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Show Numerical Predictions Flow Model Data ..... +- .. .-- ~ . J It!"~ +-(-.. '" J ,,~ · , '\'\ t J .I \ , J ~ · , ~~ ~ ~ \ · , t t ~ \'» .. .. " ......... ~ ;A;A BASELINE (Plane 3) Right (Typle. l) REBURN (Plane 3) Numerical Predictions Flow Model Data BASELINE (Plane 1) .. +- ~ 1/1/ · .. J , ~ ",o. ± t! " . " 4 ~ ~~ ~ " 1 ( , -; Fig 6 Velocity Vector Comparison Numerical Predictions vs Flow Model Data t f- "-.'" ,'\ ; t , t ,~ A . ~ t t f ,. 4 A i l' f l' t ~ 4 are coupled with the species tr ansport equations, and the heat release is related to the enthalpy of formations as the species disappear or are formed in any given furnace volume . Corrections are made for the heat of formation of the fuel itself . For a more detailed description, the reader is referred to (11). Furnace gas temperature profile data from the BSF was first used to validate heat transfer predictions . Figures 7 and 8 compare predicted temperatures to those measured in the BSF in both baseline and reburn conditions . The measured data is indicated by the square data points for 3 traverses at different planes. The agreement is usually good for the baseline case , while a few discrepancies appear in the reburn simulation . One reason for the discrepancies is the fact that under reburn conditions boiler measurements were fluctuating, making 8 measurable mean value difficult to quantify . Another problem is the aimple turbulence and mixing model adopted for hea t release calculations . Work is in progress in order to improve this part of the code. Ana lysis of pollutant formation will then be carried out and reported at a later date PILOT SCALE EXPERIMENJS ON IHE 15-30 MHt BOILER SIMULATION FACILIIY ABB -CE's Kreisinger Development Laboratory in Windsor, Connecticut has performed an extensive series of pilot scale tests under contract to ENEL Test activities have centered on experiments performed in the ABB-CE 15-30 MWt (50-100 KBTU/Hr ) Bo iler Simulation Facility . The BSF (Figure 9) replicates the aerodynamic and thermal environment of a large tangentially fired utility boiler . It models all the major aspects of a tangentially fired utility boiler including the lower furnace, the ash hopper, the main burner zone, the arch section, and the upper furnace heat transfer surfaces . The facility'S design can flexibly accommodate furnace reconfigurat ions (firing system hardware , waterwall heat transfer rate , convective section heat quench rate ) which permit simulation of ut ility scale coal, oi l, and gas fire d boiler designs . Also, to simulate coal, oil , or gas fired boiler designs the volumetric heat input rates (kW/m3 or Btu/Hr /ft3 ) are replicated by adjusting the BSF firing rate from 15-30 MWt (50-100 MBtufhr ). Successful correlations have been established betwee ~ NOz levels observed in the BSF and those observed in field utility boilers for both conventional and advanced low NOz firing systems ( ). Reburning experiments in the BSF have thus far focused on application to #6 oil fired boilers . Natural gas has been studied as the reburn fuel although #6 oil was also evaluated dur ing seversl expe riments as a reburn fuel . The BSF was configured to a number of thermal conditions, including simulations (furnace horizontal exit gas temperature and heat release) of ENEL's 35 MW. Santa Gilla Unit (the site of ENEL's first ful l scale tangentially· fired reburn demonstration) and a typical ENEL 660 ~. 011- fired unit. The firing system employed is schematically sho in Figure 10 . Reburn fuel was introduced above the main fuel admission as.embly/clo.e-coupled overfire air (OFA ) nozzles, cr.ating the reducing (aubstoichiometric or f <1 0) reburn zone . Separated overfir air (additional combustion air) was introduced nto th furnac bove th reburn zone to complete the combustion of hydrocarbons introduced as reburn fuel prior to the furnace horizontal outlet plan . R '1 rculat d flu ga (FeR was inj cted into th furnac co- xially with the re urn fuel in order to enhnnce reburn uel t p netratio and mixing into |