemetry Modules: Enable centralized access to data and alerts.
- Auto-Bypass and Redundancy Logic: Maintains output during service intervals.
These systems reduce manual intervention and allow technical oversight.
Routine maintenance supports consistent operation:
- Filter replacement: Pre-filters, coalescing filters, and carbon filters
- Sensor calibration: Verification of oxygen and dew point analyzers
- Valve and solenoid checks: Inspect actuator response and seals
- CMS bed review (PSA): Assessed via pressure decay testing and adsorption cycle logging
Control interfaces provide diagnostics and performance data. Remote connectivity can support trend tracking and offsite management.
NiGen Capabilities in Nitrogen Generator Systems
NiGen designs and delivers nitrogen systems built for demanding applications. Our PSA platforms, containerized skids, and automated monitoring provide:
- Application-specific system configuration
- Field-ready components suited for industrial use
- Support from installation to long-term service
NiGen supplies high purity nitrogen generators for rent and sale. Contact us today to learn more about our units.