Sensing Requirements for Real-Time Monitoring and Control in Energy Production

Clean, efficient energy production, such as the gasification of coal (syngas), requires physical and chemical sensors for exhaust gas monitoring as well as real-time control of the combustion process. Following a description of syngas production from coal, we outline the sensing needs for this high temperature, chemically corrosive gas stream. The performance of devices based on the wide-bandgap semiconductor SiC, for monitoring gas composition, flame dynamics and temperature, as well as combustor structural integrity in this extreme environment are reviewed. We have developed a Pt-SiO₂-SiC micro-device with a dense Pt catalytic sensing film, for fast (<1 s) detection of hydrogen containing species at 630degC. Our SiC sensor can monitor the hydrogen concentration in a 350degC simulated syngas ambient containing the common interferants CO₂, CH₄ and CO. Exposure to H₂S (~1000 ppm) and water vapor does not degrade the sensor performance.