Universal Industrial Plants

Liquid Oxygen / Nitrogen Plants -Low Pressure


Company Profile

Universal in collaboration with ING.L. & A Boschi Italy Since 1930 manufactures & suppliers premium Quality low pressure Air Separation Plants of all sizes ranging from 30m 3/hour to 50 000 3/hour.

Universal is a certified ISO 9001:2000 organisation and the latest achievment includes the successful approval for CE certification which makes our company first in Asia to certified for Cyrogenic Pressure vessel, Plant machinery exports to Europe and U.S.A .We have success in the low pressure plants as it is the technology of today and the future.We have manufactured over 300 plants since last 23 years since 1985 at New Delhi and supplied to over 40 countries worldwide.

Process Description

Air compressor Air Compressure Low Pressure

Air is compressed at low pressure of 5-7 Bar.Air can be compressed at such low pressure by trouble free rotary compressor (screw/centifrigal type advanced technology is employed in lieu of old bulky piston compressor.)

Pre Cooling System

The second stage of the process uses a low pressure refrigerent for pre cooling the processed air to tempreture aroung 12deg C before its enter the purifier.

Purification of air by purifier

The Air enters a purifier consisting of twin molecular sieve driver,working alternatevely .The molecular sieve remove the carbon dioxide & moisture from the process airenters air seperation units.

turbo expander Cyrogenic cooling of air by turbo expander

The has to be cooled to sub-zero tempreture for liquification & the cyrogenic refregeration & the cooling is provided by highly efficient turbo expandor which cools the air to tempreture almost -165 deg C to -175 deg C .

Seperation of liquid air into Oxygen Nitrogen by Air Seperation Coloumn

Oil free moisture free & carbon dioxide freeenters into low pressure plates fin type heat exchanger whrere the air is cooled below sub-zero temp by expansion process in the turbo expandor.Due to the excellent thermal efficiency we can achieve the tempreturedifference delta T as low as 2 deg c at the warm end of these exchangers.
Air get liquified when its enters the Air Seperation Column& get seperated into oxygen Nitrogen by process of rectification.
Oxygen is available at the outlet of the ASU at a purityof 99.6%
Nitrogen is also available at theoutlet as a second product at purity of 99.99 % upto 3ppm simultaneously without loss of oxygen product.

Compression of oxygen filling in the cylinder

The final product in the form compressed oxygen/nitrogen goes to the high pressure oxygen cylinder at 150 Bar or up to higher as required.
Or for pipe line supply or captive consumption.
Or for liquid plants to fills in cryogenic liquid tanks.

process drawing oxygen plant


  • High purity.
  • Quick start-up after tripping and shut down.
  • Supply of liquid oxygen / nitrogen to tank.
  • Automatic change over of molecular sieve available as option.
  • Long operation period.
  • Remote control available.
  • Very low power consumption.
  • By product : nitrogen 99.999% upto ppm.

    Basic Principle

    We are supplying low pressure plant manufactured by us with the following main components:
    1.Low pressure Rotary compressor or Oil free piston air compressors.
    2.Low pressure driers.
    3.Low pressure refrigerant drier.
    4.Turbo expander.
    5.Low pressure air separation unit.


    1. Air Compressor

    rotary screw type
    Rotary Screw Type
    A good air compressor with good quality is crucial to oxygen and nitrogen plant in its reliability maintenance, compressing capacity, product quality and efficiency. The discharge pressure of air compressor for air separation plant is usually with in 1.0Bar, so there exist a wide selection of Atlas copco rotary screw type and oil flooded, oil free screw type, centrifugal type and Rotary screw type. The selection of air compressor is subject to the size of the oxygen plant. Usually for a small-scale nitrogen plant, oil free screw type is enough. An oil-free piston type compressor is also good option if very robust compressor is required for worse site conditions.

    stationery compressor
    Stationery Compressor
    For a larger and medium – scale oxygen/nitrogen plant, there should be equipped a centrifugal air compressor. It functions stably with low operating cost, but the investment is usually very large. Beside, a centrifugal compressor needs a self-cleaning air filter.


    This air separation is a plant recovering oxygen and nitrogen from air simultaneously. It advance low pressure technology process of Boschi Italy using Rotary screw compressor (or low oil free piston compressor) and turbo expanders. The feed air entering the Molecular Sieve purification system employed to remove the moisture and Co2 from the process air. The air is liquefied by cryogenic cooling using latest plate and fin high efficiency heat exchangers and turbo expanders. The liquid air separates into oxygen nitrogen and inert gases in the air separation column.

    pre cooler system
    2.Pre-Cooler System :-

    The pre-cooler equipped in the oxygen/nitrogen plant is provided by professional manufacturer. It is skid mounted with main equipments imported. Function of pre-cooling system is to cool down the compressed air to 5~8 Degree Celsius and to discharge the condensed water.

    purifing system
    3 .Purifing System :-

    Purifying system is for secondary removal of moisture carbon dioxide and most of the hydrocarbons that would disturb processing. It works on double-layers of molecule sieve and almunia adsorption. Through reasonable structure design, the service life and adsorption performance are both strength ended, and thus to ensure a continuous performance of the fractional coulamn. Regarding the shift, there are generally two types of purifier. Automatic shift.controlled by PLC, and manual shift. Regarding the structure, there are also two types: skid-mounted type and separate-structure type. The skid-mounted purifier is easy to install and move, but the cost is relatively high. The separate-structure type is always installed at work site with low cost.

    Selection of purifying system is subject to the scale and the investment of the oxygen/nitrogen plan by the customer.

    expansion turbine
    Gas Bearing
    Expansion Turbine
    4.Expansion Turbine :-

    A oxygen/nitrogen plant always works on process of back flow expansion turbine when there is a need of expand capacity larger than 3000m/h. Small capacity plants having air flow from from 300Nm3 to 3000m3/h, its is often equipped gas-bearing expansion turbine.       
                    The turbine is to increase the the flow rate of the compressed gas through a nozzle; mean while, the speeded gas drives the wheel & output power through the rotor. During this process, both the pressure and temperature of gas lowered down, thus to provide cold capacity. In modern air separation plant, the cold capacity by turbine takes about more than 90% of entire cold capacity needed.

    cold box
    5.Cold Box :-

    Fractional column is the key part of the entire plant, where separation of oxygen/nitrogen is carried out through heat transfer by very highly efficient plate and fin tube exchanges current being used by all the leading manufacturer in the world like Linde, Air Liquid air products USA.
    Based on different processes, there are mainly two types of fractionation column single stage column and double stage column.

    The fractionation column designed and manufactured by us has a superior systematic performance, flexible and stability The purity and recovery both have been equivalent with the most advanced international technologies. We equip plate-fin type heat exchanger and full aluminum structure to main part of internal components of the cold box, which is close sealed and filled in gas to preserve pressure. Thus the cold loss caused by heat in leak is reduced to large extent. Cold box below 6000Nm/h can be assembled within our workshop, which could reduce work load at customer's work site and supplied as a packaged unit.
    cold box cold box

    instrument  control system
    6. Instument-Control System :-

    Instrument-control system, the window of the whole plant, could reflect all the information of the plant during its operation. A common instrument control system is equipped with side by cabinet and digital display together to reveal those parameters as pressure, temperature and flow rate. It is easy to operate and the cost is relatively little.

    Centrailized control system is equipped with PLC or DCS from siemens for the function of display, operation, adjusting, memorizing, recording, alarming, interlock, start-up and shut down. In the computer, there are display of main menu, process flow, parameter list, alarm and history thend. Network control of multi-computer is also achievable.
    As fast development of internet, based on DCS & PLC, the network could connect the control system at customer's end togethre with the manufacture's office for observation and supervision. Thus, if there in any problem in operating the plant, we would be able to offers a help hand in time, providing solution or technical support. Selection of control system depends finally on the requipment of the customer.

    Analysis Cabinet :-

    anaysis cabinet Analysis cabinet is to quicken the redponce speed, improve precision protect the analytical instruments, convenient check out and offer standard gas.
    The Components of analytical gas can be collocated according to customer's requirement as follow:
    Micro oxygen, micro moisture CO2 and other components of high-purity nitrogen (such as H2, CO, CH4----)

    Introducing BOSCHI Italy UBTL Series (Liquid Oxygen Series) The world standard in packed cryogenic air separation plants.

    UBT series plants are designed and buillt to meet the most severe operating conditions. Regular inspection and performance testing actual operating conditions is a pre requisite at our factory to assure highest quality.


    Some of the advantages of UBT series are :-

    -Minimization of transportation & hending expenses.
    -Rapid on-site installation & commissioning
    Over 300 air separation plant are working preoduced by universal in collaboration with ING.L.&A.BOSCHI all over the world.

    liquid oxygen storage tank Liquid Oxygen Storage Tank :-

    The cryogenic storage tank works on vaccum and power heat-insulation with operating pressure of 8Bar and 16Bar. Leading models as 5m3, 10m3, 20m3, 50m3, 100m3.
    If there is large quantity of liquid to be stored. It is recommended to equip power insulation cryogenic storage tank. Its operating pressure varies from atomospheric pressure to 8Bar or even higher. ITS CAPACITY FROM 200M3, 1000M3.
    Selection of storage tank is subject to the requirement of the customer.

    Vaporizer :-

    based on the difference of working condition, there are two type of vaporizer atomspheric vaporizer and water-shpwer vaporizer. Atomospheric vaporizer : It make use of heat capacity of nature convection air to vaporize liquid by aluminum alloys fin tube, which is used in high ambient occasion and need not any additional power and annex equipments. Its technics is simple; no any operation expense. If the conditions is available, had better to use air temperature vaporizer.

    Water bath vaporizer: It is made of stainless steel or purple copper tube, which is dip in water to heat water by steam or electric heat tube. The heated water vaporize by exchanging heat with liquid inside tube. It is fit for the north of low ambient temperature. Its technics is quite complex to atomospheric vaporizer and need operation expense.

    Introducing BOSCHI Italy UBTL Series (Liquid Oxygen Series)
    The world standard in packed cryogenic air separation plants.

    UBTL series plants are designed and buillt to meet the most severe operating conditions. Regular inspection and performance testing actual operating conditions is a pre requisite at our factoey to assure highest quality.

    Some of the advantages of UBTL series are :-

    - Minimization of transportation & hending expenses.
    - Rapid on-site installation & commissioning
      Over 300 air separation plant are working preoduced by universal in collaboration with ING.L.&A.BOSCHI all over the world.

    Process Flow Diagram

    process diagram

    Production UBTL 50 UBTL 100 UBTL 150 UBTL 200 UBTL 300 UBTL 400 UBTL 500
    Mode 1 : Liquid Oxygen (Nm3/hr) 50 100 150 200 300 400 500
    Liquid Oxygen (L/hr) 59 118 175 235 352 469 586
    Mode 1 : Liquid Nitrogen (Nm3/hr) 50 100 150 200 300



    Liquid Nitrogen (L/hr)








    Liquid Oxygen (%) 99.6 99.6 99.6 99.6 99.6 99.6 99.6
    Liquid Nitrogen (%) 99.99 99.99 99.99 99.99 99.99 99.99 99.99


    Power Consumed (KW)








    Mode 1 : Specific Power Oxygen (KW-hr/L) 1.89 1.85 1.8 1.73 1.44 1.36 1.24

    Mode 1 : Specific Power Nitrogen (KW-hr/L)

    1.4 1.36 1.31 1.26 1.05 0.99 0.9

    *Indicative : End specifications are as per actual offer.

    1. No water required for cooling the air compressor, air cooled type rotary air compressor is used.
    2. Skid mounted can option.
    3. I..S.O. Frame available.
    4.Containerized option available.
    5.Simultaneous nitrogen gas production upto 3-5ppm optional
    plain view

    plain view