MEASUREMENT OF O2 IN COMBUSTION CHAMBER WITH AN ANALYSIS OF THE BURN OUT RATIO

Abstract

An aim of this experimental research work was to achieve more detailed information about the combustion process in pulverized coal boilers. An O2 analyser was developed and manufactured for the measurement of O2volumetric concentration directly in the combustion chamber. The volumetric concentration of O2 in the combustion chamber is important information about the burn out ratio, quality of combustion and the space distribution of the flame. The uniformity of the flame or the even distribution of the combustion parameters could be a possible way how to move to satisfy new emission limits. Measured parameters of the combustion process could be used for the control system of the boiler. The O2 analyser was manufactured for the permanent measurement with acceptable results. The measurement of the air excess ratio in the combustion chamber shows that for the left and right side of the combustion chamber could be highly non-uniform. For correct interpretation of the air excess ratio measured in the combustion chamber is necessary to know local amount of the unburnedcarbon in the position of the measurement. Therefore a new extraction line with an isokinetic probe was installed in the boiler for an extraction of the particles from the combustion chamber. The extracted sample was analysed in the laboratory and in the position where the combustion process should be terminated was measured from 3-12% of the flammable substance in the analysed sample. Key words: O2-measuremet, lambda probe, pulverized coal boiler.