A Combustion Diagnosis Method for Pulverized Coal Boilers using Flame-Image Recognition Technology

A flame image recognition system (FIRES) has been developed, which calculates the estimated value of NOX emission from pulverized coal combustion by two dimensional measurements and digital image processing of flame forms. This system can be effectively applied to low NOX and high efficiency combustion is industrial and utility boilers. ITV cameras observe the flame image in the vicinity of burners through optical-fiber probes attached to each burner stage, and a minicomputer digitizes and processes the image data. The NOX-reducing index (INOX), indicating the amount of NOX reduction can be calculated from the form and the location of high radiant intensity zones. Using INOX and stoichiometric ratio of combustion, NOX concentration in ehaust gases can be acculately estimated. This paper discusses the system concepts, NOX estimation algorithm and experimental results.