Detection of NO and unburnt gases in combustion processes using SnO2 sensors operated at different temperatures
✍ Scribed by J. Huusko; H. Torvela; V. Lantto
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 365 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0925-4005
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✦ Synopsis
Four SnO,-based semiconductor gas sensors are operated simultaneously at different temperatures and their conductance responses recorded. The sensors are manufactured using thick-film technology. A small concentration (0.05 mol%) of Pd is doped in the SnO, base material as a catalytic additive. This sensor type has already been found in laboratory tests to be sufficiently selective to CO at about 500 "C in the presence of NO (and SO& and hence could be used to monitor CO concentrations in combustion gases. The present study was undertaken in order to evaluate the possibility of using the same sensor type, operating at different temperatures, for the simultaneous monitoring of both NO and unburnt gas components like hydrocarbons, in addition to CO, present in combustion gases. A dry synthetic combustion gas is used as the carrier gas, which is mixed with CO, NO and CH,. The last gas component is intended to simulate the unburnt hydrocarbon fraction. The concentrations of the active gas components vary from 100 to 1000 ppm (v/v) and the operating temperatures of the sensors are 200, 300, 400 and 500 "C.