CESI SpA, Milano, Italy Instrumental Systems for Pulverized Coal Flow and Carbon in Ash Monitoring To get the best combustion efficiency and, at the same time, the lowest emissions from a pulverized coal fired boiler of a power plant, the need is to set and to keep the correct air-fuel balancing at each burner of the furnace. The balancing of a large boiler, however, is quite a complex task because of the number of elements involved in the process, i.e. the coal grinding mills, the transport pipes and the burners. It should also be noticed that to maintain the proper air-fuel balancing after the initial setting, simple, reliable and economic methods and instrumentation are required to monitor the coal flow rate in the pipelines connecting the grinding mills and the burners. To cope with these requirements, two innovative measuring systems have been developed by CESI. The first one, based on the detection of the electrostatic charge transported by coal particles, utilises a couple of non-invasive electrostatic sensors (mounted on each pneumatic transport pipe) to provide continuous monitoring of the coal flow velocity. The second one, based on a low angle laser light scattering technique, performs a real time measurement of coal particle size distribution and concentration in each duct. The joint utilisation of the two measurements (i.e. coal particles concentration and velocity) allows to determine the desired real time coal flow rate. An additional diagnostic tool has also been developed, which provides a quasi real time monitoring of the unburned carbon concentration (UBC) in fly ashes. As it is known, UBC impacts on both combustion efficiency and environmental compliance of coal fired steam generators. Currently, the UBC content is measured off-line, upon sampling from the ash hoppers. The sampling/analysis process is quite complex and labour intensive, and it can take several hours. Of course in this way it is not possible to have on-line data, which can be easily compared with efficiency and emission data. To overcome these limitations CESI has developed an automatic sampling and analysis system based on the measurement of the carbon dioxide generated by the combustion of the sampled ashes (via laser irradiation), which is capable of measuring the UBC content in fly ashes in 10-15 minutes. The three above described measuring systems have been installed and systematically tested on a large coal fired power plant in Italy. The paper describes the basic and original characteristics of the systems and presents the most meaningful results obtained during their testing. To be presented at: Second International Conference on Clean Coal Technologies for Our Future 10-12 May 2005, Castiadas (Cagliari) PUBBLICATO A5022945 (PAD – 648576)PUBBLICATO A5052544 (PAD – 726156)