Development of dual sulfur oxides and oxygen solid state sensor for in situ measurements

Dual SOx/O-2 in situ potentiometric sensor based on zirconia solid electrolyte and a composition of metal sulfates was investigated for simultaneous measurement of both oxygen and sulfur oxide emissions in combustion gas. The BaSO4-K2SO4-SiO2-based electrochemical cell of the sensor exhibited excellent sensing characteristics for SO, measurement within a reasonably wide working temperature range of 650-1000 degrees C and measuring SOx concentrations (18-10,000 ppm). Carbon dioxide, oxygen and nitrogen oxides had no measurable effect on the SOx sensing properties of the sensor. Typical response times at 700 degrees C were in the range of 45-80 s. The sensor also showed good correlation between the measuring SOx concentration and the output EMF in accordance with the Nernst equation. The installation of the probe based on dual SOx/O-2 sensor in control loops can provide a better and a more effective way towards fuel saving and efficiency. (C) 2000 Elsevier Science Ltd. All rights reserved.