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Show Furnace Models - The use of 1sothermal flow models to predict the performance of utl1ity scale furnace systems 1s a well-establ1shed research tool. Generally, this is because conditions inside ex1sting or proposed equipment can be pred1cted by carrying out experiments in models that are smaller In size and that operate at lower temperatures. Such models yield Qua11tative 1nformation (visual flow observations) as well as Quantitative velocity/pressure distributions and gas m1xing data. These are 1mportant factors for the evaluation of improvement to unit operation and performance. Because of the ongoing interest in the deve lopment of new and improved furnace designs and firing systems, Combustion Engineerlng maintains a number of flow model1ng facflities capable of supporting and evaluating the performance of three dimensional flow moClels at the KDL facil ny. Detalls of two prevtous large scale combustor mode I test programs are summarized in Refer~nces 5 and 9. The following discusslon descrlbes three modeling test faci11t ies in current use. 1) Large Scale Tangential Fired Furnace The isothermal flow model1ng of uttlity scale furnace systems is performed in Combustion Engineering's Large Scale Furnace Aerodynamics Test Facirtty. This facility, shown in Ftgure 6,was designed and bullt in secttons so that ch~nges to geometry in terms of width, depth, and helgnt, hopper, ,nose or windbox location as we11 as. changes to the operating parameters of the uOlt. could be made easily ana inexpensively. Due t~ 1tS flexibl1ity, this model is capable of slmulat.ing ~ost utillty furnaces in existance tod~y, 1O.clud1Og front or wall fired unlts. This f~Clltty 1S presently conflgured to geometrically slmulate Combustion Engineerlng's new 50 MBtu Tangential-Fired BoUer Simulation Facl1ity and is being operated in support of an EPA sponsored program to develop sorbent injection criterla for the removal of sulfur oxides from coal fired furnace exhaust gases. Fig. 6 - Large Scale Furnace Aerodynam1cs Test Facillty Th1s test facllity was des1gned to allow the use of state-of-the-art flow modeHng instrumentat10n technolog1es. Currently 1n use in this model are a five-hole automatic p1tot tube traversing system, a laser absorption spectrophotometer l.. and a two-axiS laser doppler anemometer. I hese instruments provide Quantitative steady state and transient informat10n on flow patterns, turbulence properties, fuel-air mix1ng, and residence time d1str1but10n. Surround1ng [he furnace model 1s a three-axis instrument traversing system that allows the three dimensional placement of any instrument package around or within the furnace model envelope. A gas injection system 1s aval1able for use 1n any 1nput stream to the model. Th1s system used in conjunction with the laser absorl>tion sp.e~trophotometer, can provide steady state m1x1ng data, as as transient residence time distribution data. Also because the model is constructed primarily of plexlglas, a number of Qual1tatlve flow visual1zatlon tests have been performed and photographically recorded. A data acquisition and control room located at the facil1ty contains dedicated test loop controls and data aCQulsit ion srstem and computers. Real time display of mode operating parameters and instrumentatlon status assures that proper test conditions are maintained. Test data after processing by the facUity's computer is transmitted to the main laboratory computer for further processing and analysis. 2) Recovery Boi ler Figure 7 shows the isothermal flow model system th~t was constructed for recovery boUer testing. ThlS system Is based on the use of a wall fire(j arrangement where black 11 Quor 1s injected through multiple ports on all walls of the unit. The model was built to a 1/12 scale and was designed to simulate a typical 1500 ton per da'i blac\< liquor firing unit. It was constructed of 1/2 inch plexiglas, perforated plate, sheet metal, and cardboard tubes. The secondary and tertiary jets were scaled up in s1ze such that the Jet to main stream mass and momentum ratios of the prototype were dupl1cated in the model. Several arrangements of air introduction were modeled to Improve bed control and to reduce bed carryover whl1e increasing black liquor firing rate. 122 3) Wood Fired Furnace For .wood waste fired bOilers, a recent experlmental program has been initiated to investigate the effects of over-fired air (OFA) on the overall mixing process in a stOKer type wood fired furnace. Specifically the general objective of this work 1s to improve the mixlng of combustion pro~ucts and to reduce the potential char carryover 10 such units. Under this program a 1/12 scale ~odel was built to simulate a typical stoker flred Combustion Engineering VU40 bo 11 e,r . under vafY i ~g OF A des 1 gns and operat 1 ng condltJOns. A plexlgl~s model, siml1ar to the one f~r the recovery bOller shown in the previous flgure, was bUllt USlOg perforated plate to |