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

Dual SOx/O2 “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 SOx measurement within a reasonably wide working temperature range of 650–1000°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°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/O2 sensor in control loops can provide a better and a more effective way towards fuel saving and efficiency.