CCS and Power Systems

Crosscutting Research - Plant Optimization Technologies

Single-Crystal Sapphire Optical Fiber Sensor Instrumentation

Performer: Center for Photonics Technology

Project No: FC26-99FT40685


This effort succeeded in developing and testing a prototype temperature measurement system under full-scale operating conditions thus creating a important opportunity for process improvement, cost reduction, and greater efficiency. Specific accomplishments include:

  • Evaluated various sensor designs and selected a Fabry-Perot interferometry-based design for its self-calibrating capability, simplicity, and accuracy. This design was used in the development of a sensor prototype for full-scale testing.
  • Demonstrated in a laboratory setting that the sensor was capable of accurately measuring temperatures from room temperature up to 1,600 °C with a close resolution of approximately 0.26 °C. Sensor consistency was also demonstrated in multiple laboratory tests, which con-formed closely to B-type thermocouple data.
  • Demonstrated improved sapphire corrosion resistance compared to other ceramic materials, such as poly-crystalline alumina.
  • Tested the prototype sensor at Tampa Electric Company’s Polk Power Station under actual operating conditions; the sensor was evaluated at temperatures up to 1,400 °C.
  • The prototype sensor survived and measured temperature for seven months in the gasifier (Figure 2). This surpassed the performance of resistance-based temperature sensors, which survive on average only 14 days. Continuous opera-tion of the sensor for one year is a goal now that basic performance and survivability have been shown to be improvements over current technology.
  • Examined the sensor after an additional full-scale test failure revealed that the protective housing had broken and a crack allowed slag to reach the fiber; however, the sensor itself remained intact, proving that the sensor design and sensor are robust.
  • Completed the sensor design for testing at NETL’s combustor rig and Eastman Chemical’s full-scale gasifier

Project Details