Lean Air Unit from LT GASETECHNIK

Area of application

In chemical processes, e.g. in the production of synthetic resins or lacquers, a lean air unit is used to supply solvent boilers and reactors. The normal oxygen content in air (which is about 20.95 Vol.%) is to be reduced to a defined proportion (usually 4 to 10% Oxygen in mixed gas). For this purpose, technical air (compressed air) is mixed with nitrogen (N2), so that lean air with a defined Oxygen (O2) concentration is generated


Why should you use a Lean Air Unit from LT GASETECHNIK?

Keeping the specified oxygen content on the defined level has an influence on the quality of the production process and furthermore has safety reasons. Lean air is often used in a potentially explosive atmosphere. If the maximum permissible oxygen concentration is exceeded, this can lead to detonation and, as a result, to serious accidents. For producing lean air in hazardous area appropriate regulations must be observed and adapted components must be used.


Depending on customer specification, LT GASETECHNIK lean air systems are equipped with a gas analyzer (partly also compliant with the safety integrity level SIL 1 or 2), which measures the O2 concentration in the mixed gas. The mixing result is thus permanently monitored and optimized; In addition, the control can safely prevent inadmissible oxygen concentrations.


LT GASETECHNIK has decades of experience and comprehensive process engineering expertise for the design and manufacture of your individual lean air system, just „beyond standards“. With this solution you are on the safe side!

Lean Air Unit

Equipment variants

LT Lean Air Units are always designed according to customer specifications and are equipped accordingly. The following equipment variants are common:


  • Design of the unit for a hazardous area or for non-hazardous area
  • Gas filter on the gas inlet (police filter)
  • Pressure control of compressed Air and Nitrogen on the same mixing pressure
  • Measurement of the volume flow (temperature- and pressure-compensated)
  • Nitrogen bypass
  • Pressure controlled and/or volume-flow controlled
  • Storage of the mixed gas in a buffer tank, e. g. if the demand quantity varies
  • Continuous or discontinuous demand
  • Autonomous system with local touch-screen control panel and bi-directional connection to a higher-level process control system
  • Gas analysis, also in SIL 1 or SIL 2 versions
  • Stainless steel version for aggressive environments
  • System for outdoor or indoor installation, in a steel cabinet or in a rack
  • Pressure holding valve, for vacuum

Lean Air Unit

References (excerpt)

BASF Münster

  • Installation in ex-area
  • Capacity 40 cubic meters per hour
  • Inlet pressure:
    • Air 6 bar
    • N2 5 bar
  • Outlet pressure:
    • 5 delivery points
    • 0,5…1 bar and 1,5…2 bar
  • Buffer vessel with 500 litre
  • Controller and gas analyser
    (in the non-ex-area)


DSM Meppen

  • Capacity 200 cubic meters per hour
  • Inlet pressure:
    • Air 6 bar
    • N2 5 bar
  • Outlet pressure: 3 bar
  • Buffer vessel having 90 litre
  • Nitrogen-Bypass
  • Controller and gas analyser
    (signal transfer to the higher level process control system)


Synthopol Buxtehude

Two Lean Air units:

  • Capacity each
    400 cubic meters per hour
  • Inlet pressure:
    • Air 6 bar
    • N2 5 bar
  • Outlet pressure: 3 bar
  • Buffer vessel having 3.000 litre
  • Controller and gas analyser
  • Outdoor erection
  • Controller and gas analyser , bus-connection to the higher-level process control system with bi-directional data-exchange of all process data, alarm signals and error messages



BASF GuadalajaraLean Air Unit

  • Installation in the ex-area
  • Dynamic Lean Air Unit
  • Capacity 250 cubic meters per hour
  • Inlet pressure:
    • Air 6 bar
    • N2 4 bar
  • Outlet pressure: 3,5 bar

Safe supply of defined Oxygen concentration in your process air.

This article as PDF: LTG-Lean-Air-Units_2017-01

Please contact us for your individual solution…