Temperature measurement system for furnaces

A non-transitory computer readable medium (CRM) storing instructions for measuring furnace temperatures, the instructions comprising functionality for:

• obtaining radiance measurements from a plurality of regions of interest (ROIs) of a furnace, using a plurality of thermal imaging cameras;
• measuring a surface temperature of the furnace using a radiance measurement obtained from an ROI selected from the plurality of ROIs, comprising:
• determining an effective background radiance affecting the selected ROI, using radiance measurements obtained from ROIs different from the selected ROI;
• obtaining a compensated radiance by removing the effective background radiance from the radiance measurement obtained from the selected ROI;
• correcting the compensated radiance for an atmospheric absorption and an atmospheric emission;
• and
• converting the corrected compensated radiance to the measured surface temperature of the furnace, wherein
• the correction for the atmospheric absorption is determined based on characteristics of the furnace atmosphere that is traversed for the radiance measurement of the selected ROI, the characteristics of the furnace atmosphere comprising at least one selected from the group consisting of:
• the atmospheric distance traversed between the ROI and the one or more thermal imaging cameras;
• a linear relationship between distance and atmospheric absorption;
• and
• a level of water vapor in the furnace atmosphere,
• the correction for the atmospheric emission is determined based on characteristics of a flame front that is traversed for the radiance measurement of the selected ROI, the characteristics of the flame front comprising at least one selected from the group consisting of:
• a length of the traversed flame front;
• a type of fuel fed to a burner generating the flame front;
• and
• a fuel flow to the burner generating the flame front, and
• the correction of the atmospheric emission is dynamically updated based on the fuel flow to the burner.

A system for measuring furnace temperatures, comprising:

• a plurality of thermal imaging cameras;
• and
• a processing unit configured to:
• obtain radiance measurements from a plurality of regions of interest (ROIs) of a furnace, using a plurality of thermal imaging cameras;
• measure a surface temperature of the furnace using a radiance measurement obtained from an ROI selected from the plurality of ROIs, comprising:
• determining an effective background radiance affecting the selected ROI, using radiance measurements obtained from ROIs different from the selected ROI;
• obtaining a compensated radiance by removing the effective background radiance from the radiance measurement obtained from the selected ROI;
• correcting the compensated radiance for an atmospheric absorption and an atmospheric emission;
• and
• converting the corrected compensated radiance to the measured surface temperature of the furnace, wherein
• the correction for the atmospheric absorption is determined based on characteristics of the furnace atmosphere that is traversed for the radiance measurement of the selected ROI, the characteristics of the furnace atmosphere comprising at least one selected from the group consisting of:
• the atmospheric distance traversed between the ROI and the one or more thermal imaging cameras;
• a linear relationship between distance and atmospheric absorption;
• and
• a level of water vapor in the furnace atmosphere,
• the correction for the atmospheric emission is determined based on characteristics of a flame front that is traversed for the radiance measurement of the selected ROI, the characteristics of the flame front comprising at least one selected from the group consisting of:
• a length of the traversed flame front;
• a type of fuel fed to a burner generating the flame front;
• and
• a fuel flow to the burner generating the flame front, and
• the correction of the atmospheric emission is dynamically updated based on the fuel flow to the burner.

A method for measuring furnace temperatures, the method comprising:

• obtaining radiance measurements from a plurality of regions of interest (ROIs) of a furnace, using a plurality of thermal imaging cameras;
• measuring a surface temperature of the furnace using a radiance measurement obtained from an ROI selected from the plurality of ROIs, comprising:
• determining an effective background radiance affecting the selected ROI, using radiance measurements obtained from ROIs different from the selected ROI;
• obtaining a compensated radiance by removing the effective background radiance from the radiance measurement obtained from the selected ROI;
• and
• converting the compensated radiance to the measured surface temperature of the furnace,
• wherein the radiance measurement obtained from the selected ROI is obtained from a plurality of pixels in the ROI, averaged over at least one selected from the group consisting of space and time.