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Show Ansaldo Energia s.p.a. boilers where coal firing is opposed by Local Authorities. At the m o m e n t 660 M W e are in operation (Brindisi South unit 1) and other 660 M W e (S. Filippo del Mela units 5 and 6) are under adaptation for the use of this fuel in lieu of coal. T o be also noted that the Italian generation park includes fairly 6 0 % of boilers wall fired and another 4 0 % of boilers tangentially fired. Experience from Tansentially Fired Boilers In previous papers [7] [8] it was shown how using reburning technology it w a s possible to obtain as much as 8 0 % abatement in nitrogen oxides and to reach emission levels below the regulatory limits. Initially [9] the attention was focused to T F boilers considered intrinsically more prone to strong N O x reduction because of the high flues mixing in the combustion chamber and of the many combinations possible acting on air and fuel distribution in the windbox compartments. The application of the reburning technology to large T F boilers is substantiated by a large number of references and experimental data gathered from retrofit applications, as can be seen in fig. 1. Recently the reference of plants in commercial operation has been enriched by the reburn retrofit of two 660 M W e units located in Porto Tolle (units 1 and 4); the other 2 units (unit 2 and 3) will shortly undergo same retrofit. • ieo kin n I Uqht oil Itob Baseline NOx [mg/Nm 31 NOx reductio n 440 64/55 750 77/80 750 79/80 750 79/80 750 79/80 ENEL Porto Tolle #1&4 Porto Tolle Power Plant has four oil fired, supercritical, 660 M W e boilers with pressurized furnace, tangential firing and steam atomisation. For Unit 1, the original combustion system, based on 6 burners elevations, has been fully redesigned to meet the project goals by: • resizing of the primary combustion system (5 burners elevations, free area reduction in the windbox auxiliary air compartments, Fig. 2 A & 2B) • installation of specifically designed "close-coupled" reburn injectors (orientable nozzles, Fig. 2B) • careful location and sizing of post-combustion air injectors (OFA) on the boiler side walls (3 injection assemblies on each wall, each assembly made of 3 orientable nozzles, Fig. 2 B and general arrangement in Fig. 3) m MftNftTT* Fig. 1 - Summary of results obtained using the reburning technology in oil, tangentially-jired A B boilers with « ent reburr.Fig- 2 j -3- |