Pressure Swing Adsorption Nitrogen Generator

ON-SITE PSA (pressure swing adsorption) Nitrogen Generator PSA - Pressure Swing Adsorption Air Separation Plants With over 20 years of experience in this field, CANGAS has continued with innovative improvements of the Pressure Swing Adsorption (PSA) process and...

Product Details

ON-SITE PSA (pressure swing adsorption) Nitrogen Generator

PSA - Pressure Swing Adsorption Air Separation Plants

With over 20 years of experience in this field, CANGAS has continued with innovative improvements of the Pressure Swing Adsorption (PSA) process and strengthened its position as world leader in this field of technology. Over 3000 PSA plants - including the world‘s largest units - have already been designed and supplied by Linde. The well proven CANGAS High Performance PSA systems provide an economic and reliable separation and purification technology for a wide range of process gases. Capacities range from small plant sizes of a few hundred Nm3/h to large scale plants of over 400,000 Nm3/h feed gas flow. These PSA systems are suitable for a vast number of different applications in the refining, petrochemical, iron/steel-making, and mining industry.


Oxygen Generation
The production of gaseous oxygen with purities between 90 % and 98 % and capacities of up to 6,000 Nm3/h can be most effectively achieved by the CANGAS VPSA process (Vacuum Pressure Swing Adsorption).
The advantages of this process are low specific energy consumption and simplicity of operation with regard to start-up and turn-down operation.

Nitrogen Generation
CANGAS also supplies PSA units for the generation of nitrogen for capacities of up to 5,000 Nm3/h and purities of 95 % to 99.9999 % (and even higher).
These plants can be engineered and fabricated fully tailored to the requirements and specifications of our clients, among which are well-known companies in the oil and gas business.

Other applications
Furthermore, CANGAS PSA plants have proven their capability in the recovery of helium and in the upgrading of natural gas to pure methane.

Particular features of CANGAS  PSA technology are high product recovery rates, low operating costs and operational simplicity. Highest reliability and on-stream availability of the PSA plants is achie-ved by special design features and the application of proven high-quality plant components. The modular skid design of the PSA plants reduces erection time and costs on site. The fully prefabri-cated skids are thoroughly tested before they leave the workshop. Commissioning and start-up of the plants as well as operator training and custo-mer service are performed by experienced specialists.

What is Pressure Swing Adsorption?

Pressure Swing Adsorption, or PSA - provides for significant improvement and efficiencies in the recovery of hydrocarbons from a mixture of natural gas or process gases.

The advantages of a Pressure Swing Adsorptionplants are the high enrichment of CH4 (more than 97%) and the reduced emissions levels and reductions in waste. Next to that, the carbon molecular sieves also adsorb N2 and O2. 

The one disadvantage of Pressure Swing Adsorptionplants is the fact that H2S needs to be removed.


What is Vacuum Swing Adsorption?


Vacuum Swing Adsorptionor "VSA" is a gas separation technology that separates gases without the use of a cryogenic plant or another gas separation technology called  pressure swing adsorption or "PSA."


Using special solids within the VSA plant called adsorbents, the Vacuum Swing Adsorptionprocess segregates certain gases from a gaseous mixture under minimal pressure according to the species' molecular characteristics and affinity for the adsorbents. The primary adsorbents are called zeolites.  Zeolites are a Zeolites are a group of hydrous aluminum silicate minerals whose molecules enclose "cations" of calcium, potassium, sodium, strontium, or barium, or a similar synthetic compound that are used as molecular filters and ion-exchange agents that forms a molecular sieve and adsorb the target gas at or near ambient pressure. After the adsorbent in one vessel is fully adsorbed, the process then "swings" to a vacuum which regenerates the zeolite or adsorbent material. 

Vacuum Swing Adsorptiondiffers from cryogenic plantdistillation techniques of gas separation and pressure swing adsorption (PSA) techniques due to the fact that it operates at near-ambient temperatures and pressures.


Advantages of Vacuum Swing Adsorptionover Pressure Swing Adsorption

There are significant advantages of Vacuum Swing Adsorptionover Pressure Swing Adsorption.  These advantages include:



Vacuum Swing Adsorptionplants use an integrated rotary lobe blower which also serves as a vacuum regenerator resulting in lower feed pressures. The significantly lower pressure swings in the Vacuum Swing Adsorptionplants and therefore eliminates the need for a feed air compressor which is used in Pressure Swing Adsorption plants.  Because of this, Vacuum Swing Adsorptionplants have far lower power requirements and consumption resulting in lower energy expenses - with energy expenses about 50% lower than Pressure Swing Adsorption plants. 


Vacuum Swing Adsorptionplants' low pressure air input into the adsorber vessel (with the zeolite adsorbent) in combination with the high efficiency of the vacuum applied during the desorption stage means that only one adsorption vessel is required.


Compared with typical Pressure Swing Adsorption plants, which require feed air compressors (for generating the much higher pressures required with PSA) as well as process valves and associated dryers and feed air filtering systems, this single-vessel approach with Vacuum Swing Adsorptionplants eliminates many of the design problems associated with Pressure Swing Adsorption plants.


Maintenance issues typically associated with Pressure Swing Adsorption plants are greatly reduced with Vacuum Swing Adsorption plants. Vacuum Swing Adsorptionplants are less susceptible to "sieve dusting" found in PSA plants because the pressure swings are much lower with Vacuum Swing Adsorptionplants.  The lower operating pressures of Vacuum Swing Adsorptionplants also eliminate any water condensate - another problem found with PSA plants. 

Unlike Pressure Swing Adsorption plants,
Vacuum Swing Adsorptionplants are not as susceptible to humid environments.  


Pressure Swing Adsorption plants feed compressors require both oil and water removal equipment hardware and Vacuum Swing Adsorptionplants do not.


The previously-mentioned rotary lobe blower is a rotary device that does not require the high level of routine maintenance typical of the air compressors needed by Pressure Swing Adsorption plants. 


Vacuum Swing Adsorptionplants use of a vacuum step provides a superior regeneration of the molecular sieve, thus extending sieve life. 


Overall, the Vacuum Swing Adsorptionplant's adsorber vessel has a much longer service life than the adsorber vessels found in PSA vessels which require re-packing of sieve material every 3-5 years.


Pressure Swing Adsorption

Pressure swing adsorption is a widely used technology for the purification of gases. This regeneration process is accomplished by reducing the pressure. At the moderate pressures found in compressed air systems, such as 100 pounds per square inch, an adsorbent can support a certain amount of moisture. When that pressure is dropped to ambient air pressure, the adsorbent can only support a smaller amount of moisture. By swinging the pressure from high to low, it is possible to adsorb large quantities of moisture at the higher pressure, and then release that moisture at the low pressure. This technique is called pressure swing adsorption. By alternating between two adsorbent filled vessels, one vessel being on line and removing moisture at high pressure, and the other off line releasing the trapped moisture at low pressure, it is possible to thoroughly dry a gas.

Conventional PSA Technology

Conventional PSA systems used today in industry are made up of four to sixteen large vessels, connected by a complex network of piping and valves to switch the gas flows between the vessels. Despite their widespread use in industry, Xebec believes that conventional PSA systems suffer from a number of inherent disadvantages. These PSA systems typically operate at slow cycle speeds of 0.05 to 0.5 cycles/minute since faster cycle speeds would cause the adsorbent beads to float or fluidize in the vessel, causing the beads to wear and ultimately fail. To meet customer demands for capacity, conventional PSA systems must utilize large vessels to compensate for the slow cycle speeds, leading to higher costs and a large equipment footprint. The use of large vessels also means that these PSA systems are typically erected in the field, increasing installation costs. The network of piping and valves used in large scale PSA systems, with the associated instrumentation and process control equipment, also adds cost to the overall system.


Q: Purity, flow and pressure scope?

Answer: for CANGAS air separation products, the answer to the question is as below.

1. PSA O2 generators: purity 93±3%; flow 1~1000m³/hour; pressure, normally 4 bar, could be  10~500bar with O2 compressor.

2. PSA O2 generators with purifier: purity 96~98%; flow 1~1000m³/hour; pressure, customizable, normally 0.2 bar, could be 4~500bar with O2 compressor.

3. VPSA O2 generators: purity 90%; flow 1~10000m³/hour; pressure, customizable, normally 0.5 bar, could be 4~500bar with O2 compressor.

4. VSA O2 generators: purity 90%; flow 1~10000m³/hour; pressure, customizable, normally 0.5 bar, could be 4~500bar with O2 compressor.

5. Membrane O2 generators: purity 40%; flow 1~10000m³/hour; pressure, customizable, normally 0.2 bar, could be 4~500bar with O2 compressor.

6. PSA N2 generators: purity 95~99.999%; flow 1~10000m³/hour; pressure, customizable, normally 6 bar, could be 10~500bar with N2 compressor.

7. PSA N2 generators with purifier: purity 99.9995~99.99999% (0.5~5ppm); flow 1~10000m³/hour; pressure, customizable, normally 5 bar, could be 10~500bar with N2 compressor.

8. Membrane N2 generators: purity 90~99.9%; flow 1~10000m³/hour; pressure, customizable, normally 6 bar, could be 10~500bar with N2 compressor.

9. H2 generators by liquid ammonia decomposition: purity, H2 99.9%, N2 99.99%~99.999%; flow, H2 1~1000m³/h, N2 1~500m³/h; pressure, customizable, normally 0.2 bar, could be 5~500 bar with H2/N2 compressors.

10. Liquid (cryogenic) N2, O2 and Ar generators: purity, N2 ≤ 5ppm, O2 ≥ 99.6%, Ar ≥ 99.999%; flow, gaseous N2 100~100000m³/h, gaseous O2 100~20000m³/h, liquid Ar 40~1000m³/h; pressure, customizable, normally 0.5 bar, could be 5~500 bar with N2/O2/Ar compressors.

Actually, for air separation plants by cryogenic technology, the kinds of product gas could be customizable - gaseous O2 and N2 with liquid Ar, or gaseous N2 with liquid N2, or liquid N2 with liquid O2, or only gaseous O2, only gaseous N2, or only liquid O2, or only liquid N2. For more details, please call or email us.

11. CANGAS filters: flow 0.1~120m³/min; pressure 0~16 bar.

12. CANGAS Heatless regenerative adsorption dryer: flow 0.1~120m³/min; pressure 0~16 bar.


* High Reliability

   Proven PSA technology, simple engineering design, few moving parts and international standardized manufacturing 

   techniques ensure minimal maintenance and maximum reliability. 

* Low Cost

   Patented REFLUX high-efficiency control system reduces air consumption, saves electric power.

* Convenience

   Unattended operation controlled by PLC automatically. Optional touch screen CANBUS control, display and alarm 

   system makes all the generation system to be operated by one touch. CANBUS displays working parameters, 

   reminds filter elements replacing and instructs trouble shooting. It enables remote control.

* Easy Installation

   Skid mounted for easy installation and move.

* Longer Service-life

   Exclusive bed containment system extends Zeolite/Carbon Molecular Sieve (Z/CMS) bed life to more than ten years.

* Minimal Maintenance

   The generator has highly-reliable valves and no other moving parts. Filter elements are easily replaced.

More reliable
* CANGAS standardized air separation systems based on proven state of the art technologies in history of many years 

   application in fields.
* Simplified engineering design idea with much less moving parts, guarantees maximum reliability and minimal

More economical
* More advanced and more economical air separation modules.
* REFLUX composition control system reduces air consumption capacity, saves energy cost.
* Patented Energy Efficiency System (EES) enables CANGAS systems to produce product gases based on actual demand.
More convenient
* CANBUS multi monitoring and control system enables parameters of capacity, purity, and pressure of product gases

   online display on panel screen, gives running problem alarm, and reminds of maintenance.
* Turn-key solution and pre-commissioned.
* Skid mounted design, easy installation.

Plug and play with smart control;

Proven design with reliable parts;

More reliable, more economic, more convenient;

CE, ISO, ASME, UL, BV, GHOST, GC3 certificated;

Leader in the market with 20 years of experience;

Have exported hundreds of PSA O2/N2 units to more 50 countries;

Turn-key design with easy control, simple installation and easy operation;

Low maintenance with super long service life;

Could be containerized for easy installation, transportation and relocating;

High efficiency: ONLY 0.5kw·h for 1m³ N2 production;

18 months warranty.


N2 purifier principa

Material nitrogen generated from PSA or membrane system is fixed with a small amount of hydrogen, then the residual oxygen will react

with the hydrogen and become water vapor in the tower full of catalyzer, the reaction equation as below:

                      2H2 + O2 = 2H2O 

The water will be adsorbed by molecular sieve (drying agent) in drying tower, finally purified and dried nitrogen is generated by the purifier. 

To ensure the continuity of gas production, there are two drying towers, one is in adsorption process, and the other is in regeneration

process (by heating and cold blowing) when the system is running. 

To ensure that all the oxygen will be removed, the actual ratio of H2 and O2 is slightly higher than theoretical value.

Multilevel processing system will be adopted, if the oxygen content of the material nitrogen is higher than 2.5vol%.

Buying Guides

The following points need to be confirmed by the purchaser before quoting and purchasing.

1. Country and standards (CE, PED, ASME, UL, API, GHOST, etc.);

2. Application;

3. Site conditions: altitude, temperature, humidity, surroundings, power supply specifications;

4. Basic requirements on capacity: purity, displacement (max output flow), product gas delivery pressure;

5. Any special requirements, such as for medical, short delivery time, shockproof, explosionproof, portable, movable, oil-free for product gas, no harmful gases (CO, CO2, SO2, etc.) in product gas, low dew-point, ....