Paramagnetic sensing
KEY APPLICATIONS
Paramagnetic sensing can be used in a wide range of applications in many industries . Some of the most notable are :
• Oxidation control reactions
• Ethylene Oxide ( EO ), Pure Terephthalic Acid ( PTA ) and Ethylene Dichloride ( EDC ) manufacturing
• Marine vapor control
• Industrial and medical gas production
• Medical / patient monitoring
Paramagnetic sensing can be implemented alongside Infrared and GFC sensing in key industrial processes such as Air Separation Units and CEMS applications
THE PARAMAGNETIC PROPERTIES OF OXYGEN
The orbital motion of electrons generates magnetic fields whose net effect in a substance is expressed as its diamagnetic susceptibility . All substances have a diamagnetic component , and diamagnetic substances are repelled by a strong magnetic field .
The spin motion of electrons generates magnetic fields whose net effect in a substance is described by its paramagnetic susceptibility ( ferromagnetism being a special case ). In most gases , these fields cancel out due to paired spins .
However , there are a number of gases which display a strong paramagnetic effect , including nitric oxide , nitrogen dioxide and chlorine dioxide . The highest value is displayed by O 2 .
Paramagnetic substances are attracted to the strongest part of a magnetic field . The mass susceptibility of a paramagnetic material is inversely proportional to the absolute temperature .
The paramagnetic volume susceptibility is inversely proportional to the square of the absolute temperature , as it includes a gas density factor .
If the volume magnetic susceptibility of nitrogen is taken as zero , and O 2 is taken as 100 , then most gases would have a very small value , with only a few gases having higher values , such as nitric oxide ( 43 ). So , this physical property of O 2 can be utilized in a number of ways to measure the O 2 concentration of a gas mixture .
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