Electrochemical sensor for reactive gas mixtures
First Claim
1. An electrochemical device for monitoring constituents of an oxygen-fuel mixture comprising, a solid electrolyte electrochemical cell having a first and second electrode disposed on opposite surfaces thereof, said first electrode has a composition exhibiting negligible catalytic action on said mixture, means for supplying a first portion of said mixture to said first electrode and a second portion of said mixture to said second electrode, said first portion of said mixture forming an oxygen reference media and said first electrode serving as an oxygen reference electrode, and catalytic means for equilibrating said second portion of said mixture, said electrochemical device generating an EMF indicative of the difference between the oxygen content of said first portion of said mixture and the equilibrated second portion of said mixture.
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Abstract
An electrochemical device is designed to respond to a constituent such as oxygen in a reactive mixture which may include a fuel such as methane. The device includes an electrochemical cell employing an electrolye such as a stabilized zirconia associated with two electrodes and designed for operation at an elevated temperature such as 200°C to 1000°C. An electrode for such a cell is designed to have no catalytic action on the mixture.
The system may be arrnaged to assure a full reaction of the mixture before the cell responds to the desired constituent. Thus the mixture may also be subjected to the action of a catalyst before it reaches the electrode area. If the mixture is applied to another non-catalytic cell before it is subjected to the catalyst further information is obtained concerning the desired constitent. The amount of a constituent such as oxygen present before and after the mixture is catalyzed may be compared to provide an indication of the amount of another constituent of the mixture such as methane.
26 Citations
8 Claims
- 1. An electrochemical device for monitoring constituents of an oxygen-fuel mixture comprising, a solid electrolyte electrochemical cell having a first and second electrode disposed on opposite surfaces thereof, said first electrode has a composition exhibiting negligible catalytic action on said mixture, means for supplying a first portion of said mixture to said first electrode and a second portion of said mixture to said second electrode, said first portion of said mixture forming an oxygen reference media and said first electrode serving as an oxygen reference electrode, and catalytic means for equilibrating said second portion of said mixture, said electrochemical device generating an EMF indicative of the difference between the oxygen content of said first portion of said mixture and the equilibrated second portion of said mixture.
- 6. An electrochemical device for monitoring constituents of an oxygen-fuel mixture comprising a first solid electrolyte electrochemical cell having a first and second electrode disposed on opposite surfaces thereof, a second solid electrolyte electrochemical cell having a first and second electrode disposed on opposite surfaces thereof, means for supplying an oxygen reference media in contact with said second electrodes of said first and second solid electrolyte electrochemical devices, said second electrodes functioning as oxygen reference electrodes, means for supplying said mixture in a consecutive manner to the first electrode of said first solid electrolyte electrochemical cell device and subsequently to the first electrode of said second solid electrolyte electrochemical device, said first electrode of said first solid electrolyte electrochemical device has a composition exhibiting negligible catalytic action on said mixture, catalystic means for equilibrating said mixture following passage of said mixture in contact with said first electrode of said first solid electrolyte electrochemical device to provide an equilibrated mixture in contact with said first electrode of said second solid electrolyte electrochemical device, said first solid electrolyte electrochemical device developing an EMF between said first and second electrodes which is indicative of the actual partial pressure of oxygen in said mixture, said second solid electrolyte electrochemical device developing an EMF between said first and second electrodes which is indicative of the oxygen partial pressure of the mixture following equilibration of said mixture.
Specification