Structured Emission Thermometry Sensor for Burner Control

Abstract

The overall objective of the program is to control furnace flames for more efficient operation by applying an appropriate sensor technology in a control loop. In Phase I we measured spectra and multispectral imagery from a test furnace at Eclipse, Inc., in Rockford, IL. The test furnace was run at a variety of operating conditions with an oxy-fuel flame, fueled in some tests by natural gas and in others by propane. Using spatial, spectral, and temporal processing, several properties of the flame became observable, including the locations of principal heat release, the extent of the non-luminous portion of the flame, and the local gas temperature. Among the spectra and imagery recorded, the multi-spectral images showed the most promise as a field-compatible measurement system. In Phase II we developed algorithms, driver software, and hardware for what eventually became two independent prototypes: a sophisticated burner-mounted single line-of-sight spectral sensor and a more-mature version of the multispectral furnace imager from Phase I. The maturity of the furnace imager was advanced through significant automation of acquisition, exposure, data recording, and processing to data products. The single line of sight spectral sensor was developed using insights from the test campaigns and was applied in a practical application in an industrial facility where it was used in a control loop. The active control benefits depend on the final applications engineering but show promise to offer smaller excess-air or excess-oxygen requirements, improved response to changing fuel feed stocks, and tighter control on flame properties, resulting in a more consistent product. This thus reduces waste of fuel due to conservative excess-oxidizer requirements and also waste due to off-specification product quality.