Combustion Process Analysis and Diagnostic Using Optical Flame Scanners in Front-Fired Pulverized Coal Boiler

Abstract

The paper presents a novel concept and method of coal combustion process analysis using flame scanners supervision system. The combustion process analysis and diagnostic has a crucial influence on boiler effectiveness, especially in high variance of load demand, which is nowadays a top challenge for coal-fired power plants. The first indicator of combustion inefficiency is flame stability, which can be observed as variation of flame intensity. Nowadays, there are no validated measuring methods dedicated for industrial usage, which are able to give complete information about flame condition. For this reason, the research activity was launched and focused on usage of commercial flame scanners for fast combustion analysis based on on-line flame parameters measuring. The analysis of combustion process was performed for 650 t/h live steam power boiler, which is supplied by five coal mill units. Each coal mill supplies four pulverized coal burners pulverized fuel ((PF) burners). The boiler start-up installation consists of 12 heavy oil burners placed in PF burners equipped with individual supervisory system based on Paragon 105f-1 flame scanners, which gave the possibility to observe and analyze the PF burner flame and oil burner flame individually. The research included numerous tests in which the combustion conditions inside the combustion chamber were changed. During stable load of selected mills, the primary air flow, secondary air dampers, air–coal mixture temperature, and balance were changed. The results of the changes were observed by flame scanners and the available optical parameters of the flame were analyzed: power spectral density, average amplitude (AA) of flame fluctuation, and flame temperature.