The flow pattern of gas through blast furnaces was studied by VDEh (Veren Deutscher Eisenhiittenleute Betriebsforschungsinstitut) by injecting Kr-85 into the air stream entering the tuyeres of the 688 m³ furnace. A sketch and listing of pertinent quantities for run 10.5 of 9.12.1969 is shown in Fig. P13.1. Assuming that the axial dispersion model applies to the flow of gas in the blast furnace, compare D/ud for the middle section of the blast furnace with that expected in an ordinary packed bed.

 From Standish and Polthier, Blast Furnace Aerodynamics, p. 99, N. Standish, ed., Australian I. M. M. Symp., Wollongong, 1975.

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Iron ore dp = 13mm 17.02 m 10.37 m- 5.08 m - Top 35 mm = Coke dp = 55 mm (3 Middle = 28 mm 580800 Bottom d = 32 mm BOS (2) (1) (0) Air in At (1 At (2) 0.28s- Tracer in at (3) 1.66s 0.68s 3.52s -0.70s Width of curve at 61% of maximum height = 1.4s