Oxygen Measurement In Industrial Gas Generators

Industrial Gas Generator

Controlling quality, performance and cost of industrial gas generators.

Oxygen measurements using zirconia based sensors control quality, performance, and cost.

In this blog, we look at the importance of Zirconia oxygen instruments for maintaining the operational efficiency of industrial nitrogen and oxygen gas generators.

Why are Zirconia based sensors ideal in this application?

Zirconia, or Zirconium Dioxide (ZrO2), is characterized by its excellent mechanical properties, stability at high temperatures, thermal and corrosion resistance, chemical inertness, and consistent structure. These characteristics make Zirconia an ideal material for use in high-performance oxygen sensors, especially those required for demanding industrial applications.

Application Focus: Comparing Pressure Swing Adsoption (PSA) and Membrane Technologies for Nitrogen and Oxygen Separation

The market for industrial nitrogen and oxygen gas generators has expanded significantly in recent years as manufacturers move away from traditional bulk or bottled storage of gases to on-site and move to on-demand generation systems. Local on-demand generation systems offer greater flexibility, are more cost-effective, and eliminate road transport and many health and safety issues associated with bulk silo storage and manual handling of gas bottles.

The two common methods of separating nitrogen and oxygen from compressed air streams are; pressure swing adsorption (PSA) or membrane filters.

PSA generators use pressurized vessels containing molecular sieves. These use either carbon for nitrogen generation, or Zeolite for oxygen generation. The former works by selectively adsorbing the smaller oxygen molecules, allowing nitrogen molecules to pass through the vessel, while the latter selectively adsorbs nitrogen to create a high purity oxygen flow. Most systems use twin adsorption vessels, which are alternately regenerated as the molecular sieve materials become saturated.

Membrane systems also separate oxygen and nitrogen molecules from the compressed flow of atmospheric air. Instead of molecular sieves they use a series of hollow semi-permeable polymer fibers arranged in bundles within membrane cartridges. Each fiber contains microscopic pores, typically between 0.03 to 10 microns. These are sized to allow the passage of oxygen molecules, but to reject larger nitrogen molecules, which flow through each fiber to a suitable collecting and storage vessel.

Where are PSA and Gas Generators used?

PSA and membrane gas generators can produce exceptionally high purity nitrogen and oxygen, often more than 99%. This is crucial in the semiconductor or medical sectors where any impurities can affect yield or create a potential risk to patients. In other applications, such as nitrogen blanketing in ships carrying volatile cargoes, the need for system reliability, production capacity and purity are equally important.

Why is Oxygen Measurement Needed?

This is where a precision gas measurement and control system is crucial – which leads us back to the importance of Zirconia sensors.

Zirconia instruments offer excellent mechanical and chemical properties. Unlike competing technologies, the Zirconia sensors that PST manufactures are designed to measure partial oxygen pressure in gases, not the percentage of oxygen concentration. This approach provides extremely accurate measurements without needing reference gases, making them ideal for use in industrial gas generators, where they are typically fitted to each outlet stage for both process control, quality & safety purposes.

From the perspective of OEMs (Original Equipment Manufacturers) and end-users of nitrogen and oxygen gas generators, there are numerous benefits provided by our Zirconia oxygen sensors.

  • The devices offer exceptional levels of accuracy, across a measurement range from 0-1,000 ppm, with an output resolution and sensitivity of 1ppm or 0.1%, even in the most demanding environmental conditions.
  • They provide a fast and continuous response to changes in process conditions and are also exceptionally stable with minimal drift, plus an expected operating life without the need for recalibration of at least five years depending on application.
  • They are also easy to incorporate into gas generator control systems, with standard 4-20mA and RS485 connections, while their overall level of performance creates a secure foundation on which regulatory and quality assurance assessments can be based.
  • The accuracy and reliability of our Zirconia oxygen instruments play a key role in helping to improve the energy efficiency, gas quality and compliance of industrial gas generators, giving OEMs and end-users alike complete peace of mind.

    Learn more about our latest products for industrial gas generators.

    With over 40 years of experience in the development of innovative precision instruments, we are the application experts in gas and moisture measurements for all OEM gas generation applications. If you would like to discuss your requirements, then please contact our team today.

    Did you know?

    Zirconia or zirconium dioxide occurs naturally in the mineral baddeleyite. This is relatively rare, which is why most Zirconia is derived from Zircon sand (Zirconium silicate), using a process of either chemical decomposition or thermal disassociation.

    Zircon sand is widely found in Australia, parts of Asia and across the southern African continent. Zircon formed over millennia in deposits of sand, where heavier metal elements were consolidated over time by the action of wind and waves. The Zircon content in these deposits can range from a few percent to around fifty percent. Where commercially viable, the ore is mined and then washed through spiral separators, leaving a mix of metals including Zircon. These are separated by exploiting the different magnetic, electrostatic and density characteristics of each element.

    As well as being used as the basis of Zirconia, Zircon can also be processed to form Zirconium, which is used in the nuclear industry and as an alloy added to aluminum and steel to improve their mechanical properties and resistance to corrosion.

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