P1.23 CH4-Sensitivity of thermoelectric gas sensors
- 20. GMA/ITG-Fachtagung Sensoren und Messsysteme 2019
2019-06-25 - 2019-06-26
- P1: Sensoren
- J. Wohlrab, G. Hagen, R. Moos - Universität Bayreuth (Deutschland), H. Kohler - Hochschule Karlsruhe (Deutschland)
- 654 - 655
Recently, thermoelectric gas sensors were used for in-situ determination of the CO/HC-content during wood burning. The sensors measure a thermoelectric voltage between a catalytically activated and an inert area. Since the reaction of hydrocarbons takes place exothermically at the catalytic layer, a temperature gradient is generated between the catalyst coating and the inert layer. At an operating temperature of 600°C, a linear relationship can be established between the hydrocarbon concentration and the sensor signal. With methane, however, a huge scattering occurs. Measurements have shown that the oxidation of the highly stable methane molecules at this catalyst just starts at 600°C. The sensitivity of the sensor to methane increases with increasing operating temperature up to 800°C. This information can also be used for a new operating strategy of the sensor.