Combustion control with smart sensors
Abstract
The development of a smart infrared spectroscopic sensor capable of quantitatively monitoring CO2, CO, and NO at concentration levels representative of conditions to be found beyond the primary combustion stage of a fossil fuel power plant are reported. The sensor in the laboratory first under static gas conditions in a test cell and then in the exhaust stream of one or more types of laboratory combustors were examined. The smart sensor in a control loop was applied to demonstrate combustion control of a multiburner furnace. The smart infrared spectroscopic sensor is based on a tunable acoustooptic filter (TAOF) whose principal passband is spectrally positioned by the application of a radio frequency acoustic wave to the filter. The TAOF operates on the principle of coherent, acoustooptic diffraction of a narrow band of radiation in a birefringent crystal medium. The diffracted light is switched to an orthogonal polarization and, in some designs, is also deflected in direction. The filter and a detector are set up to perform differential absorption spectroscopy in which absorption by gaseous combustion products such as CO and CO2 provide signature infrared absorption over a well defined path. Instrument design and implementation, preparation of laboratory facilities, analytical studies required for quantitative interpretation of experimental results are outlined.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- 1984
- Bibcode:
- 1984STIN...8530303W
- Keywords:
-
- Absorption Spectra;
- Birefringence;
- Combustion Control;
- Carbon Dioxide;
- Carbon Monoxide;
- Gas Analysis;
- Infrared Spectrometers;
- Nitrogen Oxides;
- Instrumentation and Photography